Morphological And Anatomical Research On Phyllotaxy Of Antirrhinum Majus L. And The Influence Of Temperature And Hormone Treatment On It

Antirrhinum majus, Scrophulariaceae snapdragon is a kind of universal gardencultivation and ornamental plant, and one of the model plants which has two and two morephyllotaxy in the same plant. Therefore, it is significant for the flowering control anddevelopmental biology research about the study of phyllotaxy on different node and themorphological and anatomical observation of terminal buds on different node ofAntirrhinum majus caulis during developing.In this paper, we take morphology based anatomical observations for the growth ofAntirrhinum majus and the terminal buds located in the different node orders of main stemby using methods of statistics, paraffin section and microphotography and we observe thephyllotaxis, stem diameter and plant height on the different conditions.Experiment results show that, the growth cones located between the1-6thnode ordersof the main stem of antirrhinum majus generate opposite leaf primordiums and willbecome opposite phyllotaxis with oval sharp after growing.24.4%of growth cones locatedin the7thnode order generate opposite leaf primordiums and become opposite phyllotaxislater. Another75.6%ones generate alternate leaf primordiums only in one side and becomealternate phyllotaxis. In the8thnode order,84.0%of growth cones generate alternate leafprimordiums and become alternate phyllotaxis after growing. From the9thnode order, allgrowth cones generate alternate leaf primordiums in one side and become alternatephyllotaxis with increasing strip sharp. The results reveal that, the7-8thnode orders of themain stem of Antirrhinum majus are the critical nodes from opposite phyllotaxis changingto alternate ones. From13thnode order (no later than17th), the terminal bud of main stembecomes flower bud and the growing stopped. There is no flower buds in oppositephyllotaxis state. After the terminal bud of main stem’s changing, the lateral buds alsobecome flower buds and explode one after another.Different temperature and hormone treatment test result shows, temperature andhormone play a role in the phyllotaxis of Antirrhinum majus. The appropriate IAA, IBAconcentration can make the phyllotaxis of Antirrhinum majus change in advance. WhileGA3can not make the phyllotaxis of Antirrhinum majus change in advance. And the highconcentration GA3can make Antirrhinum majus leggy, even result in not-flowering. Thephyllotaxis of Antirrhinum majus change in advance that will lead to early flowering, which shows appropriate the IAA, IBA concentrations can promote flowering earlier ofAntirrhinum majus. So we can know imposing exogenous hormone on the tip ofAntirrhinum majus can play a role in the phyllotaxis. And the changes of phyllotaxis have acertain impact on the flower of Antirrhinum majus. So temperature and hormone play arole in the phyllotaxis and flowering control of Antirrhinum majus. In addition,temperature and hormones have a certain impact on the stem diameter and plant height ofAntirrhinum majus. In the same hormone concentration conditions, only the appropriateambient temperature can make plant height maximize. From the types of hormone, GA3can affect the plant height more compared to indole acetic acid IAA and indole butyric acidIBA. And GA3has a more significance in the stem diameter of Antirrhinum majus thanindole acetic acid IAA and indole butyric acid IBA.