干旱胁迫下杨树无性系苗期光合与气孔形态变异研究

为了解不同干旱胁迫处理下，杨树叶片光合特性和气孔形态的变化规律，本研究以4个杨树无性系为材料，对其干旱胁迫下光合指标与气孔形态指标进行测定分析，方差分析结果表明：除气孔器长在处理间差异不显著外，其他性状在无性系间、处理间和无性系与处理交互作用间均达极显著差异水平。随着土壤相对含水量的逐渐降低，无性系净光合速率、蒸腾速率和气孔导度都呈现出不同程度的下降；而胞间二氧化碳浓度呈现为先降后升趋势，表明当土壤相对含水量大于40%时，光合作用的主要限制因子是气孔因素，当土壤相对含水量低于40%时，光合作用的主要限制因子转换为非气孔因素。气孔形态研究结果表明，各指标均随土壤相对含水量的持续降低呈现出持续下降趋势。利用隶属函数法对不同干旱胁迫下4个杨树无性系的抗旱性进行综合评价，结果表明：白城小青黑杨的抗旱性优于其他三个无性系。

Photosynthetic and Stomatal Morphological Variation of Poplar Clones in Seedling Stage under Drought Stress

The experiment was conducted to study the changes of leaf stomatal morphological and photosynthetic characteristics of Populus spp.under different drought stress.Four poplar clones were taken as materials and investigated their photosynthetic and leaf stomatal morphological characteristics under drought stress.By ANOVA analysis,there were significant differences(P<0.01)for all traits among different source of variation in different treatment except stomatal apparatus length.With the reduction of soil relative water content,net photosynthetic rate,transpiration rate and stomatal conductance decreased,however,the intercellular CO2 concentration increased at first and then decreased.These results suggested that that drought-induced photosynthetic inhibition was due to stomatal limitation when the relative water content of soil was above 40%;However,the main limiting factor of photosynthetic inhibition of plants under severe drought stress was due to non-stomatal limitation.Drought decreased all traits of stomatal morphological characteristics.Using the method of subordinate function analysis,the drought-tolerance of Populus psedosimonii×P.nigra‘baicheng-1’was better than other clones.