长药景天花蜜腺的发育解剖学研究

The developmental anatomy on floral nectaries in Sedum spectabile

长药景天花蜜腺５枚，呈侧向扁平的舌形或弯月形，分别位于５枚离生心皮的外侧，两者的基部相连，属于子房蜜腺。蜜腺由分泌表皮、产蜜组织和仅含韧皮部的维管束组成。长药景天花蜜腺起源于心皮外侧基部的表层细胞。产蜜组织在发育过程中，细胞中的液泡体积及淀粉粒呈现有规律的消长变化。泌蜜后期，蜜腺组织从上往下液泡化，具明显的方向性。根据其结构及多糖变化分析，来自韧皮部的原蜜汁以淀粉粒形式贮存于产蜜组织中，泌蜜期水解为可溶性糖类而成为蜜汁的主要原料。

Sedum spectabile flower had five tongue shaped or new moon shaped floral nectaries,which were located on the outer surface at the base of five isolated carpels,and connected with carpels at base and belonged to the type of ovary nectaries.The nectaries were composed of epidermis,nectariferous tissue and vascular bundle which only consisted of phome.The nectaries derived from the outer superfical layers cells of ovary.During the development of nectariferous tissue,both the vacuole and starch grains changed regularly.At the late secretion stage,the nectary tissue cells vacuolized from the top to the base.Basing on the nectary structure and polysaccharide changes,It was supposed that the pre nectar from the phome were stored in starch grains in nectariferous tissue and were decomposed into soluble sugar which was the main element of the nectar.The nectar was secreted by stomata and epidermis.