水分胁迫对太阳扇扦插苗形态和生理特征的影响

Effects of water stress on the morphological and physiological characteristics of Scaevola aemula cutting seedlings

采用持续干旱和淹水处理,测定太阳扇的叶绿素、可溶性蛋白、可溶性糖、脯氨酸、丙二醛含量和抗氧化酶体系等指标的变化,分析太阳扇对不同程度水分胁迫响应特征的差异及形成的机制。结果表明:水分胁迫初期(5d)内,太阳扇受害指数和大部分生理生化指标与对照差异不显著;随着干旱胁迫强度的增加和时间的延长,太阳扇产生较严重的伤害直至最后死亡,其受害指数、脯氨酸含量、SOD、POD、CAT活性均急剧上升,叶绿素含量明显减少,而丙二醛、可溶性蛋白、可溶性糖含量呈先减少而后增加的趋势;淹水胁迫下,太阳扇可溶性糖和叶绿素含量呈先下降到实验后期有所上升,丙二醛和可溶性蛋白含量呈降-升-降的趋势,SOD、POD活性实验初期增加然后有所减少,CAT活性和脯氨酸含量均呈持续上升趋势;持续干旱和淹水胁迫对太阳扇形态和生理特征造成严重影响,太阳扇对淹水胁迫的响应不及干旱胁迫,持续干旱对扦插苗伤害较大,太阳扇基本丧失自我调节适应不良环境的能力。

A continual drought and waterlogging treatment experiment was conducted to study the variations of chlorophyll,soluble protein,soluble sugar,proline,and MDA contents and antioxidase activities of Scaevola aemula cutting seedlings under different levels of water stress,and to analyze the differences in the response characteristics and related mechanisms.At the early stage of water stress（within 5 days）,the injury indices and most of the physiological indices of the cutting seedlings had no significant differences with the control.With the increasing intensity and duration of drought stress,the cutting seedlings were damaged seriously and finally died.The injury indices,proline content,and SOD,POD,and CAT activities increased sharply,chlorophyll content decreased significantly,and the contents of MDA,soluble protein,and soluble sugar increased after an initial decrease.Under waterlogging stress,the soluble sugar and chlorophyll contents decreased first and increased slightly then,the MDA and soluble protein contents presented a trend of decreasing-increasing-decreasing,the SOD and POD activities decreased somewhat after an initial increase,and the CAT activity and proline content had a persistent increase.Overall,a continual drought and waterlogging stress had serious effects on the morphological and physiological characteristics of S.aemula.The responses of S.aemula cutting seedlings to drought stress were more drastic than to waterlogging stress,and the seedlings were failed to recover their self-adjustment adaptability to the adverse environment under persistent drought stress.