Foliar Spray of Phyto-extracts Supplemented with Silicon: An Efficacious Strategy to Extenuate the Salinity-induced Deleterious Effects in Pea (Pisum sativum L.)

A pot culture study was conducted to assess the ameliorative effect of silicon, Melia azedarchta leaf extract and sugar beet root extract, each applied individually or in different combinations, against the salinity-induced detrimental effects in pea (Pisum sativum L.). Salinity markedly inhibited the growth, photosynthetic activity, stomatal conductance, stomatal size, transpiration rate, water use efficiency, green pigments, total phenol contents, membrane stability index and productivity. However, lipid peroxidation, electrolyte leakage, H₂O₂ content and antioxidant activities i.e., superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase, leaf free proline and glycinebetaine contents were significantly enhanced by salinity. But exogenously applied Si and phyto-extracts markedly alleviated the salinity-induced drastic effects on growth, gas exchange attributes and productivity. However silicon, M. azedarchta leaf and sugarbeet root-extracts in various combinations proved to be better than their individual sprays on salt-stressed pea plants. Both phyto-extracts supplemented with silicon gave highly salinity mitigating effect by markedly improving growth, gas exchange attributes, enzymatic activities, osmolytes and yield. While, phyto-extracts and Si suppressed the lipid peroxidation, electrolyte leakage and H₂O₂ content, by strengthening the enzymatic and non-enzymatic (proline and glycinebetaine) antioxidant defense system. The phyto-extracts and Si application also checked the root/leaf sodium and chloride contents, however improved the silicon contents. Thus, it can be concluded that exogenous application of silicon in combination with phyto-extracts of M. azedarchta and sugarbeet is highly effective ameliorative approach to alleviate the salinity-induced hazardous effects in plants especially in pea, grown under saline regime.

Additional index words. salinity, silicon, Melia azedarchta, sugarbeet, gas exchange, antioxidants