荠的花蜜腺发育解剖学研究

DEVELOPMENTAL AND ANATOMICAL STUDIES ON THE FLORAL NECTARIES OF CAPSELLA BURSAPASTORIS

荠(Capsella brsa-pastoris(L.)Medic.)的花蜜腺共4枚,都呈半圆形、绿色。蜜腺由分泌表皮、泌蜜组织和维管束组成,属于结构蜜腺。在花的各部分分化后,由花托表层细胞恢复分裂能力形成蜜腺原基。在蜜腺发育过程中,泌蜜组织的液泡和淀粉粒发生有规律的变化。荠的花蜜腺按其着生位置,属于花托蜜腺;其发生方式属居间生长,4枚蜜腺同步发生;根据其结构和泌蜜前后的多糖物质变化分析,其原蜜汁源于维管束的韧皮部,通过泌蜜组织输送到气孔下腔,然后由变态气孔排出。

The development and structure of the floral nectaries of Capsella bursa-pastoris(L.)Me- dic.were examined.The nectaries consisted of four separated parts which were semiorbi- cular and were morphologically and anatomically similar to one another.They were located at the receptacle between stamens,and each part was composed of secretory epidermis,necta- riferous tissue and vascular bundles,belonging to structural nectary.When the various floral organs were developed,2—3 superficial layer cells of the receptacle between stamens became meristemoid and contributed to primordia the formation of nectary.By intercalary meriste- matic activity,the four nectaries formed synchronously.During the different stages of nec- tary differentiation,the content of starch gra ins and vacuolation in the cells of epidermis and nectariferous tissue changed regularly.According to the structural and histochemical changes the pre-nectar might be supplied by phloem.The nectar formed in nectariferous tissue was then secreted to the sub-stomatal chamber and where it was finally excreted from the stoma.