Variance Analysis Of Endogenous Cytokinin And Auxin In Different Phyllotaxis Plants

Phyllotaxis is the regular arrangement of leaves or flowers around a plant stem. The most prevalent patterns are alternate, opposite and whorled patterns. The research results show that cytokinin and auxin in shoot apical meristem(SAM) participate in the process of the formation of phyllotaxis. A mechanism based on polar transport and differential distribution of auxin regulates leaf primordium formation and position on the shoot apical meristem. Cytokinin influences the formation of phyllotaxis indirectly through effecting the distribution of auxin by regulating the expression of auxin transport protein genes and the size of SAM. Meanwhile, stabilization and change of CTK/IAA value in the shoot apical meristem is an important factor that regulates phyllotaxis stabilization and variation. This study determined the contents of cytokinin and auxin in the shoot apical meristem and the tender stems and leaves around SAM by ELISA. Results obtained by analyzing the datas as follow:1. Analysis of hormone contents of plants tested show that Hormone contents and the values of CTK/IAA at different growth and development periods were not significant no matter in opposite or alternate phyllotaxis plants.2. There are no obivious regularity about the contents of cytokinin and auxin in shoot apical meristem, tender stems, and tender leaves. Nevertheless, the value of CTK/IAA in shoot apical meristem is significantly higher than that in tender stems or leaves.3. Among different families of plants, there are no obivious regularity about the contents of hormone and the values of CTK/IAA. There are significant differences of hormone contents and CTK/IAA values in the shoot apical meristems of the same phyllotaxis plants.4. In the Apocynaceae family plants, the content of CTK and value of CTK/IAA in shoot apical meristem of the whorled phyllotaxis plant Nerium indicum Mill are always higher than that of the opposite phyllotaxis plant Catharanthus roseus (L.) Don. In the Compositae family plants, the content of CTK and value of CTK/IAA in shoot apical meristem of the opposite phyllotaxis plant Tagetes erecta L. are higher than that of the alternate phyllotaxis plant Dendranthema morifolium, and three major categories of cytokinin are all significantly higher.5. Some species of plants have different phyllotaxis types, for example, Helianthus tuberosus and Antirrhinum majus may display three common types of phyllotaxis in their development process. This study show that the content of CTK and value of CTK/IAA in shoot apical meristem of individuals with opposite phyllotaxis are significantly higher than that of individuals with alternate phyllotaxis, and three major categories of cytokinin are not lower than alternate plants. The contents of auxin have no significant differences.In conclusion, this study confirms the close relation between phyllotaxis types and hormone contents or ratios in the shoot apical meristem. In the same family or closer genetic relationship of plants, it is a trend that the contents of CTK and values of CTK/IAA in SAM of whorled phyllotaxis plants are significantly higher than that of opposite phyllotaxis plants, while opposite phyllotaxis plants are singinficantly higher than alternate phyllotaxis plants. The contents of cytokinin and values of CTK/IAA in SAM may be important factors regulating plants phyllotaxis variations.