Exogenous glutathione protected wheat seedling from high temperature and water deficit damages.

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.

Effects of jasmonic acid in foliar spray and an humic acid amendment to saline soils on forage sorghum plants' growth and antioxidant defense system.

Salinity is one of the primary abiotic stresses that cause negative physiological and biochemical changes due to the oxidative stress caused by the generation of reactive oxygen species (ROS). The effect of jasmonic acid (JA) as foliar spray and humic acid (HA) as soil amendment on the growth and biochemical attributes of forage sorghum plants exposed to salinity stress was investigated. Soil treated with NaCl at levels of 0, 2, and 4 g NaCl kg-1 dry soil (designated as S0, S1, and S2) and soil amendment with humic acid at 0, 3, and 6 g HA kg-1 dry soil (designated as HA0, HA1, and HA2). The plants were sprayed with three JA levels, including 0, 5, and 10 mM JA. Salinity stress increased carotenoid and soluble protein content, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content. In contrast, salinity stress reduced plant height, leaf area, relative growth rate, proline content, and the activity of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). At the S2 salinity level, HA2 rate increased plant high by 9.7%, relative growth rate by 70.8% and CAT by 45.5, while HA1 increased leaf area by 12.5%, chlorophyll content by 22.3%, carotenoid content by 38.1%, SOD activity by 20.9%, MDA content by 18.0%, POD activity by 24.6% and APX value by 21.7%. At the S2 salinity level, the highest plant height, chlorophyll content, soluble protein content and APX value were recorded at 5 mM JA, while the highest leaf area, the content of carotenoid, proline, and MDA, and the activity of POD and CAT were achieved at 10 mM JA. Generally, 10 mM JA and 3 g HA kg-1 dry soil produced the best positive effects on forage sorghum plants physiological responses. Our study suggested that jasmonic acid and humic acid at appropriate rates can successfully mitigate the adverse effects of salinity stress on forage sorghum.

Gibberellic acid and nitrogen efficiently protect early seedlings growth stage from salt stress damage in Sorghum.

Salinity one of environmental factor that limits the growth and productivity of crops. This research was done to investigate whether GA3 (0, 144.3, 288.7 and 577.5 µM) and nitrogen fertilizer (0, 90 and 135 kg N ha-1) could mitigate the negative impacts of NaCl (0, 100, and 200 mM NaCl) on emergence percentage, seedling growth and some biochemical parameters. The results showed that high salinity level decreased emergence percentage, seedling growth, relative water content, chlorophyll content (SPAD reading), catalase (CAT) and peroxide (POD), but increased soluble protein content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The SOD activity was decreased by nitrogen. However, the other measurements were increased by nitrogen. The interactive impact between nitrogen and salinity was significant in most parameters except EP, CAT and POD. The seedling length, dry weight, fresh weight, emergence percentage, POD, soluble protein and chlorophyll content were significantly affected by the interaction between GA3 and salinity. The GA3 and nitrogen application was successful mitigating the adverse effects of salinity. The level of 144.3 and 288.7 µm GA3 and the rate of 90 and 135 kg N ha-1 were most effective on many of the attributes studied. Our study suggested that GA3 and nitrogen could efficiently protect early seedlings growth from salinity damage.