Chapter

Role of Hormonal System in the Manifestation of Growth Promoting and Antistress Action of Salicylic Acid

June 2007

In book: Salicylic Acid: A Plant Hormone (pp.69-89)

Authors:

Salicylic acid (SA) is an endogenous plant growth regulator. When applied to wheat plants in concentration similar to that used in case of exogenous hormones (0.05 mM), SA causes growth promoting and protective effects against an abiotic stresses. SA was shown to cause changes in hormonal system associated with transitory parallel accumulation of IAA and ABA with no change in cytokinins, which took place in case of treatment of seeds before sowing as well as seedling treatment. SA-induced accumulation of ABA lead to no detrimental effects, evidenced by clearcut stimulation of growth of root cells both by division and expansion, accumulation of raw and dry mass of seedlings and productivity of wheat treated with SA. This indicated an important role to IAA in the expression of growth stimulating action of SA. ABA is likely to be intermediator in manifestation of antistress action of SA. This is evidenced by the data showing that SA-induced accumulation of ABA was followed by enhanced expression of genes of dehydrins and accumulation of proline, i.e. substances having a relation with osmoprotection of cells. Moreover, SA causes activation of superoxide dismutase and peroxidase, including anionic peroxidase, phenylalanin-ammonia-lyase, favouring accelerated lignification of cell walls of seedlings roots. This is likely to contribute to a decline in the extent of injurious effects of salinity and water deficit on plants, pretreated with SA, evidenced by a decline in the level of lipid peroxidation and leakage of electrolytes from plant tissues as well as by more intensive growth processes as compared to control plants. It is important to underline that pretreatment with SA prevents a sharp decline in IAA and cytokinin content observed under stress and maintains a high level of ABA. Such a character of SA effect on the state of hormonal system may well contribute to protective reactions of plants and acceleration of reparative processes during a post-stress period.

Role of Endogenous Salicylic Acid as a Hormonal Intermediate in the Bacterial Endophyte Bacillus subtilis-Induced Protection of Wheat Genotypes Contrasting in Drought Susceptibility under Dehydration

Article

Full-text available

Dec 2022

Endophytic Bacillus subtilis is a non-pathogenic beneficial bacterium which promotes plant growth and tolerance to abiotic stresses, including drought. However, the underlying physiological mechanisms are not well understood. In this study, the potential role that endogenous salicylic acid (SA) plays in regulating endophytic B. subtilis-mediated drought tolerance in wheat (Triticum aestivum L.) was examined. The study was conducted on genotypes with contrasting levels of intrinsic drought tolerance (drought-tolerant (DT) cv. Ekada70; drought-susceptible (DS) cv. Salavat Yulaev). It was revealed that B. subtilis 10-4 promoted endogenous SA accumulation and increased the relative level of transcripts of the PR-1 gene, a marker of the SA-dependent defense pathway, but two wheat cultivars responded differently, with the highest levels exhibited in DT wheat seedlings. These had a positive correlation with the ability of strain 10-4 to effectively protect DT wheat seedlings against drought injury by decreasing osmotic and oxidative damages (i.e., proline, water holding capacity (WHC), and malondialdehyde (MDA)). However, the use of the SA biosynthesis inhibitor 1-aminobenzotriazole prevented endogenous SA accumulation under normal conditions and the maintenance of its increased level under stress as well as abolished the effects of B. subtilis treatment. Particularly, the suppression of strain 10-4-induced effects on proline and WHC, which are both contributing factors to dehydration tolerance, was found. Moreover, the prevention of strain 10-4-induced wheat tolerance to the adverse impacts of drought, as judged by the degree of membrane lipid peroxidation (MDA) and plant growth (length, biomass), was revealed. Thus, these data provide an argument in favor of a key role of endogenous SA as a hormone intermediate in triggering the defense responses by B. subtilis 10-4, which also afford the foundation for the development of the bacterial-induced tolerance of these two different wheat genotypes under dehydration.

Effect of pre-harvest application of salicylic acid on yield and physico-chemical parameters of litchi (Litchi chinensis Sonn.) cv. China

Article

Full-text available

Apr 2023

An experiment was conducted on litchi cv. China at Horticulture garden in the Department of Horticulture (Fruit and Fruit Technology), Bihar Agricultural University, Sabour, Bhagalpur, Bihar, to study the effect of pre-harvest spray of salicylic acid on yield and physico-chemical parameters of litchi. The experiment was laid out in randomized block design with five treatments and four replications. Salicylic acid was sprayed twice i.e. 15 days and 30 days before anticipated harvesting time with different concentrations of salicylic acid (T1-50 ppm, T2-100 ppm, T3-150 ppm, T4-200 ppm and T5-control). Different concentrations have different effect on physical and biochemical parameters. Salicylic acid with T3-150 ppm has highest fruit length (3.46 cm), breadth (3.32 cm), volume (19.22 ml), weight (21.12 g), pulp (68 %), no. of fruits (4274 fruits/plant) and yield (71.25 kg/plant),), TSS (20.02 0 Brix), total sugar (13.10 %), ascorbic acid (38.21 mg/100 g pulp). Highest antioxidant (4.84 µ mol Trolox Eq. /g pulp) and anthocyanin (21.54 mg/100 g pulp) were observed in T4-200 ppm salicylic acid.

Effect of plant growth regulators on growth and physiological parameters of wheat (Triticum aestivum L.) under late sown condition

Article

Full-text available

Jan 2022

The present study entitled "Effect of plant growth regulators on growth and physiological parameters of wheat (Triticum aestivum L.) Under late sown condition" has been taken to focus the involvement and potential role of plant growth regulator and was carried out in during 2019-20 and 2020-21 at Agronomy Research Farm of C.S.A. University of Agriculture and Technology, Kanpur (U.P.). The experiment was done during Rabi (2019-20 and 2020-21) using wheat variety K-9423 using randomized block design having eleven treatments and three replications having thirty-three plots different plant growth regulators are used at various growth stages for overall development of crop. The details of the following treatments used for two years of experimentation is as follows T1: Control, T2: IAA, 25 ppm T3: IAA, 50 ppm T4: Abscisic acid 10 ppm, T5: Abscisic acid 20 ppm, T6: TRIA 5 ppm, T7: TRIA 10 ppm, T8: Brassinosteroid 5 ppm, T9: Brassinosteroid 10 ppm, T10: Cytokinin 5 ppm, T11: Cytokinin 10 ppm. Foliar spraying at two stages-first at 30 DAS (Vegetative stage) and second at anthesis in uniform dose of all treatments. The maximum Relative water content (RWC) (%) at heading stage in wheat was noted in T3 with application of IAA 50 ppm which was significantly superior over T11 and was statistically at par with T2 IAA 25 ppm and T10 Cytokinin 5 ppm. Minimum Relative water content (RWC) (%) at heading stage was observed under T5 Abscisic acid 20 ppm during both the years of investigation. The maximum Protein content in grain (%) in wheat was found in T3 with application of IAA 50 ppm which was significantly superior over T11 and was statistically at par with T2 IAA 25 ppm and T10 Cytokinin 5ppm. Least Protein content in grain (%) was observed under T5 Abscisic acid 20 ppm during both the years of investigation.

Enhancing antioxidant defense system of mung bean with a salicylic acid exogenous application to mitigate cadmium toxicity

Article

Full-text available

May 2021

Cadmium (Cd) accumulation is an emerging environmental hazard and has detrimental effects on plant growth and development. Salicylic acid (SA) is a well-known plant growth regulator that can initiate various molecular pathways to ameliorate Cd toxicity. The experiment was executed to scrutinize the mediatory role of SA to accelerate the defensive mechanism of mung bean in response to Cd stress. Mung bean plants were exposed to 0, 5, 10 and 15 mg Cd kg-1 of soil. Exogenous application of SA 0, 10-6 and 10-3 M was added prior flowering. Results exhibited that Cd stress considerably reduced the growth-related attributes i.e. shoot length, root length, fresh and dry biomass, total soluble protein, total amino acids, relative water contents and photosynthetic pigments. Cadmium stress showed a significant increase in antioxidants levels such as peroxidase (POD), ascorbate peroxidase (APX), ascorbic acid (AsA), and catalase (CAT) and promoted the accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. However, exogenously applied SA significantly improved plant biomass and photosynthetic pigments under Cd stress. Moreover, SA improved the defensive system by enhancing antioxidants’ activities under the increasing concentration of Cd stress. Furthermore, SA reduced the Cd uptake, membrane damage and, H2O2 and MDA accumulation. The study's findings concluded that exogenous-applied SA enhanced plant growth, promoted the antioxidant activities, and reduced the oxidative damage in mung bean seedlings under Cd stress.

Enhancing antioxidant defense system of mung bean with a salicylic acid exogenous application to mitigate cadmium toxicity

Article

Full-text available

Jun 2021

ADAPTATION AND IMPROVING OF SUNFLOWER PLANT UNDER STRESS CONDITIONS AT TOSHKA REGION

Article

Dec 2017

A.S. Abd – Elnaby

Salicylic acid and ROS crosstalk in plants for pathogen resistance

Chapter

Full-text available

Feb 2021

Synergistic Interactions of Arbuscular Mycorrhizal Fungi and Salicylic Acid Alleviate Adverse Effects of Water Salinity on Growth and Productivity of Watermelon via Enhanced Physiological and Biochemical Responses

Article

Aug 2023

Agri Articles (e-Magazine for Agricultural Articles) Heat Stress in Rice: Exploring the Role of Salicylic Acid for Sustainable Farming

Article

Full-text available

Jun 2023

Rice, a crucial staple crop globally, faces challenges from heat stress, which can lead to reduced growth, decreased yield, and impaired physiological processes. However, ongoing research on the use of salicylic acid (SA) to mitigate heat stress in rice offers promising solutions for sustainable farming. SA, a phenolic endogenous growth regulator, acts as a signal molecule, inducing defense mechanisms and regulating physiological and biochemical processes. Studies have shown that SA application alleviates heat stress by enhancing photosynthesis, activating antioxidant enzymes, and modulating osmotic potential and water potential. It also limits ethylene production, delaying senescence and improving yield. Moreover, SA pretreatment has been found to improve heat tolerance in rice seedlings by reducing electrolyte osmosis and oxidative stress. Foliar sprays of SA have demonstrated beneficial effects on pollen viability, seed setting, and grain quality under heat stress. Additionally, the use of SA in conjunction with other osmoprotectants has shown potential in enhancing crop resilience to heat stress. These findings highlight the potential of SA as a valuable tool in mitigating the adverse effects of heat stress on rice and improving overall productivity.

Protective role of plant growth-promoting fungi Aspergillus chevalieri OP593083 and Aspergillus egyptiacus OP593080 as biocontrol approach against Alternaria leaf spot disease of Vicia faba plant

Article

Full-text available

Jul 2023

Crop loss brought on by phytopathogens is a significant issue that affects the entire world. Synthetic pesticides have been used for years to prevent economic losses caused by phytopathogens, raising severe worries about the environment and public health. Therefore, today, there is growing interest in using helpful microorganisms to control plant pathogens. In this way, Aspergillus chevalieri AGH-1 OP593083 and Aspergillus egyptiacus AGH-4 OP593080 isolated from wheat rhizosphere have been applied as plant growth-promoting fungi (PGPF) for combating early blight disease caused by Alternaria solani ( A. solani ) and inducing the defense system and growth promotional strategies in Vicia faba . Two milligrams per milliliter ethyl acetate crude extracts of A. chevalieri and A. egyptiacus demonstrated effective antifungal efficacy against A. solani with an inhibition zone of 18 and 16 mm respectively compared with 20 mm attained by fluconazole as a positive control. Moreover, the minimum inhibitory concentrations (MIC) were (0.25 and 0.5 mg/ml) for A. chevalieri and A. egyptiacus extracts respectively. Data showed that A. chevalieri was the best isolate producing indole acetic acid (IAA) and siderophores (+ + +) followed by A. egyptiacus (+ +). Also, the best isolates capable of phosphate solubilization in the soil was A. egyptiacus (+ + +), followed by A. chevalieri (+ +). It is interesting that the PGPF isolates used, whether single or mixed, showed a significant improvement in all growth and yield as well as photosynthetic pigments in Vicia faba . Moreover, A. chevalieri and A. egyptiacus played an important role in improving plant immunity by increasing phenol, proline, and antioxidant enzymes (POD and PPO) activities, as well as reducing oxidative stress by reducing MDA and H 2 O 2 . We can conclude that A. chevalieri and A. egyptiacus are considered eco-friendly safe strong inducers of Vicia faba plant immunity alternatives to chemical pesticides against A. solani early blight to preserve plant, soil, and human health.

