城市胁迫环境下的二球悬铃木叶片气孔数量特征分析

对采自上海市区14个样点的二球悬铃木叶片气孔的研究结果表明，在3个采样时期，叶片气孔数量特征如气孔密度和气孔长径在不同环境胁迫程度下均表现出显著的差异，随着环境胁迫程度的增强，观察到气孔密度(SD)逐渐增加而气孔长径(SL)逐渐降低的趋势，两者之间表现出极显著的线性相关：SL=-0.0375SD 29.275，r=0.7609，p=0.0041(5月初)；SL=-0.0255SD 25.116，r=0.7407，p=0.0024(9月底)；SL=-0.0335SD 25.678，r=0.7152，P=0.0040(11月初)．而气孔的空间分布型却未受任何影响，气孔密度和气孔长径可作为指示小尺度上环境胁迫的有效指标．

A Study on Stomatal Traits of Platanus Acerifolia under Urban Stress

The foliar stomatal traits of Platanus acerifolia from 14 sites categorized with different stress levels in Shanghai were studied. Results showed the seasonal variation of stomatal traits was somewhat puzzling, but the data set showed the significant negative relation between stomatal density (SD) and stomatal length (SL) through all the sample periods: in the early May, SL=-0.037 5SD+29.275,r=0.760 9,p=0.004 1;and in the late September, SL=-0.025 5SD+25.116,r=0.740 7,p=0.002 4;and in the early November, SL=-0.033 5SD+25.678,(r=0.715 2),p=0.004 0.The trend showed in sites with high stress levels foliar stomatal length decreased and stomatal density increased, while in sites with low stress levels variation of foliar stomatal length and stomatal density showed the contrary results, which implicated the responses of stomata to the stressful environment at small scale, however, the stomatal distribution pattern indices seemed to keep the constant mean type distribution pattern, thus all these can be interpreted that stomatal density and stomatal length were more sensitive and available to indicate urban environmental stress than the stomatal distribution pattern indices.