Abstract:

In order to explore the influence on climate change to crop’s photosynthetic physiology characteristics, the environmental factors and rape’s photosynthetic physiology indexes were measured by using LI-6400 portable photosynthesis system in rape blooming period. The rape’s photosynthetic physiology index’s difference was studied in different years and in different sowings. The results showed that: diurnal change of rape leaf’s net photosynthetic rate presented a bimodal pattern, and had a midday depression, also morning’s net photosynthetic rate high to afternoon’s. The rape’s transpiration rate presented a bimodal pattern. The stomatal conductance presented “S” pattern in all. The diurnal change of photosynthetic active radiation and temperature presented a signal pattern. The air humidity presented “S” pattern. By significantly relativity analysis, the photosynthetic active radiation was a main environmental factor which effected net photosynthetic rate in rape blooming period (R2=0.6916). The photosynthetic active radiation and temperature were main environmental factors which effected transpiration rate (RPAR2=0.7133，RT2=0.5611). The air humidity was a main environmental factor which affected the stomatal conductance (R2=0.5503). The rape not only external environment but also internal environment were all in suitable state in moist year, which rape’s photosynthetic physiology indexes were higher than in drought year. The different sowing rape’s transpiration rate showed very significantly different (P<0.001). The net photosynthetic rate and stomatal conductance showed significantly different (P<0.05). But the intercellular CO2 concentration showed not significantly different.