Effect of Soil and Foliar Applications on Growth and Yield of Green Bean (Phaseolus vulgaris L.) Plants Under Salinity Stress

Research

Full-text available

Apr 2023

During the two autumn seasons of 2020 and 2021, two field tests were conducted in the Experimental Farm of El Kassasien Research Station in Ismailia, Egypt in order to study the interaction effects of soil application treatments i.e., B. subtilis inoculant, AMF, vermicompost (VC) and corn stalk(CS), and foliar applications treatments, i.e. potassium silicate (4 cm / liter), Salicylic acid(SA) (150 mg / liter) and tap water control treatment, to reduce the negative impact of soil salinity on the growth and yield of snap bean grown in saline soil The foliar spray treatments with SA gave the highest values for all the studied traits, growth characteristics, i.e. plant height, number of branches, number of leaves, dry weight of the plant, as well as leaves or pods pigments, whether for, and the content of plants from NPK, in addition to the yield of pods and its components.The best soil additives had an effect on all the studied traits is the addition of VC + AMF followed by the addition of CS + AMF. These additions caused a substantial increase in plant growth measurements, as well as a significant increase in the leaves and pods pigment, plant's content of elements, also led to a significant increase in pod yield, its composition, as well as its quality The interaction between the study factors had a significant effect on all the studied traits, and the best data for these traits were obtained from the soil application of (VC) + (AMF) with (SA) spraying due to its role in reducing the negative effect of soil salinity. The effect of applied treatments was estimated in terms of the rhizosphere biology, Biologically, AMF root colonization% and dehydrogenase activity recorded increases in their result, especially at soil application, Co-addition of AMF, VC and SA as foliar Decrease the impacts of abiotic salinity stress. Accordingly, a possible reduction in salinity stress can be achieved using AMF, VC with SA as foliar spray in salt affected soil for green bean The cultivation of plants enhanced their growth and photosynthesis and Reduced osmotic stress under salinity conditions. In addition, the oxidoreductase enzyme catalase and accumulation of proline decrease after 30 days of planting in both seasons. This research reveals that higher levels of antioxidant enzymes and proline content, which decrease ion toxicity and cell membrane injury, were principally responsible for the enhanced tolerance to salinity. Antioxidative responses in green bean plants subjected to different osmotic potentials induced by salinity stress were record lower value in our treatment than control.it is may be due to our treatment give the plant the superiority to overcome the osmotic stress due to makes the plant more resistant and tolerant to salinity by increasing microbiota in rhizosphere and the presence of mycorrhizae, making the plant get its need of NPK.so that the plant have more defense and did not need more antioxidant enzyme, Thus, the plant did not need to make proline as a defense system against salinity in green bean, thereby mycorrhizae, VC and SA increasing osmotic adjustment and protection from free radicals in Phaseolus vulgaris L .

Miracle molecule: Salicylic acid

Article

Jan 2023

Exogenous application of salicylic acid mitigates salt stress in rice seedlings by regulating plant water status and preventing oxidative damage

Article

Full-text available

Jan 2023

Salicylic acid (SA) is a hormone participating in the acclimation of plants to biotic and abiotic stresses, including salinity. We investigated the possible underlying mechanism of mitigating salt stress by SA using NaCl-treated rice plants sprayed twice with exogenous SA at different concentrations. SA application resulted in increased growth, relative water content, proline accumulation, the quantum efficiency of photosynthesis and activity of superoxide dismutase in NaCl-treated plants. Application of SA decreased Na+ concentration and increased K+ concentration, thus increasing the K+/Na+ ratio. The application of SA mitigated the effect of NaCl by improving plant water status, ion homeostasis and decreased oxidative damage. Foliar application of 0.5 mM SA was more effective in mitigating the salt stress while 2 mM SA was inhibitory, and the second spray of SA showed no significantly enhanced ameliorating effect over the first spray.

Salicylic acid increases tolerance of Vigna mungo cv. T9 to short-term drought stress

Article

Dec 2022

Drought stress severely affects plant growth and productivity. Black gram is an extensively cultivated legume crop worldwide. Its production has not improved much in the last decade as it is adversely affected by biotic and abiotic stresses among which drought is a major factor. Salicylic acid (SA) pre-treatment to a Vigna mungo variety significantly increases chlorophyll, proline, carbohydrate, and total phenolic content. APX, GPX and SOD activities also increase and CAT activity decreased. At molecular level, induced expression of various stress-related genes, i.e. heat shock protein (Hsp), calmodulin (CAM), malate dehydrogenase (MD), metallothionein (MT), mitogen-activated protein kinase (MAPK), tryptophan synthase (TSN), zinc finger (ZF), phenylalanine ammonia lyase (PAL) and WRKY proteins are analysed by quantitative RT PCR after 1 mM SA treatment under short-term drought stress. It is observed that 1 mM SA pre-treatment is optimum to increase tolerance against short-term drought stress. https://rdcu.be/c1OEt

Endophyte mediated plant health via phytohormones and biomolecules

Chapter

Jan 2023

Endophytes are ubiquitous symbiotic microorganisms living with different plant tissues without any harmful effects. Endophytes usually establish around the roots or cuticle surface of the leaf, while some minute fractions are also associated with seeds. Fungi and bacteria act as endophytes that are essentially involved in plant growth and development processes such as nitrogen fixation, phytohormone signaling, phytoremediation, secondary metabolite secretion, and regulation of plant metabolism. These interactive mechanisms among endophytes and host plants are essential to combat biotic and abiotic stress responses in plants. As the scenario of current agricultural practices is to apply environment-friendly approaches to combat biotic and abiotic stress, therefore, the current research programs channel towards beneficial endophytic-plant associations for biocontrol of plant diseases. The critical regulators for the association between microorganisms and host plants are biomolecules, including phytohormones. Several biomolecules such as antifungal compounds, compatible solutes, osmoprotectants, enzymes, siderophores, and secondary metabolites are contributed by endophytes during microbial-host association. Similarly, phytohormones such as auxin, cytokinin, gibberellins, ABA (abscisic acid), and SA (salicylic acid) are released by endophytes to interact with the host system where phytohormone and biomolecule-mediated signaling governs several kinds of mechanisms for plant disease control. The mechanisms include signaling for nutrient uptake, nutrient utilization, and abiotic and biotic stress tolerance. The current chapter discusses the role of different biomolecules and phytohormones released from endophytes in encountering stress response and disease management. Various signaling mechanisms supporting these symbiotic associations in plants are also discussed.

Role of Salicylic Acid on Postharvest Physiology of Plants

Chapter

Oct 2022

The decay of vegetables and fruits causes a major loss to the harvested produce. Synthetic pesticides and fungicides have been used frequently to overcome the degradation in perishable produce. These chemicals are harmful to the environment and human health. Therefore, environmental safe methods and techniques are required to be adopted to maintain the preserve quality of harvested produce, one of such is the application of salicylic acid (SA). SA plays a critical role in the regulation of cascade responses against stress and developmental processes of plants. This chapter emphasizes the biosynthesis and metabolism of the SA in plants. In addition, we have elaborated the role of preharvest factors that affect the postharvest quality of perishable crops. The impact of SA on ethylene production also has been described in detail. SA also plays a significant role in reducing the occurrence of diseases of horticultural produce by promoting systemically acquired pathogen resistance mechanisms. It also modulates antioxidant enzyme activities, thus reducing oxidative stress and increasing horticultural products’ resistance to chilling injury. Therefore, SA may be successfully used as an alternative to toxic synthetic chemicals for postharvest management of fresh horticultural products to improve shelf life and ensure food health.

Regulation of Photosynthesis by Salicylic Acid Under Optimal and Suboptimal Conditions

Chapter

Oct 2022

Salicylic acid (SA) is an imperative plant hormone that regulates plant growth, photosynthesis, and different metabolic processes. SA as a signaling molecule plays an imperative role in plant acclimation against different abiotic stresses. The impact of exogenously applied SA on the processes of photosynthesis under optimal and suboptimal conditions is controversial. The SA application improves the stomatal conductance, electron transportation, and antioxidant activities at lower concentration and thus improves the photosynthetic efficiency. The mode of SA action depends on the plant species, environmental conditions and method, and the dose of SA application. The suboptimal environmental conditions can increase the endogenous SA levels which provide them protection against these conditions. Moreover, exogenously applied SA alleviates the negative effects of different stresses and improves the plants’ photosynthetic efficiency and their acclimation to changing environmental conditions. Therefore, in this chapter, we discussed the role of SA on photosynthesis under normal and stressed conditions.

Salicylic Acid‐Mediated Physiological and Molecular Mechanisms in Plants Under Abiotic Stress

Chapter

Oct 2022

Abiotic stresses such as drought, salinity, heavy metals, metalloids, cold, UV‐B radiation, etc., are a challenge to crop yields and agricultural productivity. These stresses individually or combined induce several adverse effects in plant growth and development, including biochemical, physiological, and molecular processes, and finally reduce 50–70% of crop yield. Phytohormones such asauxins, brassinosteroids (BRs), abscisic acid (ABA), cytokinins (CKs), (GAs), salicylic acid (SA), ethylene, and gibberellin play a significant role in plants’ growth and alleviate the plant tolerance to different abiotic stresses. In particular, being an endogenous plant growth regulator and a signaling molecule, SA involves in the regulations of plant signaling processes to ameliorate stress tolerance. Thus, in several recent studies, SA has increasingly been acknowledged in improving plant stress‐tolerance via SA‐involved metabolic processes. It is considered a mitigating tool and all‐rounder in plants and also is well known that SA theoretically generates a wide range of metabolic processes in plants under different stress conditions. Although it actively mitigates plants under adverse environmental conditions, SA‐induced plant tolerance remains least discussed. Accordingly, understanding the recent updates of SA mechanism in plants would help to speed up the process of developing plants’ abiotic stress tolerance. According to recent reports, in this book chapter, we present an overview of SA's background and biosynthesis under both different stress and normal conditions in plants. Besides, we review the SA functions in plants and cross‐talk potential mechanisms and finally highlight unexplored aspects of SA significantly.

Foliar Application of Salicylic Acid on Growth and Yield Components of Tomato Plant Grown under Salt Stress

Chapter

Full-text available

Sep 2022

Abiotic environmental stresses such as drought stress, mineral deficiency, heat stress, and salinity stress are major limiting factors of plant growth and productivity. Tomato (Solanum lycopersicum L.), one of the important and widespread crops in the world, is sensitive to moderate levels of salt in the soil. So many authors have reported large variation among tomato genotypes in their response to salinity. The present study was conducted to study the effect of different concentrations of salicylic acid on growth parameters, yield, and yield attributes of tomato under saline conditions. Tomato plants cv. Marmande were grown under normal or saline (100 mM NaCl) conditions. Different levels of salicylic acid: SA (0, 0.01, 0.1, and 1 mM) were applied as a foliar spray. The study was conducted at the vegetative and reproductive stage. Salt stress reduced significantly the whole plant growth at the two stages. Application of SA caused a significantly increase in biomass under non-saline conditions. However, in salt medium, treatment of leaves by SA induces a slight increase in biomass, leaf area and ameliorates the fruit diameter compared with plant grown only in the presence of salt. The beneficial effect of SA is more pronounced with the dose 0.01 mM.

