干旱胁迫对槐树幼苗生长和生理生态特征的影响

Effect of Drought Stress on Growth and Eco-physiological Properties of Sophora japonica Seedlings

以盆栽当年生槐树幼苗为材料,研究干旱胁迫对槐树幼苗生长和若干生理生态指标的影响。结果表明:随着干旱胁迫程度的加剧,槐树幼苗的生长受到明显抑制,叶片相对含水量、净光合速率、蒸腾速率、气孔导度逐渐下降,水分利用效率和脯氨酸含量则显著上升;叶绿素a、叶绿素b、叶绿素总量、类胡萝卜素含量随土壤含水量的降低,先减小后增大,而叶绿素a/叶绿素b、类胡萝卜素/叶绿素总量无显著变化;干旱胁迫下,净光合速率的下降是由气孔因素与非气孔因素双重作用造成的,轻度和中度干旱胁迫下气孔限制是光合速率下降的主要原因,而重度干旱胁迫下非气孔限制是光合速率下降的主要原因。

Experiment on effect of drought stress on growth and coo-physiological properties of Sophora japonica was carried out with potted seedlings of the current year, including 4 levels of drought stress： no stress（control）, light one, moderate one and severe one. The result showed that with the drought stress developing, the growth of seedlings was obviously restrained, relative leaf water content（RWC）, net photosynthesis rate（Pn）, transpiration rate（Tr）, stomatal conductance（Gs） decreased, while water use efficiency（WUE） and free praline（Pro） content increased evidently. Contents of chlorophyll a（Chla）, chlorophyll b（Chlb）, total chlorophyll（Chl） and carotenoid（Car） pigment decreased first and increased along with the decrease of water content in the soil. In the same time, the ratio of Cha/Chb and Car/Chl had no remarkably change. The decrease of Pn was caused by stomatal and non-stomatal inhibition. Under light and moderate drought stress, the decrease of Pn was mainly caused by the stomatal inhibition, while under severe stress by the non-stomatal factors.