Effect of seed dressing with gibberellins and brassinosteroids on enzymatic activity and seed quality of soya bean at different vigour levels under low temperature

Gibberellin (GA3) and brassinosteroid (EBL) interactions can stimulate germination, extend seedling growth and induce low temperature stress tolerance. The effects of GA3 and EBL on seed quality, α-amylase and total dehydro­genase activities of soya bean seeds at different vigour and temperature levels were studied. The results showed that medium vigour seeds dressed with 100 ppm GA3, 0.25 ppm EBL plus 50 ppm GA3, and 0.50 ppm EBL plus 100 ppm GA3 had significantly higher germination (GP) and seedling vigour rates (SVR) than those of untreated seeds. Similarly, 0.50 ppm EBL resulted in higher SVR of low and medium vigour seeds when compared to the control under low temperature. All soya bean seeds dressed with 100 ppm GA3 had higher GP, vigour, shoot and root lengths, and SVR under both temperatures than those of the untreated seeds, and mean germination time decreased. At 15°C, all seeds dressed with 0.50 ppm EBL plus 100 ppm GA3 had higher α-amylase activity than the untreated seeds, whereas seeds with low and medium seed vigour dressed with 100 ppm GA3 and 0.25 ppm EBL plus 50 ppm GA3 had higher total dehydrogenase activity than the untreated seeds.