中文摘要：

通过对小麦冠层温度的长期观测，发现自然界存在冠层温度持续偏低的低温种质和冠层温度持续偏高的高温种质．在扬花结实期，低温种质冠层温度比高温种质低1～4℃．低温种质功能叶片叶肉细胞小，排列紧密，层数较多，通常比高温种质多1～2层叶肉细胞．低温种质陕229、901和小偃6号3片功能叶的平均厚度分别为166、192和165μm，平均比高温种质薄26μm；3片功能叶叶脉的平均间距分别为257、231和245μm，平均比高温种质小31μm；3片功能叶大叶脉平均横截面积分别为5961、6580和5603μm^2，平均比高温种质大837μm^2；小叶脉平均横截面积分别为1624、1521和1472μm^2，平均比高温种质大246μm^2．在扬花结实期，低温种质陕229、901和小偃6号3片功能叶平均叶绿素含量分别为2．8749、2．8162和2．4129g·100g^-1FW；净光合速率分别为10．8640、10．8003和10．1939μmol·m^-1·s^-1;蒸腾速率分别为0．0076、0．0074和0．0067mol·m^-2·s^-1，均明显高于高温种质．结果表明，植物的冠层温度与植物本身的器官结构和生理功能联系密切．

英文摘要：

Through a long-term observation on wheat canopy temperature, it was found that in the nature, there existed low temperature wheat germplasm （LTWG） with constant low canopy temperature, and high temperature wheat germplasm （HTWG） with constant high canopy temperature. The study on the leaf structure and some physiologic characteristics of LTWG during its blooming and milk-filling stages showed that the canopy temperature of LTWG was 1 -4℃ lower than that of HTWG. The mesophyll cells of LTWG functional leaves were smaller, more compact in cell arrangement, and 1 - 2 cell layers more than those of HTWG＇ s. The average thickness of three LTWG functional leaves was 166,192 and 165μm, being 26μm thinner than that of HTWG, average vein interval of three functional leaves was 257,231 and 245μm, being 31μm smaller than that of HTWG, average transverse area of big veins of three functional leaves was 5 961,6 580 and 5 603μm^2, being averagely 837μm^2 more than that of HTWG, and average transverse area of small veins was 1 624, 1 521 and 1 472μm^2, being averagely 246 μm^2 more than that of HTWG. The chlorophyll content of three LTWG functional leaves was 2. 8749, 2. 8162, and 2. 4129 g·100^-1 g FW, net photosynthetic rate was 10. 864, 10. 8003, and 10. 1939μmol·m^-2·s^-1, and transpiration rate was 0. 0076, 0. 0074, 0. 0067 mol·m^-2·s^-1, respectively, which were all higher than those of HTWG. It was revealed that there were close relationships among canopy temperature, organ structure, and physiologic function.