Roles of Irrigation Intervals and Growth Regulators on Faba Bean Productivity and its Components

Article

Dec 2021

Effect of spraying salicylic acid and biostimulant (Biomagic) on productivity and quality of pomegranate under heat stress in Siwa Oasis

Article

Jan 2022

This study was implemented through the project (Sustainable development of fruit trees affected by some environmental stress in Matrouh governorate) funded by Regional Development Centers (RDC), Academy of Scientific Research and Technology (ASRT) (Call no. 2/2019/ASRT-RDC). It was carried out on 81 trees of Manfalouty pomegranate cv (Punica granatum) during the two successive seasons of 2020 and 2021 at the Khamisa research station of D.R.C. at Siwa Oasis-Matrouh Governorate-Egypt. The study aimed to investigate the influence of salicylic acid (SA) and the biostimulant biomagic to improve fruit productivity and the quality of pomegranate var. "Manfalouty." All the treatments were subjected to the same agricultural practice. The foliar treatments were used, tap water (T1), salicylic acid 100 ppm (T2), salicylic acid 200 ppm (T3), biomagic at 7.5 cm/l (T4), biomagic at 8.5 cm/l (T5), salicylic acid 100 ppm + biomagic 7.5 cm/l (T6), salicylic acid 100 ppm + biomagic 8.5cm/l (T7), salicylic acid 200 ppm. The obtained results showed that all the treatments were affected by spraying fruit trees with salicylic acid in combination with biomagic, followed by the solo concentrations of each treatment in both seasons. Meanwhile, T9 gave the best vegetative growth, fruit physical, chemical properties, and gave the lowest total acidity, fruit cracking percentage, and sunburn percentage in the 1st and 2nd season, respectively.

Effect of Drought and Salicylic Acid on Vegitive Growth and Prolin Accumulation of Two Cowpea (Vigna unguiculata L.) Plants

Article

Full-text available

Apr 2022

Roles of Irrigation Intervals and Growth Regulators on Faba Bean Productivity and its Components

Article

Full-text available

Dec 2021

One of the most significant factors limiting plant output on the majority of agricultural fields across the world is water stress, which is one of the environmental stresses. Salicylic acid (SA) and gibberellic acid regulates plant growth, makes plants more tolerant to water shortages and play a key role in many physiological processes. The present work was designed with the objective to investigate the effects of addition of SA and GA and irrigation intervals (14, 21, 28 days) on growth parameters, morphological parameters, photosynthetic pigments, protein, total carbohydrates and productivity of faba bean. This is achieved through a field experiment during winter season of 2016/2017 at Tag El-Ezz farm Mansoura city, Egypt. All vegetative growth parameters, yield parameters and chemical content were found to be increased by widening the irrigation periods from 14 days to 21 days, while narrowing the irrigation intervals to 28 days gave reverse effect. Addition of SA (1.0 ppm) and/ or GA (150 ppm) to faba bean at 14-21 days' irrigation period show maximum increase in plant characteristics (i.e. plant height, fresh, dry weight, chlorophyll and micronutrients contents).

The use of osmoregulators and antioxidants to mitigate the adverse impacts of salinity stress in diploid and tetraploid potato genotypes (Solanum spp.)

Article

Full-text available

Feb 2022

Background Many arid and semi-arid areas endure from extensive salinization of agricultural land. Nevertheless, it must either develop salinity-tolerant varieties or use agronomic treatments to alleviate the symptoms of stress. Although the cultivated potato, Solanum tuberosum L., is relatively salt sensitive, salinity tolerance was demonstrated in several Solanum relatives. Knowledge of genetic variation for salinity tolerance across diverse species is required for breeding of salinity-tolerant cultivars. Higher osmotic pressures associated with salinity impede plant development and cause plant death; yet, the exogenous application of cellularly recognized molecules to withstand such stress might be a key method. Results In vitro studies were performed to determine how much genetic variability for salinity tolerance exists in S. tuberosum ( tbr ), a tetraploid species and S. chacoense ( chc ) , a diploid species in which 13 genotypes were evaluated under 100, 200 or 300 mmol L ⁻¹ NaCl and the average tested parameters were compared with the control (no stress). A further experiment was conducted to investigate the effect of exogenous application of osmoregulators and antioxidants, namely, glycine betaine (GB), proline (P) and salicylic acid (SA) at 400, 200 and 100 mg L ⁻¹ , respectively, which applied solely to counteract the harmful effect of stress on potato plants. The results showed that when plants exposed to salinity, root characteristics, plantlet water content % (PWC), chlorophyll and K ⁺ content, and callus formation all substantially reduced; however, Cl ⁻ and Na ⁺ levels, as well as catalase and peroxidase activity, were elevated. In general, chc showed more tolerance compared to tbr with genetic diversity within and among species. Under stress, chc clones, ‘A-6’, ‘C-8’ and ‘D-2’ and tbr cultivars, ‘Diamond’ and ‘Russet Burbank’ were more tolerant and yielded the greatest salinity tolerance index. Under stress but with applied GB, SA and P, the adverse consequences of stress were relieved. GB was found to be a good treatment for enhancing all the examined traits. Conclusion The results indicated that there is a significant genetic variation in salt tolerance between ( tbr ) cultivars and ( chc ) clones. GB followed by SA and P could completely or partly reverse the adverse impact of salinity stress on potato plants. Graphical Abstract

STUDIES ON THE EFFECT OF FOLIAR APPLICATION OF PLANT DEFENSE ACTIVATORS ON SEED YIELD AND QUALITY IN RADISH

Thesis

Full-text available

Feb 2022

Paranjay Rohiwala

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.

plants-11-00115-v2

Article

Dec 2021

Effect of Salt Stress and Foliar Application of Salicylic Acid on Morphological, Biochemical, Anatomical, and Productivity Characteristics of Cowpea (Vigna unguiculata L.) Plants

Article

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Dec 2021

Effect of Salt Stress and Foliar Application of Salicylic Acid on Morphological, Biochemical, Anatomical, and Productivity Characteristics of Cowpea (Vigna unguiculata L.) Plants

Article

Full-text available

Dec 2021

The present study aimed to investigate the impact of salinity on vegetative growth, chemical constituents, and yields of cowpeas (Vigna unguiculata) and the possible benefits of salicylic acid (SA) on these plants after damage from salinity. To achieve these objectives, two pot experiments were carried out at the Faculty of Agriculture, Al-Azhar University, Egypt, during the two growing seasons of 2019 and 2020. The results revealed that salinity significantly decreased, and SA treatment substantially increased the plant height, number of compound leaves, number of internodes per plant, fresh weights of leaves and stems, productivity, photosynthetic pigments content, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) of the cowpea plants compared with the control. The anatomical structure of stems and leaves of the plants were also investigated, and it was found that positive variations in the anatomical structure of the median portion of the main stems and blades of mature foliage leaves were detected in the stressed and SA-treated plants. In conclusion, SA treatment increased the salt stress tolerance of cowpea plants by improving the morphological and physiological attributes of the plants.

Effect of Addition of Tertiary Butyl Hydro Quinon (Tbhq) And Vitamin E) Antioxidants on The Stability of Sun Flower And Olein Oil Before And After Frying

Article

Full-text available

Nov 2021

Hagir Abdallah

The aim of this study was to evaluate the effect of addition of two types of antioxidants (Tertiary Butyl Hydro Quinon (TBHQ) and Vitamin E) on the stability of two oils (sun flower and olein oil) before and after frying. Nowadays a great attention has focused on the peroxide values of different foodstuffs, since there was a link between the accumulation of the free radical and the adverse effect on human health. Generally, peroxide value was taken as a quality indicator for a wide range of food products. The impact of frying conditions (oil type, temperature, frying time) on peroxide value was investigated in this study. The results obtained that there was a high peroxide value of oils used in this study even before frying for both tested oils (olein and sun flower). Upon addition of antioxidants, there was a significant decrease in peroxide value for the two oils tested especially in case of vitamin E. The main recommendations of this study was the oil used in frying must be with low (as possible) peroxide value to get good organoleptic quality for the potato frying products, so due to its stability, olein oil is good for frying of both chips and French fries.

Mitigation of Cadmium Induced Oxidative Stress by Using Organic Amendments to Improve the Growth and Yield of Mash Beans [Vigna mungo (L.)]

Article

Full-text available

Oct 2021

Cadmium (Cd) stress is a serious environmental hazard that has devastating impacts on plant growth and productivity. Moreover, the entrance of Cd into the human food chain by eating Cd-contaminated food also poses serious health issues. Organic amendments (OA) possess an excellent potential to reduce the adverse impacts of Cd stress. Therefore, the aim of this study was to determine the potential of different OA in improving the mash beans growth and yield grown under Cd-contaminated soil. The soil was spiked with different concentrations of Cd (0, 10 and 20 mg/kg) and subjected to different OA, i.e., control, cow manure (5%), sugarcane press mud (5%) and a combination of cow manure (2.5%) and sugarcane press mud (2.5%). Results indicated that Cd stress induced a significant reduction in growth and yield traits, leaf water status, photosynthetic pigments, protein accumulation and anti-oxidant activities. However, the application of OA appreciably reduced the Cd-induced toxic effects and caused a significant increase in growth and yield. The application of 5% sugarcane press mud remained the top performer and it increased the mash bean growth and yield through improved photosynthetic pigments, leaf water status (56%) and reduced Cd uptake (18%), hydrogen peroxide (H2O2 ) production (38.52%), electrolyte leakage (EL) (42.13%) malondialdehyde (MDA) accumulation (55.88%) and increased accumulation of soluble protein (60.15%) and free amino acids (54%) through improved activities of anti-oxidant enzymes. Therefore, these findings suggested that the application of sugarcane press mud enhanced the growth and yield through reduced Cd accumulation, enhanced photosynthetic pigments, leaf water status, protein and amino accumulation and reduced H2O2 , EL and MDA accumulation through a stronger anti-oxidant defense system

Effect of salicylic acid in two stages of application on wheat crop

Article

Full-text available

Sep 2021

Salicylic acid (SA) is a plant growth regulator and participates in several physiological and biochemical processes. Its use can assist in the growth, development, productivity and quality of several crops. Thus, the objective of this work was to evaluate the effect of salicylic acid in two application stages on wheat crop. The experiment was conducted under field conditions and designed as randomized blocks, with four replications. Treatments 0.5 and 1.0 mM of SA were applied in stages 1 and 10, beginning and end of vegetative growth of wheat plants, besides a control treatment (without SA). Phytointoxication and SPAD index evaluations were performed at 14, 21, 28, and 35 days after application (DAA) of SA and the end of the experiment, 109 DAA the plants were tracked to quantify the mass of a thousand grains, hectoliter weight and grain yield. The application of SA did not cause symptoms of phytointoxication and increased the values of the SPAD index and all components of grain yield compared to the control treatment (without SA). The application of SA promoted a greater increase in the variables analyzed when applied in stage 10 of wheat plants.

The effect of titanium dioxide nanoparticles and salicylic acid on growth and biodiesel production potential of sunflower (Helianthus annus L.) under water stress

Article

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Dec 2021

SA-Mediated Regulation and Control of Abiotic Stress Tolerance in Rice

Article

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May 2021
INT J MOL SCI

Environmental or abiotic stresses are a common threat that remains a constant and common challenge to all plants. These threats whether singular or in combination can have devastating effects on plants. As a semiaquatic plant, rice succumbs to the same threats. Here we systematically look into the involvement of salicylic acid (SA) in the regulation of abiotic stress in rice. Studies have shown that the level of endogenous salicylic acid (SA) is high in rice compared to any other plant species. The reason behind this elevated level and the contribution of this molecule towards abiotic stress management and other underlying mechanisms remains poorly understood in rice. In this review we will address various abiotic stresses that affect the biochemistry and physiology of rice and the role played by SA in its regulation. Further, this review will elucidate the potential mechanisms that control SA-mediated stress tolerance in rice, leading to future prospects and direction for investigation.

