Silicon Mediated Approach in Enhancing Water Stress Tolerance of Alternanthera Sissoo
Abstract and Figures
Water stress causes various plant morphological, physiological, and biochemical responses. Silicon application may reduce the water stress tolerance in plants by increasing the physiology parameters and the crop’s vegetative growth. Hence, the study aims to evaluate the effect of water stress levels on Alternanthera sissoo, known as Brazilian spinach, and determine which silicon (Si) level is the best under water scarcity. The method implied measuring the water stress by different levels of water level applied to the plant which are 100 % (well-watered), 75 % (moderate water deficit), 50 % (high water deficit), and 25 % (severe water deficit). The variation of silicon concentrations is S0 (control), S1, S2 and S3 (0, 0.6, 0.9 and 1.2 %v/v) arranged in the Randomized Complete Block Design (RCBD) in the greenhouse. Growth, physiological, and biochemical parameters were analyzed during the experiment. The research findings showed that water stress results were statistically reduce the leaf area, leaf number root length, fresh weight, chlorophyll content, relative water content (RWC), and malondialdehyde (MDA). The root length, leaf area, and malondialdehyde (MDA) show the interaction between water stress level and silicon concentration. The study proposed that the Si nutrient management strategy has the potential to minimize the impacts of drought stress in Brazilian spinach. Regarding research findings, it was determined that the optimal water requirement for Alternanthera sissoo is 50 % of the water treatments, with a silicon concentration of 1.2 %v/v. This is essential for better water management of the plant. HIGHLIGHTS Water stress affects Alternanthera sissoo’s growth, physiological, and biochemical properties For water saving, 50 % of water is enough for optimum Alternanthera sissoo growth Silicon fertilizers alleviate the water stress effect in Alternanthera sissoo effectively Silicon fertilizers offers a water saving solution to drought stress impact in climate change, urging further exploration GRAPHICAL ABSTRACT
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This study examines the combined effects of nano-silica (Nano-Si), plant growth-promoting rhizobacteria (PGPR), and Azotobacter chroococcum (AZ) biofertilizers on growth, physiological performance, and essential oil (EO) yield and composition in Satureja montana, a medicinal plant valued for its aromatic properties. Field experiments were conducted using a Completely Randomized Design (CRD) with three replicates over two growing seasons (2022 and 2023). Treatments included individual applications of Nano-Si, PGPR, and AZ, as well as a combined PGPR + AZ treatment, with a control group for comparison. The combined PGPR + AZ treatment significantly increased flowering branch count (10.5), plant height (44.6 cm), and leaf number (115), compared to other treatments and the control. Nano-Si treatment alone achieved the highest biomass, with shoot, leaf, and root dry weights reaching 115 g, 30.3 g, and 16 g, respectively, in 2023, demonstrating its role in enhancing plant growth. Chlorophyll content was also highest in Nano-Si treatments (58.5 SPAD units in 2022 and 55.3 in 2023). Additionally, both Nano-Si and PGPR + AZ treatments elevated photosynthesis rates (7.02 µmol CO₂ m⁻² s⁻¹ in 2022 and 7.83 µmol CO₂ m⁻² s⁻¹ in 2023). Nano-Si further improved water use efficiency, mesophyll efficiency, and quantum yield, contributing to overall better physiological performance under potentially stressful conditions. In terms of EO production, Nano-Si and PGPR + AZ yielded the highest outputs, reaching 51.16 g and 52.2 g in 2022 and 2023, respectively. GC-MS analysis showed that carvacrol (42.2%), γ-terpinene (22.3%), and p-cymene (12.2%) were the primary EO components, with concentrations positively influenced by Nano-Si and PGPR + AZ treatments. These findings demonstrate that combining nanotechnology with biofertilizers can optimize growth, physiological function, and secondary metabolite production in S. montana. This study provides valuable insights for sustainable cultivation practices that enhance the productivity and quality of medicinal and aromatic plants.
