The Study of Floral Development, Microsporogenesis and Pollen Wall Development in Lonicera japonica Thunb.

• Main Authors: Liu, Mao-Sen, 劉茂森
• Other Authors: Chen Su-Hwa
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/08649865869730506490

碩士 === 國立臺灣大學 === 植物學系 === 85 === The early floral development, anther tissue differentiation and the changes in ultrastructures of microsporocytes, tapetum and anther wall layer during the development of Lonicera japonica Thunb. pollen were studied with light and electron microscope. The ontogenic sequence of flower development was initiated by sepal and petal primodia, followed by stamen primodia, and consequently, the pistil primodium. Immediately after initiation of stamen primodium, it differentiated toform a four-microsporangiate anther. The anther wall layers were developedthrough dicotyledonous type and were composed of of epidermis, endothecium,middle layer (one layer), and tapetum.The tapetum was dual origin. On pre-meiotic stage, callose wall was deposited around pollen mothercells with some cytoplasmic channels between pollen mother cells. The cytoplasmic channels retained until pollen mother cells have completed its meiosis. The cytokinesis of pollen mother cells in Lonicera japonica Thunb. was simultaneous. Once meiosis was started, the tetrahedral tetrads enclosed in the callose wall was formed. After callose wall was dissolved, four microspores were released into the anther loculus, where mitosis was taking place, producing a big vegetative cell and a small generative cell. The generative cell wall was then dissloved, and many oil drops accumulated around generative cell which sliped into the center of vegetative cell later.Before pollen grains maturation, a number of starch grains were appeared in them. The mature pollen grains were tri-colporate; oil drops and starch grains were the main storage materials. Tapetal cell wall began to degenerate on pre-meiotic stage, but tapetal cells invaded around microspore after free microspore stage. On bicellular stage, the border of tapetal cells was not evident and then the tapetal materials penetrated into cavity of bacula of pollen wall. At amyloplast stage,tapetal cell inclusions reduced as residuces rapidly while lots of starch grains accumulated in pollen grain. At anthesis, the residuous tapetum as a film containing polysaccharides and lipid coated around the mature pollen grain. At the tetrad stage, fibrous glycocalyx was deposited between the callose wall and cell membrane of tetraspores. Primexine was accumulated on glycocalyx,on which exine material secreted by microspore was also accumulated. The accumulation of exine including spines, tectum, bacula and foot layer has beenpartially finished before callose was dissolved on amyloplast stage. While the formation of intine was first initiated at bicellular stage and finished at amyloplast stage as exine. The results of this study present a detailed in formation about the microsporogenesis and pollen wall development of Lonicera japonica Thunb., andascertained that exine is derived from a combined contribution from tapetum and microspore, rather than from either of them.