Physiological Responses and Antioxidant of Wheat Cultivars in PGR -Mediated Alleviation of Drought Stress

Article

Apr 2021

Drought is one of the most important abiotic stresses and factors limiting the successful production of plant products worldwide and has adverse effects on plant growth and other metabolic processes. The role of exogenous individual or combined application of Silicon (Si) and Cycocel (CCC) (control, 3.6gL-1 Si, 210mgL-1 CCC, and 3.6gL-1 Si + 210mgL-1 CCC) on grain yield and some key physiological characteristics of wheat (Triticum aestivum L.) cv. Gascogen (drought-sensitive) and Aflak (drought-tolerant) was investigated under field water-stress conditions (100% and 40% field capacity). Drought stress caused a considerable reduction in biological yield, yield and yield components, relative water content and leaf water potential of both cultivars. Application of Si and CCC effectively improved these parameters in water-deficit treatments. Moreover, water-limited conditions markedly promoted the activities of key antioxidant enzymes including peroxidase, ascorbate peroxidase, catalase and superoxide dismutase as well as the levels of Malondialdehyde (MDA) and hydrogen peroxide (H2O2), while enhancing the accumulation of soluble sugars, potassium, magnesium and calcium in leaf tissues. Application of Si and CCC further enhanced the activities of the key antioxidant enzymes and accumulation of osmolytes, and decreased the levels of H2O2 and MDA in drought stressed plants; the positive effects of Si were greatest when it was applied with CCC. Synergistic effects of Si + CCC application on yield and physiological parameters were apparent compared with Si or CCC applied separately water-stress alleviation and yield improvement in the wheat cultivars by Si and CCC application was attributable to partly improved osmotic adjustment and antioxidant activity as well as to more favorable water status under stress conditions. Overall, Si and CCC application proved to have great potential in promoting grain yield of wheat in drought-prone areas.

Evaluation of Salicylic Acid Application on Biomass and Some Morphological Traits of Dragonhead under Water Deficit Conditions

Article

Full-text available

Jan 2015

To investigate the effect of salicylic acid on some morphological traits and yield of dragonhead under water deficit conditions, a field experiment was done at Department of Natural Resource and Watershed of Piranshahr, Iran, in 2012. The experiment was arranged as a split plot, based on randomized complete block design with three replications. The experimental treatments consisted of three levels of irrigation after 40, 80 and 120 mm evaporation from pan as the main plots and three levels of the plant foliar application with salicylic acid as the subplots (0, 0.5 and 1 mM). The results showed that the irrigation treatments had significant effects on the plant height, the main stem diameter, number of lateral branches, floral branches length, number of leaves and biological yield. The maximum and minimum value of the mentioned traits respectively was obtained in the treatments of 40 and 120 mm. Salicylic acid effect on the biological yield was significant, so that the maximum biological yield (638 g.m-2) belonged to the 1 mM salicylic acid application, while the control had 24.8 percent increase and had no significant difference with the 0.5 mM salicylic treatment. Interaction of the water deficit stress and salicylic acid on the number and length of floral branches in the plant was significant. The highest number of floral branches (mean 3.73 per plant) was observed in 40 mm evaporation from the pan with foliar application of 0, 0.5 and 1 mM salicylic acid and its lowest value was obtained with two levels, 80 and 120 mm, of evaporation from the pan without salicylic acid application.

Changes in antioxidant enzymes activities and alkaloid amount of Catharanthus roseus in response to plant growth regulators under drought condition

Article

Full-text available

Sep 2021
IND CROP PROD

Drought stress affects plant growth and is considered as one of the most important issues in In Middle East. In order to manage the critical water, it is essential to develop strategies to improve plant growth and biochemical characteristics. Plant growth regulators may afford a safe solution to increasing crop productivity via several mechanisms. Thus, the current study investigated the influence of salicylic acid and jasmonic acid on some physiological and antioxidant responses of Catharanthus roseus to drought stress under field conditions in Ahvaz and Tehran, Iran. The results indicated drought stress decreased total fresh and dry weights, relative water content, and concentration of photosynthetic pigments. In contrast, the activity of antioxidant enzymes and alkaloid contents would be increased. Foliar application of salicylic acid had a significant impact on all studied traits, but jasmonic acid had an effect only on total fresh and dry weights, concentration of photosynthetic pigments, and alkaloid contents. The activity of antioxidant enzymes including peroxidase, ascorbate peroxidase, superoxide dismutase, and polyphenol oxidase enhanced by spraying salicylic acid in deficit and good irrigation conditions. Foliar application of salicylic acid 10 mM on activity of antioxidant enzymes and salicylic acid 1 mM on relative water content and photosynthetic pigment content were more effective than other salicylic acid concentrations. Foliar application of jasmonic acid increased total fresh and dry weights also carotenoid content, but decreased total chlorophyll contents under stress conditions, in both places. Application of salicylic acid 0.1 mM + jasmonic acid increased total fresh and dry weights in any irrigation regimes, while this treatment increased carotenoid contents only under drought conditions in Ahvaz. Application of salicylic acid alone and with jasmonic acid significantly increased the alkaloid contents under severe drought stress. Salicylic acid improved C. roseus physiological performance and alkaloid contents, also it could be a way for periwinkle to alleviate the adverse effects of drought stress.

The Effect of Salicylic Acid on the Performances of Salt Stressed Strawberry Plants, Enzymes Activity, and Salt Tolerance Index

Article

Full-text available

Apr 2021

The influence of salicylic acid (SA) on growth, yield, fruits’ quality and enzymes’ activities was monitored in strawberry plants cv. Camarosa grown under salinity stress via two pot experiments in two successive years of 2018 and 2019. The examined concentrations of SA were 30, 60, and 90 ppm, which foliary applied in addition to control (sprayed with water), while the used levels of salinity were 20, and 40 mM as NaCl as irrigation application in addition to control (without salinity). The results showed a significant effect of salinity at 40 mM where the mean values of shoot fresh and dry weights, chlorophyll, leaves’ NPK, yield plant􀀀1, yield ha􀀀1, and fruits’ ascorbic acid were significantly decreased. However, the 40 mM salinity resulted in a significant increase in leaves’ content of Na and proline as well as catalase (CAT) and peroxidase (POD) enzymes’ activity and the fruits’ TSS and acidity. The application with 90 ppm SA was found to be the most significant positive treatment for all of the studied characters except the Na leaves’ content. Regarding tolerance index percentages (STI%), the high values of CAT, POD, and proline referred to the ability to use them as indicators for strawberry salinity response in other physiological and plant breeding studies. The findings of this study suggest that the 90 ppm SA foliar application can ameliorate the negative effect of salinity on the growth of strawberry cv. Camarosa.

Effects of Chitosan and Salicylic Acid on Physiological Characteristics of Eggplant (Solanum melongena)

Article

Full-text available

Feb 2021

Eggplant (Solanum melongena) falls under the fruit species under the family of Solanaceae. It is grown widely throughout tropical and subtropical Zones in the world. It is a good source of phenolics, flavonoids, vitamins, calcium and protein. Due to its high nutritional properties, the demand for eggplant is increasing annually. However, due to limited planting space, it is difficult for the producers to increase the production in order to meet the demand. Thus, the objective of this study is to improve the growth and development of selected physiological characteristics of eggplant with chitosan and salicylic acid. The experiment was carried out in factorial randomized complete block design (RCBD) with 4 replications. This experiment was conducted at Field 15, Universiti Putra Malaysia. The plants were treated with chitosan and salicylic acid at four different rates; 0, 2, 4 and 6 ml/L for chitosan and 0, 50, 100 and 150 mg/L for salicylic acid. The treatments were applied either alone or in combination. Results revealed that the application of chitosan combined with salicylic acid influenced the physiological characteristics of the eggplant compared to the control group. Combination of 4 ml/L chitosan with 150 mg/L salicylic acid gave the highest mean values of plant height (107.13 cm), number of branches (14.91), number of leaves (136.08), total number of flowers per plant (101.8), compared to other treatments. Therefore, due to cost effectiveness and better impact on physiological characteristics the combination of 4 ml/L chitosan and 150 mg/L salicylic acid as foliar fertilizer is recommended to improve the growth and development of eggplant. Keywords: Solanum melongena, chitosan, salicylic acid, physiology

The Effect of Priming on Germination Characteristics of Barley Seeds under Drought Stress Conditions

Article

Full-text available

Jun 2020

Seed priming methods have been used to increase germination and seedling establishment under different abiotic stress conditions. Seed priming was used in barley to increase seed germination and tolerance on stress exposure. Barley seeds were treated with various priming agents for different time and temperatures. The effect of priming was assessed on germination characteristics on subsequent exposure to drought (PEG-12 bar) stress for 7 days. Seed priming treatments significantly (p≤ 0.01) affected germination percentage (GP), normality seedling percentage (NSP), germination Index (GI), germination uniformity (GU), means time to germination (MTG), coefficient of velocity of germination (CVG), seedling vigor index (SVI) and coefficient of allometry (AC). Seed priming with gibberelic acid (GA), salicylic acid (SA), ascorbic acid (ASc), hydropriming (HP), osmopriming (OP) and combined treatments (CT) significantly (p≤ 0.01) increased germination characteristics, compared to the unprimed. Seed priming with concentrations 25, 50 ppm of GA for 15 h at 10°C, 25 ppm of SA for 12 h at 10°C, 50 ppm of ASc for 12 h at 15°C, treatment 16 h hydropriming at 10°C and -15 bar PEG for 24 h for osmopriming may be considered as optimal treatment for priming of barley seeds in drought stress conditions. In some cases, combined treatments are better than the separate treatments. Seed priming with PEG (potential -l5 bar PEG for 24 h at 10°C) was more effective in drought stress than the other treatments.

Components of the Phenylpropanoid Pathway in the Implementation of the Protective Effect of Sodium Nitroprusside on Wheat under Salinity

Article

Full-text available

May 2023

Nitric oxide (NO) is a multifunctional, gaseous signaling molecule implicated in both physiological and protective responses to biotic and abiotic stresses, including salinity. In this work, we studied the effects of 200 µM exogenous sodium nitroprusside (SNP, a donor of NO) on the components of the phenylpropanoid pathway, such as lignin and salicylic acid (SA), and its relationship with wheat seedling growth under normal and salinity (2% NaCl) conditions. It was established that exogenous SNP contributed to the accumulation of endogenous SA and increased the level of transcription of the pathogenesis-related protein 1 (PR1) gene. It was found that endogenous SA played an important role in the growth-stimulating effect of SNP, as evidenced by the growth parameters. In addition, under the influence of SNP, the activation of phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), and peroxidase (POD), an increase in the level of transcription of the TaPAL and TaPRX genes, and the acceleration of lignin accumulation in the cell walls of roots were revealed. Such an increase in the barrier properties of the cell walls during the period of preadaptation played an important role in protection against salinity stress. Salinity led to significant SA accumulation and lignin deposition in the roots, strong activation of TAL, PAL, and POD, and suppression of seedling growth. Pretreatment with SNP under salinity conditions resulted in additional lignification of the root cell walls, decreased stress-induced endogenous SA generation, and lower PAL, TAL, and POD activities in comparison to untreated stressed plants. Thus, the obtained data suggested that during pretreatment with SNP, phenylpropanoid metabolism was activated (i.e., lignin and SA), which contributed to reducing the negative effects of salinity stress, as evidenced by the improved plant growth parameters.

Evaluation of Spray Solution of Salicylic Acid and Water Stress on Medicinal Plant Verbascum songaricum

Article

Full-text available

Jan 2023

Since the exogenous application of salicylic acid can increase drought stress tolerance through improving metabolic pathways and increasing net photosynthesis, and in order to investigate the effect of salicylic acid application and drought stress on some morphological and physiological traits of Verbascum songaricum, an experiment was conducted in 2015 was carried out in the form of chopped plots in the form of a randomized complete block design in four replications under the conditions of the research farm of Azad University, Isfahan Branch. The present study was conducted with the aim of determining the effect of salicylic acid application at three control levels, 50 and 150 ppm, and water deficit stress at two levels of regular irrigation and water deficit stress (irrigation at the time of 50% soil crop capacity). Finally, root length, dry weight, number of secondary branches, number of leaves, number of flowers on the main stem, height of flowering stem, carotenoid, chlorophyll b, chlorophyll a antioxidant and anthocyanin were evaluated. The test results showed that stress had a reducing effect on growth and effective factors on performance. As a result of stress, the ratio of leaf area first decreased, but increased with increasing dryness. The initial decrease of this characteristic was due to the decrease in the leaf area, and its final increase due to the more severe decrease in the dry weight of the entire aerial organ compared to the leaf. The application of salicylic acid improved the morphological and physiological characteristics of Verbascum plant under the stress of low irrigation. While, the treatment of 50 ppm salicylic acid showed the greatest effect on most of the studied traits. As a result, the use of salicylic acid is recommended to improve the vegetative growth and increase the reproductive efficiency of the Verbascum songaricum plant and reduce production costs under stress conditions. In the present study, salicylic acid foliar application showed high efficiency in increasing the yield of Verbascum plant in Isfahan weather conditions.

