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干旱胁迫对红花檵木叶片色素含量及光合特性的影响

Effects of Drought Stress on Pigment and Photosynthetic Characteristics in Leaves of Loropetalum chinense var.rubrum

  • 摘要: 以两年生红花檵木实生苗为材料,采用盆栽控水法,以正常供水为对照(CK),探讨了轻度(T1)、中度(T2)和重度(T3)干旱胁迫下叶片色素含量和光合指标的变化。结果表明:随胁迫程度的加重,叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素总量(Chl)和类胡萝卜素(Cx+c)总体呈上升趋势,叶绿素a与b比值(Chla/Chlb)则有所下降,且随时间的推移CK、T2、T3花色素苷含量下降,叶色返青;干旱胁迫显著降低了红花檵木的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs),增加了胞间CO2浓度(Ci)及水分利用效率(WUE),各光合指标之间存在显著的相关性。研究认为,红花檵木为偏旱性植物,可以通过色素含量的增加以及水分利用效率的提高来适应水分亏缺的环境,夏季高温条件下土壤含水量过高或过低,会加快花色素苷的分解,出现返青现象,影响其观赏价值。

     

    Abstract: A water-controlling pot experiment was conducted to evaluate the effect of slight,moderate and severe drought stress on pigment and photosynthetic characteristics in leaves of two-year-old seedlings of Loropetalum chinense var.rubrum.The results showed that the amount of Chla, Chlb, Chl and Cx+c all increased generally,while the Chla/Chlb ratio decreased with the aggravation of drought stress.The anthocyanin content decreased in CK,T2 and T3 under continuous drought,which turned leaves green.Drought stress reduced the Pn,Tr,Gs and enhanced the Ci and WUE in Loropetalum chinense significantly,and there were significant correlations among these photosynthetic indices.In summary,Loropetalum chinense tended to be a kind of xerophile plant,which could bear slight drought stress by increasing the chloroplast pigment contents and leaf water use efficiency.In practice,inappropriate water supply should be avoided,otherwise the ornamental value would be affected for the degradation of anthocyanin.

     

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