CaM对渗透胁迫下小麦幼苗ABA合成的介导作用研究

Study of CaM Function in the Process of ABA Synthesis in Roots of Winter Wheat Seedlings Under Osmotic Stress

ABA作为干旱信号物质在植物抗逆生理反应过程中起着至关重要的作用,揭示ABA合成及其信号转导机制对于探明植物干旱信息的感受机制尤为重要。通过外使CaM拮抗剂TFP、ABA以及分根试验,研究了渗透胁迫下小麦幼苗根系和叶片中ABA和CaM含量和时间的变化。渗透胁迫均促进根系和叶片ABA和CaM含量不同程度地提高,根系ABA含量峰值出现的时间早于叶片,而CaM峰值出现的时间晚于叶片。但根系和叶片ABA峰值均不晚于CaM。不同浓度TFP和ABA处理都能提高根系和叶片ABA和CaM含量,与渗透胁迫相比,ABA呈现先升高后降低趋势,且最大值出现的时间类似,但CaM呈持续上升趋势。TFP处理抑制根系CaM含量增加,而对叶片有促进效应。ABA处理呈现浓度效应。与全根胁迫相比,分根胁迫对胁迫根系ABA含量影响不明显,但与正常对照相比,显著提高了未胁迫部分根系ABA含量,但二者峰值出现的时间分别滞后6和18 h;叶片ABA和CaM含量也相应提高,且最大值滞后12 h。CaM可能未参与渗透胁迫下ABA的合成过程,渗透胁迫引起ABA合成后,调控胞内CaM水平。

ABA plays an important role in the process of drought resistance as a drought signal molecular, so it＇ s necessary to investigate the mechanism of ABA synthesis and it＇s signal transduction. Under PEG stress, both the ABA and CaM contents and the time of the largest values apperance were measured using the roots and leaves of 2-leaf-old winter wheat seedlings treated with ABA, part-roots stress and pre-treated with exterior TFP for 24 h respectively.ABA and CaM contents of roots and leaves were all increased at different extend by PEG, the time of the largest ABA apperance in root was prior to that of the leaves, but CaM was late. And the time of the largest ABA content were not late to that of CaM either in roots or in leaves.The ABA and CaM contents both roots and leaves were all enhanced by exterior TFP and ABA, and CaM contents appeared rise continually. Compared to PEG stress, the time of the largest ABA appearance was similar. When subjected to partroots stress, the ABA content of roots which were subjected to stress didn＇t be affected, but it was increased in the roots of non-stressed seedlings, and the time of the largest value were lagged for 6 h and 18 h in both sressed-roots and non-stressed roots respectively; the CaM contents were all increased in both part of roots and leaves too. Compared to control, the times of the largest CaM and ABA values in leaves were all lagged for 12 h. CaM may not participate in the process of ABA synthesis of root under PEG stress .The ABA regulated the CaM level after synthesis under PEG stress.