低温小麦种质叶片结构及某些生理特性

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165 μm，平均比高温种质薄26 μm；3片功能叶叶脉的平均间距分别为257、231和245 μm，平均比高温种质小31 μm；3片功能叶大叶脉平均横截面积分别为5 961、6 580和5 603 μm²，平均比高温种质大837 μm²;小叶脉平均横截面积分别为1 624、1 521和1 472 μm²，平均比高温种质大246 μm².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2.4129 g·100 g^-1 FW;净光合速率分别为10.8640、10.8003和10.1939 μmol·m^-2·s^-1;蒸腾速率分别为0.0076、0.0074和0.0067 mol·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.

Leaf structure and some physiologic characteristics of low temperature wheat germplasm

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 to approximately 4 degrees C lower than that of HTWG. The mesophyll cells of LTWG functional leaves were smaller, more compact in cell arrangement, and 1 to approximately 2 cell layers more than those of HTWG's. The average thickness of three LTWG functional leaves was 166,192 and 165 micro/m, being 26 microm thinner than that of HTWG, average vein interval of three functional leaves was 257,231 and 245 microm, being 31 microm smaller than that of HTWG, average transverse area of big veins of three functional leaves was 5 961,6 580 and 5 603 microm2, being averagely 837 microm2 more than that of HTWG, and average transverse area of small veins was 1624, 1521 and 1 472 microm2, being averagely 246 microm2 more than that of HTWG. The chlorophyll content of three LTWG functional leaves was 2.8749, 2.8162, and 2.4129 g x 100(-1) g FW, net photosynthetic rate was 10.864, 10.8003, and 10.1939 micromol x m(-2) x s(-1), and transpiration rate was 0.0076, 0.0074, 0.0067 mol x m(-2) x 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.