复合外源物质对玉米幼苗抗寒性的影响

Effects of different exogenous compounds on cold resistance of maize seedlings

关键词:  复合外源物质, 玉米幼苗, 抗寒效果, 低温胁迫, 抗寒性

Key words:  exogenous compound, maize seedlings, effects of cold resistance, chilling stress, chilling tolerance

摘要:

该研究采用不同浓度的水杨酸(SA)、脱落酸(ABA)、磷酸二氢钾(KH₂PO₄)以及抗坏血酸(V_C)进行正交组合获得不同浓度组合的复合外源物质,同时以蒸馏水处理作为对照,将其喷施于玉米幼苗后进行低温胁迫处理,在胁迫结束后使幼苗恢复生长,并测定叶片相关生长指标及生理生化指标的变化。结果表明:(1)与对照组相比,9种复合外源物质处理均可显著提高玉米幼苗的相对生长速率、干物质积累速率及脯氨酸含量,降低相对电导率,总体上提高了玉米幼苗的素质。(2)在4 ℃低温胁迫下,9种复合外源物质处理下幼苗相对生长速率、干物质积累速率、根系活力、脯氨酸含量、可溶性蛋白含量及可溶性糖含量,均显著高于对照,并减缓了丙二醛的积累和相应的膜脂过氧化,降低了相对电导率,提高了玉米幼苗的耐冷性。低温胁迫条件下,水杨酸、脱落酸、磷酸二氢钾和抗坏血酸四种物质组成的复合物可以提高玉米幼苗的耐冷性,其中以SA 0.14 g·L^-1+ ABA 0.015 g·L^-1+ KH₂PO₄ 3.0 g·L^-1+ V_C 3.0 g·L^-1的复合物效果最好。该研究结果为新型复合抗寒剂的应用推广提供了技术支持。

Abstract:

We studied the effects of different combinations of exogenous compounds on cold tolerance of maize seedlings to improve their cold resistance in order to provide technology support for the application and popularization of new composite cold resistant agent. Different exogenous compounds were obtained by orthogonal experiment with different concentrations of Salicylic acid(SA), Abscisic acid(ABA), Potassium dihydrogen phosphate(KH₂PO₄)and Vitamin C(V_C). We tested these compounds against control by spraying distilled water on the seedlings, growth indice and physiological and biochemical indices of leaves of maize seedlings. The main results are as follows:(1)Compared to control, the pretreated maize seedlings with nine exogenous compounds had higher relative growth rate, dry weight accumulation rate and free proline content but the seedlings had lower relative electrical conductivity under different treatments.(2)When transferred to chilling stress at 4 ℃, as compared to control of water treatment, the pretreated seedlings with nine exogenous compounds cold resistant agent could maintain higher relative growth rate, dry weight accumulation rate, root vigor, proline content and soluble protein content of the maize seedlings, the soluble sugar content as well. At the same time, the pretreated reduced MDA content and lipid peroxidation, which finally enhanced chilling tolerance of the maize seedlings. The study confirmed that under the circumstance of chilling stress, the pretreatments with nine exogenous compounds which be composed of SA, ABA, KH₂PO₄ and V_C all could increase chilling tolerance of maize seedlings to different contents. Comprehensive analysis of various growth and physiological indices showed that different exogenous compounds had different effects. Of all treatments, the compound of SA 0.14 g·L^-1 + ABA 0.015 g·L^-1 + KH₂PO₄ 3.0 g·L^-1 + V_C 3.0 g·L^-1pretreatment produced the best effect.