The rising popularity of the Sissoo spinach is growing in the vegetable industry along with the increase in its demand. However, water stress conditions may affect the plants' growth, physiology, and water status. Hence, the research study aims to evaluate Sissoo spinach's growth, physiological parameters, and water status once subjected to water deficit. Besides, it also focuses on determining the optimum water requirement for Sissoo spinach. There were four different water treatments consisting of 100% (well-watered), 75% (moderate water deficit), 50% (high water deficit), and 25% (severe water deficit) water treatments arranged in Randomized Complete Block Design (RCBD) with five replications in the greenhouse. The research findings show that the results are statistically significant for most parameters: plant height, number of leaves, chlorophyll content, stomatal conductances, plant water status, and chlorophyll fluorescence. Contrarily, the stem diameter, fresh weight, dry weight, and leaf area data do not show any significant differences. As it comes to the point of research findings, the optimum water requirement for Sissoo spinach was 50% water treatment. This is crucial to prevent unnecessary, avoidable water application onto plants.
The use of household waste in the form of rice washing water, pineapple skin waste, and leftover rice as liquid organic fertilizer (LOF) has the potential to create a good growing medium so as to increase plant growth. Brazilian Spinach (Alternanthera sissoo) is a leafy vegetable that has the potential to diversify vegetable consumption in urban areas where it is expected to grow well in tight spaces, particularly under shading. This study aimed to find out the effects of applying liquid organic fertilizer made of household waste and the shading on the growth of the Brazilian spinach plant. The study used a split plot design with a main plot consisted of 0%, 50% and 70% shading, while subplot consisted of LOF washing water (20 ml/l), pineapple peel waste (30 ml/l) and leftover rice (50ml/l). Each treatment was repeated 3 (three) times. The results of the study showed that the SPAD value of Brazilian spinach under shading treatment and LOF treatment of rice washing water linearly continued to increase until 8 (eight) weeks after planting. Regarding the vegetative growth of Brazilian spinach, the 0% shading treatment was the best treatment in terms of increasing the non-edible leaf fresh weight and root dry weight. Meanwhile, the LOF had an insignificant effect on all treatments. In conclusion, Brazilian spinach can grow more optimally in no-shade conditions.
Powdery mildew, caused by Sphaerotheca fuliginea (Schlecht.) Poll., and melon aphids (Aphis gossypii Glover) are a typical disease and insect pest, respectively, that affect cucumber production. Powdery mildew and melon aphid often occur together in greenhouse production, resulting in a reduction in cucumber yield. At present there are no reports on the physiological and biochemical effects of the combined disease and pest infection/infestation on cucumber. This study explored how cucumbers can regulate photosynthesis, protective enzyme activity, and basic metabolism to resist the fungal disease and aphids. After powdery mildew infection, the chlorophyll and free proline contents in cucumber leaves decreased, while the activities of POD (peroxidase) and SOD (superoxide dismutase) and the soluble protein and MDA (malondialdehyde) contents increased. Cucumber plants resist aphid attack by increasing the rates of photosynthesis and basal metabolism, and also by increasing the activities of protective enzymes. The combination of powdery mildew infection and aphid infestation reduced photosynthesis and basal metabolism in cucumber plants, although the activities of several protective enzymes increased. Aphid attack after powdery mildew infection or powdery mildew infection after aphid attack had the opposite effect on photosynthesis, protective enzyme activity, and basal metabolism regulation. Azoxystrobin and imidacloprid increased the contents of chlorophyll, free proline, and soluble protein, increased SOD activity, and decreased the MDA content in cucumber leaves. However, these compounds had the opposite effect on the soluble sugar content and POD and CAT (catalase) activities. The mixed ratio of the two single agents could improve the resistance of cucumber to the combined infection of powdery mildew and aphids. These results show that cucumber can enhance its pest/pathogen resistance by changing physiological metabolism when exposed to a complex infection system of pathogenic microorganisms and insect pests.
Background
Soil salinization leads to a significant decline in crop yield and quality, including licorice, an important medicinal cash crop. Studies have proofed that the application of exogenous silicon can significantly improve the ability of licorice to resist salt stress, however, few studies concentrated on the effects of foliar silicon application on the morphology, physiological characteristics, and anatomical structure of licorice leaves under salt stress. In this study, the effects of Si (K 2 SiO 3 ) on the structural and physiological characteristics of Glycyrrhiza uralensis Fisch. and G. inflata Bat. leaves under different salt concentrations (medium- and high-salt) were studied.
