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Role of Salicylic Acid in Plants

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... Former studies reported that exogenous SA induces PR gene expression, disease resistance or both in potato (Navarre and Mayo 2004) and in different monocots (Takatsuji 2014). Exogenously SA application inhibits the biosynthesis of plant hormone stomatal closure, ethylene and uptake of root ion (Raskin 1992). Previous studies also revealed that exogenous SA application induced identical set of mRNAs after pathogen infection (Sarowar et al. 2005;Shahda 2000). ...
... In our study, application of SA and BA demonstrated the satisfactory control against common blight of beans since it increased the resistance at the concentrations 1.2µgmL −1 of both compounds against the pathogen. Our results consents with other studies viewing that treatment of plants with SA may provide a considerable protection against pathogen of bacterial blight (Raskin 1992). ...
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This study deals with the potentiality of salicylic (SA) and benzoic (BA) acids for controlling the common blight of beans (CBB) caused by Xanthomonas axonopodis pv. phaseoli (Xap). Impacts of the application of SA and BA (1.2 µg mL−1) on the plant biological parameters, bacterial count, disease severity, phenolic and salicylic acid contents as well as catalase activity in treated plants were investigated. In vitro, application of the both compounds at different concentrations (0.4, 0.8 and 1.2 µg mL−1) significantly suppressed growth of the pathogen. Under greenhouse conditions, application of BA and SA considerably reduced the disease development by 81 and 71%, respectively after 4 days of the application as compared to infected control. After 12 days of BA application, plants were protected 49.2% from disease as compared with SA (44.6%). SA-treated plants showed significant increases in the SA content and total phenolic content. Also, BA-treated plants showed an increment in the total phenolic content. Bean plants treated with SA showed higher catalase activity than those treated with BA. In conclusion, this study supports the use of SA and BA as abiotic elicitors to protect bean plants from the common blight disease. This protection may be attributed to the resistance induction, activation of defense enzymes as well as augmentation the phenolic content and salicylic acid in the host cells.
... Salicylic acid (SA, 2-hydroxy benzoic acid) has pivotal roles in the regulation of many aspects of plant growth and physiological processes such as defense responses, thermogenesis, seed germination, flowering and senescence (Raskin, 1992;Rivas-San Vicente and Plasencia, 2011). It is generally accepted that there are two SA biosynthesis pathways in plants: the isochorismate (IC) pathway and the phenylalanine ammonia-lyase (PAL) pathway (Métraux, 2002;Chen et al., 2009b). ...
... CBP60g, the closely related family member to SAG202, was not directly regulated by AtNAP TF; however, CBP60g might also have a role in leaf senescence because its expression profile showed a senescence-associated elevation ( Supplementary Fig. S2). In defense response, both CBP60g and SAG202 are involved in the induction of SA; after pathogen infection, SA level was elevated to a very high level in local leaves and leaded to a suicide cell death (Raskin, 1992;Zhang et al., 2010b). However, in age-dependent leaf senescence, SA level in senescing leaves was up-regulated to about 4 times higher than that in non-senescing leaves (Morris et al., 2000;Zhang et al., 2013;Zhang et al., 2017b) and resulted in a gentle and slow programmed cell death (PCD) necessary for remobilization of nutrients released during senescence to active growing tissues or storage organs such as seeds and trunk (Gan and Amasino, 1997). ...
Article
Salicylic acid (SA) is an important plant hormone that regulates defense responses and leaf senescence. It is imperative to understand upstream factors that regulate genes of SA biosynthesis. SAG202/SARD1 is a key regulator for isochorismate synthase 1 (ICS1) induction and SA biosynthesis in defense responses. The regulatory mechanism of SA biosynthesis during leaf senescence is not well understood. Here we show that AtNAP, a senescence-specific NAC family transcription factor, directly regulates a senescence-associated gene named SAG202 as revealed in yeast one-hybrid and in planta assays. Inducible overexpreesion of AtNAP and SAG202 lead to high levels of SA and precocious senescence in leaves. Individual knockout mutants of sag202 and ics1 have markedly reduced SA levels and display a significantly delayed leaf senescence phenotype. Furthermore, SA positively feedback regulates AtNAP and SAG202. Our research has uncovered a unique positive feedback regulatory loop, SA-AtNAP-SAG202-ICS1-SA, that operates to control SA biosynthesis associated with leaf senescence but not defense response.
... The Pharma Innovation Journal http://www.thepharmajournal.com line with those recorded by Atik et al. (2013) [4] , Abdalla (2014) [1] , Raskin (1992) [15] , Segarra et al. (2006) [16] , Park et al. (2007) [13] , Bari and Jones (2009) [5] and Mady (2009) [11] . Atik et al. (2013) [4] noted positive response of three systemic acquired resistance inducers (salicylic acid, Bion and beta amino butyric acid) against Alternaria alternata, causing Alternaria leaf spot of tomato. ...
... The Pharma Innovation Journal http://www.thepharmajournal.com line with those recorded by Atik et al. (2013) [4] , Abdalla (2014) [1] , Raskin (1992) [15] , Segarra et al. (2006) [16] , Park et al. (2007) [13] , Bari and Jones (2009) [5] and Mady (2009) [11] . Atik et al. (2013) [4] noted positive response of three systemic acquired resistance inducers (salicylic acid, Bion and beta amino butyric acid) against Alternaria alternata, causing Alternaria leaf spot of tomato. ...
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Study of Salicylic acid under in vitro condition resulted that SA at 200 ppm (68.45%) concentration was most effective in inhibiting mycelial growth followed by 150 ppm (46.98%) concentration. For activation of defense mechanism of plants, salicylic acid was evaluated through interaction between root dipping and foliar spray. Salicylic acid was proved to be most effective in treatment combination (root dip of 200 ppm and foliar spray of 150 ppm) against Alternaria solani and recorded minimum per cent disease intensity i.e., 17.41%, 20.43% at 45 DAS and 60 DAS, respectively.
... Phytoalexins like camalexin from Arabidopsis thaliana are known to restrict growth of several pathogenic microorganisms [Glazebrook & Ausubel, 1994]. The transcriptional changes also affect the regulation of several plant hormones including ethylene (ET) [Ecker & Davis, 1987], jasmonic acid (JA) [Wasternack & Parthier, 1997] and salicylic acid (SA) [Raskin, 1992], all well known to play roles in different pathways of plant immune response. Several MAPK cascades have been proposed to be involved in SA-mediated defense gene activation, with the MPK4 cascade negatively regulating SA signaling [Petersen et al., 2000;Beckers et al., 2009;Alhoraibi et al., 2019]. ...
... Recent studies revealed SA to be directly perceived by NPR proteins [Neeley et al., 2019;Wang et al., 2020]. Besides pathogen defense, SA is also involved in regulation of developmental processes like seed germination and flower development [Raskin, 1992]. In plants, the two metabolic pathways for SA synthesis are the ICS and the PAL pathway, both starting from chorismate. ...
Thesis
Systemic acquired resistance (SAR) is an important defense mechanism in plants initiated after exposure to biotrophic pathogens. SAR is characterized by accumulation of PR proteins in non-infected tissues, as well as increased concentrations of the phytohormone salicylic acid (SA). SA is directly perceived by NPR1, the key regulator of SAR. Through interaction with TGA transcription factors and NIM1-INTERACTING (NIMIN) proteins, NPR1 mediates the SA-dependent induction of PR1 gene expression. The Arabidopsis genome contains four NIMIN genes – NIMIN1 (N1), N1b, N2, and N3 – but members of the NIMIN family can also be found in other higher plants. While NIMIN proteins share their general domain architecture and a C-terminal EAR motif, they differ in other aspects. NIMIN genes are expressed differentially during pathogen infection and development. NIMIN proteins can be subdivided based on their NPR1-interaction motifs, the DXFFK and the EDF motif. N1-type proteins harbor both domains, while N2-type and N3-type proteins carry only the DXFFK or the EDF motif, respectively. Accordingly, NIMIN proteins interact differentially with NPR1: N1, N1b and N2 bind to the C-terminal moiety while N3 binds to the N-terminus. Overexpression studies revealed a role for the N1 and N3 proteins in the transcriptional repression of PR1 gene induction. Strikingly, infiltrated plants overexpressing Arabidopsis N1 and N3 or tobacco N2c also manifest significantly accelerated cell death. These numerous differences indicate diverse functions of NIMIN proteins during SAR establishment and beyond. The objective of this work was to further characterize differences between NIMIN proteins from Arabidopsis and tobacco regarding biochemical properties and biological functions with special emphasis on their cell death promoting activity. For this purpose, reporter constructs harboring promoter and coding regions from Arabidopsis and tobacco NIMIN genes were analyzed in transient gene expression experiments in Nicotiana benthamiana and in transgenic tobacco plants. Functional domains were examined using the introduction of targeted mutations to study their significance for NIMIN protein function. The following results were obtained: 1. The N1b 1135 promoter region is functional and two reporter genes under its control, GUS and the proapoptotic Bax, are active during transient overexpression. In transgenic tobacco plants the N1b promoter is not responsive to chemical induction by SA or its functional analog BTH and phenotypical studies showed no expression during plant development. To what extent the N1b gene is expressed in plants must therefore remain open. 2. Transient overexpression of Arabidopsis N1 and N3 and tobacco N2 type genes N2c and N2-like (FS) results in accelerated cell death. This enhanced emergence of cell death is associated with strong protein accumulation. In transgenic tobacco plants overexpression of the N1, N2c and FS genes is also accompanied by emergence of cell death, especially in the flower area, and low seed production. The affected plants often display defects in growth and leaf morphology. 3. The ability to promote cell death requires the C-terminal EAR motif, a transcriptional repression domain. Mutation of the EAR motif in N1, N2c and FS significantly reduces the emergence of cell death. In yeast the EAR motifs of N1 and N3 interact with a N-terminal fragment of the transcriptional co-repressor TOPLESS (TPL). Transient overexpression of this TPL1/333 fragment also induces cell death but coexpression with N1 or N3 reduces cell death emergence, indicating that NIMIN proteins not only affect NPR1 but also modulate the activity of TPL. 4. The enhanced emergence of cell death mediated by overexpression of NIMIN genes and Bax interferes with measurement of SA induced activity of the PR1 promoter. However, using EAR motif mutans with reduced cell death emergence, like the N1 F49/50S E94A D95V EAR mutant, which is also unable to bind NPR1, allows the analysis of the transcriptional repression of the PR1 promoter mediated by cell-death promoting NIMIN proteins. 5. N1 contains a conserved N-terminal domain (N1nT) of 15 amino acids which regulates its accumulation. In N-terminal position, this domain functions autonomously with other NIMIN proteins and Venus, increasing their accumulation. Mutational analysis has not yet revealed reliance on certain sequences. Presence of the N-terminal methionine is not required for function of the N1nT domain hinting at a function at the mRNA level. NIMIN proteins are multifunctional and could perform different functions through their conserved domains. The results indicate that NIMIN proteins, through their interaction with TOPLESS, could also affect other hormone-dependent signal pathways. While the exact mechanism remains unclear, the enhanced protein accumulation bestowed by the N1nT domain of N1 could allow for more effective study of poorly accumulating proteins.
... SA was listed within the plant hormone group two decades ago (Raskin, 1992a(Raskin, , 1992b. A hormone is an organic molecule that works locally and/or at a distance from its synthesis site at very low concentrations, according to a well-recognized concept. ...
Chapter
Salicylic acid (SA) is an essential phytohormone that regulates plant growth, development, and defense during stress conditions. SA, in low amounts, participates in the coordination of physiological processes such as closure of stomata, uptake of nutrients, synthesis of chlorophyll pigments, protein synthesis, homeostasis of phytohormones, transpiration and photosynthesis in plants. It also plays an important signaling molecule in local and systemic disease resistance response of plants after pathogen attack. Similarly, SA-dependent signaling pathways regulate plant responses to abiotic stress factors altering antioxidant enzyme activities. Besides the vegetative development, SA induces flowering by increasing cell metabolic rate, increasing flower life, and retarding senescence. Although there are several studies on the effects of SA during vegetative development, few studies on the relation in reproductive organ development is available. Some of them concerns pollen viability and pollen tube growth. In a case study, different concentrations of SA (0.005, 0.025, 0.05 and 0.25 mM) improved the pollen germination in kiwifruit (Actinidia deliciosa). In recent years SA has been the focus of intensive research due to its physiological functions during growth-development and stress defense. The discovery of its targets and the understanding of its molecular mechanisms in developmental and physiological processes could help to clear the complex SA signaling network, confirming its critical role in plant growth, development, and defense. In the present chapter, we aimed to focus the role of SA during plant reproductive development under regular and/or stress conditions.
... SA is an endogenous signaling molecule derived from hydroxybenzoic acid. It is classified as a hormone-like substance [12] and is predominantly active in plant immune responses to avirulent pathogens [13]. Most studies on its effects have focused on SA-induced systemic acquired resistance. ...
