年龄效应对热带胎生睡莲'黑美人'叶片生长和胎芽退化的影响OA

[Objectives]This study aimed to explore the effects of different plant ages of tropical viviparous water lily on leaf growth and epiphyllous bud degeneration.[Methods]The leaves of one to four-year-old potted'Black Beauty'as materials,the morphological parameters of leaves were measured at different ages,combined with paraffin sectioning,the tissue structure changes of leaves,leaf navels,and leaf veins at corresponding periods were observed,and the differences in carbohydrate and sucrose metabolic enzyme activities between the leaves and leaf navels were compared.[Results]As the plant age increased,the leaf area and thickness of'Black Beauty'continuously increased,and the chlorophyll and carotenoid contents first increased and then decreased.However,the chlorophyll content in leaves with epiphyllous bud degeneration decreased.Compared with the anatomical structures of leaves at different ages,the leaf navels of one to four years old were raised and the cells were tightly arranged,while the surface of the four-year-old leaf navel of epiphyllous bud decline was smooth with relatively loose epidermal cells.However,there was no significant difference in the structure of leaves and leaf veins.The soluble protein content and the activities of peroxidase,catalase and sucrose synthase in the leaf and leaf navel of'Black Beauty'increased first and then decreased with age.Meanwhile,the contents of soluble sugar and reducing sugar initially decreased and then increased,while the starch content,superoxide dismutase activity and sucrose phosphate synthase activity consistently decreased.These indicators showed that the leaves were greater than the leaf navels,but there was no significant difference between the degenerated epiphyllous bud and the normal one.[Conclusions]The relationship between viviparous leaves(source)and leaf navel(sink)of water lilies varied with age and was influenced by plant age.Leaves no longer had the viviparous ability,but the entire plant had not entered a senescence state.Therefore,the epiphyllous bud degeneration might be regulated by finely controlling local cell death events.