Results
Compared with the control (without salt), the plant height, total dry weight, leaf area, leaf number, relative water content, xylem area, phloem area, ratio of palisade to spongy tissue, gas exchange parameters, and photosynthetic pigment content of both licorice varieties were significantly reduced under high-salt (12S) conditions. However, the thickness of the leaf, palisade tissue, and spongy tissue increased significantly. Applying Si to the leaf surface increased the area of the vascular bundle, xylem, and parenchyma of the leaf’s main vein, promoted water transportation, enhanced the relative leaf water content, and reduced the decomposition of photosynthetic pigments. These changes extended the area of photosynthesis and promoted the production and transportation of organic matter. G. uralensis had a better response to Si application than did G. inflata .
Conclusions
In conclusion, foliar application of Si can improve water absorption, enhance photosynthesis, improve photosynthetic capacity and transpiration efficiency, promote growth and yield, and alleviate the adverse effects of salt stress on the leaf structure of the two kinds of licorice investigated.
Water is essential for the crops’ growth. Scarcity in water will lead to water stress. It is vital to manage irrigation in crops to avoid water stress. Leafy vegetables, such as spinach ( Spinacea oleracea L.), require higher water demand than other vegetables. Therefore, this study was conducted to evaluate the growth of spinach grown under various irrigation regimes and to determine at which irrigation set is the most suitable one to avoid water stress. Three irrigation treatments were applied, (T0) common practice (control), (T1) water matric potential = 30centibars, and (T2) water matric potential = 60centibars, measured for 60 days. The treatments were arranged in Complete Randomized Design (CRD) with four replications. There were significant differences to the irrigation treatments for plant height, number of root length including the biomass of spinach. T0 was found to be the right rate of water irrigation levels for spinach growth that was watering spinach twice a day until soil was wet. Spinach also can tolerate to mild water stress which was at 30centibars but water set at 60centibars will cause water stress. The highest spinach yield was achieved with adequate water supply, while yield was lower at lower water irrigation levels.
Plant growth and productivity are limited by the severe impact of salt stress on the fundamental physiological processes. Silicon (Si) supplementation is one of the promising techniques to improve the resilience of plants under salt stress. This study deals with the response of exogenous Si applications (0, 2, 4, and 6 mM) on growth, gaseous exchange, ion homeostasis and antioxidant enzyme activities in spinach grown under saline conditions (150 mM NaCl). Salinity stress markedly reduced the growth, physiological, biochemical, water availability, photosynthesis, enzymatic antioxidants, and ionic status in spinach leaves. Salt stress significantly enhanced leaf Na⁺ contents in spinach plants. Supplementary foliar application of Si (4 mM) alleviated salt toxicity, by modulating the physiological and photosynthetic attributes and decreasing electrolyte leakage, and activities of SOD, POD and CAT. Moreover, Si-induced mitigation of salt stress was due to the depreciation in Na⁺/K⁺ ratio, Na⁺ ion uptake at the surface of spinach roots, and translocation in plant tissues, thereby reducing the Na⁺ ion accumulation. Foliar applied Si (4 mM) ameliorates ionic toxicity by decreasing Na⁺ uptake. Overall, the results illustrate that foliar applied Si induced resistance against salinity stress in spinach by regulating the physiology, antioxidant metabolism, and ionic homeostasis. We advocate that exogenous Si supplementation is a practical approach that will allow spinach plants to recover from salt toxicity.
