Impact of High Temperature on Germination, Seedling Growth and Enzymatic Activity of Wheat

Abstract

Global warming has increased the temperature significantly over a large extent both spatially and temporally. The threat of heat stress during the germination and seedling establishment stages in the wheat crop is now more prevalent than ever before. The present experiment assessed the effect of elevated temperature on the germination and early seedling growth of wheat genotypes. The seeds were sown under four temperatures, viz., 20 °C, 25 °C, 30 °C and 35 °C; the germination, seedling vigor and enzyme activities in 8-day-old seedlings were assessed. The temperature significantly influenced germination and early seedling growth. The germination percentage at 20 and 25 °C was statistically on par with and higher than at 30 and 35 °C. The seedling vigor parameters were maximum at 25 °C and showed a reduction at higher temperatures. Genotypic differences were observed for early heat stress as the genotypes WH 730, WH 1123 and HD 2967 showed tolerance towards heat stress during germination, whereas the genotypes PBW 725 and WH 1105 were susceptible. Antioxidant enzyme activities in seedlings increased with the rise in temperature. Catalase, peroxidase and superoxide dismutase enzymes showed increased activities at higher temperature levels.

Keywords

• heat stress
• germination
• seedling growth
• sowing time
• antioxidant enzymes