中文摘要：

在室外盆栽条件下研究了春小麦Triticumn aestivum品种定西-24生长和光合作用对增强UV—B辐射和干旱胁迫的响应及机制。结果表明，干旱明显影响定西-24叶绿素b的含量，对叶绿紊a和类胡萝卜素含量的影响不显著。UV—B辐射以及与干旱复合都降低叶片叶绿素a、b和类胡萝卜素的含量，且复合作用大于UV—B辐射单独作用．UV—B辐射以及与干旱的复合胁迫显著地影响到类黄酮含量的积累（P〈0．05）。各处理间光合作用的大小顺序为：对照〉复合〉干旱〉UV—B辐射。干旱和UV—B复合作用下较单独作用气孔阻力有所增加。胞间CO2浓度在干旱和复合作用下升高．而在UV—B辐射下下降。收获期春小麦的总生物量比对照明显减少，其中，干旱作用下致使总生物量下降的幅度大于UV-B辐射与复合作用。同时，小穗组成和产量特征也发生变化。UV—B辐射对产量的影响大于干旱和复合作用,复合作用的减产效应低于干旱。干旱和UV—B辐射使定西-24的收获指数增加10％，在两者复合作用时收获指数变化不大。干旱和复合作用下，植物根系的根冠比增大．而UV—B辐射胁迫下根冠比变化不大。这些结果说明，UV-B辐射和干旱之间存在相互作用，一种胁迫可以减缓（轻）另外一种胁迫对春小麦的抑制作用。

英文摘要：

The response pigments contents, photosynthesis, biomass and yield of spring wheat cultivars Dingxi-24（Triticum aestivum cv. Dingxi-24）to enhanced UV-B radiation and soil drought under the field condition of pot cultivation. The radiation or drought, simply or combined, led to the decrease in foliar flavnoid content, but only there is statistically significant under the condition of the combination. The water stress caused the reduction of chlorophyll b, but not the content of chlorophyll a and carotenoids. UV-B radiation and the combination all led to significantly the reduction of photosynthetic pigments. Various treatments could inhibit the photosynthesis, and the ordination is control〉combination 〉drought〉UV-B. The drought played more obvious roles in stomatal resistance. There was higher internal carbon dioxide concentration under the condition of drought and the combination, and lower internal COt under the condition of UV-B radiation. At harvest, the total bio- mass were significantly declined comparison to cohtrol, the order from high to low was control〉combination〉UV-B〉drought. The composition of spikes and yield were also negatively impacted. The results showed that there were interactive between UV-B radiation and soil drought, suggesting that one stress factor might alleviate the inhibitory effect of another stress on spring wheat.