沙枣幼苗在干旱胁迫下的光合特性研究

Photosynthetic Characteristics of Elaeagnus angustifolia Seedlings under Drought Stress

采用盆栽控水方式研究了沙枣幼苗在干旱胁迫下的光合特性,研究结果表明:(1)沙枣在轻度干旱胁迫条件下叶绿素a、叶绿素(a+b)含量都处于最高水平,且随着干旱程度的提升,沙枣的叶绿素a/b也在不断增大,表明沙枣不仅是抗旱能力较强的树种,也是耐阳树种。(2)干旱胁迫也引起了沙枣光合特征值的变化,净光合速率变化曲线呈现“单峰型”,并未出现“光合午休”现象;随着干旱胁迫的加重,沙枣叶片的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)在同一时间点均呈下降的趋势,且在重度干旱胁迫条件下降尤为明显;蒸腾速率(Tr)和气孔导度(Gs)当Pn和Gs下降的同时C没有表现出规律的升降趋势,表明沙枣光合特性的变化同时受气孔和非气孔双重因素的控制。

The photosynthetic characteristics of Elaeagnus angustifolia seedlings under drought stress were studied by pot water control. The results showed that:(1) the contents of chlorophyll a and chlorophyll(a+b) of Elaeagnus angustifolia seedlings were at the highest level under mild drought stress, and the chlorophyll a/b of Elaeagnus angustifolia also increased with the increase of drought degree, indicating that Elaeagnus angustifolia is not only a tree species with strong drought resistance, but also a sun resistant tree species.(2) Drought stress caused the changes of photosynthetic characteristic values of Elaeagnus angustifolia. The change curve of net photosynthetic rate of Elaeagnus angustifolia showed a “mono-peak type”, and there was no phenomenon of “photosynthetic noon-break”. With the aggravation of drought stress, the net photosynthetic rate(PN), transpiration rate(TR) and stomatal conductance(GS) of Elaeagnus angustifolia leaves decreased at the same time point, especially under severe drought stress. When PN and GS decreased, CI did not show a regular upward and downward trend, indicating that the changes of photosynthetic characteristics of Elaeagnus angustifolia were controlled by both stomatal and non stomatal factors.