Induction of Heat Tolerance in Maize through Exogenous Application of Salicylic Acid, Ascorbic Acid and Hydrogen Peroxide in a Field Study

Abstract

M aize (Zea mays L.) is an important cereal crop and cultivated under divergent climatic conditions of spring and summer seasons in Pakistan (Tariq et al., 2002). Being monoecious crop and very much sensitive to high temperatures (Ullah et al., 2020) which causes severe irreversible changes in Abstract | Temperature is a very important factor that affects crop yield. Maize, a monoecious plant, is adversely affected by high temperature during anthesis. Asynchronous fertilization and pollen desiccation reduce maize yield by reducing grain number and their size. Spray of hydrogen peroxide (H 2 O 2 ), salicylic acid (SA) and ascorbic acid (AsA) may induce heat stress tolerance. Spray of SA, AsA, and H 2 O 2 increased chlorophyll, relative water and nutrient contents, membrane stability index (MSI) and antioxidants activities in heat stress. Moreover, foliar application of chemicals during normal and late planting improved the grain yield by increasing both the grain number and size. Foliar spray of SA, AsA and H 2 O 2 may induce heat tolerance by improving antioxidant activities which stabilized membrane and maintaining relative water, chlorophyll and nutrient content in ear leaves of maize during heat stress.