THE GRADIENT VARIATION OF PHOTOSYNTHETIC ECOPHYSIOLOGY ON PLATEAU TYPE KENY RICE
高原粳稻光合生理生态的梯度变化

The light-photosynthesis and the ecophysiology responese of variouskinds of keny typical rice (Oryza sativa subap, Keng Ting) at differentaltitudes to light and temperature were investigated under field cultureand pot culture conditions. The five varieties of keny rice were used:Keng No, 10, Dao No 4, Mei Dan, 79-2 and Chu Keng No.3 altitudes of2510, 2490, 2400, 2200 and 1850m, respectively. The results indicatedall photosynthetic characteristics of keny rice varieties at different altitu-des showed apparent gradient variations. Under lower intensity of illumi-nation, the photosynthetic rate at the ear-bearing stage would graduallydecrease in Keng rice varieties along with the increase in altitude. Underhigher intensity of illumination, however, the rate would gradually incr-ease along with the increase in altitude. The relationships between phot-osynthesis of Keng rice and illumination could be determined by the cur-ve equation: p=a blgI, where p is photosynthetic rate, I is light inten-sity. The light saturation point of keng rice showed a tendency to incre-ase with the rise of altitude. The effects of shading on yield parametersof keng rice at highter altitudes were much greater than of keng rice atlower altitudes. The plateau keng rice varieties have high coldtolerancewhen different varieties exposed to low temperature at the blooming stage. The results suggested that different photosynthetic ecophysiology res-ponses to light-temperature were determined by their difference in matabo-lic pattern and adaptability to the environment.