Regulatory role of phytohormones in plant growth and development

Chapter

Jan 2023

GERMINATION PERFORMANCE OF PISTACHIO (PISTACIA VERA L.) UNDER SALCYLIC ACID AND SALT STRESS EFFECT EFFET DE L'ACIDE SALICYLIQUE SUR LA GERMINATION DE DEUX VARIETES DE PISTACIA VERA L. (BAYADHI AND ACHOURI)

Article

Full-text available

Dec 2022

Description of the subject: Salicylic acid (SA) is considered to be a potent plant hormone in preventing germination seeds in many plants. Objective: The present study was to compare the effect of different concentration of salicylic acid (SA) on the germination vigour and rooting ability of two varieties of Pistacia vera L. (Bayadhi and Achouri) subjected to salt stress. Methods: Seeds were pretreated with four concentrations of salicylic acid (0.25-0.5-0.75 and 1 mM), and then sprayed with H2O and NaCl solution. The untreated seeds were used as control. The following parameters were evaluated; germination speed, germination percent and radicle elongation. Results: The obtained results showed a reduction in germination parameters of the untreated seeds (control), especially in presence of 100 mM NaCl compared to 50 mM NaCl. However, the SA treated seeds performed better than the untreated seeds. Significant difference between the treatments effect on germination were observed at p≤0.05. The doses of 0.25 and 0.5mM SA had a positive effect on the speed, the rate of germination and the radical elongation than 0.75mM SA, even when seeds were sprayed with water or solution of NaCl. On the other hand, the dose of 1mM SA produced a significant reduction of germination and root elongation, in the presence or the absence of salt stress. Conclusion : It can be concluded that the lowest doses of salicylic acid increased significantly the germination performance compared to the highest doses depending on the dose used and the variety.. Résumé Description du sujet : L'acide salicylique est considéré comme étant une hormone essentielle qui est impliqué dans l'amélioration de la germination de plusieurs plantes. Objectifs : Cette présente étude a pour objectives de comparer l'effet de différentes concentrations de l'acide salicylique sur la germination et l'élongation d la radicule de deux variétés de Pistacia vera L. (Bayadhi et Achouri), soumises à l'eau distillé et un stress salin. Méthodes : Les graines des deux variétés ont été pré-traitées avec quatre doses d'acide salicylique (0,25-0,5-0,75 et 1 mM), puis arrosées avec H2Od soit une solution de NaCl. Les graines non traitées et arrosées avec H2O ont été utilisées comme témoins. La cinétique de germination et le taux final ont été évalués, ainsi que la longueur de la radicule. Résultats : Les résultats obtenues ont démontré une réduction de la germination des graines non traitées et soumises au stress salin, spécialement les raines arroses avec 100 Mm NaCl. Par contre, les graines traitées avec l'AS ont enregistré une bonne germination en comparaison avec celles non traitées. Des différences significatives de la germination ont été observes entre doses appliquées à p≤0,05. Les doses 0,25 et 0,5mM AS ont enregistrée un effet positif sur la vitesse et le taux de germination ainsi que la longueur de la radicule par rapport à 0,75mM AS, soit quand les raines ont été arrosées avec l'H2Od soit sous l'arrosage par 100 Mm NaCl. La dose la plus forte d'AS (1mM) a réduit significativement la germination et a donné les radicules les plus courts sous toutes les conditions de l'expérimentation. Conclusion : Suite à ces données, il a été constaté que les doses les plus faibles de l'acide salicylique ont augmenté considérablement les paramètres de la germination des deux variétés du pistachier. On peut suggérer que l'effet de l'acide salicylique dépend des doses appliquées et de la variété.

Mechanisms Underlying Root System Architecture and Gene Expression Pattern in Pearl Millet (Pennisetum glaucum)Der Wurzelsystemarchitektur und dem Genexpressionsmuster bei Perlhirse (Pennisetum glaucum) zugrunde liegende Mechanismen: Physiological Response to Simulated Drought ConditionsPhysiologische Reaktion auf simulierte Trockenheit

Article

Full-text available

May 2022
GESUNDE PFLANZ

Pearl millet could be considered a drought-tolerant crop, but the mechanisms modulating this tolerance are not extensively documented. Deciphering the physiological and molecular mechanisms underlying drought tolerance in pearl millet with regards to the root system will underpin precision in breeding. This study was conducted to unravel the mechanism of pearl millet adaptability to drought stress. A pot experiment was laid out in a 2 × 3 factorial arrangement in completely randomized design. The pearl millet variety IP14599 was exposed to three drought/control regimes: control and 25 and 50% relative water content (RWC). Rhizosheath, root system architecture (RSA) traits, gas exchange parameters, antioxidant enzymes, total soluble sugars, and gene expression profiling were evaluated at both seedling and vegetative growth stages after drought treatment. The results showed that at both growth stages, IP14599 plants had higher shoot/root dry weight, seminal roots, rhizosheath weight, and root hair length at 50% stress than those exposed to the 25% stress regime. Drought stress induced an increase in antioxidant enzymes, while the variety was better adapted at 50% drought stress and maintained higher photosynthetic efficiency compared to the control without drought stress. Four drought responsive genes (GBSS11a, FPS, ELIP, and RubSc) were identified and shown to play vital roles in the hardiness of pearl millet. The ability of the plant to adapt to drought stress conditions could be attributed to its superior rhizosheath and RSA during its growth stages. Therefore, the protocol used in this study could be reliable for evaluation of other cereal crops for their RSA characteristics and to validate the functions of drought-responsive genes in P. glaucum seedlings when subjected to drought stress.

The growth and seed yield of dill affected by foliar spray of salicylic acid

Conference Paper

Full-text available

Jan 2022

An experiment was conducted as a randomized complete block design with three replications at the research farm of the Faculty of Agriculture, University of Tabriz in 2019 to investigate the effects of salicylic acid foliar spray on growth and seed yield of dill (Anethum graveolens L.). Experimental treatments were foliar spraying of water and salicylic acid (SA1, SA2: 0.6 and 1.2 mM). Salicylic acid treatment increased the percentage of green cover, leaf water content, chlorophyll content, and seed yield of dill. Foliar application of salicylic acid at a concentration of 1.2 mM was identified as the best treatment for improving these traits.

Changes in growth and essential oil content of dill (Anethum graveolens) organs under drought stress in response to salicylic acid

Article

Full-text available

Jun 2021

Some of the harmful impacts of water shortage on crop performance may be alleviated by growth regulators such as salicylic acid. So, an experiment was arranged as a split-plot design based on randomized complete blocks in three replicates to assess changes in essential oil content of dill (Anethum graveolens L.) organs in response to water availability (water supply after 70, 100, 130, 160 mm evaporation as normal watering and mild, moderate and severe stresses, respectively), and salicylic acid (SA) levels (water spray and 0.6, 1.2 mM SA). Irrigation levels and salicylic acid treatments were assigned to the main and sub-plots, respectively. The results showed that chlorophyll a and especially chlorophyll b decreased with increasing drought stress. The ground green cover and plant organ masses (leaves and stem, flowers, and seeds) were only decreased under severe water deficit. Essential oil percentage of dill organs increased with increasing water deficit up to moderate stress, but thereafter it was decreased as water deficit severed. The highest essential oil yield of the vegetative parts and flowers was also produced in moderately stressed plants, but the greatest essential oil yield of seeds was recorded under mild water deficit. Exogenous salicylic acid enhanced the essential oil percentage of all dill organs, especially under moderate water limitation. The essential oil yield of dill organs was also increased by the salicylic acid treatment. The application of 1.2 mM salicylic acid was more effective in improving essential oil production of dill.

Phytohormone transporters during abiotic stress response

Chapter

Full-text available

Jun 2021

In the future, abiotic stress will be a chief danger with respect to fulfilling the needs of agricultural crops in terms of their production for feeding the world's population. Abiotic stress includes heat, cold, salinity, flooding, drought, UV radiation, and nutrient stress. These stresses are causing a huge effect on the production and productivity of agricultural crops leading to a reduction in average yields. Under abiotic stress conditions, crops decrease their growth and cause slower development. As a response to abiotic conditions, alterations in physiological, anatomical, morphological, and molecular parameters have been observed in plants. In accordance to this, phytohormones control signaling of such responses in abiotic stress conditions. Various sorts of phytohormones are known in plants (auxins, CKs, ethylene, gibberellins, brassinosteroids, jasmonates, and strigolactones), and many more are being investigated. Involvement of theses messengers in growth and development of crops are now gaining importance with respect to developing tolerant varieties for such conditions. Thus, this chapter focuses on various sorts of phytohormones and their functioning, transporters involved in abiotic stresses, and how they respond in such conditions to provide tolerance to crops.

Effect of salicylic acid priming on seed germination and morphophysiological and biochemical characteristics of tomato seedling (Lycopersicom esculentun)

Article

Full-text available

Sep 2020

DOR: 98.1000/2383-1251.1399.7.165.13.1.1575.41 Extended abstract Introduction: Seed germination is a complex and dynamic stage of plant growth, and seed priming is a technique by which the seeds obtain germination potential physiologically and biochemically before being placed on growth media and facing the ecological conditions of the environment. Seed priming increases yield and antioxidant enzymes in plants by increasing germination and seed vigor and as a result, increases percentage of germination. Several studies have investigated the effect of seed priming with organic materials including salicylic acid on improving seed germination in various plant species. Research results have shown that salicylic acid can be used as a growth regulator to increase the germination of plants. Tomato, with scientific name of Lycopersicon esculentum (Mill), belongs to the Solanaceae family and is widely adapted to different climatic and soil conditions. The aim of this study was to evaluate the effect of different concentrations of Salicylic acid on seed germination and some factors of morphophysiologic and biochemical traits of tomato seedlings. Materials and methods: This research was conducted as factorial in a completely randomized design, including priming treatment in 3 time frames (12, 18 and 24 hours) with three replications. Priming treatments consisted of salicylic acid (2, 2.5 and 3 mg/l) and distilled water. The measured traits were germination parameters including percentage, time, rate, and uniformity of germination and morphological traits including transplant height, crown diameter, root length, leaf number, and leaf area, shoot and root fresh and dry weight and biochemical traits including chlorophyll, peroxidase enzyme, proline, total nitrogen, potassium, calcium, phosphorus, and sodium. Results: The favorable effect of salicylic acid was obtained at the concentration of 3 mg/l on mean germination time compared to the distilled water. The positive effect of salicylic acid was observed on transplant height and leaf area (at the concentration of 3 mg/l at 18 and 24 hours’ time frame), shoot and root fresh and dry weight (at 24 hours) compared to the control. Immersion in distilled water for a period of 12 and 24 hours resulted in the highest root length, while salicylic acid treatment reduced root length significantly. The highest transplant height (14.3 cm), leaf number (34), chlorophyll index (59), peroxidase enzyme (10873 unit/g.min-1), total nitrogen (2.89%), potassium (9.81%), and proline content (14.80 µM/g fresh weight) were observed in 24 hours treatment with concentration of 3 mg / l salicylic acid. Conclusion: According to the results of this study, salicylic acid at certain concentration improves seeds germination of tomato plants through the regulation of physiologic and biochemical processes. It seems that salicylic acid led to increase in plant growth and improvement of seed germination and morphophysiological parameters of the tomato via affecting cell growth and division. Seed priming with salicylic acid at the concentration of 3 mg/l and in longer time frames had positive effect on most traits, whereas the results for each trait were different in relation to priming time. Highlights: 1-Priming of tomato seed in distilled water for 18 hours reduces the time of seed germination. 2-Salicylic acid can be used as an appropriate pretreatment for producing seedlings with better quantitative and qualitative characteristics by affecting the morpho-physiologic and biochemical properties of tomato seedlings.