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Acclimation to salt stress in plants is regulated by complex signaling pathways involving endogenous phytohormones. The signaling role of salicylic acid (SA) in regulating crosstalk between endogenous plant growth regulators’ levels was investigated in barley (Hordeum vulgare L. ‘Ince’; 2n = 14) leaves and roots under salt stress. Salinity (150 and 300 mM NaCl) markedly reduced leaf relative water content (RWC), growth parameters, and leaf water potential (LWP), but increased proline levels in both vegetative organs. Exogenous SA treatment did not significantly affect salt-induced negative effects on RWC, LWP, and growth parameters but increased the leaf proline content of plants under 150 mM salt stress by 23.1%, suggesting that SA enhances the accumulation of proline, which acts as a compatible solute that helps preserve the leaf’s water status under salt stress. Changes in endogenous phytohormone levels were also investigated to identify agents that may be involved in responses to increased salinity and exogenous SA. Salt stress strongly affected endogenous cytokinin (CK) levels in both vegetative organs, increasing the concentrations of CK free bases, ribosides, and nucleotides. Indole-3-acetic acid (IAA, auxin) levels were largely unaffected by salinity alone, especially in barley leaves, but SA strongly increased IAA levels in leaves at high salt concentration and suppressed salinity-induced reductions in IAA levels in roots. Salt stress also significantly increased abscisic acid (ABA) and ethylene levels; the magnitude of this increase was reduced by treatment with exogenous SA. Both salinity and SA treatment reduced jasmonic acid (JA) levels at 300 mM NaCl but had little effect at 150 mM NaCl, especially in leaves. These results indicate that under high salinity, SA has antagonistic effects on levels of ABA, JA, ethylene, and most CKs, as well as basic morphological and physiological parameters, but has a synergistic effect on IAA, which was well exhibited by principal component analysis (PCA).
... Under stressful conditions, growth hormones are considered vital for several processes in the life cycle of plants; where endogenous levels of growth substances change throughout the growing season with corresponding variations in growth and development. Salicylic acid is one of the naturally occurring phyto-chemicals considered to be a potent plant hormone because of its diverse regulatory role in plant metabolism (Raskin, 1992a(Raskin, , 1992b. It plays an important role in the regulation of plant growth, development, ripening, flowering, and responses to abiotic stresses (Vicente and Plasencia, 2011). ...
... Moreover, the SA can negatively influence the growth, interfere in seed germination, cell growth, respiration, and seedling establishment. Finally, they can act as a mechanism for regulating thermogenesis and disease resistance (Rizzini, 1970;Raskin, 1992;Vlot et al., 2009). ...
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Salicylic acid has one of its characteristics the allelopathic potential. The present paper, is a research quantitative in nature aimed to assess the allelopathic potential of salicylic acid to identify the best concentration range for other pure substances. The bioassays were performed in a BOD incubator, seeking to assess the seedling growth by measuring the radicle and hypocotyl length. Each bioassay occurred for 12 days. The concentrations of salicylic acid used in the bioassays were: 1000, 750, 500, 250, 125, and 62.5 ppm and control. The obtained data were submitted to the tests: Kolmogorov-Smirnov normality, the two-way ANOVA with repetition, and Tukey. Based on the results obtained, it was possible to observe that several concentrations demonstrated significant differences, i.e., there is an allelopathic activity in both species (Euphorbia heterophylla and Bidens pilosa). The highlights were for the concentrations of 750 and 1000 ppm for E. heterophylla and 500, 750 and 1000 ppm for B. pilosa. However, there was no significant difference between these concentration groups. The radicle’s length was the part most negatively affected. These results can be used to identify better concentrations for other pure substances, which are usually obtained in small quantities, being useful in the formulation of a product with characteristics of bio-herbicides.
... Salicylic acid (SA) is a small phenolic substance that is widely present in plants. It is also an important plant hormone that is involved in various developmental stages and physiological mechanisms in plants [48]. Xie et al. [49] found that under normal conditions, SA may reduce the activity of α-amylase by regulating the expression of HvWRKY38, thus inhibiting seed germination. ...
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Salinity reduces agricultural productivity majorly by inhibiting seed germination. Exogenous salicylic acid (SA) can prevent the harm caused to rice by salinity, but the mechanisms by which it promotes rice seed germination under salt stress are unclear. In this study, the inhibition of germination in salt-sensitive Nipponbare under salt stress was greater than that in salt-tolerant Huaidao 5. Treatment with exogenous SA significantly improved germination of Nipponbare, but had little effect on Huaidao 5. The effects of exogenous SA on ion balance, metabolism of reactive oxygen species (ROS), hormone homeostasis, starch hydrolysis, and other physiological processes involved in seed germination of rice under salt stress were investigated. Under salt stress, Na+ content and the Na+/K+ ratio in rice seeds increased sharply. Seeds were subjected to ion pressure, which led to massive accumulation of H2O2, O2−, and malonaldehyde (MDA); imbalanced endogenous hormone homeostasis; decreased gibberellic acid (GA1 and GA4) content; increased abscisic acid (ABA) content; inhibition of α-amylase (EC 3.2.1.1) activity; and slowed starch hydrolysis rate, all which eventually led to the inhibition of the germination of rice seeds. Exogenous SA could effectively enhance the expression of OsHKT1;1, OsHKT1;5, OsHKT2;1 and OsSOS1 to reduce the absorption of Na+ by seeds; reduce the Na+/K+ ratio; improve the activities of SOD, POD, and CAT; reduce the accumulation of H2O2, O2−, and MDA; enhance the expression of the GA biosynthetic genes OsGA20ox1 and OsGA3ox2; inhibit the expression of the ABA biosynthetic gene OsNCED5; increase GA1 and GA4 content; reduce ABA content; improve α-amylase activity, and increase the content of soluble sugars. In summary, exogenous SA can alleviate ion toxicity by reducing Na+ content, thereby helping to maintain ROS and hormone homeostasis, promote starch hydrolysis, and provide sufficient energy for seed germination, all of which ultimately improves rice seed germination under salt stress. This study presents a feasible means for improving the germination of direct-seeded rice in saline soil.
... Salicylic acid (SA) is a phenolic compound, which plays an important role in regulation of plant growth and development, fruit yield, flowering and physiological processes and synthesis of auxins and cytokinins [3]. It also regulates a number of processes in plants including disease resistance, seed germination, sex polarization and ethylene production [4]. ...
... Salicylic acid is also used for induction of flowering in marigold. It regulates a number of processes in plants including disease resistance, seed germination, sex polarization and ethylene production (Raskin et al., 1992). Exogenous administration of salicylic acid before the reproductive stage of marigold plants may result in increased biomass production and total flavonoids content. ...
... SA lowers the pH of the water and thus prevents the growth of bacteria in vase solution. (Raskin, 1992;Popova et al., 1997;Bleeksma and van Doom, 2003). In studies, it was determined that SA was an effective biocide in increasing vase life of the different cut flower species (Kazemi et al., 2012;Vahdati et al., 2012;Kazaz et al., 2017;Bayat and Aminifard, 2017). ...
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The study was carried out to determine the effect of Aminoethoxyvinylglycine (AVG) (10 and 5 ppm), salicylic acid (SA) (100 ppm) and citric acid (CA) (100 ppm) applications on vase life, relative fresh weight, daily water uptake and total water uptake (100 ppm) of narcissus (Narcissus tazetta L.) cut flower. In the research, the longest vase life was obtained from 5 ppm AVG application with 12 days. In addition, 10 ppm AVG and 100 ppm citric acid applications significantly increased vase life compared to control. Fresh weight, daily water uptake and total water uptake were significantly higher in AVG (10 and 5 ppm) applications compared to other applications. As a result, it was determined that AVG has a positive effect on vase life of Narcissus tazetta flower.
... The crop was discovered to be a good source of medicinal preparation against vomiting and paralysis (Islam et al., 2010). Salicylic acid (SA) is a hormonelike substance, which plays an important role in regulating a number of physiological processes such as growth, photosynthesis, nitrate metabolism, ethylene production, heat production and flowering (Raskin, 1992;Hayat and Ahmad, 2007). SA is an endogenous growth regulator, phenolic in nature, which regulates stomatal closure, transpiration and drought tolerance (Shakirova et al., 2013. ...
Article
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Field experiment was conducted to study the influence of salicylic acid in the mitigation of moisture stress in sweet pepper. Treatments consisted of four rates (0, 0.2, 0.4 and 0.6gL-1) of salicylic acid and three moisture stress stages (vegetative, flowering and fruit setting). These were laid out in split plot design with three replications. Results of the study revealed that exogenous application of salicylic acid significantly (p< 0.05) decreases canopy temperature in sweet pepper. This however, increases the number of fruits per plant, average fruit weight and fresh fruit yield irrespective of the rate applied. The yield and yield components were also higher from plants that were subjected to moisture stress at vegetative stage and the control. Based on the existing findings, moisture stress in sweet pepper could be mitigated by foliar spray of salicylic acid at the vegetative stage. Further investigation is thus recommended to justify the best rate to apply.
... SA was listed within the plant hormone group two decades ago (Raskin, 1992a(Raskin, , 1992b. A hormone is an organic molecule that works locally and/or at a distance from its synthesis site at very low concentrations, according to a well-recognized concept. ...
Chapter
Elicitation is the term used to describe the utilization of molecules that activate plant defense responses, generating increased resistance to biotic and abiotic stresses. Elicitors are defined as natural or synthetic substances that, when applied to plants in small concentrations, initiate or increase the synthesis of secondary compounds related to plant defense. Additionally, elicitors may play an important role in stimulating the biosynthetic pathways for the production of commercially important secondary compounds. In this sense, elicitation has been considered as a technological tool widely tested in order to maximize the production of bioactive compounds, both in medicinal plant species and species categorized as functional foods, bringing significant economic benefits to the pharmaceutical and therapeutic industry (including nutraceuticals). The elicitation can be applied in the culture of cells and tissues and in intact plants. Salicylic acid (SA) is classified as an abiotic elicitor that alters the expression of genes encoding key enzymes of secondary plant metabolism, significantly increasing the production of bioactive compounds such as essential oils, phenolic acids, flavonoids, tannins, alkaloids, tannins, among others. In this chapter we will address the theme “Elicitation of Plants with Salicylic Acid” and adopt the following sequence of topics: (a) definitions of elicitation and elicitors, (b) elicitation as a tool to increase the production of bioactive compounds in plants, (c) SA mechanisms of action as an eliciting molecule and (d) examples of studies about SA elicitation in medicinal plants.
... SA has been reported to act as a regulator in the reduction/oxidation balance of plant cells, inducing morphological, physiological, and adaptive responses in plants [11]. It also participates in the activity of catalase, mitochondrial oxidase, and other related enzymes [12,13]. Thus, it is united specifically with iron-containing enzymes such as peroxidases (PODs), catalases (CATs), and aconitases [14]. ...
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(1) Background: Raisins contain a wide range of hormones, minerals, vitamins, and antioxidant enzymes that may contribute to the health benefits of consumers. (2) Methods: The aim of this research was to compare the hormone, mineral, vitamin, and antioxidant capacities of Gök Üzüm (Vitis vinifera L.) raisins immersed in oak ash (OA) and potassium carbonate (PC) dipping solutions before drying. (3) Results: Abscisic acid (ABA) (5751.18–11,868.40 ng g−1) and riboflavin (95.17–135.54 mg 100 g−1) were the most abundant hormone and vitamin quantified in Gök Üzüm raisins. Glutathione S-transferase (540.07–744.85 EU gr berry−1), 6-glucose phosphate de-hydrogenase (214.50–317.43 EU gr berry−1), and glucose-6-phosphate dehydrogenase (208.25–241.86 EU gr berry−1) enzymes presented the highest antioxidant activity in the samples. Raisins obtained after drying by immersion in OA presented higher indol-3-acetic acid (IAA), ABA, sal-icylic acid (SA), cytokinins (CK), and zeatin contents; glutathione reductase (GR), glu-cose-6-phosphate dehydrogenase (G6PD), glutathione S-transferase (GST), 6 glucose phosphate dehydrogenase (6GPD), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) en-zymatic activity; vitamin B1, B2, B6, C, and A contents; and nitrogen (N), phosphorus (P), man-ganese (Mn), calcium (Ca), sulfur (S), potassium (K), iron (Fe), sodium (Na), and magnesium (Mg) levels compared to the grapes dried after PC applications. (4) Conclusions: Drying Gök Üzüm grapes after the application of OA dipping solution promotes a higher content of hor-mones, minerals, vitamins, and antioxidant enzymes compared to PC treatments. These results could help raisin producers to make decisions when using a dipping solution to dry grapes.
... Salicylic acid (SA) is a molecule related to the stress response in plants (Hayat and Ahmad 2007) and is therefore considered a candidate for exogenous applications as an activator of induced systemic resistance. In particular, acetylsalicylic acid (the active ingredient in aspirin) is a phenolic compound analogous to SA, which has been identified as a low-cost, non-phytotoxic product (Raskin 1992). Typically caused by local infection, plants respond with a cascade of salicylic acid-dependent signaling that leads to systemic expression of broad-spectrum resistance and long-lasting resistance that is effective against fungi, bacteria, and viral infections; salicylic acid acts as a potent plant growth regulator that can effectively modulate various plant growth responses (Hayat et al. 2010). ...
