Muhammad Ali, Sobia Afzal, Aasma Parveen, Muhammad Kamran, Muhammad Rizwan Javed, Ghulam Hassan Abbasi, Zaffar Malik, Muhammad Riaz, Salman Ahmad, Muhammad Sohaib Chattha, Mohsin Ali, Qurban Ali, Muhammad Zahir Uddin, Muhammad Rizwan, Shafaqat Ali

Plant Physiol. BioChem. 2021 Jan;158:208-218. doi: 10.1016/j.plaphy.2020.10.040.

Abstract

Silicon (Si), a major contributing constituent for plant resistance against abiotic stresses. In spite of this, the detailed mechanisms underlying the potential of Si in mitigating salt toxicity in maize (Zea mays L.) are still poorly understood. The present study deals with the response of Si application on growth, gaseous exchange, ion homeostasis and antioxidant enzyme activities in two maize cultivars (P1574 and Hycorn 11) grown under saline conditions. Salt stress remarkably reduced the plant tissue (roots and shoots) biomass, relative water contents (RWC), membrane stability index (MSI), gaseous exchange characteristics, and antioxidant enzymatic activities i.e., superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and catalase (CAT). However, salt-induced phytotoxicity increased the plant tissue concentration of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), Na⁺/K⁺ ionic ratio, Na⁺ translocation (root to shoot), and its uptake. The detrimental effects were more prominent in Hycorn 11 cultivar than the P1574 cultivar at higher salinity level (S2; 160 mM NaCl). The addition of Si alleviated salt toxicity, which was more obvious in P1574 relative to Hycorn 11 as demonstrated by an increasing trend in RWC, MSI, and activities of SOD, POD, APX and CAT. Besides, Si-induced mitigation of salt stress was due to the depreciation in Na⁺/K⁺ ratio, Na⁺ ion uptake at the surface of maize roots, translocation in plant tissues and thereby significantly reduced Na⁺ ion accumulation. The findings showed a new dimension regarding the beneficial role of Si in maize plants grown under salt toxicity.

See: https://pubmed.ncbi.nlm.nih.gov/33281032/

Figure 1: The effect of exogenous silicon (Si) supply on physiological parameters such as relative water contents (A), membrane stability index (B), and total chlorophyll contents (C) of two maize (Zea mays L.) cultivars grown in saline medium. The bar values depict the average of four replicates and the error bars not sharing the same lowercase letters differ significantly from each other according to the honest significant difference (HSD) test at 5% probability level. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)