Effects of different exogenous hormones on germination and seedling physiology of maize under low temperature stress
[Objective]To study the effects of exogenous brassinolide(BR)and abscisic acid(ABA)on germination and seedling growth and physiological characteristics of maize under low temperature stress.[Method]Under the condition of low indoor temperature of 10℃,the cold-sensitive material Shen 137,the cold-resistant materials LH82,PHG47 and PHG29 were used as experimental materials,and five different concentrations of exogenous BR and ABA were used for seed soaking and culture.25℃distilled water as positive control CK+,10℃distilled water as negative control treatment CK-.The optimal concentration of BR and ABA was screened out,and the seed germination,seedling traits and physiological characteristics of four maize varieties Shen 137,LH82,PHG47 and PHG29 were compared by using the optimal concentra-tion.[Result]Under low temperature stress,the germination rate,germ length,radicle length and fresh germ weight of maize varieties decreased significantly.The levels of malondialdehyde,proline and soluble sugars in seedlings increased significantly,and the activities of antioxidant enzymes increased significantly.Appropriate application of BR and ABA treatment can effectively alleviate the inhibition of low temperature stress on maize growth.The increase in germination index,aboveground and underground biomass index and the decrease in MDA content of Shen 137 maize showed that 0.10 mg/L BR and 5 mg/L ABA treat-ment had the best alleviating effect.[Conclusion]The application of 0.10 mg/L and 5 mg/L could effec-tively alleviate the damage caused by low temperature stress on the growth of Shen137,LH82,PHG47 and PHG29 maize,but had different alleviating effects on the four maize varieties under low temperature,and the order of alleviating effect was:LH82>PHG47>PHG29>Shen137.
cornlow temperature stressgermination periodseedling stageexogenous brassinolideabscisic acid
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