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Background Salicylic acid participates in the regulation of the plant's response to a series of environmental stresses such as extreme temperatures, salinity, and oxidative condition of potato growth, so it is necessary to determine a safe application dosage for potato in field conditions. Methods The purpose of the research was to evaluate the effect of increasing doses of acetylsalicylic acid on the agronomic traits of two potato cultivars in Lima, Peru. In a field experiment, an RCBD with 3 replications was used under a split-plot arrangement in which five doses (0.0, 0.2, 0.4, 0.6, and 0.8 mM) of acetylsalicylic acid plus control with Biol (biostimulant) were assigned to plots, and two potato cultivars ('Perricholi' and 'Unica') were assigned to subplots. The average temperatures were between 15 and 21º C, the air relative humidity was between 61 and 73% and the soil was loam textural class, free of salts. Results No statistical differences were found for the number and weight of tubers and biomass due to the effect of the application of the treatments. The effects of doses of acetylsalicylic acid showed statistical differences for sprouting, vegetative vigor, and percentage of flowering; likewise, significant interactions ( p < 0.05) were shown between potato cultivars and dose of acetylsalicylic acid for the number of stems per plant and percentage of flowering, which indicated a specific effect for the dose of acetylsalicylic acid in each potato cultivar. Statistical differences (p < 0.05) were found between the two potato cultivars for most of the characters studied. Conclusion No dose of the product significantly affected the potato yield in two potato cultivars however, the effect of the dosage of acetylsalicylic acid improved the performance of the crop in terms of sprouting in the field, vegetative vigor, a greater number of stems per plant as well as stimulation of flowering, with respect to control.
... However, foliar application of salicylic acid (1mM) was found to result in 24% increase in number of pods in rapeseedas compared to unsprayed treatment (Yazdanpanah et al., 2015).Anincrease in number of podsupon foliar application of SA was also observed by some workersin garden pea (Thompson et al., 2017), Indian mustard (Sharma et al., 2013) and broad bean (Akram, 2007). Salicylic acid is known to be associated with better tolerance to high temperature thereby reducing physiological loss of pollinated flowers and increasing photosynthetic efficiency in plants (Raskin, 1992). The same mechanismmight have helped the radish seed crop in retaining higher number of siliquae per plant. ...
Thesis
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The present investigation entitled “Studies on the effect of foliar application of plant defense activators on seed yield and quality in radish” was carried out in the Department of Seed Science and Technology, Dr. Y. S Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during 2018-2019. Under this study radish seed crop cv. Japanese white was used and two separate experiments were conducted. Under first experiment there were 13 treatments including control viz., salicylic acid @ 50ppm (T1), salicylic acid @75ppm (T2), salicylic acid @100ppm (T3), jasmonic acid @ 55 ppm (T4), jasmonic acid @ 110 ppm (T5), jasmonic acid @ 165 ppm (T6), butyric acid @ 250ppm (T7), butyric acid @ 500 ppm (T8), butyric acid @ 750ppm (T9), potassium nitrate @ 1% (T10), potassium nitrate @ 1.5% (T11), potassium nitrate @ 2% (T12) and untreated control (T13). Three foliar applications were given, first at initiation of flowering stalk, second at flowering and third at pod development stage. The severity of alternaria blight was recorded lowest (11.79 %) in the plots sprayed with butyric acid @ 750ppm (T9) followed by 13.57 % in salicylic acid @100ppm (T3). The maximum seed yield (1063.71 kg/ha) was observed from salicylic acid @100ppm (T3) which was at par with potassium nitrate @ 2% (T12) in which the yield was 1004.59 kg/ha. The other seed yield parameters like number of siliqua/plant, length of siliqua, number of seeds/siliqua and 1000 seed weight were observed significantly higher i.e. 312.47, 7.43cm, 6.40, 17.36g respectively under salicylic acid @100ppm (T3) which was found at par withpotassium nitrate @ 2% (T12). Seed quality and health testing of harvested seed was also done following standard blotter paper method, roll paper towel method and grow out test. The maximum germination (94%), SVI-I (2,275.59), SVI-II (1,292.45) and other seed quality parameters like seedling length (24.21 cm), seedling dry wt. (13.75 mg), seedling emergence (83.75%), normal seedling (83.25%) and speed of germination (93.08) were found highest in salicylic acid @100ppm (T3) which was followed by potassium nitrate @ 2% (T12) in which the values for the germination, SVI-I and SVI-II were 93%, 2215.99, 1222.98, respectively and for other seed quality parameters like seedling length, seedling dry weight, seedling emergence, normal seedling and speed of germination were 23.83cm, 13.15mg, 82.75%, 82.25% and 92.84 respectively.The infected seed percent (2.75%) and total seed microflora (24%) observed from salicylic acid @ 100ppm (T3) were also significantly lower as compared to control. In the second experiment, radish seed was subjected to priming treatment with different defense activators.There were 13 treatments viz. salicylic acid @ 25ppm (T1), salicylic acid @50ppm (T2), salicylic acid @75ppm (T3), jasmonic acid @ 55 ppm (T4), jasmonic acid @ 110 ppm (T5), jasmonic acid @ 165 ppm (T6), butyric acid @ 250ppm (T7), butyric acid @ 500 ppm (T8), butyric acid @ 750ppm (T9), potassium nitrate @ 1% (T10), potassium nitrate @ 2% (T11), potassium nitrate @ 3% (T12) and Control (T13). The primed seeds were evaluated for seed quality and health parameters. The maximum germination (95.50%), SVI-I (2217.10) & SVI-II (1248.37) and other parameters were found significantly superior in potassium nitrate @ 2% (T11) which was observed at par with salicylic acid @ 50ppm (T2). Thus it can be concluded from the study that foliar application of plant defense activators like salicylic acid @ 100 ppm or potassium nitrate @ 2% at three stages were effective in reducing the severity of alternaria blight (52.04% & 44.80% respectively) and increasing the seed yield (27.30% & 20.23% respectively) and other seed quality parameters in radish seed crop cv. Japanese white as compared to control. Also seed priming with plant defense activators like potassium nitrate @ 2% or salicylic acid @ 50 ppm were effective treatments in enhancing the seed quality parameters in radish.
... Salicylic acid (SA) has been known as a signal molecule in the induction of defence mechanisms in plants for a long time (Raskin, 1992 ), furthermore it also participates in the signalling of abiotic stresses (Khan et al., 2015 ). Earlier only in a few studies were described the parallel changes in SA and PA contents during plant growth or under stress conditions (Iqbal et al., 2006a , b ;Majláth et al., 2011 ;Pál et al., 2014 ;Glaubitz et al., 2015 ). ...
Chapter
Salicylic acid (SA) is generally present in plants in quantities of a few μg/g fresh mass or less, either in the free state or in the form of glycosylated, methylated, glucose-ester or amino acid conjugates. It directly or indirectly affects various physiological processes, including germination, vegetative growth, flower induction, thermogenesis, ion and nutrient uptake, nitrogen metabolism, transpiration, photosynthesis, and respiration. SA may also contribute to maintain cellular redox homeostasis, through the regulation of antioxidant enzymes. SA, as a signalling molecule, plays role in local and systemic acquired resistance against pathogens as well as in acclimation to abiotic stressors. Negative or positive interactions of SA with other hormones like abscisic acid, cytokinins, ethylene, gibberellins or jasmonic acid have an important role in the fine-tuning of the immune response during stress conditions. Natural polyamines (PAs) are water-soluble aliphatic amines present in all cells, but have not been given the status of plant hormones, because of their general relatively high, 10⁻⁹–10⁻⁵ M concentration. They play an essential role in regulating plant development and life functions, such as plant growth, cell division and differentiation, transcription and translation. PAs are suggested to be considered not only as direct protective molecules, but also as versatile compounds that play key role in the regulation of stress tolerance, interacting directly with other metabolic pathways and hormonal crosstalk, and activate the expression of stress-responsive genes. In redox regulation, PAs have dual role, as they are both sources of reactive oxygen species and potential quenchers of them, so they also play a role in the regulation of plant redox homeostasis. In addition, despite of numerous reviews published on the interactions between SA and phytohormones, the synthesis of current information on the relationship between SA and PAs is scarce. This chapter will provide insight in the mode and levels of the connection between SA and PAs.
... SA was also reported to protect ultra-structures in Musa acuminata seedlings under chilling stress [73][74][75]. Mutlu showed that external application of SA results in cold tolerance by enhancing antioxidant enzymes, ice nucleation activity, and the patterns of apoplastic proteins in H [76,77]. vulgare genotypes. SA mediated increased synthesis of total phenolics and the activity of PAL was reported to improve chilling tolerance in cold-stored lemon fruit [78][79][80]. ...
Article
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Abiotic stresses have been recognized as the potential threat for agricultural production across the globe. Anthropogenic activities related to industrialization and urbanization also have aggravated the degradation of agricultural system as they are experiencing increasing impact of abiotic stresses. These stresses potentially induce various adverse effects on plants affecting their physiological, biochemical and molecular processes ultimately leading huge loss in crop productivity. Plant hormones are recognized amongst the handiest tools to mitigate the abiotic stress. Salicylic acid (SA) is one of most essential and multifaceted plant hormone that not only play vital role in plant defense but also have active participation in conferring abiotic stress tolerance. The present review deals with the illustrations of studies carried out by different workers on the role of SA in combating various types of abiotic stresses like metal stress, salinity stress, temperature stress and water stress in different crops
... Salicylic acid (SA) is an endogenous growth regulator of phenolic nature, which participates in the regulation of physiological processes in plants. For example, SA is postulated to play a role as a natural inductor of thermogenesis, to induce flowering in a range of plants, to control ion uptake by roots and stomatal conductivity (Raskin, 1992). Exogenous application of SA may influence a range of diverse processes in plants, including stomatal closure, ion uptake and transport (Gunes et al., 2005), membrane permeability (Barkosky and Einhellig, 1993), as well as photosynthetic and growth rates (Khan et al., 2003). ...
... SA was listed within the plant hormone group two decades ago (Raskin, 1992a(Raskin, , 1992b. A hormone is an organic molecule that works locally and/or at a distance from its synthesis site at very low concentrations, according to a well-recognized concept. ...
Chapter
Abiotic pressures including drought, high temperature, flooding and salinity influence the development and productivity of plants. Also, global climate change will increase the incidence and magnitude of abiotic stress, indicating that a variety of growth with improved stress tolerance is crucial to future sustainable crop production. Salicylic acid (SA) is a phenolic compound formed by a varied variety of plant species to varying degrees and it considers a naturally occurring plant hormone that serves as an essential signaling agent that contributes to abiotic stress tolerance. This endogenous driver of plant growth engages in various physiological and metabolic reactions and picking up of ions and movement. Also, involved in endogenous signaling is salicylic acid which activates plant defense against abiotic stresses. SA helps plants react to abiotic stresses including heavy metal toxicity, temperature changing, UV light and osmotic force pressures. SA influence often depends on many variables, such as implementation style, concentration, environmental circumstances, plant species and organs. SA synthesis occurs through two pathways, isochorismate (IC) and the ammonia-lyase phenylalanine (PAL) pathway. It consists of genes that encode chaperones, heat shock proteins, antioxidants and secondary metabolite biosynthesis genes including sinapyl alcohol dehydrogenase, cinnamyl alcohol dehydrogenase and cytochrome. One significant and notable general belief is low concentrations of SA increase plant antioxidant capacity, but high of it induce cell death or abiotic stress susceptibility. This chapter presents an overview of the historical and background of the role of the SA, chemical composition, synthesis and metabolism of SA, transport of SA in plants, the response of plant stages to SA, the role of SA response in plants under abiotic stresses and the role of biotechnology for reducing the abiotic stress.
... AMF (T) + Vd, AMF (Gi) + Vd, SA (0.5mM) + Vd and SA (1 mM) + Vd applications resulted in the suppression of the disease development, which was 53%, 21.8%, 43.8%, and 35.3% respectively; as well, the values of vascular health and suppression rate (56%, 46.6%, 46.6%, and 50%, respectively) should be noted. The best suppression of disease was observed in AMF (T) + Vd (53% -56%) application according to 0-5 scale and 0-3 scales ( Table 3) Salicylic acid, as well as serving as a growth regulator, acts as a signal in the plant's defense mechanism against pests and diseases, promoting plant's resistance positively (Raskin, 1992;Arıcı and Yardımcı, 2001). Various studies have shown that SA increases the resistance to pathogens in different plants and decreases the disease severity. ...
... Role of salicylic acid in plant physiology Salicylic acid (SA) is a phenolic compound which regulates plant growth and development and has the capacity to prevent the incidence of systemic diseases in plants (Abdul et al., 2013;Mohammad, 2014). SA is an important regulator of plant growth that generates a wide range of metabolic and physiological responses in plants involved in plant defense in addition to their impact on plant growth and development (Raskin, 1992). Salicylic acid also activates the generation of reactive oxygen species (ROS) and other defensive processes such as hypersensitive response and cell death (Vlot et al., 2009). ...
Article
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The experiment included two sorghum varieties, four salicylic acid (SA) rates, and three application times in a factorial design. Following foliar application of 0.5 or 1mM salicylic acid (SA), stem borer severity and stem lodging percentage were significantly reduced compared to controls (distilled water). For Meko, applying 0.5mM SA after 30 days of planting resulted in a 15% increase in grain yield above the control. Similarly, the application of 1Mm SA, 15 days after planting, increased the grain yield of ESH-1 by more than 20% than control. When sprayed with 0.5mM SA 30 days after planting, the hybrid ESH-1 produced the maximum dry biomass per plant (210.4g), while plants treated with distilled water produced the lowest dry biomass per plant (154.2 g). Similarly, for Meko, the highest dry biomass per plant (207.5 g) was found in plants sprayed with 0.5mM SA 45 days after planting, while the lowest dry biomass (124.3 g) was found in plants sprayed with distilled water 15 days after planting. So, in the Melkassa area, foliar sprays of 0.5 mM and 1 mM salicylic acid (SA) can boost grain yield of Meko and ESH-1 sorghum genotypes.