The presence of abundant oil palm residues in Malaysia prompted the need to utilize this waste to avoid environmental pollution. Palm oil mill effluent (POME) is a thick, brownish liquid effluent comprising large amounts of solids and high organic content, convertible into a valuable source of biomass. Based on the nutrient content of POME, this waste has the potential to be utilised as an alternative source of plant nutrients and organic medium in different agricultural crop production. Very recent Brazilian spinach (Alternanthera sissoo) is getting rapid interest among scientists and nutritionists for its easy growing and great nutritional values. But growing this spinach in Malaysia is still unfamiliar and no information about growing it using POME. Therefore, a study was conducted to determine the effects of different ratios of POME on growth and yield performance of Brazilian spinach (Alternanthera sissoo). The experiment was conducted at Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, Sandakan campus, Sabah, Malaysia. The stem cuttings of Brazilian spinach were transplanted into polybags containing different ratios of POME, cocopeat and sands as T1 (70% POME + 15% cocopeat + 15% sand), T2 (60% POME + 20% cocopeat + 20% sand), T3 (50% POME + 25% cocopeat + 25% sand) and T4 (normal soils) as control treatment following randomized complete block design (RCBD) with four replications. Among all the measured parameters significantly (P≤0.05) the highest plant height (30.68 cm), maximum numbers of branches (14.50), maximum numbers of leaves (60.50), canopy coverage area (29.13 cm 2), highest growth rate (78.0%), maximum fresh weight (330 g) and maximum dry weight (79.63 g) all were achieved from the Brazilian spinach grown under T1, followed by T2 and T3. So, from the overall findings undoubtedly it can be concluded that T1 was the best treatment for overall growth and yield of Brazilian spinach.
Plants face various abiotic stresses such as drought and salinity during growing stages adversely affect their physiological and biological processes. The use of bioactive compounds could mitigate the detrimental effects of abiotic stresses. The experimental layout was a split split-plot system based on a randomized complete block design with three replications. The treatments included three levels of potassium silicate (0, 3, and 6 cm L⁻¹ or 0, 12, and 24 L⁻¹ of K2SiO3 ha⁻¹) combined with three levels of Aloe saponaria L. extract (Ae) 0, 0.5, and 1% under two levels of irrigation regimes (IR70 and IR100; representing irrigation at 70 and 100% of crop evapotranspiration). The obtained results revealed that control roselle plants were adversely affected by drought, which recorded the lowest growth and yield parameters. Meanwhile, the exogenous addition of Ae and KSi significantly improved the growth and yield of deficit and full irrigated roselle plants. The foliar application of Ae (1%) and KSi (3 or 6 cm L⁻¹) under full irrigation led to a significant increase in growth and yield parameters of roselle. In addition, considerable enhancements in yield quality of roselle plants under deficit irrigation were recorded.
Pemanfaatan keanekaragaman hayati flora masih sangat potensial dieksplorasi sebagai sumber obat. Salah satu penggunaan fitokimia adalah pemanfaatannya sebagai imunomodulator untuk membantu imunitas tubuh memerangi agen infeksius. Tanaman bayam Brasil mempunyai potensi untuk dikembangkan sebagai salah satu imunostimulan berbasis herbal karena nilai nutrisi dan senyawa fitokimia yang dikandungnya. Penelitian ini bertujuan untuk mempelajari efek ekstrak daun bayam Brasil terhadap respon imun mencit jantan dilihat dari jumlah limfosit dan nilai indeks limpa dan timus. Ekstrak daun bayam Brasil diperoleh dengan metode maserasi menggunakan pelarut etanol 96%. Deteksi fitokimia menggunakan metode biokimia kualitatif dan GC-MS. Uji in vivo dilakukan dengan memberikan 6 perlakuan pada mencit jantan peroral dalam 7 hari yaitu perlakuan akuades, kontrol negatif (Na-CMC-akuades), kontrol positif (imunostimulan komersil), dan tiga dosis ekstrak daun bayam Brasil yaitu 0,1563 mg/g BB; 0,312 mg/g BB), dan 0,468 mg/g BB. Jumlah limfosit dipreparasi dan dihitung dengan apusan darah, serta penghitungan indeks limpa dan timus berbasis perhitungan berat segar. Hasil identifikasi biokimia kualitatif menunjukkan kandungan flavonoid, alkaloid, saponin, tanin dan steroid dalam ekstrak daun bayam Brasil. Analisis GC-MS menunjukkan 3 senyawa dominan yaitu neophytadiene, phytol dan ?-Tocopheryl acetate. Pemberian ekstrak daun bayam Brasil dengan dosis 0,1563 mg/g BB paling efektif meningkatkan jumlah limfosit hewan uji. Nilai indeks timus dan limpa berkorelasi dengan meningkatnya jumlah limfosit pada pemberian ekstrak daun bayam Brasil. Hasil ini menunjukkan potensi dasar penggunaan daun bayam Brasil sebagai imunostimulan