Integrated Application of Selenium and Silicon Enhances Growth and Anatomical Structure, Antioxidant Defense System and Yield of Wheat Grown in Salt-Stressed Soil

Abstract

Selenium (Se) and silicon (Si) are considered advantageous elements to induce plants’ tolerance to various environmental stresses. Wheat yield is negatively affected by salinity stress, especially in dry and semi-dry areas. Therefore, the objective of the current study was to investigate the effects of Se, Si and their combinations (0 as control, Se15, Se30, Si15, Si30, Se15 + Si15, and Se30 + Si30 mM) in alleviating the deleterious effects of salinity stress (7.61 dS m−1, real field conditions) on anatomical characteristics as well as the physio-biochemical and productivity parameters of wheat plants. The selenium and silicon treatments and their combinations caused significant amelioration in growth, anatomical and physiological attributes, and grain yields of salinity-stressed wheat in comparison with the untreated plants (control treatment). The integrated application of Se30 + Si30 significantly increased plant growth (i.e., plant height 28.24%, number of tillers m−2 76.81%, fresh weight plant−1 80.66%, and dry weight plant−1 79.65%), Fv/Fm (44.78%), performance index (PI; 60.45%), membrane stability index (MSI; 36.39%), relative water content (RWC; 29.39%), total soluble sugars (TSS; 53.38%), proline (33.74%), enzymatic antioxidants (i.e., CAT activity by 14.45%, GR activity by 67.5%, SOD activity by 35.37% and APX activity by 39.25%) and non-enzymatic antioxidants (i.e., GSH content by 117.5%, AsA content by 52.32%), yield and its components (i.e., number of spikelets spike−1 29.55%, 1000-grain weight 48.73% and grain yield ha−1 26.44%). The anatomical traits of stem and leaves were improved in wheat plants treated with Se30 + Si30. These changes resulting from the exogenous applications of Se, Si or their combinations, in turn, make these elements prospective in helping wheat plants to acclimate successfully to saline soil.

Influence of Nano Silicon and Nano Selenium on Root Characters, Growth, Ion Selectivity, Yield, and Yield Components of Rice (Oryza sativa L.) under Salinity Conditions

“…In this regard, Gong et al [ 16 , 53 ] reported that dry matter yield of wheat plants was improved when Si was applied. According to Ma and Yamaji [ 54 ], the positive effect of Si is due to its deposition in the roots, decreases, and provides binding sites for metals, resulting in a reduction in the uptake and translocation of toxic metals and salts from the roots to the shoots.…”

“…The beneficial effects of NPs-Si as a foliar application at the boating growth stage might be mainly attributed to reducing Na + uptake, matching with increasing K + and Ca +2 uptake, keeping healthy flag leaf, increasing photosynthesis with high net assimilation rate, and translocation from sources to sin. In this regard, Si is reported to enhance growth and yield of higher plants, particularly under biotic and abiotic stresses [ 16 ].…”

“…Among the nutritional elements, silicon (Si) is thought to be one of the most beneficial to plant life [ 15 ]. Si’s potential to mitigate the harmful effects of salt stress on plant growth is well documented [ 16 ]. Several studies have revealed that silicon improves salt tolerance in a variety of crop species [ 16 , 17 , 18 ].…”

“…Si’s potential to mitigate the harmful effects of salt stress on plant growth is well documented [ 16 ]. Several studies have revealed that silicon improves salt tolerance in a variety of crop species [ 16 , 17 , 18 ]. The application of micronutrients can promote the growth and yield of crops by increasing plant hydration status, changing the ultrastructure of leaf organelles, activating plant defense mechanisms, and mitigating particular ions [ 16 , 19 ].…”

Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity

“…Jiang et al [131] highlighted the TaSOS1 gene in response to salt stress in two spring T. aestivum genotypes, Seri M82 (salt-sensitive) and CIGM90.863 (salt-tolerant), and observed a higher expression of most of the 18 TaSOS1 genes in the roots of salt-tolerant seedlings than the salt-sensitive seedlings. Recently, several exogenous protectants (i.e., GA, salicylic acid (SA), melatonin (MT), silicon, selenium) have been used to upregulate the antioxidant machinery in plants under salinity [132][133][134][135]. For instance, Ahmad et al [133] found increased activities of SOD (9%), APX (13%), CAT (26%), GR (40%) and POD (98%) when seed priming was conducted with 0.5 mM GA. Foliar spraying of SA (0.5 mM) enhanced AsA, GSH, total phenols and anthocyanin biosynthesis and increased SOD and CAT activities, thus reducing the H 2 O 2 and O 2…”