... The development of technologies for transforming biomass into valuable products dates back to 38,000 years ago [1]. The leaves and bark of the willow tree were used to treat pain as early as the fourth century BC, ultimately leading, in the 19th century, to the isolation of salicylates from different tree species and plants as active compounds to be used in the manufacture of commercial painkillers [2]. The industrial exploitation of rapid-growth and short-rotation crops of herbaceous species such as miscanthus [3], wheat [4], and camelina straw [5], and trees such as eucalyptus [5] and poplar [6], among others, has developed an important economic activity in the field of bioenergy [7] and in the development of biobased products in different sectors, namely the pulp and paper industry [8] and the manufacture of furniture and wood panels [6]. ...
Article
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Lignocellulosic residues have the potential for obtaining high value-added products that could be better valorized if biorefinery strategies are adopted. The debarking of short-rotation crops yields important amounts of residues that are currently underexploited as low-grade fuel and could be a renewable source of phenolic compounds and other important phytochemicals. The isolation of these compounds can be carried out by different methods, but for attaining an integral valorization of barks, a preliminary extraction step for phytochemicals should be included. Using optimized extraction methods based on Soxhlet extraction can be effective for the isolation of phenolic compounds with antioxidant properties. In this study, poplar bark (Populus salicaceae) was used to obtain a series of extracts using five different solvents in a sequential extraction of 24 h each in a Soxhlet extractor. Selected solvents were put in contact with the bark sample raffinate following an increasing order of polarity: n-hexane, dichloromethane, ethyl acetate, methanol, and water. The oily residues of the extracts obtained after each extraction were further subjected to flash chromatography, and the fractions obtained were characterized by gas chromatography coupled with mass spectrometry (GC–MS). The total phenolic content (TPC) was determined using the Folin–Ciocalteu method, and the antioxidant activity (AOA) of the samples was evaluated in their reaction with the free radical 2,2-Diphenyl-picrylhydrazyl (DPPH method). Polar solvents allowed for higher individual extraction yields, with overall extraction yields at around 23% (dry, ash-free basis). Different compounds were identified, including hydrolyzable tannins, phenolic monomers such as catechol and vanillin, pentoses and hexoses, and other organic compounds such as long-chain alkanes, alcohols, and carboxylic acids, among others. An excellent correlation was found between TPC and antioxidant activity for the samples analyzed. The fractions obtained using methanol showed the highest phenolic content (608 μg of gallic acid equivalent (GAE)/mg) and the greatest antioxidant activity.
... SA takes part in plant responses to many abiotic stresses such as drought, salinity, chilling, heat, and heavy metal toxicity [10,11,[53][54][55][56][57][58]. However, since its mode of action depends significantly on numerous aspects, such as the plant species, the environmental conditions, the concentration used, the duration of exposure, and the concentrations of other external agents [4,20,59], data on exogenously applied SA on plant physiological processes under stress or non-stress conditions remain controversial [20]. ...
Article
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Salicylic acid (SA), an essential plant hormone, has received much attention due to its role in modulating the adverse effects of biotic and abiotic stresses, acting as an antioxidant and plant growth regulator. However, its role in photosynthesis under non stress conditions is controversial. By chlorophyll fluorescence imaging analysis, we evaluated the consequences of foliar applied 1 mM SA on photosystem II (PSII) efficiency of tomato (Solanum lycopersicum L.) plants and estimated the reactive oxygen species (ROS) generation. Tomato leaves sprayed with 1 mM SA displayed lower chlorophyll content, but the absorbed light energy was preferentially converted into photochemical energy rather than dissipated as thermal energy by non-photochemical quenching (NPQ), indicating photoprotective effects provided by the foliar applied SA. This decreased NPQ, after 72 h treatment by 1 mM SA, resulted in an increased electron transport rate (ETR). The molecular mechanism by which the absorbed light energy was more efficiently directed to photochemistry in the SA treated leaves was the increased fraction of the open PSII reaction centers (qp), and the increased efficiency of open reaction centers (Fv’/Fm’). SA induced a decrease in chlorophyll content, resulting in a decrease in non-regulated energy dissipated in PSII (FNO) under high light (HL) treatment, suggesting a lower amount of triplet excited state chlorophyll (3Chl*) molecules available to produce singlet oxygen (1O2). Yet, the increased efficiency, compared to the control, of the oxygen evolving complex (OEC) on the donor side of PSII, associated with lower formation of hydrogen peroxide (H2O2), also contributed to less creation of ROS. We conclude that under non stress conditions, foliar applied SA decreased chlorophyll content and suppressed phototoxicity, offering PSII photoprotection; thus, it can be regarded as a mechanism that reduces photoinhibition and photodamage, improving PSII efficiency in crop plants.
... Under stressful conditions, growth hormones are considered vital for several processes in the life cycle of plants; where endogenous levels of growth substances change throughout the growing season with corresponding variations in growth and development. Salicylic acid is one of the naturally occurring phyto-chemicals considered to be a potent plant hormone because of its diverse regulatory role in plant metabolism (Raskin, 1992a(Raskin, , 1992b. It plays an important role in the regulation of plant growth, development, ripening, flowering, and responses to abiotic stresses (Vicente and Plasencia, 2011). ...
Research
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Traditional Ready to eat Rice based snacks
... In 1828, a small amount of salicin, which is a glucoside of salicyl alcohol, was isolated by the German scientist Johann Andreas Buchner. Salicin is one of the salicylates found not only in willow tree bark but in 36 other plants as well (Raskin, 1992;Hayat et al., 2010). Synthetic SA also began its first commercial production in Germany in 1874. ...
Article
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Soil salinity has become a hot debate and has gained a great scientific interest towards global food security for an increasing population. Because salinity has numerous negative effects on crop physiology and results loss of productivity. Various attempts to overcome salinity have led to detrimental effects. However, scientists have been recruited to use certain eco-friendly techniques to increase stress tolerance in plants by rising the emission rate. One of them, which is naturally present in certain plant species, is Salicylic acid, a well-known growth regulator. Since plant hormones can monitor plant development and growth, they also serve as a strong protector against various abiotic stresses. But their concentration decreases beyond the level of protection when exposed to abiotic stressors such as NaCl stress. Thus, by increasing the amount of endogenous SA, externally supplied SA has found considerable beneficial effects on plant stress resistance. SA introduces many physiological, biochemical, and molecular modifications to plants under salt stress that include immunity. Evidence of external application of SA under salt stress tolerance in plants is discussed in this review. In addition, low SA concentrations have also been addressed and its cross-talk with other regulators. Key words: Salicylic acid, Salt stress, Antioxidants, Hormonal cross-talk
... Salicylic acid is a phenolic plant hormone that functions as a signal molecule, regulating physiological and biochemical processes. Endogenous SA administration has been shown to change gene regulation in response to biotic stressors (Raskin, 1992). ...
Article
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The major population of the world is dependent on rice for food. Global warming creates drought conditions mostly in north eastern countries. It is a very challenging task to cultivate drought-sensitive variety in drought-prone areas. To overcome this problem we induced changes in the drought-sensitive variety of rice (Swarna MTU 7029) for drought tolerance. Drought condition was exposed for 7 days and 14 days to SA treated and untreated 56 days old rice plants. Rice seeds were presoaked with 0.5mM SA. The experiment was designed in four groups control (untreated), drought-SA, drought +SA, and SA control. On the 7 th and 14 th of drought stress, SA improved drought tolerance indicator proline, carotenoid, and total soluble sugar. Starch and protein content were augmented in salicylic acid-treated plants compared to untreated rice plants under drought stress. Antioxidants such as SOD, CAT, and APX levels drastically increased in salicylic acid-treated plants during both 7 th and 14 th days of drought stress. Therefore, salicylic acid improved antioxidative enzymes content in MTU 7029 rice variety after 7 and 14 days of drought stress.
... Similar elevation in proline content was observed by Tasgin et al., (2006) in bean, wheat, and tomato under drought stress condition. Our observations were in conformity with studies reported by (Raskin, 1992;Shah, 2003), suggesting that SA application alleviates detrimental effects of drought stress by accumulating proline. Nazar et al., (2015) also reported the amelioration of drought-induced oxidative stress due to the accumulation of proline in mustard. ...
Article
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Plant growth and rice productivity are negatively affected by the alarming rise of abiotic and biotic stress factors. Drought stress is a significant factor that directly affects numerous physiological, biochemical and molecular responses in plants. The exogenous application of plant growth regulators such as salicylic acid is a crucial route to alleviate the detrimental effects of water scarcity and plant efficacy. The research was conducted to evaluate the impact of foliar-applied salicylic acid of 0.25 mM concentration on morphological, physiological and biochemical alterations in rice plants under two levels of polyethylene glycol 6000 induced drought stress (8%, 16%). Drought stress increased lipid peroxidation, ion leakage, proline accumulation but decreased the leaf relative water content, root and shoot biomass. In contrast, foliar application of 0.25 mM SA mitigated PEG-induced drought stress by enhancing the LRWC, proline accumulation, decreasing the lipid peroxidation and electrolyte leakage. It was observed that SA treatment led to substantial improvement in plant biomass at both the drought stress levels, thereby increasing the plant acclimation under water deficit conditions.
... Many physiological phenomenon, such as resistance to pathogens and insects, development of pollen, root growth and senescence can be modulated by Jasmonates (Lorenzo et al. 2004). Salicylic acid (SA) plays a key role in flowering , growth and development, stomatal behavior, ethylene biosynthesis, and respiration (Raskin 1992). ...
Article
Agricultural productivity suffers a heavy loss due to plant pathogens, insect pests and various abiotic stresses. Agriculture being the world's largest economic sector, it is the need of time to find and establish the ideal strategy for sustainable agriculture and improvement in crop growth. Endophytes are microorganisms that asymptomatically grow within the plant tissues without causing any disease to the host. Endophytic fungi live in symbiotic association with plants and play an important role in plant growth promotion, higher seed yield and plants resistant to various biotic, abiotic stresses and diseases. Many are able to produce antimicrobial compounds, plant growth hormones and various agrochemi-cal bioactive metabolites. These mycoendophytes hold enormous potential for the development of eco-friendly and economically viable agricultural products. In this review we focused on the endophytic fungi recovered from different medicinal plants, their active principles involved in plant growth enhancement and the applications of fungal endophytes in agriculture. Moreover, we also discussed about endophytic fungi and their pragmatic approach towards sustainable food and agriculture.
... Salicylic acid and other salicylates are known to affect various physiological and biochemical activities of plants and may play a key role in regulating their growth and productivity (Arberg, 1981) [2] . Salicylic acid has been found to play a key role in the regulation of plant growth, development, interaction with other organisms and in the responses to environmental stresses (Raskin, 1992a, b;Yalpani et al., 1994;Senaratna et al., 2000) [14,15,21,18] . Salicylic acid pre treatment helped to improve emergence, seedling growth and biochemical parameters, but salicylic acid was relatively more effective at sub optimum (15 0 C) than at optimum temperature (Bedi and Dhingra, 2007) [17] . ...
... The postharvest quality of many cut flowers is reduced by ethylene [12]. In previous studies, salicylic acid (SA) was used to prolong the life of cut lilies [13]. SA is a simple phenolic compound involved in the process of plant growth [14]. ...
Article
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In this study, we were investigated the effect of lysosomal extracts (named as lysosomal enzymes) on extending the vase life of cut flowers. The results confirmed that senescence of cut freesia treated with lysosomal enzymes delayed. Also, the results for cut roses and lilies showed a similar pattern. In the case of them the fresh weight was lower than that of the control group, but time the ornamental value was retained increased by about 2 days. The reasons have explained as results by the change including stomata, accumulation of microbial population, and soluble carbohydrate contents. In conclusion, pretreatment with lysosomal enzymes has enhanced vase life and ornamental value of cut flowers. It has an important significance in improving the marketability of cut flowers in the flower industry. Therefore, lysosomal enzymes have the potential to be used sufficiently as eco-friendly and effective materials for pretreatment agents in the cut flower industry.
... Moreover, a significant increase was observed in pod weight and grain yield in SA treated plants over the control, reaching a maximum when plants were treated with 0.362 mM SA at the 24th day (Kumar et al. 1999). After this and several other studies, some authors believe that SA may also have flowering-inducing effects (Raskin 1992;Hegazi and El-shraiy 2007). ...
Article
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Stimulating the production of secondary metabolites by elicitation seems to be an accepted tool in several in vitro cultures. In vivo application of chemical elicitation is, however, much less frequently discussed. The paper summarizes the experimental findings on the effects of jasmonic acid, methyl-jasmonate (MeJa) and salicylic acid (SA) treatments on medicinal and aromatic plants. Growth behaviour, yield, stress responses, essential oil (EO) and phenolic compounds are discussed. Exogenous application of MeJa or SA mostly by foliar spraying in concentrations between 10 ⁻⁴ and 4 mM, induced various changes in the plants. In most cases, the elicitation enhanced the volatile accumulation, although the opposite reaction was observed too. Numerous in vivo trials also demonstrated an altered EO composition. Positive effects of treatments on the concentration of phenolic type compounds were described, while in some cases the components exhibited contradictory behavior or no significant changes. Unfortunately, phenolic composition was rarely determined. There is evidence for the dose dependency of the reactions to both elicitors, but systematic studies on this issue are missing. Some results indicate that lower concentrations in replication may be at least as effective as higher ones. Changes in secondary metabolite accumulation may be induced by the elicitors directly or through other physiological processes. The in vivo results should be considered in the complex system of plant ontogenesis, environmental conditions, timing of the treatment, type of the elicitor and concentration. Research results indicate a promising aspect of chemical elicitation in vivo , but further well-designed studies are needed for the individual species.
