PHOTOAUTOTROPHIC GROWTH AND PHOTOSYNTHETIC CHARACTERISTICS OF CARROT CALLUS
ZENG Xiao Mei WANG Ling Jian XIA Zhen Ao SHEN Yun Gang ( Shanghai Institute of Plant Physiology and Ecolology, Chinese Academy of Sciences, Shanghai 200032)
Photoautotrophic carrot callus was induced by gradually lowering the sucrose concentration in culture medium. In the course of induction, the net photosynthetic rate on chlorophyll basis of callus increased gradually with the decreasing of sucrose concentration in culture medium, and the net photosynthetic rate of photoautotrophic callus could even be higher than that of leaf. In the course of changing into pholoaulotrophic callus, its chlorophyll content increased gradually, and the dark respiratory rate and the ratio of Chl a/Chl b decreased gradually. Parallel with these was the development of the microstructure of thylakoid of callus.