Studies On Function Of Microfilaments And Actin MRNA During The Development Of Callus

After dedifferentlation and redifferentiation,the explants had three fates: abnormal plantlets, death and healthy plants. The correlation between microfilaments,actin mRNA and development had been reported. We studied development mechanism by the distribution of microfilaments and actin mRNA in cotton callus ,healtny plants and abnormal plantlets.FITC-Phalloidin as fluorescence probe was used to investigate the meristem of the cotton root ,abnormal plantlets and callus that was unable to germinate into healthy plants. The results showed that there was a great deal of microfilaments in root meristematic cells, there was a few microfilaments in cotton callus and abnormal plantlets; By alignment of PEAc17 with cotton actin. We obtained a fragment which showed 82% similarity to cotton actin. It was used to prepare RNA probe with DIG labeling. Distribution of actin mRNA in root tip and callus was examined by in situ hybridization. Signals were strong in the cell periphery of procambium, and longitudinal signals were stronger than lateral ones ; In root ground meristem cytoplasm, concentration in the perinuclear region was stronger than one in the cell periphery. In cell periphery of root ground meristem, Distribution of actin mRNA was heterogeneous, longitudinal signals were stronger than lateral ones; In callus meristem cytoplasm, concentration in the perinuclear region was low;. Concentration in the cell periphery region was high and distribution of actin mRNA was heterogeneous. In the cell periphery of callus parenchyma, signals were feeble and heterogeous. In the perinuclear of callus parenchyma, concentration was low. The distribution and concentration of microfilaments and actin mRNA had distinct variation during development of callus. Then microfilaments and actin mRNA may play important roles during callus development...