... Las rodajas de los hongos secos se cortan y se muelen para después colocar 10 g del producto en una bolsa de papel filtro (8 μm) para su maceración con 150 ml de tequila blanco (100 años salicina. Años más tarde, se inició la producción comercial de AS en Alemania, y fue hasta 1898 que se le otorga el nombre comercial de aspirina por la Bayer Company (Raskin, 1992). ...
Thesis
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Actualmente, se ha incrementado la producción de alimentos funcionales y nutracéuticos como una estrategia para disminuir y prevenir enfermedades. En este contexto, los hongos son valorados por su aporte nutrimental a la dieta humana y propiedades funcionales. G. lucidum, hongo no comestible funcional contiene compuestos bioactivos como terpenoides, polisacáridos y proteínas que muestran efectos positivos a la salud. La ingesta de extractos de G. lucidum ha mostrado efectos hipocolesterolemiantes, hipoglucémicos y prebióticos que disminuyen el riesgo de padecer diversas patologías. En México, no se han realizado trabajos acerca de la toxicidad de los extractos mexicanos de G. lucidum (cepa CP-145), además, la escasa información existente que hay a nivel internacional es de especies extranjeras y no puede extrapolarse a las especies mexicanas debido a las diferentes condiciones de crecimiento que modifican las propiedades y contenido del extracto. Por tanto, en el presente estudio se evaluó la toxicidad aguda del extracto de G. lucidum en ratas Wistar acorde al protocolo 423 de la OECD/OCDE. Se formaron 5 grupos experimentales con 6 ratas (3 hembras y 3 machos) cada uno. Se utilizaron dosis orales crecientes del extracto de G. lucidum (300, 1000, 2000 y 5000 mg/kg de peso corporal). Se llevó un registro de la ingesta, peso y comportamiento durante 14 días. Se analizaron parámetros bioquímicos en sangre y orina complementándose con un examen histopatológico de las secciones hepáticas y renales. No se observaron cambios en el comportamiento, ingesta y peso corporal de las ratas. Las concentraciones de glucosa y perfil lipídico en plasma se mantuvieron estables. Los parámetros relacionados con daño hepático (transaminasas) e inflamación (proteína C reactiva) no mostraron diferencias significativas entre los grupos experimentales. Asimismo, en los valores asociados a daño renal (albúmina, creatinina, urea, glucosa en orina y nitrógeno uréico) obtenidos no se observaron cambios significativos que indiquen una lesión o inflamación renal en las ratas. Las histopatologías mostraron citoarquitectura normal, sin daños en los tejidos. Por lo que, la ingesta aguda del extracto de G. lucidum no causó muerte, toxicidad y daño en la función hepática y renal en las ratas en ninguna de las dosis empleadas.
... Spirulina platensis is a blue green alga rich in proteins, vitamins, minerals, carotenoids and antioxidants that help plants acclimate to heat stress and produce a good yield. Salicylic acid is a phenolic compound that functions as a plant growth regulator and boosts photosynthesis under heat stress by affecting different physiological functions and biochemical reactions (21)(22)(23). Accordingly, the present research object investigates the effect of spray with different salicylic acid concentrations and the numbers of sprinkles with blue green algae extract to alleviate heat stress on plants, consequently developing yield aspects. ...
Article
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Increasing temperature is a global issue due to the existing climate change problem that reduces agricultural productivity and increases prices. It badly affects the yield, and active constituents of medicinal and aromatic plants, especially in newly reclaimed lands in desert areas. The Hibiscus sabdariffa L. is a remarkable crop known for its calyces to make a refreshing drink. It is in other food industries and has many healing effects. A split-plot field experiment was conducted on Hibiscus sabdariffa L. at Siwa Oasis, Egypt, during the 2018 and 2019 seasons for studying to reduce the harmful effect of heat stress on plants and yield improvement. Spraying with three salicylic acid concentrations was put to main plots as 0, 500 and 1000 mg/l and the number of sprays with Spirulina platensis algae extract was allotted to subplots and used as 0, 1 and 2 times in the season. Some quantity and quality parameters were under investigation. The significant highest increases in dry weight per plant, number of fruits per plant, dry yield of sepals per hectare and sepal's anthocyanin content were from the combination among spraying with salicylic acid at the concentration of 500 mg/l and spraying with blue green algae extract twice through the season. This treatment was helpful to decrease the high temperature injury on growth through the summer months.
... With the carboxyl group at the C-1 atom and the hydroxyl group at the C-2 atom, the aromatic ring resembles so-called salicylic acid, now known under the trade name Aspirin. This drug was introduced in 1898 by the Bayer company and is the world's best-selling anti-inflammatory painkiller [52]. Salicylic acid also has antimicrobial activity against Propionibacterium acnes and is sometimes used in cosmetic products [53]. ...
Article
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Four aerobic bacteria with bacteriolytic capabilities were isolated from the brackish water site Strait Uzynaral of Lake Balkhash in Kazakhstan. The morphology and physiology of the bacterial isolates have subsequently been analyzed. Using matrix assisted laser desorption ionization-time of flight mass spectrum and partial 16S rRNA gene sequence analyses, three of the isolates have been identified as Pseudomonas veronii and one as Paenibacillus apiarius. We determined the capability of both species to lyse pre-grown cells of the Gram-negative strains Pseudomonas putida SBUG 24 and Escherichia coli SBUG 13 as well as the Gram-positive strains Micrococcus luteus SBUG 16 and Arthrobacter citreus SBUG 321 on solid media. The bacteriolysis process was analyzed by creating growth curves and electron micrographs of co-cultures with the bacteriolytic isolates and the lysis sensitive strain Arthrobacter citreus SBUG 321 in nutrient-poor liquid media. One metabolite of Paenibacillus apiarius was isolated and structurally characterized by various chemical structure determination methods. It is a novel antibiotic substance.
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The potato tuber induction and subsequent developmental process are complex phenomenon involving several stages which includes the stolons formation, initiation of tuber by sub-apical swelling, longitudinal expanding of tissues and tuber growth. Potato tubers are known to serve as food storage organ and vegetative propagation for next generation. The potato tuberization process has been reported to be regulated via various extrinsic and extrinsic factors including light, temperature, photoperiod, phytohormones and balanced nutrition. The phytohormones including auxins, cytokinins, gibberellins, abscisic acid, ethylene, brassinosteroids, jasmonic acid, salicylic acid and strigolactones have been reported to play an important role in potato tuberization and development. Studies on endogenous hormone content and their synergestic relationship are of special interest in potato tuber formation. The gibberellins stimulate the tuberizationin potato tactfully via normalizing the shoot growth, while the cytokinins, auxins and abscisic acid evidently regulate the sink activity of the tubers via controlling cell division and cell expansion. The salicylic acid and associated compounds have also been reported to influence the tuber inducing activities and tolerance to biotic and abiotic stresses in potato, however, the tuber inducing activities of salicylic acid is unexplored. Molecular and proteomic studies have greatly extended the knowledge on the mechanism of phytohormone regulating the tuberization in potato. This chapter provides biochemical, genetic and molecular mechanism regulating the potato tuberization and further development mediated by different phytohormones with special emphasis on role of salicylic acid in tuber development.
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Chinese medicine has a long tradition of use against rheumatoid arthritis (RA). The formulations are based on combinations of typically 5–10 plants, which are usually boiled and administered as a decoction or tea. There are few clinical trials performed so the clinical evidence is sparse. One fundamental of traditional medicine is to prevent disease. RA is an autoimmune, inflammatory and chronic disease that primarily affects the joints of 0.5%–1% of the population. In two out of three of the cases, the patients are characterised by the presence of autoantibodies such as the rheumatoid factor and the more disease‐specific autoantibody against citrullinated proteins, so‐called ‘ACPA’ (anticitrullinated protein/peptide antibodies). ACPA positivity is also strongly associated with specific variations in the HLA‐DRB1 gene, the shared epitope alleles. Together with smoking, these factors account for the major risks of developing RA. In this review, we will summarise the background using certain plant‐based formulations based on Chinese traditional medicine for the treatment and prevention of RA and the strategy we have taken to explore the mechanisms of action. We also summarise the major pathophysiological pathways related to RA and how these could be analysed. Finally, we summarise our ideas on how a clinical trial using Chinese herbal medicine to prevent RA could be conducted.
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Salicylic acid (SA) is the seventh class of phytohormones after the worldwide acceptance of brassinosteroids as the sixth and five other classical ones. It is a beta hydroxy phenolic acid and is represented by the analogues; salicylic acid, acetyl salicylic acid and methyl salicylic acid. It is basically a defence related hormone and is primarily responsible for the development of systemic resistance against pathogens and tolerance to abiotic stress in plants. Under normal growth conditions, SA regulates several physiological responses such as stomatal movements, pigment accumulation, photosynthesis, ethylene biosynthesis, secondary metabolite production, heat production, enzyme activities, abscission reversal, nutrient uptake, flower induction and overall growth and development of the plant. Exogenous application of SA also affects the growth, physiology, yield, and quality of the produce in several fruit crops, grown under different environmental conditions. Besides this, SA also affects the post-harvest attributes of the fruits; maintenance of quality, prevention of fruit decay and pathogen attack, and increase in the shelf life of the fruit. All this information is comprehensively presented in this chapter, besides an outline of the scheme of SA biosynthesis.
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Plants are exposed to challenging environmental conditions throughout the life cycle which greatly affect their potential growth, development, and productivity. To survive in these unfavourable situations, they have developed efficient and effective mechanisms to endure environmental catastrophe. Glutathione, the major source of plant non-protein thiols has been known widely for its functions in redox homeostasis, antioxidant biochemistry, detoxification and stress tolerance. It has been found that stress often resulted in the alteration of glutathione status which leads to changes in several signaling cascades and hence potential responses take place. An in-depth understanding at the molecular level can help to discern various stress response mechanisms in plants. Till date, the crosstalk between GSH and various phytohormones viz. ethylene (ET), salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), etc. along with nitric oxide (NO) signaling has been studied. However, the molecular mechanism is yet to be explored in the context of plant defense response. Interestingly, a vibrant interaction of GSH, the reduced form of glutathione, with SA has been observed in model as well as in target plants. Here, we will discuss the crosstalk of GSH and SA at genomics and proteomics levels which eventually will open up further avenues in the understanding of stress mitigation in planta.
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In this report, we present five new alkali metal complexes (1– 5) that displayed excellent anticancer and antibacterial activities in solutions. 1,10-phenanthroline (phen), salicylic acid (sa) benzoic acid (ba), and p-aminobenzoic acid (paba) ligands were employed in complexation reactions. The complexes were characterized by a variety of analytical techniques including infrared and UV-vis spectroscopy, elemental analysis, ¹H NMR, ¹³C NMR, and single-crystal X-ray diffraction analysis. We described the structures of three mononuclear lithium complexes [Li(phen)2(sal)] (1), [Li(phen)2(ba)] (2), {[Li(phen)(H2O)3].(paba)} (3), a mononuclear sodium complex [Na(phen)(paba)(H2O)] (4) and an unsual tetranuclear cesium complex [Cs4(phen)4(paba)4(H2O)2] (5). The complexes in solution displayed excellent activities against oral and lung cancer cells with the least toxicity toward normal cells when compared to the standard drug 5-fluorouracil and cisplatin.
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Increasing demand for worldwide food production in the farming area is a vital push for the improvement of new disease-management techniques that are not just effective against known pathogens, but also against the ones that will evolve. Plants possess specialized structures, chemicals, and advanced mechanisms to defend themselves from pathogens. Understanding these defense mechanisms and pathways is critical for developing innovative approaches to protect crop plants from diseases as pathogens are continually evolving intricate mechanisms to overcome plant defenses. Plant defense pathways involve a number of signaling compounds that regulate the production of defense-related chemicals. Salicylic acid (SA) or 2-hydroxybenoicacid, a key signaling molecule which is a phenolic plant hormone, is distributed in a wide range of plant species. It play important roles in the regulation of plant growth and development, such as stomatal closure, seed germination, flowering, and thermogenesis, and regulate plant responses to biotic stresses such as a diverse range of phytopathogens (biotrophic and semibiotrophic) and is essential for the establishment of both local and systemic acquired resistance. The compound that is in the center of interest in this book chapter is SA due to the mechanism, biosynthesis, and function of salicylate in plants toward biotic stress tolerance. The adverse effects of overuse of pesticides have led to the development and adoption of genetically engineered crops including those expressing genes involved in SA-mediated defense pathways for enhanced defense capabilities and higher yields under biotic stress with reduced use of harmful pesticides. This book chapter focuses on the latest developments in the plant-pathogen interaction and in particular, on the functional role played by SA in plant defense. A better understanding of plant defense mechanisms (actions of SA as a signaling molecule) will enable scientists to develop more efficient methods of protecting plants from pathogens for sustainable agriculture.
