外源钙对低温胁迫下尾巨桉幼苗生理特性及内源激素的影响

Effects of Exogenous Calcium on Seedling Physiological Characteristics and Endogenous Hormone of Eucalyptus urophylla×E.grandis under Low Temperature Stress

以1年生尾巨桉无性系幼苗为试验材料,在4℃低温条件下,研究外源Ca^(2+)对尾巨桉幼苗丙二醛、渗透调节物质(脯氨酸、可溶性糖)、抗氧化酶(CAT、SOD、POD)活性及内源激素(CTK、GA、ABA)含量的影响。结果表明,在低温胁迫下尾巨桉幼苗生物量、CTK、ABA和GA含量显著低于常温处理,MDA、脯氨酸和可溶性糖含量显著高于常温处理。与不加钙处理相比,低温胁迫下,加CaCl_2处理显著降低了尾巨桉幼苗MDA含量及ABA水平,而脯氨酸、可溶性糖、CTK、GA含量及CAT、POD和SOD保护酶活性则显著升高,其中10mmol·L^(-1)CaCl_2处理尾巨桉的效果显著优于其他浓度Ca^(2+)的处理。低温胁迫下尾巨桉幼苗的生长受到抑制,适当浓度(10~20mmol·L^(-1))的外源钙可以减缓低温胁迫对幼苗造成的伤害,从而提高桉树幼苗对低温胁迫的适应能力。

Exogenous Ca^2＋ with different concentrations were sprayed on the 1-year-old seedlings of Euca- lyptus urophylla × E. grandis, and the effects of exogenous Ca^2＋ on MDA, osmotic adjustment substances （proline,soluble sugar）, activities of antioxidant enzymes （CAT, SOD, POD） and endogenous hormones （CTK,GA,and ABA） were researched under the stress of 4℃. The biomass and CTK,ABA and GA con- tents of the seedlings decreased significantly and the contents of MDA,proline and soluble sugar increased dramatically under cold stress compared to the treatment of normal temperature. Compared with the ab- sence of calcium,the calcium significantly reduced the contents of MDA, ABA levels and dramatically in- creased the contents of proline, soluble sugar,CTK,and GA and the activities of CAT, POD, SOD under low temperature stress. The addition of 10 mmol ·L^-1 CaC12 showed a better effect than other concentra- tions of calcium. The seedlings growth under low temperature stress was restrained. The appropriate con- centration （10--20 mmol ·L^-1） of calcium reduced the harm of low temperature on seedlings,meanwhile exogenous calcium enhanced the cold tolerance of the seedlings.