Silicon Nutrition in Plants under Water-Deficit Conditions: Overview and Prospects

Abstract

Drought is one of the major constraints for sustainable crop production worldwide, especially in arid and semiarid regions. The global warming and climate change scenario has worsened the dilemma of water scarcity, creating an immediate threat to food security. Conserving water resources and exploiting various strategies that enable plants to withstand water deficits need to be urgently addressed. Drought adversely affects plant growth by modulating a range of physio-chemical, metabolic, and molecular processes inside the plant body, which ultimately reduces crop productivity. Besides developing drought-tolerant cultivars, better nutrient management could be a promising strategy to enhance drought tolerance in crop plants. Silicon, a quasi-essential element, is known to play a vital role in improving crop performance under a range of biotic and abiotic stresses. This review discusses the potential of Si application in attenuating the adverse effects of water-deficit stress. Silicon enhances plant growth by improving seed germination, cell membrane stability, carbon assimilation, plant–water relations and osmotic adjustment (by accumulating soluble sugars, proline and glycine betaine). It triggers the activity of antioxidants, promotes the biosynthesis of phytohormones, enhances nutrient acquisition and regulates the activity of vital enzymes in plants under drought stress. Silicon also induces anatomical changes in the plant cell wall through the deposition of polymerized amorphous silica (SiO2-nH2O), thereby improving stem and leaf erectness and reducing lodging. Further, Si-mediated physiological, biochemical and molecular mechanisms associated with drought tolerance in plants and future research prospects have been elucidated.

Tolerance of Two Sorghum Varieties to Salinity Using Different Nutritional Practices and Two Leaching Requirements

“…Silicone can also have an impact on the leaf area of the plant. [29] mentioned that silicon has a role in improving plant growth indicators, including leaf area, by reducing the influence of biotic and abiotic stress on the plant. Also, micronutrients could have a role in influencing the leaf area of the plant, as indicated by [30] that fertilizing with iron and zinc has a significant effect in increasing the leaf area of the sorghum plant.…”

“…While the treatment of the sorghum variety has significantly affected the leaf area of the plant, the variety (C 2 ), which achieved a leaf area of 0.45 M 2 , outperformed the variety (C 1 ), which achieved a leaf area of 0.34 M 2 , and this may be due to the difference between the two varieties in their genetic characteristics [14]. The results of Table (3) also indicate that the interaction between leaching requirements and the fertilization treatment has significantly affected the leaf area of the plant, with the highest average of the leaf area being 0.50 m 2 for the interaction treatment (L 1 F 5 ) and the lowest average was 0.27 m 2 for the treatment (L 1 F 0 ), which may be due to the role of leaching requirements in reducing soil salinity [24], in addition to the impact of fertilization treatments, whether in improving soil properties, increasing plant resistance to Environmental stresses, or improving plant growth indicators [31,22,30,21,29]. The results of Table (3) also indicate that the interaction between the sorghum variety and the leaching requirements, and the interaction between the sorghum variety and fertilization treatment, and the triple interaction between the treatment of sorghum variety, leaching requirements, and fertilization treatment, did not have a significant effect on leaf area of the plant.…”

“…The highest mean was 11373.6 (kg ha -1 ) for the treatment (F 6 ), compared to the lowest mean of 4777.2 (kg ha -1 ) for the treatment (F 0 ).This can be due to fertilization with nitrogen and phosphorus, which affect the growth and development of the plant through their active role in the biochemical and physiological processes of the plant [44,45] and the role of potassium humates [33]. Silicon may also have a role in increasing the biological yield of the plant, through improving plant growth (Tables 2-4) by improving cell membrane stability, carbon absorption, plant water relations, plant osmotic regulation (through the accumulation of dissolved sugars, proline and glycine betaine), stimulating antioxidants, improving the biosynthesis of plant hormones, improving the absorption of nutrients and regulating the effectiveness of vital enzymes in the plant [29]. These results also confirm [20] who found that micronutrients (Fe, Zn and B) have a role in increasing the biological yield of the sorghum plant.…”

Exogenous silica nanoparticles improve drought tolerance in ginger by modulating the water relationship

“…6,9 So far, the key mechanisms related to Si-alleviated drought stress mainly include improving water uptake and transport, modulating stomatal behavior and transpirational water loss, accumulating osmoprotectants, and inducing signal pathways, which together contribute to increased whole-plant water balance under water deficit conditions. 10 SiNPs have been demonstrated to have positive effects in improving plant performance in stressful environments including salt and drought stress. 11,12 For example, soil application of 10, 50 and 100 mg L −1 SiNPs played a vital role in enhancing the photosynthesis efficiency and stomatal conductance of hawthorn seedlings under water deficit stress conditions.…”

Antioxidant production promotes defense mechanism and different gene expression level in Zea mays under abiotic stress

“…The water has been shortening due to shortage or less rainfalls; the water has been becoming scarce throughout the country, causing salt stress 5 , 6 . The water limitations and salt stresses also adversely affect other crop plants like wheat, rice, barley, and oat crops 7 . The maize plant suffers from salt and drought stress at anthesis and the grain filling stages up to 40–80% yield loss.…”