Field application of silicon alleviates drought stress and improves water use efficiency in wheat

Abstract

Detrimental impacts of drought on crop yield have tripled in the last 50 years with climate models predicting that the frequency of such droughts will intensify in the future. Silicon (Si) accumulation, especially in Poaceae crops such as wheat (Triticum aestivum L.), may alleviate the adverse impacts of drought. We have very limited information, however, about whether Si supplementation could alleviate the impacts of drought under field conditions and no studies have specifically manipulated rainfall. Using field–based rain exclusion shelters, we determined whether Si supplementation (equivalent to 39, 78 and 117 kg ha-1) affected T. aestivum growth, elemental chemistry [Si, carbon (C) and nitrogen (N)], physiology (rates of photosynthesis, transpiration, stomatal conductance, and water use efficiency) and yield (grain production) under ambient and drought (50% of ambient) rainfall scenarios. Averaged across Si treatments, drought reduced shoot mass by 21% and grain production by 18%. Si supplementation increased shoot mass by up to 43% and 73% in ambient and drought water treatments, respectively, and restored grain production in droughted plants to levels comparable with plants supplied with ambient rainfall. Si supplementation increased leaf-level water use efficiency by 32–74%, depending on Si supplementation rates. Water supply and Si supplementation did not alter concentrations of C and N, but Si supplementation increased shoot C content by 39% and 83% under ambient and drought conditions, respectively. This equates to an increase from 6.4 to 8.9 tonnes C ha-1 and from 4.03 to 7.35 tonnes C ha-1 under ambient and drought conditions, respectively. We conclude that Si supplementation ameliorated the negative impacts of drought on T. aestivum growth and grain yield, potentially through its beneficial impacts on water use efficiency. Moreover, the beneficial impacts of Si on plant growth and C storage may render Si supplementation a useful tool for both drought mitigation and C sequestration.

Effects of leaf silicon on drought performance of tropical tree seedlings

“…hydroponics or greenhouses [12] and only few field studies were undertaken (e.g. [16]), precluding conclusions about the relevance of Si-mediated drought resistance for wild tropical seedlings. Particularly, the very low water potentials of droughted tropical soils [17] have not been reached.…”

Limited effects of crop foliar Si fertilization on a marginal soil under a future climate scenario

“…It can increase plant C content through stimulating the formation of phytoliths, this way enhancing long-term C sequestration potential [ 11 ]. Hence Si treatment is expected to have a great potential to improve crop performance on marginal soils, and has been proposed as a large scale sustainable solution to counteract negative impacts of drought on crops [ 12 , 13 ]. However, despite multiple tests of individual mechanisms associated with crop response to Si treatments, an exhaustive assessment of the impacts of Si treatment on soil functioning and associated ecosystem services has to the best of our knowledge so far not been performed, especially in the context of climate adaptation of marginal soils.…”

Integrated physiological, transcriptomic, and metabolomic analyses of drought stress alleviation in Ehretia macrophylla Wall. seedlings by SiO2 NPs (silica nanoparticles)

“…In recent times, silicon-based fertilizers have received increasing attention for their ability to alleviate the adverse effects of drought stress in plants (Malik et al, 2021). It has been reported that silicon fertilizers can alleviate drought stress by improving the antioxidant defense systems and photosynthetic metabolism (Johnson et al, 2022;, maintaining intracellular homeostasis (Bhardwaj and Kapoor, 2021), tuning the auxin levels (Mir et al, 2022), and regulating the homeostasis of the oxidation of nitroso-compounds (Bhardwaj et al, 2022). The bioavailability of silicon fertilizers is less, however, NP-based silicon fertilizers were more likely to penetrate into the leaf cells and play a more direct function (Biju et al, 2021), leading to the usage of nanoparticles (NPs) could be an important approach to alleviate soil salt stress (Badawy et al, 2021).…”