紫玉兰光合特性的日变化

Diurnal Change of Photosynthesis Magnolia liliflora

分别在晴天和阴天适宜条件下,对紫玉兰采用TPS1便携式光合测定系统测定其叶片的光合速率、蒸腾速率、气孔导度、胞间CO2浓度等的日变化.结果表明:在晴天,紫玉兰的光合作用日变化呈双峰型,存在光合午休现象,阴天则为单峰型.蒸腾速率在很大程度上决定于气孔导度,气孔导度与光合速率日变化趋势有很强的正相关关系.

Under the proper condition of sunny and cloudy day, TPS1 portable photosynthesis system is used to study the characteristics and the diurnal changes of Magnolia Liliflora in the natural conditions such as photosynthetic rate（ Pn）, transpiration rate（ Tr）, stomatal conductance （C）, CO2 concentration between the cells. The results show that： In sunny day, the diurnal changes curves of photosynthetic rate of Magnolia liliflora take on a double peak curve,and has ＇noon break＇. But in cloudy day,it takes on a single peak curve. The stomata conductance of Magnolia liliflora is positively correlated with the photosynthetic rate, and it is largely decided by the transpiration rate.