[Observation amyloplasts in the gravity-insensitive mutant of rice under gravity and microgravity conditions]

Using histochemistry and optical microscope, we examined the number and the size of amyloplasts in specialized tissues of gravitropically receptive organs-tissues such as the coleoptile and sheath of rice mutant (insensitive to gravity) and wide type (Oryza sativa L. subsp. japonica) (Zhonghua 11). We found there was no statistical difference between the mutant and wide type, both of which grew on earth or on the clinostat respectively. On earth, it was found that amyloplasts sedimented at the distal end of each cell of the special starch sheath tissues and re-sedimentation of amyloplasts toward the direction of gravity was almost completed in 5 minutes after inverting the seedlings. On the clinostat, amyloplasts dispersed in the starch sheath tissue. Such observations indicated that the mutation was not resulted from the starch-deficiency or starch-absence, the further research is going on.