钙对水稻幼苗抗冷性的影响

Effect of Calcium on the Cold-resistance of Rice Seedlings

ＣａＣｌ２浸种提高水稻幼苗叶片中结合态钙、内源抗氧化剂（ＧＳＨ、ＡｓＡ）含量和膜保护酶（ＣＡＴ、ＳＯＤ和ＰＯＤ）活性，也增加可溶性蛋白质中煮沸稳定蛋白质（ｂｏｉｌｉｎｇ－ｓｔａｂｌｅｐｒｏｔｅｉｎ）的含量。冷胁迫期间，ＣａＣｌ２并能减少因冷胁迫引起的ＧＳＨ、ＡｓＡ含量，ＣＡＴ、ＳＯＤ和ＰＯＤ活性以及煮沸稳定蛋白质下降的程度。在恢复期间，经ＣａＣｌ２处理的幼苗其ＧＳＨ、ＡＳＡ、ＣＡＴ、ＳＯＤ和ＰＯＤ以及煮沸稳定蛋白质水平均有回升。

Rice seeds submerged in CaCl230mmol/L solution for one day were usedas experimental material. By comparingthe contents of endogenous antioxidants(GSH and AsA ), the activities ofmembrane protecting enzymes (SOD,CAT and POD), and the content of soluble proteins before and after chillingstress and on the 3fh day of recovery,the mechanisms by which Ca affectscold resistance of rice seedlings werestudied. The results indicated that treatment with CaCl2 increased the survivalrate of seedlings after cold treatment at1℃ and under a PFD of 150 μmol m-2s-1 for 2 d.Treatment with CaCl2 increased thecontent of Ca in the leaves, especiallythat of combined Ca (Fig. 1 ); It alsoincreased the contents of GSH andAsA, reduced the extent of decline ofGSH and AsA caused by chilling stressand kept the contents of GSH and AsAas high as those in normal seedlings during the recovery period (Fig. 2); Theactivities of CAT, SOD and POD wereincreased by CaCl2 and kept at high levels after chilling and the recovery period, in a manner similar to that of GSHand AsA (Fig. 3). The content of boiling-stable protein was higher in CaCl2treated leaves than in untreated ones before and after chilling treatment, andespecially after recovery for 3 d, whenit increased in CaCl2-treated leaves butdecreased in untreated leaves (Fig. 6).By SDS-PAGE analysis, It was foundthat CaCl2 increased significantly thecontent of the large molecular weight(>67 kD) protein in both unstressedand stressed seedlings, and increased thecontent of small molecular weight(<17.5 kD) protein during recoveryperiod (Fig. 7). Therefore, we suggestthat the alleviation of chilling injury bytreating with CaCl2 could be associatedwith the enhancement of protective ability of the cell.