甘蓝型油菜花的蜜腺发育与传粉的协调性研究

用扫描电子显微镜、石蜡切片和组织化学等方法研究了油菜花蜜腺的发育过程,探讨了油菜花蜜腺发育与传粉之间的协调关系,旨在揭示油菜花蜜腺的生殖生物学意义.油菜花共有4枚蜜腺,蜜腺随着花蕾膨大生长发育,盛花期蜜腺体积达到最大.蜜腺表皮上有正常气孔和退化的气孔,退化的气孔失去开闭功能,演变成花蜜分泌的出口.在泌蜜盛期,雄蕊发育成熟,油菜传粉受精.之后,花萼花瓣开始萎缩进入花败期,此时蜜腺呈绿色,继续存在,没有衰退现象.随着花萼花瓣的衰败脱落,子房明显开始膨大,进入幼果期,蜜腺开始衰老,直至完全脱落.解剖观察发现油菜花蜜腺内无维管组织,细胞内有叶绿体,证明其蜜腺分泌的蜜汁主要是由蜜腺自身光合作用产生的.泌蜜盛期与传粉期吻合,有利于传粉和提高结实率.

Coordination between the Nectary Development and Pollination in B.napus L.

To elucidate the role of nectary in reproductive biology,we investigated the development of nectary and the relationship between nectary development and pollination in B.napus(Brassicaceae)by means of scanning electron microscopy,paraffin sectioning together with histochemistry methods.As the bud expanded,four nectaries of B.napus grow up and reached the maximum at anthesis.Both normal and modified stomata were observed on the surface of the nectary.The modified stomata lost the ability to open and closed the aperture and finally developed into the organ where the the secretion of nectary occurred.The B.napus was pollinated when stamen matured.After the pollination,calyxes and petals shrank and became senescent.By contrast,nectary continued to exist without any fading.In the period of young fruit,ovary expanded obviously and floral nectary began to age and disappeared at last.The anatomy analysis showed that chloroplast but no vascular tissue was found in the nectary,indicating that the secretion of nectary was produced from the photosynthesis itself.Our results demonstrated that the secretion of nectary is correlated with the pollination,which contributes to the pollination and ripening rate in B.napus.