龙眼花蜜腺的发育解剖学研究

Anatomical Study on Development of the Floral Nectary in Dimocarpus longan Lour

龙眼花蜜腺肥厚碟状,着生于雄蕊和花瓣之间的花筒上。蜜腺的原始细胞由花筒内表面的2～3层细胞脱分化产生。花盘蜜腺由分泌表皮、产蜜组织、维管速组成。泌蜜之前,产蜜组织、分泌表皮内无淀粉粒。产蜜组织分化,PAS反应颜色深的细胞成网状分布,第一、二次泌蜜末期细胞内出现淀粉粒,它们构成向表皮的蜜汁通道。原蜜汁由维管束的筛管提供,通过共质体途径到达蜜汁通道,在细胞内积累加工后泌出,由胞间隙、细胞壁运至表皮内方由表皮毛排出,部分蜜汁通过表皮细胞排出。

The floral nectary in Dimocarpus longan Lour is disc nectary between petals and stamens on the floral tube.The nectary originates from the outer 2～3 layers cells of the inner side of floral tube. The nectary is composed of epidermis,nectariferous tissue and vascular bundles.The epidermis and nectariferous tissue has no starch grains before secreting nectar.The nectariferous tissue is differentiated:PASreaction the dense cells in which starch grains appear after secreting first and second time distribute by net,they make up the nectar passages.Prenectar is provided by sieves of vascular bundles and transported into nectar passage cells.There it is accumulated and processed and secreted out of cells,then it passes through intercellular space and cell wall to the space inside the epidermis.Most of nectar exudes out through trichomes,some of it exudes out through epidermis cells.