干旱胁迫对几种楸树苗木叶片荧光特性的影响

Effects of drought stress on the fluorescence characteristics of four type of Catalpa spp.

在模拟干旱胁迫条件下,对4种不同类型楸树叶片的叶绿素荧光动力学参数进行了研究,结果表明,干旱胁迫对楸树叶片的叶绿素荧光参数存在显著影响。随着干旱胁迫的加剧,PSⅡ最大光化学量子效率(Fv′/Fm′)、光化学猝灭系数(qP)呈现"降低—增加—降低"的规律;原初光能转化效率(Fv/Fm)在干旱胁迫初期降低,之后升高,再降低。说明胁迫初期楸树发生光抑制,逆境适应调整后,PSⅡ反应中心开放增加,减少了光抑制,后期干旱胁迫加剧,光抑制增大。Fv/Fo、NPQ、ETR、ΦPSⅡ等指标在胁迫初期升高,后期降低,说明经受适度的干旱胁迫,植株可作出一系列适应性调节,体现出自身的保护机制。4种不同类型楸树对干旱胁迫逆境的适应能力不同,Fv/Fm反映其光抑制的大小,按其变化可得出抗旱性从大到小依次为南阳楸、金丝楸、圆基长果楸、楸树。

The chlorophyll fluorescence parameters, e.g. Fv/Fm, Fv＇/Fm＇ φPSⅡ, qp, NPQ, ETR, for four type of Catalpa spp. were determined and analysed using chlorophyll fluorescence kinetics technology under drought stress. The results showed that the Fv/Fm and qp had the trend of decrease--increase --decrease with the increase of drought stress. It indicated that photoinhibition took place at the first stage of drought stress, then the tree adjusted itself and the reaction center began to open and reduce the photoinhibition. An the end, the photoinhibition began to increase. The results of Fv/Fm ,NPQ,ETR,φPSⅡ increase in the early,and reduce in the later. The results showed that the tree could adapt the adversity and the plant had protection mechanism. There were great different of the capability to react to drought stress for four type of Catalpa. According to Fv/Fm, the ability of drought resistance of four type of Catalpa spp. was ＇ Nanyang＇ , ＇ Jinsi＇ , ＇ Yuanjichangguo＇ , Catalpat bungei.