干旱胁迫对毛竹幼苗生理特性的影响

Effects of drought stress on physiological characteristics of Phyllostachys edulis seedlings

以1年生毛竹为试验材料,采用盆栽方式,设置对照(CK)、轻度(LS)、中度(MS)和重度干旱胁迫(HS)4个不同处理,研究不同水分条件下毛竹幼苗生理响应。结果表明:随着水分胁迫程度的加强,毛竹幼苗净光合速率(Pn)、蒸腾速率(Tr)显著下降(P<0.01),降幅分别达54.7%和49.7%,水分利用效率(WUE)在轻度胁迫条件下明显提高,但在中度和重度胁迫下又有一定程度下降;叶绿素a和叶绿素b含量显著下降(P<0.05和P<0.01),降幅分别为42.1%和28.2%,水分胁迫对叶绿素a/b(Chl-a/Chl-b)影响不显著;SOD活性、CAT活性和MDA含量显著上升(P<0.01、P<0.05和P<0.01);各生理指标间存在着相关性,经主成分分析,可将9个单项耐旱生理指标综合成为2个相互独立的综合指标,为评价毛竹苗期抗旱性提供参考。

A pot experiment was conducted to study the physiological responses of 1-year old Phyllostachys edulis seedlings to drought stress. Four treatments were installed,i.e.,control （CK）,light （LS）,medium （MS）,and heavy （HS） drought stress. With increasing drought stress,the net photosynthetic rate （Pn） and transpiration rate （Tr） decreased significantly by 54.7% and 49.7%,respectively,WUE increased obviously under LS but decreased to some extent under MS and HS,Chl-a and Chl-b contents decreased significantly by 42.1% and 28.2%,respectively,but Chl-a/Chl-b was less affected,and the SOD and CAT activities as well as the MDA content increased significantly. There existed close correlations among these physiological indices. Principal components analysis （PCA） showed that the nine individual drought-tolerance indices could be integrated to two separate,comprehensive ones,and used as a reference to evaluate the drought resistance of P. edulis seedlings.