ABSTRACT
High temperatures (HT) and drought are two major factors restricting wheat growth in the early growth stages. This study investigated the role of glutathione (GSH) amendment (0.0, 0.5, 1.0, and 2.0 mM) to soil in mitigating the adverse effect of HT (33 °C, with 25 °C as a control), water regimes (60% of field capacity and control), and their combinations. HT decreased the length, project area, surface area, volume, and forks of the root, while drought had the reverse effect. Shoot length, leaf area, leaf relative water content, and shoot and root dry matter were significantly decreased by HT and drought, and their combined impact was more noticeable. GSH significantly promoted the root system, shoot growth, and leaf relative water content. The combined treatment reduced chlorophyll a, chlorophyll b, and total chlorophyll. However, 0.5 mM GSH raised chlorophyll a, chlorophyll b, and total chlorophyll by 28.6%, 41.4%, and 32.5%, respectively, relative to 0.0 mM GSH. At combined treatment, 0.5 mM GSH decreased malondialdehyde (MDA) by 29.5% and increased soluble protein content by 24.1%. GSH meaningfully enhanced the activity of superoxide dismutase, catalase, and ascorbate peroxide in different treatments. This study suggested that GSH could protect wheat seedlings from the adverse effects of HT and/or drought stresses.
