Foliar application of hydrogen peroxide (H2O2) modulates growth, inorganic ion and osmolyte accumulation of soybean (Glycine max) cultivars under drought stress

Abstract

• Sensitivity to drought differed among the cultivars and depends on the severity of stress. • Cultivars-1 and 2 shows stronger tolerance mechanism to drought condition. • Foliar application of H 2 O 2 enhanced glycine betaine and total soluble sugar. • H 2 O 2 differentially induced accumulation of inorganic ion among the cultivars. Soybean ( Glycine max ) is a valuable and highly nutritional crop with many cultivars in the Temperate and Tropical environments but threatened by drought. Further to this, the application of signaling molecules as ameliorative strategy against adverse effects of drought on soybean cultivars still remains unclear. This study investigates the variation in drought tolerance and effects of foliar application of hydrogen peroxide (H 2 O 2 ) on drought stress in three soybeans cultivars (NGBO 03519 , 03515 and 03524) under normal irrigation, mild drought and severe drought. Mild and severe drought exerted negative effects on growth and metabolic processes of G. max cultivars. Severe drought decreased the photosynthetic pigments in all cultivars, but substantially increased the root biomass and triggered the accumulation of glycine betaine in NGBO 03519 and NGBO 03515. Drought significantly enhanced total soluble sugar in NGBO 03515 and NGBO 03524 cultivars while severe drought decreased Ca 2+ , Mg 2+ , Cl − , and SO 4 2− in NGBO 03524. Foliar-applied H 2 O 2 ameliorated impact of drought and positively enhanced biomass, photosynthetic pigment, ion accumulation, and consequently resulted into improved plant growth. The results indicated that H 2 O 2 sustained higher cell turgor in NGBO 03515 and NGBO 03524 cultivars by significantly enhancing K + under severe drought. Conclusively, the study indicated that while NGBO 03519 may have sturdy fitness to resist severe drought, H 2 O 2 is essential for cell expansion and growth of NGBO 03515 and 03524.