低温胁迫下不同外源激素对玉米发芽及幼苗生理特性的影响

Effects of different exogenous hormones on germination and seedling physiology of maize under low temperature stress

【目的】探究外源油菜素内酯(BR)与脱落酸(ABA)对低温胁迫下玉米发芽及幼苗生长与生理特性的影响。【方法】在室内低温10℃条件下,以寒敏感材料沈137、耐寒材料LH82、PHG47和PHG29为试验材料,分别用5种不同质量浓度的外源BR与ABA浸种、培养作为试验处理;25℃蒸馏水作正向对照(CK+)、10℃蒸馏水作负向对照(CK-)。筛选出BR与ABA的最佳缓解质量浓度,利用最佳缓解质量浓度对沈137、LH82、PHG47和PHG29 4个玉米品种种子的萌发、苗期性状和生理特性进行比较。【结果】低温胁迫下,玉米种子的发芽率、胚芽长、胚根长、胚芽鲜质量等显著降低;幼苗的丙二醛、脯氨酸及可溶性糖含量显著升高,抗氧化酶活性显著增强;适当外施BR与ABA处理能有效缓解低温胁迫对玉米生长的抑制程度,沈137玉米萌发期指标、苗期地上部与地下部生物量指标的增加,MDA含量的降低表明0.10 mg/L BR与5 mg/L ABA处理缓解效果最好。【结论】外施0.10 mg/L BR与5mg/L ABA可有效缓解低温胁迫对玉米生长造成的损害。但对4个玉米品种的缓解能力不同,缓解效果由强到弱顺序为:LH82>PHG47>PHG29>沈137。

【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 concentration.【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 treatment had the best alleviating effect.【Conclusion】 The application of 0.10 mg/L and 5 mg/L could effectively 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.