雄全异株桂花不同花期光合和内源激素的变化

Photosynthesis and hormone study of male and hermaphroditic Osmanthus fragrans at different flowering stages

【目的】桂花(Osmanthus fragrans)同时拥有雄株和两性株,具有极为罕见的雄全异株繁育系统。对桂花不同花期的光合特性及花部组织的内源激素含量进行测定,比较雄性和两性桂花在不同花期的光合及内源激素含量的变化规律,为评价雄性和两性桂花生长适应性及后续生理生态学研究提供参考。【方法】利用Li-6400XT光合作用测量系统对雄性和两性桂花不同花期的光合特性进行测量,并利用酶联免疫吸附分析法对生长素(IAA)、茉莉酸(JA)、脱落酸(ABA)、赤霉素(GA_(3))和玉米素核苷(ZRs)5种植物激素含量进行测定。【结果】雄性桂花的气孔导度和净光合速率在不同花期均低于两性桂花的;测定的5种激素中,平均激素含量最高的为脱落酸;茉莉酸含量在雄花的花期内持续增加,玉米素核苷含量在两性花的花期内不断升高。【结论】气孔导度是影响桂花净光合速率的一个关键因子,与净光合速率呈正相关;脱落酸和茉莉酸的不断积累可能导致了雄性桂花花瓣的大量脱落;玉米素核苷在两性桂花花期的积累对果实的发育有促进作用。研究结果可为雄全异株桂花不同花期阶段提供基础生理数据,为后续探索雄花花瓣脱落及果实发育提供参考。

【Objective】Osmanthus fragrans with both male and hermaphroditic plants,possesses an extremely rare breeding system of androdioecy.The photosynthetic characteristics and endogenous hormone content of O.fragrans at different flowering stages were measured,and the changes of photosynthesis and endogenous hormone content in male and hermaphroditic O.fragrans at different flowering stages were compared,providing references for the evaluation of growth adaptability and subsequent physiological and ecological research of male and hermaphroditic O.fragrans.【Method】The photosynthetic characteristics of male and hermaphroditic flowers at different flowering stages were measured by Li-6400 XT photosynthetic measurement system,and five plant hormones including auxin(IAA),jasmonic acid(JA),abscisic acid(ABA),gibberellin(GA_(3)) and zeatin nucleosides(ZRs) were measured by the enzyme-linked immunosorbent assay.【Result】The stomatal conductance and net photosynthetic rate of males were lower than that of hermaphroditic at different flowering stages.ABA had the highest hormone content among the five measured hormones.The content of JA continued to increase during the flowering period of male flowers and the content of ZRs continued to increase during the flowering period of hermaphroditic flowers.【Conclusion】Stomatal conductance was a key environmental factor affecting the net photosynthetic rate of O.fragrans,and was positively correlated with the net photosynthetic rate.The continuous accumulation of abscisic acid and jasmonic acid may lead to the mass abscission of male osmanthus petals.The accumulation of ZRs in the flowering stage of hermaphroditic flowers promoted the fruit development.The results provided basic physiological data for the different flowering stages of androdioecious O.fragrans,and provided references for the subsequent exploration of the mechanism of male flower petal abscission and fruit development.