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Foods that contain hydroxybenzoic acid derivatives (HBA) include red fruits, black radish, onion, and potato peel. HBA are widely known for their anti-inflammatory, anti-cancer, and especially antioxidant capabilities; however, a comprehensive study of the mechanism and kinetics of the antiradical action of these compounds has not been performed. Here, we report a study on the mechanisms and kinetics of hydroperoxyl radical scavenging activity of HBA by density functional theory (DFT) calculations. According to the results, HBA exert low HOO• antiradical activity in the nonpolar environment with overall rate constants in the range of koverall = 5.90 × 10-6 - 4.10 × 103 M-1 s-1. However, most HBA exhibit significant HOO• antiradical activity (koverall = 105 - 108 M-1 s-1) by the single electron transfer (SET) reaction of the phenoxide anions in water at physiological pH. The overall rate constant increases with increasing pH values in the majority of the substances studied. At pH ≤ 4, gentisic acid had the best HOO• antiradical activity (log(koverall) = 3.7-4.8), however at pH > 4, the largest HOO• radical scavenging activity (log(koverall) = 4.8-9.8) was almost exclusively found for gallic and syringic acids. Salicylic and 5-sulphosalicylic acids have the lowest antiradical activity across most of the pH range. The activities of the majority of the acids in this study are faster than the reference compound Trolox. Thus, in the aqueous physiological environment, these HBA are good natural antioxidants.
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Phytohormones play important roles in germination, blossom, senescence, abscission of plants by a series of signal transduction and molecular regulation. The purpose of this research was to investigate the influence of root restriction (RR) cultivation on plant endogenous hormone variation tendency at different growth stages in diverse organs or tissues. ‘Muscat Hamburg’ (Vitis ‘Muscat of Alexandria’ × Vitis ‘Trollinger’) grapevine was used as test material. High Performance Liquid Chromatography (HPLC) was used to quantify hormone levels, qRT-PCR was used to quantify the expression of genes related to hormone biosynthesis pathway, and determined parameters of growth and photosynthetic, aiming to investigate the influence of root restriction on the formation and metabolism of phytohormones, as well as the degree of correlation between phytohormones and plant growth and photosynthetic intensity under root restriction. By measuring the photosynthetic rate of leaves at the stages of core-hardening, veraison and maturity, it was found that root restriction could reduce most photosynthetic parameters. The results also revealed that RR treatment increased abscisic acid (ABA), salicylic acid (SA), zeatin riboside (ZR), N6-(delta 2-isopentenyl)-adenine nucleoside (iPR) concentrations, while reduced auxin (IAA), 3-indolepropionic acid (IPA), 3-indolebutyric acid (IBA), gibberellin A3 (GA3), zeatin (ZT), N6-(delta 2-Isopentenyl)-adenine (iP), kinetin (KT), jasmonic acid (JA) and methyl jasmonate (MeJA) concentrations in most organs and at most developmental stages. RT-qPCR was carried out to further explore the effect of root restriction on genes expression of ABA, SA and IAA biosynthesis pathways at molecular level. Meanwhile, through correlation analysis, we found that different phytohormones contributed differently to physiological indicators, there existed strong correlation of ABA, KT, MeJA, iPR, SA, JA with leaf photosynthesis, GA3, IBA, ZR, IAA, ZT with fruit quality. In addition, we also found that the shoot growth related parameters were closely correlated with JA, IPA and iP. To sum up, our results suggested that RR treatment could significantly increase soluble solid content, regulate the growth and photosynthesis of grapevine, by affecting the biosynthesis of phytohormones. It could further prove that root restriction was a feasible technique to ameliorate the phenomenon of low quality in grape berry in southern China.
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Current trends in population growth suggest that global food production is unlikely to meet future demands under projected climate change scenarios unless the pace of plant improvement is accelerated. Plant production is facing many challenges due to changing environmental conditions and the growing demand for new plant-derived materials. These challenges come at a time when plant science is making significant progress in understanding the basic processes of plant growth and development. Major abiotic stresses like drought, heat, cold and salinity often cause a range of morphological, physiological, biochemical , and molecular changes affecting plant growth, development, and productivity; so sustainable food production poses a serious challenge to much of the world, particularly in emerging countries. This underscores the urgent need to find better ways to translate new advances in plant science into concrete successes in agricultural production. In order to overcome the negative effects of abiotic stress and to maintain food security in the face of these challenges, new, improved, and resilient plant varieties, contemporary breeding techniques, and a deep understanding of the mechanisms for offsetting harmful climate change are undoubtedly necessary. In this context, Improvement of Plant Production in the Era of Climate Change is a guide to the most advanced techniques that help in understanding plant response to abiotic stress, leading to new horizons and the strategy for the current translation studies application to overall solution to create a powerful production and crop improvement in such an adverse environment. FEATURES • Provides a state-of-the-art description of the physiological, biochemical, and molecular-level understanding of abiotic stress in plants. • Courses taught in universities from basics to advanced level in field of plant physiology, molecular genetics, and bioinformatics will use this book. • Focuses on climatic extremes and their management for plant protection and production, which is great threat to future generation and food security. • Understanding of new techniques pointed out in this book will open the possibility of genetic engineering in crop plants with the concomitant improved stress tolerance. • Addressing factors that are threatening future food production and providing potential solutions to these factors. • Written by a diverse group of internationally famed scholars, this book adds new horizons in the field of abiotic stress tolerance.
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Legumes are grown in more than 120 countries across all the continents. 90% of the global production of legume are produced in small group of countries such as India, Turkey, Pakistan, Bangladesh, Nepal, Iran, Mexico, Myanmar, Ethiopia, Australia, Spain, Canada, Syria, Morocco and Egypt. Legume are vegetarian sources of proteins and are an integral part of daily diet in several forms universally. Legume crops are great worth crops and play a dynamic role in crop diversification and economic sustainability of legume farming systems in dry areas. Most of the legume crops are grown under rainfed agroecosystem with poor level of input use which has resulted in low production. In this chapter we focus on (i) ecology and adaptation of legumes crop (ii)physiological responses of grain legumes to stress environments (ii) agronomic approaches to stress management.
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The study was carried out in the Laboratory of Plant Tissue Culture/ Department of Horticulture and Landscape Gardening /College of Agricultural Engineering Sciences /University of Baghdad in the period from July 2018 to August 2019. The main aim of the study was the propagating Origanum Vulgare histologically by identifying the combination of appropriate growth regulators for all propagation stages. As well as, study the possibility of stimulating the active compounds (volatile oil) of Origanum Vulgare by adding different concentrations of the growth regulator (salicylic acid) and comparing them with the same active compounds of the mother plant. The seeds were sterilized using a 10% sodium hypochlorite solution for 15 minutes, while the establishment stage, seeds was germinated within five days on Murashige and Skoog (MS) medium free of growth regulators. For the multiplication stage, different concentrations of salicylic acid (1, 2, and 3 mg.L-1) were used in combination with 0.5 mg.L-1 Benzyl adenine (BA). The addition of salicylic acid gave the highest average shoot length by 11.9, and the concentration of 2 mg.L-1 gave the highest average shoot number by 11, while the highest wet weight was 0.316 mg, and the highest dry weight was 0.067. Moreover, the effect of salicylic acid on the dyes has a significant effect in increasing the percentage of dyes, where the concentration of 3 mg.L-1 was given the highest Anthocyanin content was 186.25 mg/100g. In addition, the concentration of 2 mg.L-1 of salicylic acid gave the highest chlorophyll content was 372.96 mg/100g. As for the effect of salicylic acid on the active compounds of volatile oil, the results showed that the addition of 2 of salicylic acid gave the highest concentrations of the compounds (Al-pinene, Limonene, Carvacrol and Linalool). Finally, the concentration of 1 mg. L-1 was characterized by increasing Terpinen and Sapinen concentration, while the compound Thymol has reached 17.37 mg. L-1 in the comparison treatment.
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Maintenance of nutritional quality in crops is vital to provide quality human food as well as animal feed under stressful environmental conditions. The aim of the present review is to assess the effects of heat stress on qualitative traits of field crops. Environmental stresses significantly affect the nutritional properties and quality traits of crops through physiological and biochemical alterations occurring at different growth stages. Among environmental stresses, heat stress is the most pertinent especially under the current changing climate. Heat stress generally affects the grain quality depending upon crop cultivars. Several studies have proposed different management approaches for enhancing the grain quality of crops under heat stress environments. For managing heat stress, the grain quality may serve as a critical parameter for discriminating the crop genotypes having a higher potential to grow under heat stress conditions. Among heat stress mitigating strategies, seed priming and application of osmoprotectants, organic acids, and other antioxidants have the potential to increase the grain quality of many field crops.
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Phenolic compounds are important bioactive components in plant kingdoms with ubiquitous distribution amid immense structural diversity. They are indispensable in developmental and physiological stages of a plant besides having specific response in protection, adaptability, environmental and climatic resilience. In the present study, total phenolic content (TPC) was evaluated in 9 different rice ecotypes (PB-1, PB-1121, PB-1509, Pusa-RH-10, CSR-30, PR-126, HKR-47, Govind and Sharbati) belonging to basmati and non-basmati rice varieties. TPC distribution was measured in both shoot and root system at 14 days old seedling stage. In shoot, the average TPC distribution was 254.38 μg of GAE/gm FW, ranged from 170.33 μg to 357.62 μg of GAE/gm FW. For root, the TPC ranged from 64.58 μg to 105.27 μg of GAE/gm Fw with an average of 84.82 μg of GAE/gm FW. Hence, increased TPC was observed in shoots compared to roots, also there was a positive correlation in TPC distribution between shoot and root. Furthermore, the TPC distribution was more profound in shoot and root of basmati varieties compared to non-basmati varieties. Therefore, differential TPC distribution represents significant physiological feature during the developmental process for optimum growth and metabolism within the rice varieties according to their ecological behavior.
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Drought has a detrimental effect on crop production, affecting economically important plants’ growth rates and development. Catharanthus roseus is an important medicinal plant that produces many pharmacologically active compounds, some of which have significant antitumor activity. The effect of bulk salicylic acid (SA) and salicylic acid nanoparticles (SA-NPs) were evaluated on water-stressed Catharanthus roseus plants. The results showed that SA and SA-NPs alleviated the negative effects of drought in the treated plants by increasing their shoot and root weights, relative water content, leaf area index, chlorophyll content, and total alkaloids percentage. From the results, a low concentration (0.05 mM) of SA-NPs exerted positive effects on the treated plants, while the best results of the bulk SA were recorded after using the highest concentration (0.1 mM). Both treatments increased the expression level of WRKY1, WRKY2, WRKY40, LEA, and MYC2 genes, while the mRNA level of MPKK1 and MPK6 did not show a significant change. This study discussed the importance of SA-NPs in the induction of drought stress tolerance even when used in low concentrations, in contrast to bulk SA, which exerts significant results only at higher concentrations.
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Treatments of primary leaves of asparagus bean (Vigna sesquipedalis Fruhw.) with salicylate had different effects on resistance to local lesion development caused by tobacco necrosis virus (TNV), depending upon the concentration used for treatment. At 1 mm, salicylate slightly reduced lesion size but not virus accumulation, while at 3 mm it significantly decreased lesion size and virus accumulation. Treatments with 5 mm solutions appreciably increased both parameters, but also damaged the leaf tissue.The hypersensitive reaction of the leaves to virus inoculation was accompanied by the accumulation of five host-coded protein bands (VS0to VS4). However, three (or more) days after treatment with salicylate at any concentration between 1 and 5 mm only one band accumulated and this band appeared to correspond to VS1. This finding clearly questions the role of the VS1 protein in limiting the spread and multiplication of TNV.The leaves responded rapidly to treatment with salicylate with stomatal closure, increased K+ leakage and ethylene production. These responses are generally considered to be general reactions to stress. None of them however, was correlated with any of the observed changes in TNV infection.
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Screening for the pathogenesis-related (b) protein patterns of 11Nicotiana species and 30N. tabacum varieties has revealed both inter- and intraspecific variability and 7 different b-proteins (b0, b1, b1, b1, b2, b3 and b4) have been clearly defined. Their genetic determinants are sexually transmitted independently of theN gene conferring resistance to TMV, and a monogenic inheritance has been demonstrated for one of them (b1). Grafting experiments have revealed the existence of a species-aspecific mobile compound responsible for the expression of the b-protein genes, the production of which is probably under the control of theN gene. Among the 5 intraspecific and 6 interspecific hybrids studied, one of them, theN. glutinosa x N. debneyi together with its amphidiploid, synthesizes b-protein (b1) in a constituve way and possesses a high level of resistance to necrosis-inducing viruses. The amphidiploid is able to transfer these two properties to otherNicotianae not only by crossing but also by grafting; it therefore appears to permanently synthesize the mobile compounds. Furthermore, the hypersensitive reaction to TMV in these hybrids is only completely broken down at 35 C, whereas this normally occurs at 30 C in plants with theN gene.
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Polyclonal and monoclonal antibodies that recognize the 35-, 36-, and 37-kDa alternative oxidase proteins of Sauromatum guttatum (Schott) were used to isolate a cDNA clone, pAOSG81, from an S. guttatum cDNA expression library. A fusion protein with an apparent molecular mass of 48 kDa was expressed from a pUC119 derivative of pAOSG81 (pAOSG81-119) in Escherichia coli cells and was recognized by the monoclonal antibodies. When the in vitro translated and immunoprecipitated products made from mRNA hybrid-selected by pAOSG81 were analyzed, a single band corresponding to a protein with an apparent molecular mass of 42 kDa was observed. DNA sequence characterization showed that pAOSG81 contains the entire coding region of a protein with a calculated molecular mass of 38.9 kDa, a putative 63-amino acid transit peptide, and a 9-amino acid match to the authentic N-terminal sequence of the 36-kDa alternative oxidase protein. Analyses of the deduced amino acid sequence indicate: (i) that the transit peptide is predicted to form amphiphilic helices, and (ii) that three regions of the processed protein are likely to form transmembrane alpha-helices. We conclude from these data that pAOSG81 represents a nuclear gene, aox1, encoding a precursor protein of one or more of the alternative oxidase proteins of S. guttatum.
