Abstract:

The light response curve and diurnal variation of net photosynthetic rate of different Fagopyrum dibotrys mutants bred by Co60γ irradiation was studied during rapid growth period for developing new germplasms by the Li-6400 portable photosynthetic system. The results showed that the red leaves and red stems had higher photosynthetic capacity under low light, but the green stem had higher photosynthetic capacity under high light; the diurnal net photosynthetic rate of three Fagopyrum dibotrys sunny day exhibited double-peak pattern, which was caused principally by stomatal limitation and midday depression were appeared; the diurnal net photosynthetic rate of green stem are higher than red stem and red leaves; light and higher temperature was main factor that affected the Fagopyrum dibotrys photosynthetic rate, red stem needs higher carbon dioxide concentration, but that suppress green stem and red leaves, and lower relative humidity was another factors affected red leaves photosynthetic rate. The researches indicated Fagopyrum cymosum mutants had lower photosynthesis capacity than original plants.