Phenotype Analysis Of Arabidopsis Temperature Sensitive Mutant Ckts And Its Relation To Cytokinin

Cytokinin influences the growth and development of plants in many aspects. On the condition of low temperature, plants will show slowly growth. In the study, cytokinin and temperature Sensitive Mutant (ckts), which shows various growth speeds in different temperature, was isolated and characterized. This mutant exhibits the slow growth of primary root in all temperature, especially in low temperature. It is sensitive to exogenous auxin (IAA,2,4-d) in low temperature environment, and it was found that ckts is a response genes for cytokinin when treated by the6-BA. The wild type, treated by mitotic inhibitors Lovastatin (LVST), showed similar phenotypes to the mutant, such as shortening of primary root and primary root disorder, while the mutant didn’t change significantly in the same condition. These facts illustrated that the mitotic of ckts was inhibited. Phenotypes of the mutant, including apical meristem, embryonic development, primary root length, anthocyanin accumulation, etc, were investigated in different temperature. Results indicated that ckts was a mutant of stunting, especially the growth was inhibited in17℃. Results of PI staining showed that the shorten ckts primary root was due to the disordered meristem and weakened meristematic potential. Genes of the signal transduction pathways of cytokinins were studied and the expression of ARR15ARR (A type), ARR12ARR (B type) in22℃,27℃and17℃were significantly decreased. When mutants were treated by cytokinins, the expression quantity of ARR12is still very low, ARR15in ckts was normally induced, and the degree was stronger than it in the wild type.In conclusion, low temperature impacted the development of ckts mutants heavily. Low expression of cytokinin response factors made ckts sensitive to cytokinins. These facts illustrated that there might be temperature and hormone regulation system in plants, regulating the growth of Arabidopsis thaliana root.