Analysis of Net Photosynthetic Rate,Transpiration Rate Change and Its Influencing Factors of Saxifrage in Winter

Comparison between diurnal variation of photosynthetic rate and transpiration rate,the influencing factors of cultivars and wild species of Saxifrage leaves in the Xiangxi winter was analyzed by Li-6400 portable photosynthesis system.The results showed that the net photosynthetic rate of Saxifrage showed a single peak in the winter,the net photosynthetic rate peaks of wild(14:30) was later than that of the cultivated species(13:00),and the average net photosynthetic rate of the wild species was significantly lower than that of cultivated species.Transpiration rate was not fully synchronized with net photosynthetic rate.The lowest value was at 10:00 by the air humidity.Correlation studies indicated that the photosynthetic active radiation and temperature were the major environmental factors to net photosynthetic rates.And the transpiration rate was affected by the humidity of the air.The internal physiological factors were non-stomatal factors that affected net photosynthetic rate and transpiration rate.