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Healthy tobacco plants accumulate beta-1,3-glucanases (glucan endo-1,3-beta-glucosidase; EC 3.2.1.39) in their roots and in specific parts of the flowers. After infection with tobacco mosaic virus, acidic and basic beta-1,3-glucanases are induced in the inoculated and virus-free leaves of the plant. An analysis of cDNA clones demonstrated that at least five genes for acidic beta-1,3-glucanases are induced after tobacco mosaic virus infection. Southern blot analysis indicated that the tobacco genome contains approximately eight genes for acidic beta-1,3-glucanases and a smaller number of genes encoding basic beta-1,3-glucanases. Genes from both gene families were cloned and sequenced. The basic isozymes contain a C-terminal extension that is cleaved off during their targeting to the vacuoles. This extension is absent in the acidic isozymes, which accumulate extracellularly. Northern blot hybridization showed that genes encoding acidic and basic beta-1,3-glucanases are strongly induced after tobacco mosaic virus infection or salicylate treatment of tobacco. The cloning of these genes is a first step toward the identification of regulatory elements involved in their coordinate induction.
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Infection of Nicotiana tabacum var. “Samsun” and “Samsun NN” with tobacco mosaic virus “Wageningen” U 1 (TMV W U 1) at 30 °C leads to systemic mosaic symptoms in both varieties. Electrophoretic patterns of soluble leaf proteins in polyacrylamide gels showed identical changes for both varieties and were the same as those in the combination TMV W U 1-Samsun at 20 °C and similar to those in the combination TMV W U 1-Samsun EN, in which identical symptoms are induced. Four new protein components (I to IV) accumulating at 20 °C in Samsun NN plants showing local lesions did not increase in amount after transfer of these plants to 30 °C; bands I, II and IV were considerably reduced, whereas band III appeared unaffected.When Samsun plants were infected with the Holmes' ribgrass strain of TMV (TMV HR) at 20 °C, both free TMV HR coat protein and relatively small amounts of the new components I to IV were apparent, proving that these components cannot be products of the N gene. The formation of small local lesions on the variety Samsun EN upon infection with TMV HR resulted in induction of the new components I to IV in apparently trace amounts, whereas quantitative changes seemed to be extremely limited. Inoculation of Samsun NN plants with TMV HR led to symptoms under greenhouse conditions only. In this combination, systemic acquired resistance was expressed when traces of protein components I to IV were present. In general, the changes in soluble proteins were connected with the type of symptoms—either mosaic or localized necrosis—produced, rather than the genetic make-up of the host plant variety.
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As found earlier, supply of EDTA was obligatory for both flowering and satisfactory vegetative growth in Wolffia microscopica. It is now shown that the metal affecting growth and flowering is most probably iron. Omission of Fe but not of Cu, Zn, Mn and B from the medium markedly affects vegetative growth. There exists also a strong interaction between EDTA and Fe, one being largely inactive in the absence of the other. When Fe-EDDHA is substituted for Fe-citrate and EDTA in the medium, no great effect is seen in vegetative growth, but flowering takes place even under continuous light. Studies with (59)Fe show that, in the medium containing Fe-EDDHA, Fe uptake is stimulated several-fold; this is apparently associated with the flowering condition.
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Salicylic acid and acetylsalicylic acid at concentrations of 10(-6)M to 10(-4)M effectively inhibit ethylene production by pear cell suspension cultures. Results suggest these acids act by blocking the conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene.
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The activity of the ethylene-forming enzyme (EFE) in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells was almost completely abolished within 10 min by 0.4 mM of the metal-chelating agent 1,10-phenanthroline. Subsequent addition of 0.4 mM FeSO4 immediately reversed this inhibition. A partial reversion was also obtained with 0.6 mM CuSO4 and ZnSO4, probably as a consequence of the release of iron ions from the 1,10-phenanthroline complex. The inhibition was not reversed by Mn(2+) or Mg(2+). Tomato cells starved of iron exhibited a very low EFE activity. Addition of Fe(2+) to these cells caused a rapid recovery of EFE while Cu(2+), Zn(2+) and other bivalent cations were ineffective. The recovery of EFE activity in iron-starved cells was insensitive to cycloheximide and therefore does not appear to require synthesis of new protein. The EFE activity in tomato cells was induced by an elicitor derived from yeast extract. Throughout the course of induction, EFE activity was blocked within 10-20 min by 1,10-phenanthroline, and the induced level was equally rapidly restored after addition of iron. We conclude that iron is an essential cofactor for the conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene in vivo.
Article
Infection of the second true leaf (leaf 2) of cucumber with Colletotrichum lagenarium systemically protected the first true leaf (leaf 1) and leaf 3 from subsequent disease caused by the fungus. Protection of leaf 3 was consistently better than leaf 1. Excising the stem below the petiole of leaf 3 at the time leaf 2 was inoculated did not affect protection of leaf 1. When the petiole of inducer leaf 2 was girdled with cotton and hot water prior to inoculation with C. lagenarium, resistance was not induced in leaves 1 or 3. Similarly, when the petiole of inducer leaf 1 was girdled prior to inoculation with C. lagenarium, resistance was not induced in leaf 2. Resistance was not induced in leaf 2 if its petiole was girdled prior to the inoculation of inducer leaf 1. Inoculating leaf 5 with the fungus induced resistance in leaves 1 to 4 and 6 to 10, but protection was greater in leaves 9 and 10. Resistance was not induced in cucumber plants once they set fruit, and was markedly reduced when induced at the time of flowering.
Article
SUMMARY Spraying tobacco plants with salicylic acid induces both the synthesis of 'pathogenesis-related' (PR) proteins and resistance to viruses that can induce necrotic lesions. We show that spraying Samsun NN tobacco with salicylic acid induced the production of PR-1 mRNAs and inhibited the systemic multiplication of alfalfa mosaic virus (A1MV) by 90%. Salicylic acid treatment also induced the synthesis of PR proteins in bean and cowpea plants, and reduced by 75 % the production of local lesions in A1MV-infected bean plants. Salicylic acid inhibited the replication of A1MV in cowpea protoplasts by up to 99%, depending on the mode of application. In A1MV- inoculated cowpea protoplasts, the production of viral minus-strand RNA, plus-strand RNA and coat protein was abolished, indicating that salicylic acid inhibits an early step in the A1MV replication cycle. The viability of the cells and the synthesis of host proteins were not affected by salicylic acid. Another aromatic compound, p-coumaric acid, induced neither PR proteins nor resistance to virus infection.
Article
PREVIOUS investigations of the auxin metabolism in plant tissues led to the following findings of a ring hydroxylation resulting in 2-hydroxyindolyl-3-acetic acid1,2, and a hydroxynaphthalene-1-acetic acid, which probably hydroxylated in the 8-position, and their glucosidos2. Other known products of the auxin metabolism were the aspartic acid conjugates3 and the betad-glucose esters4,5 of the free auxinic acids. Analogues of the last two metabolites have also been described for benzoic acid4,6. In wheat coleoptiles no hydroxylation of benzoic acid could be demonstrated.
Article
Trans-cinnamic acid, coumarin, salicylic acid, resorcinol, gallic acid, tannic acid and rutin counteracted the abscission-inducing effect of ABA. This inhibitory action of phenolic compounds on ABA-induced abscission may indicate that they have a regulatory role in the process.
Article
The influence of 12 naturally occurring phenolic acids on the uptake of potassium by barley (Hordeum vulgare L. cv. Karlsberg) was examined using 86Rb-labelled potassium solutions. Without exception, all compounds tested, including both cinnamic acid and benzoic acid derivatives, caused a significant reduction of uptake. In addition, the inhibitory capacities of 15 variously substituted benzoic acids were determined over a range of different concentrations of inhibitors. For each of these compounds an inhibition constant (Ki), defined as the concentration required to produce a 50 per cent reduction of uptake, was determined. The Ki values were found to be strongly correlated with the octanol-water partition coefficients of the compounds under examination. It is clear from this study and previous work upon phosphate uptake that phenolic acids exert a generalized inhibitory effect upon active ion-uptake which is almost certainly mediated through reversible alterations in membrane permeability.
Article
Infection of plants by viruses can lead to a systemic or a localized infection. Systemic infections can produce protection against related viruses, as seen in the phenomenon of cross‐protection. The mechanisms thought to be involved are discussed. Localized infections also produce protection but against a wide range of unrelated pathogens, including bacteria and fungi. This involves an active response by the infected plants, switching on a number of different resistance mechanisms for the different types of pathogens. Research on these plant‐coded, induced proteins thought to be involved in resistance is discussed.
Article
GA3 as well as SA increase the protein content of the stem and the leaves at 1 day under both 8- and 24-h photoperiods. A new protein band with Rm 0.47 seems to be associated with floral bud initiation as it develops within 1–3 days in the stem as well as in the leaves of plants exposed to inductive treatments regardless of whether the induction is caused by 8-h photoperiods or by treatment with GA3 of SA under 24-h photoperiods. Another band with Rm 0.23 developed only in the stem of water-as well as GA3- or SA-treated plants under 8-h photoperiods. It may possibly be associated with extension growth.
Article
The involvement of plastids in phenolic metabolism has been studied in Petunia after an isolation method of pure and physiologically intact chloroplasts has been adapted.Feeding experiments with [14C] phenylalanine demonstrated in these isolated organelles: the synthesis of cinnamate and benzoate derivatives which, with the exception of the first term of each serie, are o-hydroxylated (o-coumaric acid, coumarin and salicylic and gentisic acids); the lack of formation of labelled p-hydroxylated derivatives and flavanoids.The results are in agreement with the characterization, in the plastids of specific enzymes (PAL, cinnamate-2-hydroxylase) and the absence of cinnamate-4-hydroxylase.All these data suggest that the formation of p-hydroxylated derivatives, esters and flavonoids often characterized in chloroplasts may involve a cooperation between different organelles.
Article
The duckweed, Lemna paucicostata 6746, is a short-day plant and is known to remain vegetative under long-day conditions in nutrient solutions containing EDTA. Lemna paucicostata, strain LP6, is a new strain in which so far it has not been possible to induce flowering in vitro either under SD or LD conditions. Here the induction of flowering is reported in both plants under otherwise non-inductive conditions by the use of salicylic acid, a phenol. Aspirin (acetylsalicylic acid) also brings about a similar effect. Flowering in Lemna paucicostata 6746 can be induced to the extent of 60% which is in contrast to an earlier report [1]. The effects of salicylic acid and aspirin on L. paucicostata LP6 are even more striking since almost 90–100% plants could be induced to flower.
Article
By feeding ortho-3H cinnamic acid to Melilotus and ortho-3H cinnamic and benzoic acids to Gaultheria it has been shown that ortho-coumaric acid biosynthesis involves an efficient migration and retention of the ortho proton while salicylic acid biosynthesis involves a much lower retention.
Article
Plants can be systemically immunized against diseases caused by fungi, bacteria, and viruses by restricted infection with fungi, bacteria, or viruses. Immunization followed by a booster inoculation protects cucumber, watermelon, and muskmelon throughout the season, and a single immunization protects cucumber against at least 10 unrelated diseases.
Article
Occurence of PAL, cinnamate-hydroxylase and p-coumarate-hydroxylase, is found in cell-free extracts from Quercus pedunculata roots; moreover, an enzyme system which catalyzes benzoïc acid formation from cinnamic acid is caracterized for the first time. Role of these enzymes and their interactions within the same organ are discussed.
Article
Gentisic acid has been shown to be one of the most commenly occurring aromatic acids of green plants. The systematic distribution of the compound is described and its possible relationship lignification is discussed. Methods for its separation from other phenolic constituents of plants and for the identification of the compound are described.
Article
This paper deals with some properties of enzymes involved in the synthesis of phenolic acids, with special reference to their intracellular location. The results obtained can be summarized as follows: 1.1. Two phenylalanine ammonia-lyase isoenzymes coexist in Quercus roots as has been previously described for oak leaves. The cinnamate-sensitive isoenzyme is associated with the microsomal fraction whereas the benzoate-sensitive isoenzyme is located in the “F 10 000” fraction including mitochondria and microbodies.2.2. The cinnamate 4-hydroxylase, catalyzing p-coumarate formation, is tightly bound to microsomes and the “benzoate synthase”, an emzyme involved in the benzoic acid formation from t-cinnamate, is confined to the “F 10 000” fraction, presumably in microbodies.These data show that phenolic acids biosynthesis pathways are closely compartmented in organelles so that phenylpropanoid compounds are mainly formed in microsomes whereas C6−C1 acids are formed in microbodies. The regulation of these pathways seems to involve sophisticated mechanisms, associating isoenzymes with tight compartments.
Article
We show here that Agrobacterium tumefaciens virulence (Vir) gene expression is activated specifically by the plant molecules acetosyringone (AS) and α-hydroxyacetosyringone (OH-AS). These molecules induce the entire vir regulon in Agrobacterium as well as the formation of T-DNA intermediate molecules. AS and OH-AS occur specifically in exudates of wounded and metabolically active plant cells and probably allow Agrobacterium to recognize susceptible cells in nature.