THE EFFECT OF SHADING AND SPRAYING SALICYLIC ACID IN-RECIPES VEGETATIVEE GROWTH OFTHE TOMATO PLINT Lycopersicon esculentum Mill MANNER VERTICAI TRAINING METHOD

Article

Full-text available

Jun 2018

An experiment was done by design Complete Randomized sectors RCBD experiment carried out in the Dept. of Horticulture- Faculty of Agric., University of Diyala during Spring season 2015, to study the impact of global shading and spraying of Salicylic acid on some recipes vegetative growth of tomato crop. It included three shading levels (without shading 0% , 35% and 65%) and four concentrations of Salicylic acid (0 , 75, 150, 225 mg gm-1) splashed on the first two installments after month and the second two months after planting seedlings to study plant height, leaf area, stem diameter, number of leaves, and the percentage of dry matter. The differences between the averages was tested by a polynomial Duncan at 0.05 level of significance. The results showed that increasing shading treatment at level 65% caused a significant increase in plant height, while this treatment led to obtain a significant decrease in the average number of leaves and the average stem diameter per plant compared to shading 35% and 0%, while the treatment of shading level 35% caused moral superiority in leaf area and the percentage of dry matter. While spraying of Salicylic acid resulted a superiority of moral qualities of the plant and leaf area, the length and number of leaves and the percentage of dry matter in leaves. Treatments did not differ in the stem diameter. While there were significant differences between some overlap interactions in all traits.

تأثير التظليل والرش بحامض السالساليك في صفات النمو الخضري لنبات الطماطة بطريقة التربية العمودية

Article

Full-text available

Jun 2018

Role of superoxide dismutases (SODs) in controlling oxidative stress in plants

Article

Full-text available

May 2002
J EXP BOT

Ruth Grene

Reactive O2 species (ROS) are produced in both unstressed and stressed cells. Plants have well‐developed defence systems against ROS, involving both limiting the formation of ROS as well as instituting its removal. Under unstressed conditions, the formation and removal of O2 are in balance. However, the defence system, when presented with increased ROS formation under stress conditions, can be overwhelmed. Within a cell, the superoxide dismutases (SODs) constitute the first line of defence against ROS. Specialization of function among the SODs may be due to a combination of the influence of subcellular location of the enzyme and upstream sequences in the genomic sequence. The commonality of elements in the upstream sequences of Fe, Mn and Cu/Zn SODs suggests a relatively recent origin for those regulatory regions. The differences in the upstream regions of the three FeSOD genes suggest differing regulatory control which is borne out in the research literature. The finding that the upstream sequences of Mn and peroxisomal Cu/Zn SODs have three common elements suggests a common regulatory pathway. The tools are available to dissect further the molecular basis for antioxidant defence responses in plant cells. SODs are clearly among the most important of those defences, when coupled with the necessary downstream events for full detoxification of ROS.

Proline under Stress: Biological Role, Metabolism, and Regulation

Article

Full-text available

Mar 1999
RUSS J PLANT PHYSL+

Recent advances in the study of the numerous biological functions of stress-induced proline accumulation are reviewed in relation to the realization of plant adaptation, proline anabolic and catabolic transformations, and expression of the genes encoding the key enzymes of proline synthesis and degradation. A model of proline homeostasis under stress conditions is put forward to account for the existing physiological, biochemical, and molecular-biological evidence.

Salicylic acid induced physiological and biochemical changes in wheat seedlings under water stress

Article

Full-text available

Feb 2003

Salicylic acid (SA) is an important signal molecule modulating plantresponses to stress. It is recently reported to induce multiple stresstolerancein plants including drought. An experiment was, therefore, conducted toascertain the effect of salicylic acid on the growth and metabolic profile ofwheat seedlings under water stress. Irrespective of the SA concentration(1–3 mM) and water stress, SA treated plants showed, ingeneral, a higher moisture content, dry mass, carboxylase activity of Rubisco,superoxide dismutase (SOD) activity and total chlorophyll compared to those ofuntreated seedlings. SA treatment, under water stress, protected nitratereductase (NR) activity and maintained, especially at 3 mM SAconcentration, the protein and nitrogen content of leaves compared to watersufficient seedlings. Results signify the role of SA in regulating the droughtresponse of plants and suggest that SA could be used as a potential growthregulator, for improving plant growth under water stress.

Effects of salicylic acid and cold on freezing tolerance in winter wheat leaves

Article

Full-text available

Nov 2003

The effects of salicylic acid (SA) (0.01, 0.1 and 1 mM) and cold on freezing tolerance (freezing injury and ice nucleation activity) were investigated in winter wheat (Triticum aestivum cv. Dogu-88) grown under control (20/18 C for 15, 30 and 45-day) and cold (15/10 C for 15-day, 10/5 C for 30-day and 5/3 C for 45-day) conditions. Cold acclimatisation caused a decrease of injury to leaf segments removed from the plants and subjected to freezing conditions. Exogenous SA also decreased freezing injury in the leaves grown under cold (15/10 C) and control (15 and 30-day) conditions. Cold conditions (10/5 and 5/3 C) caused an increase in ice nucleation activity by apoplastic proteins, which were isolated from the leaves. For the first time, it was shown that exogenous SA caused an increase in ice nucleation activity under cold (15/10 and 10/5 C) and control conditions. These results show that salicylic acid can increase freezing tolerance in winter wheat leaves by affecting apoplastic proteins.

Roles of the reactive oxygen species-generating peroxidase reactions in plant defense and growth induction

Article

Full-text available

Jun 2003

Tomonori Kawano

Extracellularly secreted plant peroxidases (POXs) are considered to catalyze the generation of reactive oxygen species (ROS) coupled to oxidation of plant hormone indole-3-acetic acid (IAA) and defense-related compounds salicylic acid (SA), aromatic mono-amines (AMAs) and chitooligosaccharides (COSs). This review article consists of two parts, which describe H 2 O 2 -dependent and H 2 O 2 -independent mechanisms for ROS generation, respectively. Recent studies have shown that plant POXs oxidize SA, AMAs and COSs in the presence of H 2 O 2 via a conventional POX cycle, yielding the corresponding radical species, such as SA free radicals. These radical species may react with oxygen, and superoxide (O 2 ·) is produced. Through the series of reactions 2 moles of O 2 · can be formed from 1 moles of H 2 O 2 , thus leading to oxidative burst. It has been revealed that the ROS induced by SA, AMAs and COSs triggers the increase in cytosolic Ca 2+ concentration. Actually POXs transduce the extracellular signals into the redox signals that eventually stimulate the intracellular Ca 2+ signaling required for induction of defense responses. On the other hand, IAA can react with oxygen and plant POXs in the absence of H 2 O 2 , by forming the ternary complex enzyme-IAA-O 2 , which readily dissociates into enzyme, IAA radicals and O 2 · . This article covers the recent reports showing that extracellularly produced hydroxy radicals derived from O 2 · mediate the IAA-induced cell elongation. Here a novel model for IAA signaling pathway mediated by extracellular ROS pro-duced by cell-wall POXs is proposed. In addition, possible controls of the IAA-POX reactions by a fungal alkaloid are discussed. Keywords Indole-3-acetic acid · Plant defense mechanism · Plant peroxidase · Reactive oxygen species · Salicylic acid

Surface signaling in pathogenesis

Article

Full-text available

Jun 1995

Surface signaling plays a major role in fungal infection. Topographical features of the plant surface and chemicals on the surface can trigger germination of fungal spores and differentiation of the germ tubes into appressoria. Ethylene, the fruit-ripening hormone, triggers germination of conidia, branching of hyphae, and multiple appressoria formation in Colletotrichum, thus allowing fungi to time their infection to coincide with ripening of the host. Genes uniquely expressed during appressoria formation induced by topography and surface chemicals have been isolated. Disruption of some of them has been shown to decrease virulence on the hosts. Penetration of the cuticle by the fungus is assisted by fungal cutinase secreted at the penetration structure of the fungus. Disruption of cutinase gene in Fusarium solani pisi drastically decreased its virulence. Small amounts of cutinase carried by spores of virulent pathogens, upon contact with plant surface, release small amounts of cutin monomers that trigger cutinase gene expression. The promoter elements involved in this process in F. solani pisi were identified, and transcription factors that bind these elements were cloned. One of them, cutinase transcription factor 1, expressed in Escherichia coli, is phosphorylated. Several protein kinases from F. solani pisi were cloned. The kinase involved in phosphorylation of specific transcription factors and the precise role of phosphorylation in regulating cutinase gene transcription remain to be elucidated.

Antagonistic Effects of Abscisic Acid and Jasmonates on Salt Stress-Inducible Transcripts in Rice Roots

Article

Full-text available

Dec 1997

Abscisic acid (ABA) and jasmonates have been implicated in responses to water deficit and wounding. We compared the molecular and physiological effects of jasmonic acid (JA) (< or = 10 microM), ABA, and salt stress in roots of rice. JA markedly induced a cationic peroxidase, two novel 32- and 28-kD proteins, acidic PR-1 and PR-10 pathogenesis-related proteins, and the salt stress-responsive SalT protein in roots. Most JA-responsive proteins (JIPs) from roots also accumulated when plants were subjected to salt stress. None of the JIPs accumulated when plants were treated with ABA. JA did not induce an ABA-responsive group 3 late-embryogenesis abundant (LEA) protein. Salt stress and ABA but not JA induced oslea3 transcript accumulation. By contrast, JA, ABA, and salt stress induced transcript accumulation of salT and osdrr, which encodes a rice PR-10 protein. However, ABA also negatively affected salT transcript accumulation, whereas JA negatively affected ABA-induced oslea3 transcript levels. Endogenous root ABA and methyl jasmonate levels showed a differential increase with the dose and the duration of salt stress. The results indicate that ABA and jasmonates antagonistically regulated the expression of salt stress-inducible proteins associated with water deficit or defense responses.

Osmotic Stress Induces Rapid Activation of a Salicylic Acid-Induced Protein Kinase and a Homolog of Protein Kinase ASK1 in Tobacco Cells

Article

Full-text available

Feb 2000

In tobacco cells, osmotic stress induced the rapid activation of two protein kinases that phosphorylate myelin basic protein. Immunological studies demonstrated that the 48-kD kinase is the salicylic acid-induced protein kinase (SIPK), a member of the mitogen-activated protein kinase family. SIPK was activated 5 to 10 min after the cells were exposed to osmotic stresses, and its activity persisted for approximately 30 min. In contrast, the 42-kD kinase was activated within 1 min after osmotic stress, and its activity was maintained for approximately 2 hr. Moreover, in addition to myelin basic protein, the 42-kD kinase phosphorylated casein and two transcription factors, c-Jun and ATF-2. This latter enzyme was inactivated by a serine/threonine-specific phosphatase but, unlike SIPK, was not affected by a tyrosine-specific phosphatase. After the 42-kD kinase was purified to apparent homogeneity, tryptic peptide analysis indicated that it is a homolog of Arabidopsis serine/threonine kinase1 (ASK1).

Role of extracellular peroxidase in the superoxide production by wheat root cells

Article

Full-text available

Feb 2001

Extracellular peroxidase has been shown to contribute to superoxide production in wounded wheat (Triticum aestivum L. cv. Ljuba) root cells. The superoxide-synthesizing system of root cells was considerably inhibited by KCN and NaN3 and activated by MnCl2 and H2O2. Treatment of roots with salicylic acid and a range of di- and tri-carbonic acids (malic, citric, malonic, fumaric, and succinic acids) stimulated superoxide production in both root cells and extracellular solution. The H2O2-stimulated superoxide production in the extracellular solution was much higher when roots were preincubated with salicylic or succinic acid. Exogenous acids enhanced peroxidase activity in the extracellular solution. Pretreatment of root cells with the detergents trypsin and sodium dodecyl sulfate had similar effects on the peroxidase activity. Significant inhibition of both superoxide production and peroxidase activity by diphenylene iodonium suggests that the specificity of the latter as an inhibitor of NADPH oxidase is doubtful. Results obtained indicate that extra-cellular peroxidase is involved in the superoxide production in wheat root cells. The mobile form of peroxidase can be readily secreted to the apoplastic solution and serve as an emergency enzyme involved in plant wound response.

