外源油菜素内酯对低温胁迫下水稻幼苗生长及生理特性的影响

Effect of Exogenous 2,4-Epibrassinolide on Germination and Physiological Characteristics of Rice Seedlings under Chilling Stress

以水稻品种‘湘早籼45号’为试验材料,喷施不同浓度的外源2,4-表油菜素内酯(2,4-Epibrassinolide,EBR)进行低温(4℃)处理,测定水稻幼苗形态特征、壮苗指数、抗氧化酶活性、丙二醛(MDA)含量及可溶性蛋白含量等指标。结果表明:适宜浓度的外源EBR能有效缓解低温胁迫对水稻幼苗的损伤,并以1.0μmol/L EBR处理效果最佳,其株高、茎粗、地上部分鲜质量、地上部分干质量、地下部分鲜质量、地下部分干质量以及壮苗指数相比低温对照显著提高9.22%~40.74%;而根系的长度、表面积、体积、连接数和根尖数相比低温对照显著增加14.42%~42.8%。同时,1.0μmol/L EBR处理能显著提高水稻幼苗根系的SOD、POD、CAT活性,相比低温对照增加14.88%~73.92%,并且能显著降低水稻幼苗叶片和根系MDA含量的积累,增加可溶性蛋白含量。因此,在生产上,喷施1.0μmol/L EBR溶液能够增加水稻幼苗的低温耐受性,有利于培育水稻壮苗。

With rice variety‘Xiangzaoxian 45’as a test material,different concentrations of exogenous 2,4-Epibrassinolide(EBR)were sprayed under chilling stress(4℃)to determine morphological characteristics,strong seedling index,antioxidant enzyme activity,malondial dehyde content and soluble protein content of rice seedlings.The results showed that appropriate concentration of exogenous EBR could increase the tolerance of rice seedlings under chilling stress.Among them,1.0μmol/L EBR treatment showed the best performance.The plant height,stem thickness,above ground fresh mass,above ground dry mass,underground fresh mass,underground dry mass and the seedling index significantly increased by 9.22%-40.74%compared with the control under chilling stress.The length,superficial area,volume,linking number and root tip number significantly increased by 14.42%-42.8%compared with the control underchilling stress.1.0μmol/L EBR treatment could significantly improve the activities of SOD,POD and CAT in the roots of rice seedlings,which increased by 14.88%to 73.92%compared with the controlunderchilling stress,while it could significantly reduce the accumulation of malondial dehyde in leaves and roots of rice seedlings,and increase the content of soluble protein.Therefore,spraying of 1.0μmol/L EBR could increase the chilling stress tolerance of rice seedlings in production,and this was conducive to cultivate strong rice seedlings.