渗透胁迫对连香树幼树生理特性的影响

Effects of osmotic stress on the physiological characteristics in young trees of Cercidiphyllum japonicum

以2年生连香树实生苗为试材,研究不同渗透胁迫对其生理特性的影响。结果表明,随着胁迫浓度的增加和时间的延长,叶片中总叶绿素含量明显降低。随着聚乙二醇(PEG)浓度的增加,可溶性蛋白、可溶性糖、脯氨酸和丙二醛(MDA)含量增加,保护性酶过氧化物酶(POD)活性升高,过氧化氢酶(CAT)活性下降,而超氧化物歧化酶(SOD)活性先升高,并在PEG胁迫浓度为150 g.L-1时达到最大值,随后降低。连香树在渗透胁迫下通过增加渗透调节物质含量,降低水势,加强保水力来提高其耐旱能力,并通过增强抗氧化酶活性,提高抗氧化能力,减轻渗透胁迫伤害。连香树具有一定的耐旱性。

To investigate the response of Cercidiphyllum japonicum under the osmotic stress,eight types of biochemical and physiological index in the leaves of young trees of C.japonicum that treated with polyethylene glycol（PEG） at different concentrations were measured.The results showed that the content of chlorophyll were significantly decreased with the increase of the concentration of PEG and lengthening of time.Accompanying with the increase of concentration of PEG,we found the abundance of soluble protein,soluble sugar,proline and malondialdehyde（MDA） and the activity of peroxidase（POD） were increased,while the activity of catalase（CAT） was decreased.Stringly,under the same condition,the activity of superoxide dismutase（SOD） was firstly increased and then decreased under serious stress.These findings suggest that the C.japonicum could adjust the contents of osmotic substance for the adaption of the osmotic stress,and improve the activity of protective enzymes to enhance the ability of antioxygenic.The results showed that C.japonicum could normally grow under moderate stress.