Article
METHYL salicylate has been found to occur both in the free state1 and as the aglycone of a primeveroside, gaultherin2 in Gaultheria procumbens L. (Ericaceæ).
Article
IN the course of chromatographic studies on the phenolic constituents of Theobroma cacao L., an ultra-violet fluorescent compound (compound A), possessing an RF value of 0.28 in benzene/acetic acid/water, was shown to be widely distributed throughout the tissues of the plant1. This compound has now been shown to possess chromatographic and ultra-violet fluorescence properties identical with those of gentisic acid (2 : 5 dihydroxy benzoic acid). Chromatographic examination of a large number of leaf hydrolysates has revealed that gentisic acid is widely distributed in the plant kingdom, and it would appear to be one of the most commonly occurring aromatic acids of plant tissue. This acid, although usually present in very small or trace quantities, can readily be detected by the chromatographic technique described. The presence of other fluorescent aromatic acids, namely, caffeic, ferulic and sinapic acids in leaf hydrolysates has recently been reported2.
Article
Cultured cells of Mallotus japonicus converted exogenous o-hydroxybenzoic acid into its O-glucoside after a lag period of 8 hr during which time the aglycone was taken up rapidly by the cells, partly excreted and then re-absorbed. The glucosylation of the aglycone into o-O-β-d-glucosylbenzoic acid began almost simultaneously with the induction of glucosyltransferase activity, and ca 78% of the aglycone administered was transformed into the glucoside in 12 hr. On the other hand, m- and p-hydroxybenzoic acids were glucosylated immediately after administration, the latter yielding both its O-glucoside and glucose ester. Inhibitor experiments suggested the possible participation of either 70S or 80S ribosomes in the glucosylation of isomeric hydroxybenzoic acids.
Article
The 1-octanol-water partition coefficients are presented for 54 organic compounds. The additive-constitutive nature of the logarithm of partition coefficients is considered. It is postulated that intramolecular hydrophobic bonding can result in lower than expected values for partition coefficients in certain types of compounds.
Article
Cloudberry (Rubus chamaemorus L.) is very resistant to deterioration by micro-organisms and has a good keeping quality. In the present study the natural content of some organic acids, often used as food preservatives, has been determined by gas chromatography. Benzoic acid was found in the greatest amount (about 50 mg/100 g cloudberry). Sorbic acid, salicylic acid, ϱ-hydroxy-, methyl-ϱ-hydroxy-and propyl-ϱ-hydroxy-benzoic acid were found in smaller amounts (less than 1 mg/100 g cloudberry).The amount of benzoic acid changes very little with the degree of ripeness or place of growth.
Article
Injection of leaves of tobacco (Nicotiana tahacum cv. ‘Xanthi’ nc) with salicylic acid (SA) or phenylsene (PS) had an effect on the local lesion development caused by tobacco mosaic virus (TMV), depending upon the concentration used and the time interval between injection and challenge inoculation. Maximum reduction in lesion size was obtained with 0.75 mM SA or with 8 mM PS. Concentrations higher than 1 mM SA or 25 mM PS damaged the leaf tissue, PS being far less toxic than SA. The leaves responded rapidly to injection with SA or PS. A time interval of only 1 h between injection and TMV inoculation reduced the lesion size significantly. Isolated tobacco cell walls incubated with SA yielded carbohydrate fractions capable of reducing lesion size significantly after injection. Cell walls incubated without SA or with PS did not yield active carbohydrate fractions.
Article
Die Biosynthese der Gentisinsure wurde mittels markierter Vorstufen in vier Arten hherer Pflanzen untersucht. Es konnte gezeigt werden, da Gentisinsure ber die Zwischenstufen Zimtsure, Benzoesure und Salicylsure gebildet wird. Die Hydroxylierung erfolgt hier erst auf der Stufe der Benzoesuren, whrend andere Hydroxybenzoesuren (z. B. 4-Hydroxybenzoesure und Vanillinsure) durch unmittelbaren Abbau aus den entsprechend substituierten Zimtsuren entstehen.Biosynthesis of gentisic acid was investigated by the use of labelled precursors in four species of higher plants. We showed that gentisic acid is formedvia the intermediates cinnamic, benzoic, and salicylic acid. Thereby hydroxylation occurs at the benzoic acid level, whereas other hydroxybenzoic acids (e.g. 4-hydroxybenzoic and vanillic acid) originate by immediate degradation of correspondingly substituted cinnamic acids.
Article
Abscisic acid, a potent growth inhibitor inhibits hypocotyl growth ofRaphanus sativus seedlings. Phenolic compounds,viz., trans-cinnamic acid, chlorogenic acid, ferulic acid, salicylic acid, tannic acid and quercetin when applied with ABA, antagonize ABA action and restore normal seedling growth. Gibberellic acid promotes hypocotyl growth and on combined application with ABA, the ratio of their concentrations determines the course of the resultant growth. This interaction can be modulated by phenolic compounds. Phenolic compounds in low concentrations when present together with GA and ABA, favour GA-induced growth by antagonizing the inhibitory influence of ABA. The inhibitory action of abscisic acid on a wide range of growth processes is so far known to be reversed only by growth promoting hormones,viz., IAA, GA and cytokinins. Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA, establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones.
Article
Ethylene production by apple discs is effectively inhibited by salicylic acid. Inhibition is pH dependent, being greatest from pH 3.5–4.5 and minimal at pH 6.5 and above. With 100 μM salicylic acid maximal inhibition, approximately 90%, is achieved in 3 h with an apparent Ki of 40 μM. At somewhat higher concentrations salicylic acid also inhibits the conversion of 1-aminocyclo-propane-1-carboxylic acid to ethylene by pear discs and mung bean hypocotyls. Salicylic acid interferes with action of the putative ethylene-forming enzyme and in this respect is somewhat more effective than cobalt ion. The inhibitory effects of salicylic acid and cobalt ion are not additive. Implications for the limits and locus of salicylic acid inhibition are discussed.
Article
Aqueous salicylate solutions stimulated ethylene formation only when injurious, or potentially injurious, concentrations were exogenously supplied to soybean cuttings. Stimulation occurred via the biochemical sequence involving ACC as an intermediate, and was attributable to stimulation of ACC synthesis but not of EFE activity. Similar results were obtained by testing wound-induced ethylene, whereas the production of virus-induced ethylene was not affected by salicylate. Prolonged salicylate treatments which did not produce evident injurious effects inhibited soybean growth and rooting, probably through the moderate antiauxinic property attributable to salicylates. These findings are discussed in relation to other results obtained from similar or different plant materials.
Article
Residues from corn and rye plants were allowed to decompose in soil for periods up to 30 days at 22–23 C, and the identity of some of the compounds produced as well as their relative phytotoxicity to lettuce seed and seedlings were determined. Paper, thin-layer, and gas chromatography were the principal methods used to identify the various compounds formed. The identities were confirmed by comparison with known synthetic compounds. Eighteen compounds were identified in the decomposing corn residues. Of these, salicylaldehyde, and butyric, phenylacetic, and 4-phenylbutyric acids were volatile, and benzoic,p-hydroxybenzoic, vanillic, ferulic,o-coumaric,o-hydroxyphenylacetic, salicylic, syringic,p-coumaric,trans-cinnamic, and caffeic acids were not volatile. Resorcinol,p-hydroxybenzaldehyde, and phloroglucinol were also found. In the decomposing rye residues, nine compounds were identified, including vanillic, ferulic, phenylacetic, 4-phenylbutyric,p-coumaric,p-hydroxybenzoic, salicylic, ando-coumaric acids, and salicylaldehyde. In the lettuce seed bioassay, most of the above compounds from corn and rye decomposition products exhibited some phytotoxicity. Phenylacetic, 4-phenylbutyric, salicylic, benzoic, ando-hydroxyphenylacetic acids were highly inhibitory to the growth of lettuce at concentrations between 25 and 50 ppm. The others reduced growth significantly at 100 ppm. Most of the phototoxic spots were located in theR f 0.37–0.97 zone when developed in 2% acetic acid solvent.
Article
Changes in the mitochondrial electrontransport chain were followed in the thermogenic inflorescence ofSauromatum guttatum Schott from 5d before thermogenesis to 3d thereafter. The capacities of the alternative and cytochrome pathways of mitochondrial electron transport were found to be developmentally coordinated to contribute to the thermogenic events in the appendix and the sterile floral regions. Electron flow through the alternative pathway, is believed primarily responsible for heat production, and this pathway was expressed to the highest degree in both tissues during thermogenesis. In the appendix, the cytochrome chain was shut down considerably during thermogenesis, forcing electron flow through the alternative pathway and thus yielding maximum heat production. The shut-down of the cytochrome chain does not occur in the sterile floral region which may explain why this region is not as thermogenic as the appendix. Cytochrome-oxidase difference spectra indicated that the cytochrome oxidase of appendix mitochondria was not capable of accepting electrons on the day of thermogenesis, and that this capacity was partially restored by the following day even though the tissue was senescing at this time point. Relative levels of messenger RNAs for cytochrome-oxidase subunits I and II were found to decrease the day before thermogenesis, which could result in lower levels of these proteins in appendix mitochondria on the day of thermogenesis. The capacity for overall mitochondrial protein synthesis was also investigated and was found to drop continuously from 5d before thermogenesis to 3d thereafter, even though the capacities of the electron-transport chain were changing dramatically. The levels of mitochondrial ribosomal RNA levels decreased during development, which could explain the overall drop in mitochondrial translational efficiency. Experiments concerning the synthesis of the alternative-oxidase proteins indicated that they were most likely nuclearly encoded, and that their expression could be induced by salicylic acid.
Article
Inoculation of half-leaves of Nicotiana tabacum var. Samsun NN, with tobacco mosaic (TMV) virus induced a high level of resistance to TMV in the opposite half-leaves. Challenge inoculation with TMV of the resistant half-leaves 7 days after the first inoculation resulted in limited lesion formation; the lesions were consistently only one-fifth to one-third as large (in diameter) as were lesions in susceptible half-leaves, and they usually were fewer in number. Similarly, inoculation of lower leaves on a plant induced resistance in upper leaves and vice versa. Resistance was first detected in 2–3 days, reached a maximum in about 7 days, and persisted for at least 20 days. The uninoculated resistant leaves or half-leaves proved to be free of virus. The highest level of resistance developed when plants were kept at 20°C before and after the challenge inoculation. Resistance could be detected in plants kept at 29° after challenge. Complete protection was not obtained by increasing the ratio of the area first inoculated to that challenged. Resistance was induced by mixed infections by TMV and potato virus X (PVX), but leaves highly resistant to TMV alone were only slightly resistant when challenged with TMV plus PVX. Resistance was induced by TMV infection in detached leaves, in excised shoots, and in plants kept in the dark 2 days before challenge inoculation. No resistance was induced by mechanical or chemical injury or by viruses that do not cause necrosis.The resistance induced by TMV is not specific for TMV. Leaves with TMV-induced resistance were resistant not only to TMV but also to tobacco necrosis virus, to turnip mosaic virus, and to tobacco and tomato ringspot viruses. The resistance was not as effective against these viruses as against TMV, but each of these local-lesion viruses induced a resistance in Samsun NN tobacco indistinguishable from that induced by TMV.
Article
A pathogenesis-related (PR) protein was found in both the infected and the uninfected leaves of cucumber plants inoculated on the first true leaf with a fungal, a bacterial or a viral pathogen. This host-coded protein was detected up to five leaves above the infected leaf. The protein was purified from the intercellular fluid by ion-exchange chromatography and by high performance liquid chromatography on ion-exchange and phenyl-sepharose columns. The purified PR-protein was shown to be a chitinase with a molecular mass of 28 000 as determined by SDS-polyacrylamide gel electrophoresis and by gel filtration.
Article
Radioactive p-hydroxybenzoic, vanillic and syringic acids were shown to be synthesized in a variety of plants from the corresponding hydroxycinnamic acids labelled in the β-position. Decarboxylation of the hydroxybenzoic acids indicated that nearly all the activity was contained in the carboxyl carbons. In addition to the formation of C6-C1 acids by removal of a 2-carbon fragment from C6-C3 acids, some species were capable of O-methylating protocatechuic to vanillic acid or hydroxylating it to yield gallic acid. Demethoxylation of sinapic and dehydroxylation of caffeic acid occurred in some species. Ortho hydroxybenzoic acids were shown to arise from phenylalanine and cinnamic acid.
Article
The synthetic chelating agent EDDHA (ethylenediamine-di-o-hydroxyphenylacetic acid) and salicylic acid (SA) induce or enhance flowering in Lemna gibba L., strain G3, and Pistia stratiotes L. In L. gibba G3 these compounds also induce gibbosity, a swelling of the lower side of the fronds. EDTA (ethylenediaminetetraacetic acid) brings about similar effects in L. gibba G3. However, it is markedly less effective than EDDHA and SA and there are strong arguments in favour of a recent conclusion that it brings about its effect via a different mechanism. Ethylene induces gibbosity in L. gibba G3, however, neither in this species nor in P. stratiotes does it affect flowering. The effect of EDDHA/SA as well as ethylene on L. gibba G3 is specifically negated by autoclaved GA3 is i.e., break-down products of GA3 such as allogibberic acid, whereas non-autoclaved GA3 is ineffective. On the other hand GA3 induces profuse flowering in P. stratiotes whereas autoclaved GA3 is less effective. In the light of the various results it could be hypothesized that a gibberellin and ethylene in combination with another factor are involved in flowering of L. gibba G3.