Role of superoxide dismutases (SODs) in controlling oxidative stress in plants

Article

Full-text available

Jun 2002

Reactive O(2) species (ROS) are produced in both unstressed and stressed cells. Plants have well-developed defence systems against ROS, involving both limiting the formation of ROS as well as instituting its removal. Under unstressed conditions, the formation and removal of O(2) are in balance. However, the defence system, when presented with increased ROS formation under stress conditions, can be overwhelmed. Within a cell, the superoxide dismutases (SODs) constitute the first line of defence against ROS. Specialization of function among the SODs may be due to a combination of the influence of subcellular location of the enzyme and upstream sequences in the genomic sequence. The commonality of elements in the upstream sequences of Fe, Mn and Cu/Zn SODs suggests a relatively recent origin for those regulatory regions. The differences in the upstream regions of the three FeSOD genes suggest differing regulatory control which is borne out in the research literature. The finding that the upstream sequences of Mn and peroxisomal Cu/Zn SODs have three common elements suggests a common regulatory pathway. The tools are available to dissect further the molecular basis for antioxidant defence responses in plant cells. SODs are clearly among the most important of those defences, when coupled with the necessary downstream events for full detoxification of ROS.

Stress-Induced Phenylpropanoid Metabolism

Article

Full-text available

Aug 1995
PLANT CELL

Coordinate Gene Activity in Response to Agents That Induce Systemic Acquired Resistance

Article

Full-text available

Nov 1991
PLANT CELL

In a variety of plant species, the development of necrotic lesions in response to pathogen infection leads to induction of generalized disease resistance in uninfected tissues. A well-studied example of this "immunity" reaction is systemic acquired resistance (SAR) in tobacco. SAR is characterized by the development of a disease-resistant state in plants that have reacted hypersensitively to previous infection by tobacco mosaic virus. Here, we show that the onset of SAR correlates with the coordinate induction of nine classes of mRNAs. Salicylic acid, a candidate for the endogenous signal that activates the resistant state, induces expression of the same "SAR genes." A novel synthetic immunization compound, methyl-2,6-dichloroisonicotinic acid, also induces both resistance and SAR gene expression. These observations are consistent with the hypothesis that induced resistance results at least partially from coordinate expression of these SAR genes. A model is presented that ties pathogen-induced necrosis to the biosynthesis of salicylic acid and the induction of SAR.

Water stress-induced abscisic acid accumulation triggers the increased generation of reactive oxygen species and up-regulates the activities of antioxidant enzymes in maize leaves

Article

Full-text available

Jan 2003

The interrelationship among water-stress-induced abscisic acid (ABA) accumulation, the generation of reactive oxygen species (ROS), and the activities of several antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) was investigated in leaves of detached maize (Zea mays L.) plants exposed to -0.7 MPa water stress induced by polyethylene glycol (PEG 6000). Time-course analyses of ABA content, the production of ROS, and the activities of antioxidant enzymes in water-stressed leaves showed that a significant increase in the content of ABA preceded that of ROS, which was followed by a marked increase in the activities of these antioxidant enzymes. Pretreatment with an ABA biosynthesis inhibitor, tungstate, significantly suppressed the accumulation of ABA, and also reduced the increased generation of ROS and the up-regulation of these antioxidant enzymes in water-stressed leaves. A mild oxidative stress induced by paraquat, which generates O(2)(-) and then H(2)O(2), resulted in a significant enhancement in the activities of antioxidant enzymes in non-water-stressed leaves. Pretreatment with some ROS scavengers, such as Tiron and dimethylthiourea (DMTU), and an inhibitor of NAD(P)H oxidase, diphenyleneiodonium (DPI), almost completely arrested the increase in ROS and the activities of these antioxidant enzymes induced by water stress or ABA treatment. These data suggest that water stress-induced ABA accumulation triggers the increased generation of ROS, which, in turn, leads to the up-regulation of the antioxidant defence system.

Superoxide synthase and dismutase activity of plasma membranes from maize roots

Article

Full-text available

Jun 2003

Superoxide synthase and superoxide dismutase activity have been monitored in isolated maize ( Zea mays) root plasma membranes spectrophotometrically by determination of nitro-blue tetrazolium and cytochrome c reduction, respectively. Superoxide production was induced by NADH and NADPH, with similar kinetics and approaching saturation at 0.06 mM in the case of NADPH and 0.1 mM in the case of NADH, with rates of 18.6 +/- 5.0 and 21.8 +/- 7.2 nmol/min. mg of protein, respectively. These activities exhibited a broad pH optimum between pH 6.5 and 7.5. Diphenylene iodonium inhibited about 25% (10 microM DPI) and 40% (100 microM DPI) of this activity, imidazole inhibited about 20%, while KCN, a peroxidase inhibitor, did not show any significant inhibition. Superoxide-dismutating activity was shown to occur in the same isolates and depended on the quantity of plasma membrane protein present. Growth of plants on salicylic acid prior to membrane isolation induced a rise in the activity of both of the enzymes by 20-35%, suggesting their coordinated action.

Salinity up-regulates the antioxidative system in root mitochondria and peroxisomes of the wild salt-tolerant tomato species Lycopersicon pennellii

Article

Full-text available

Jun 2004

The effect of salinity on the antioxidative system of root mitochondria and peroxisomes of a cultivated tomato Lycopersicon esculentum (Lem) and its wild salt‐tolerant related species L. pennellii (Lpa) was studied. Salt stress induced oxidative stress in Lem mitochondria, as indicated by the increased levels of lipid peroxidation and H2O2. These changes were associated with decreased activities of superoxide dismutase (SOD) and guaiacol peroxidases (POD) and contents of ascorbate (ASC) and glutathione (GSH). By contrast, in mitochondria of salt‐treated Lpa plants both H2O2 and lipid peroxidation levels decreased while the levels of ASC and GSH and activities of SOD, several isoforms of ascorbate peroxidase (APX), and POD increased. Similarly to mitochondria, peroxisomes isolated from roots of salt‐treated Lpa plants exhibited also decreased levels of lipid peroxidation and H2O2 and increased SOD, ascorbate peroxidase (APX), and catalase (CAT) activities. In spite of the fact that salt stress decreased activities of antioxidant enzymes in Lem peroxisome, oxidative stress was not evident in these organelles.

Effect of salicylic acid and (2′-5′)-oligoadenylates on protein synthesis in tobacco leaves under heat shock conditions: A comparative study

Article

Jan 1999
RUSS J PLANT PHYSL+

Antiviral agents, salicylic acid (SA, 10 -4 M) and (2′-5′)-oligoadenylates ((2-5)A, 10 -9 M), affected the protein synthetic machinery in tobacco (Nicotiana tabacum L., cv. Samsun NN) leaves. They activated protein synthesis, changed the pattern of synthesized proteins, and improved the thermotolerance of protein synthesis. SA and (2-5)A most prominently enhanced the synthesis of the following polypeptides: 109, 90, 65, 36, and 20-14 kD. They changed the composition of protein isoforms, possibly through protein modification. On two-dimensional elecrophoregrams, a 90-kD polypeptide, induced by these compounds, coincided with a heat-shock protein of 90 kD. Several low-molecular-weight proteins might be classified as pathogenesis-related proteins. The effect of salicylic acid on reprogramming tobacco leaf genome was inferior to that of (2-5)A.

The role of hormonal changes in protective action of salicylic acid on growth of wheat seedlings under water deficit

Article

Jan 2001

The role of Cucumis sativum L leaves and content of phytohormones under soil drought

Article

Jan 1993

Induction of wheat resistance against environmental salinization by indolylacetic acid

Article

Jan 1997

The effects of exogenous treatment of wheat (Triticum aestivum) seeds or seedlings with salicylic acid (SA) on the rate of germination and the ratio of indolylacetic acid (IAA) to abscisic acid (ABA), as well as on the lectin level in the roots of 4-day wheat seedlings during salt stress were studied. SA at 0.1 mM increased the rate of seed germination at various degrees of medium salinization (0.5-1.5% NaCl). Pretreatment of the seedling with SA led to marked accumulation of ABA in the roots of the seedlings, which, however, did not inhibit growth processes due, apparently, to the stimulating effect of SA on the IAA level. SA induced a twofold accumulation of lectin in the roots of 4-day wheat seedlings and fully relieved the salt stress (2% NaCl)-induced decrease of the IAA level and lectin accumulation and reduced the salinization-induced sharp increase of the ABA content in the roots of the seedlings. The data suggest a protective effect of SA on wheat plants during salt stress.

Are Plant Hormones Involved in Root to Shoot Communication?

Chapter

Dec 1993
ADV BOT RES

Michael B Jackson

Publisher Summary This chapter explains the growth and behavior pattern of roots and shoots And discusses the generation of hormone like messages due to environmental changes in detail. Hormonal messages are recycled between roots and shoots. Roots import hormones and shoots acts as active hormone sinks. Various techniques to measure hormone levels and activities are described, the primary being the samples taken from the sap. Hormone traffic between roots and shoots forms the basis for the morphological and functional control that roots can exert on shoots. Regulation of root: shoot ratio by roots with mineral supply is explained in detail. Hormone like action on roots is responsible for regulation of protein levels in leaves and flowering in plants. The influence of hormone like messages by roots for development of shoots is presented. The influence of plant hormones cytokinins, gibberellins, abscisic acid, auxin and ethylene are explained. Cytokinins are main source of hormones in plants. They are carried by transpiration from the root tips present on a root system to recipient shoot tissues. Gibberellins are important in delaying leaf senescence. The output of gibberellins under stress is discussed. Abscisic acid is an important regulator of stomatal closure. Ethylene–mediated responses in the shoot are explained.

Isolation, Chromosomal Localization, and Differential Expression of Mitochondrial Manganese Superoxide Dismutase and Chloroplastic Copper/Zinc Superoxide Dismutase Genes in Wheat

Article

Jun 1999

Guohai Wu

Superoxide dismutase (SOD) gene expression was investigated to elucidate its role in drought and freezing tolerance in spring and winter wheat (Triticum aestivum). cDNAs encoding chloroplastic Cu/ZnSODs and mitochondrial MnSODs were isolated from wheat. MnSOD and Cu/ZnSOD genes were mapped to the long arms of the homologous group-2 and -7 chromosomes, respectively. Northern blots indicated that MnSOD genes were drought inducible and decreased after rehydration. In contrast, Cu/ZnSOD mRNA was not drought inducible but increased after rehydration. In both spring and winter wheat seedlings exposed to 2°C, MnSOD transcripts attained maximum levels between 7 and 49 d. Transcripts of Cu/ZnSOD mRNA were detected sooner in winter than in spring wheat; however, they disappeared after 21 d of acclimation. Transcripts of both classes of SOD genes increased during natural acclimation in both spring and winter types. Exposure of fully hardened plants to three nonlethal freeze-thaw cycles resulted in Cu/Zn mRNA accumulation; however, MnSOD mRNA levels declined in spring wheat but remained unchanged in winter wheat. The results of the dehydration and freeze-thaw-cycle experiments suggest that winter wheat has evolved a more effective stress-repair mechanism than spring wheat.

Osmotic Stress Induces Rapid Activation of a Salicylic Acid-Induced Protein Kinase and a Homolog of Protein Kinase ASK1 in Tobacco Cells

Article

Jan 2000
PLANT CELL

Monika Mikołajczyk

In tobacco cells, osmotic stress induced the rapid activation of two protein kinases that phosphorylate myelin basic protein. Immunological studies demonstrated that the 48-kD kinase is the salicylic acid–induced protein kinase (SIPK), a member of the mitogen-activated protein kinase family. SIPK was activated 5 to 10 min after the cells were exposed to osmotic stresses, and its activity persisted for ∼30 min. In contrast, the 42-kD kinase was activated within 1 min after osmotic stress, and its activity was maintained for ∼2 hr. Moreover, in addition to myelin basic protein, the 42-kD kinase phosphorylated casein and two transcription factors, c-Jun and ATF-2. This latter enzyme was inactivated by a serine/threonine–specific phosphatase but, unlike SIPK, was not affected by a tyrosine-specific phosphatase. After the 42-kD kinase was purified to apparent homogeneity, tryptic peptide analysis indicated that it is a homolog of Arabidopsis serine/threonine kinase1 (ASK1).

