中文摘要：

采用水培实验及光照培养箱培养方法,通过测量玉米木质部伤流液及露珠中三氯乙烯（TCE）和1,2,3-三氯苯（TCB）两种有机污染物的浓度,对比探讨了两种有机污染物在水-玉米-空气系统中的传输过程和机制。结果表明,露珠中TCE与TCB均主要来源于随水蒸气的叶面挥发过程;水培条件下TCB在玉米木质部伤流液中的浓度与根外部水溶液中TCB浓度呈正相关,而露珠中TCB浓度与外部水溶液浓度呈负相关,蒸腾流浓缩系数（TSCF）值由暴露时间决定。实验条件下,根外部溶液浓度较低时,露珠中TCB浓度远大于木质部伤流液中TCB浓度;而高浓度时,木质部伤流液中TCB浓度远大于露珠中浓度。露珠中TCE浓度远大于木质部伤流液中TCE浓度,且与根外部水溶液浓度呈正相关;而木质部伤流液中TCE浓度随营养液中TCE浓度增加而减小。

英文摘要：

Corn seedlings were exposed separately to culture solutions of trichloroethylene（TCE）or 1,2,3-trichlorobenzene（TCB）.Concen-trations of TCE and TCB in xylem saps,dewdrops,and final culture solutions were determined to evaluate the transport processes of the two organic compounds in water-corn-air systems.The results indicated that TCE and TCB in dewdrops originated mainly from their volatilization with water vapor from the seedling leaves.The TCB concentrations in xylem saps were positively related to the respective concentrations in the externa（lculture）solution.In contrast,the TCB concentrations in dewdrops were negatively related to those in the external solution.The transpiration stream concentration facto（rTSCF）was found to vary with the exposure time.The TCB concentrations were higher in dewdrops than in xylem saps when the seedlings were exposed to low TCB concentrations in the external solution;the reverse occurred when the seedlings were exposed to high TCB concentrations in the external solution.The TCE concentration in dewdrops increased with increasing TCE concentration in the external solution,and was generally much higher than that in the xylem sap;the TCE concentration in xylem saps decreased sharply with increasing TCE concentration in the external solution.