Alleviation of drought stress by root-applied thiourea is related to elevated photosynthetic pigments, osmoprotectants, antioxidant enzymes, and tubers yield and suppressed oxidative stress in potatoes cultivars

The growth and productivity of plants are enhanced by the use of thiourea (TU) under stressful conditions. When TU is applied as a rooting medium, it improves plant growth characteristics and other physiological parameters in stressed environment. A pot experiment was conducted in the botanical garden of the Government College University, Faisalabad 38000, Pakistan to examine the TU-mediated fluctuations in some crucial physio-biochemical parameters and the oxidative defense of potatoes under a restricted water supply. For this purpose, two potato cultivars (potato-SH-5 and potato-FD-73) were sown in pots containing 10 kg of soil. Water was regularly applied to the pots until germination. After 2 weeks of germination, drought stress with 65% field capacity was imposed, while the control was subjected to 100% field capacity. TU, as a rooting medium, was applied at the vegetative stage (0 (no application), 0.5, 0.75 mM). A substantial reduction in the total number of leaves, leaf area, tuber biomass (fresh and dry weight), photosynthetic pigments, membrane permeability, and leaf relative water content (RWC) was recorded in plants under drought stress conditions as compared to control plants. The damaging effects of water stress were more critical for cv. potato-FD-73 as compared to cv. potato-SH-5. In contrast, drought stress enhanced the malondialdehyde (MDA) and hydrogen peroxide (H