Hormonal Changes in Developing Kernels of two Spring Wheat Varieties Differing in Storage Capacity

Article

Oct 1984
PLANT BIOLOGY

PARTICIPATION OF SALICYLIC-ACID IN GRAVITROPISM IN PLANTS

Article

Jan 1991
Dokl Akad Nauk SSSR

Histochemical Detection and Role of Phenolic Compounds in the Defense Response of Lactuca spp. to Lettuce Downy Mildew (Bremia lactucae)

Article

Dec 2001

The occurrence of phenolic compounds (PC) in the defence reaction of Lactuca spp. was detected by histochemical methods. Four staining methods, including three for light and one for fluorescence microscopy, were used for imaging the location of PC in cells of genotypes with different resistance mechanisms after infection by Bremia lactucae, race NL16. The results showed that the major role of phenolic compounds in studied Lactuca spp. is connected with their overexpression and localized accumulation during a hypersensitive response (HR). In incompatible interactions a slight accumulation of phenols near the cell wall of infected cells was detected. The negative reaction to staining with aniline sulphate verified the absence of lignin creation. In both compatible and incompatible interactions structural modifications in the host cells occurred as a callose deposition. Frequently, these deposits were widespread in susceptible genotypes. Intensive and rapid accumulation of autofluorescent phenolics was linked with the onset of HR, the main cytological feature of resistance to lettuce downy mildew in Lactuca spp.

Pathways to abscisic acid-regulated gene expression

Article

CHRISTOPHER D. R OCK

375 summary Recent progress in ABA signalling is summarized from the perspectives gained by genetic (mutant) analysis, 'reverse genetics' (starting from unknown ABA-inducible sequences and working backwards) and biochemical studies. What emerges is a cell-biological model of overlapping tissue-specific stress (e.g. drought, salt and cold) and developmental (e.g. sugars and other hormones) response pathways that integrate into responses mediated by ABA, including but not limited to seed maturation, dormancy, inhibition of cell division and germination, stomatal closure and changes in gene expression leading to stress adaptation. ABA signalling involves putative ABA receptors (extracellular or intracellular), cell-surface membrane proteins including ion channels, glycoproteins and membrane tracking components, secondary messengers such as phosphatidic acid, inositol 1,4,5-trisphosphate, cyclic ADP-ribose and calcium, and protein phosphorylation}dephosphorylation cascades leading to chromatin remodelling and binding of transcriptional complexes to ABA-responsive promoter elements. The large gaps in our understanding of complex regulatory networks such as ABA signalling can be best addressed by multidisciplinary, integrated approaches such as those discussed.

Role of Salicylic Acid in Plants

Article

Nov 2003
Annu Rev Plant Physiol Plant Mol Biol

Ilya Raskin

ABA-induced proline accumulation in barley leaf segments: Dependence on protein synthesis

Article

Nov 1987
PHYSIOL PLANTARUM

Pierantonio Pesci

The kinetics of proline accumulation in barley (Hordeum vulgare L. cv. Georgie) leaf segments showed a lag phase of ca 3 h when the increase was induced by abscisic acid (ABA), but not when the accumulation of the imino acid was promoted by isobutyric acid (IBA). Cycloheximide (CHI) supplied together with ABA, either from the beginning of the treatment or some time before the end of the lag phase, completely abolished ABA-induced proline accumulation, whereas no block was observed when the inhibitor was supplied after the lag phase. Cordycepin (COR) exibited a similar effect. The IBA-induced increase in proline was not influenced by CHI for at least 5 h. When segments were pretreated with ABA for a period longer than the lag phase in the absence of salts in the external medium, there was no significant increase in proline. If KCI was added to the incubation medium after such a pretreatment, however, proline increased even after removal of the hormone from the external medium. This increase in proline occurred without any lag phase, and was only partially inbibited by CHI and rapidly and totally blocked by fusicoccin (FC). These results suggest that some protein, characterized by a fast turnover and possibly conferring the sensitivity to KCI, is synthesized during the early hours (lag phase) of the ABA treatment. The synthesis of this protein(s) does not seem to be involved in the increase in proline induced by IBA and is thus a peculiar aspect of that mediated by ABA.

Dehydrins: Emergence of a biochemical role of a family of plant dehydration proteins

Article

Aug 1996
PHYSIOL PLANTARUM

Timothy Close

A number of proteins have been identified that typically accumulate in plants in response to any environmental stimulus that has a dehydrative component or is temporally associated with dehydration. This includes drought, low temperature, salinity and seed maturation. Among the induced proteins, dehydrins (late embryogenesis abundant [LEA] D-II family) have been the most commonly observed, yet we still have an incomplete knowledge of their fundamental biochemical role in the cell. Current research trends are changing this situation: immunolocalization and in vitro biochemical analyses are, through analogies to other more fully characterized proteins and molecules, shaping our understanding. In brief, dehydrins may be structure stabilizers with detergent and chaperone-like properties and an array of nuclear and cytoplasmic targets. Recent progress on the mapping of dhn genes and the inheritance of freezing tolerance in barley and other Triticeae species tentatively points to dehydrins as key components of dehydration tolerance.

Tansley Review No. 120

Article

Jun 2002
NEW PHYTOL

Chris Rock

Recent progress in ABA signalling is summarized from the perspectives gained by genetic (mutant) analysis, ‘reverse genetics’ (starting from unknown ABA‐inducible sequences and working backwards) and biochemical studies. What emerges is a cell‐biological model of overlapping tissue‐specific stress (e.g. drought, salt and cold) and developmental (e.g. sugars and other hormones) response pathways that integrate into responses mediated by ABA, including but not limited to seed maturation, dormancy, inhibition of cell division and germination, stomatal closure and changes in gene expression leading to stress adaptation. ABA signalling involves putative ABA receptors (extracellular or intracellular), cell‐surface membrane proteins including ion channels, glycoproteins and membrane trafficking components, secondary messengers such as phosphatidic acid, inositol 1,4,5‐trisphosphate, cyclic ADP‐ribose and calcium, and protein phosphorylation/dephosphorylation cascades leading to chromatin remodelling and binding of transcriptional complexes to ABA‐responsive promoter elements. The large gaps in our understanding of complex regulatory networks such as ABA signalling can be best addressed by multidisciplinary, integrated approaches such as those discussed. Contents Summary I. INTRODUCTION 358 II. GENETIC ANALYSIS OF ABA RESPONSES 359 III. ‘REVERSE GENETIC’ ANALYSIS OF ABA‐REGULATED GENE EXPRESSION 371 IV. BIOCHEMICAL AND CELLULAR ANALYSES OF ABA SIGNALLING 378 V. CONCLUSIONS AND PERSPECTIVES 387 Acknowledgements 387 References 387

Salicylic Acid Influences Net Photosynthetic Rate, Carboxylation Efficiency, Nitrate Reductase Activity, and Seed Yield in Brassica juncea

Article

Jun 2003

Aqueous solutions of salicylic acid (SA) were applied to the foliage of 30-d-old plants of mustard (Brassica juncea Czern & Coss cv. Varuna). The plants sprayed with the lowest used concentration (10−5 M) of SA were healthier than those sprayed with water only or with higher concentrations of SA (10−4 or 10−3 M). 60-d-old plants possessed 8.4, 9.8, 9.3, 13.0 and 18.5 % larger dry mass, net photosynthetic rate, carboxylation efficiency, and activities of nitrate reductase and carbonic anhydrase over the control, respectively. Moreover, the number of pods and the seed yield increased by 13.7 and 8.4 % over the control.

Acetyl salicylic acid (Aspirin) and salicylic acid induce multiple stress tolerance in bean and tomato plants

Article

Feb 2000

The hypothesis that physiologically activeconcentrations of salicylic acid (SA) and itsderivatives can confer stress tolerance in plants wasevaluated using bean (Phaseolus vulgaris L.) andtomato (Lycopersicon esculentum L.). Plantsgrown from seeds imbibed in aqueous solutions (0.1--0.5 mM) of salicylic acid or acetyl salicylic acid(ASA) displayed enhanced tolerance to heat, chillingand drought stresses. Seedlings acquired similarstress tolerance when SA or ASA treatments wereapplied as soil drenches. The fact that seedimbibition with SA or ASA confers stress tolerance inplants is more consistent with a signaling role ofthese molecules, leading to the expression oftolerance rather than a direct effect. Induction ofmultiple stress tolerance in plants by exogenousapplication of SA and its derivatives may have asignificant practical application in agriculture,horticulture and forestry.

Effects of Salicylic Acid on Heavy Metal-Induced Membrane Deterioration Mediated by Lipoxygenase in Rice

Article

Nov 1999

Deterioration of membranes caused by lipoxygenase (LOX) activity under 10 µM PbCl2 or 10 µM HgCl2 was partially alleviated by the exogenous application of 100 µM salicylic acid (SA). In two cultivars of rice (Oryza sativa L. cvs. Ratna and IR 36), the presence of SA ameliorated the increased leakage of electrolytes, injury index, and the content of malondialdehyde caused by these heavy metals. Lead decreased H2O2 content whereas Hg increased it in both cultivars. Application of SA increased H2O2 in presence of Pb, while decreased it in presence of Hg. Both Pb and Hg decreased superoxide dismutase activity, while increased peroxidase activity. The activity of catalase was decreased by Hg but increased by Pb and SA reversed their effects. Thus, SA ameliorated the damaging effects of Pb and Hg on membranes.

Hydroponic treatment with salicylic acid decreases the effects of chilling injury in maize (Zea mays L.) plants

Article

Apr 1999

The addition of 0.5 mM salicylic acid (SA) to the hydroponic growth solution of young maize (Zea mays L.) plants under normal growth conditions provided protection against subsequent low-temperature stress. This observation was confirmed by chlorophyll fluorescence parameters and electrolyte leakage measurements. In addition, 1 d of 0.5 mM SA pre-treatment decreased net photosynthesis, stomatal conductivity and transpiration at the growth temperature (22/20 °C). Since there was only a slight decrease in the ratio of variable to maximal fluorescence (Fv/Fm) the decrease in photosynthetic activity is not due to a depression in photosystem II. The analysis of antioxidant enzymes showed that whereas SA treatment did not cause any change in ascorbate peroxidase (EC 1.11.1.11) and superoxide dismutase (EC 1.15.1.1) activities, there was a decrease in catalase (EC 1.11.1.6) activity, and an increase in guaiacol peroxidase (EC 1.11.1.7) and glutathione reductase (EC 1.6.4.2) activities after the 1-d SA treatment at 22/20 °C. In native polyacrylamide gels there was, among the peroxidase isoenzymes, a band which could be seen only in SA-treated plants. It is suggested that the pre-treatment of maize plants with SA at normal growth temperature may induce antioxidant enzymes which lead to increased chilling tolerance.

Seed germination and dormancy

Article

Jan 1997

J D Bewley

Changes in the hormonal status of wheat seedlings induced by salicylic acid and salinity

Article

Mar 2003
PLANT SCI

The treatment of wheat plants with 0.05 mM salicylic acid (SA) increased the level of cell division within the apical meristem of seedling roots causing an increase in plant growth and an elevated wheat productivity. It was found that SA treatment caused accumulation of both abscisic acid (ABA) and indoleacetic acid (IAA) in the wheat seedlings but did not influence cytokinin content. SA treatment reduced the damaging action of salinity on seedling growth and accelerated reparation of the growth processes. SA-treatment diminished changes in phytohormones levels in wheat seedlings under salinity. It prevented any decrease in IAA and cytokinin contents and thus reduced stress-induced inhibition of plant growth. A high ABA level was also maintained in SA-treated wheat seedlings providing the development of antistress reactions, for example, maintenance of proline accumulation. Thus SA's protective action includes the development of antistress programs and acceleration of growth processes recovery after the removal of stress factors.

Delayed ripening of banana fruit by salicylic acid

Article

Oct 2000

Salicylic acid treatment has been found to delay the ripening of banana fruits (Musa acuminata). Fruit softening, pulp:peel ratio, reducing sugar content, invertase and respiration rate have been found to decrease in salicylic acid treated fruits as compared with control ones. The activities of major cell wall degrading enzymes, viz. cellulase, polygalacturonase and xylanase were found to be decreased in presence of salicylic acid. The major enzymatic antioxidants namely, catalase and peroxidase, were also found to be decreased in presence of salicylic acid during banana fruit ripening.

Induction of expression of the dehydrin gene TADHN and accumulation of abscisic acid in wheat plants in hypothermia

Article

Apr 2005

A whole complex of defensive mechanisms has developed in plants in the course of evolution. It is aimed at adaptation to changing germination conditions (in particular, fluctuations in ambient gas temperature), related to the expression of a number of genes encoding the so-called stress pr

Role of Hormonal System in the Manifestation of Growth Promoting and Antistress Action of Salicylic Acid

Abstract

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