CAJ | 학술논문

对银杏(Ginkgo biloba L.)胚珠贮粉室的早期发育过程以及珠心细胞死亡的细胞学机制进行了研究.DNA电泳出现DNA ladder和TUNEL标记说明参与形成贮粉室的珠心细胞死亡是程序性死亡(PCD)过程,并且显示出在贮粉室形成中,PCD的发生有一定的空间分布式样.结合扫描电镜观察,贮粉室的早期发育可分为4个阶段:起始事件是位于珠孔端的3至4层珠心细胞纵向伸长;接着,位于珠心组织最上部(珠孔端)的珠心细胞启始死亡;然后,这些已经纵向伸长的珠心细胞向基地和侧向地逐渐死亡,形成一个空腔;最后,珠孔端珠心表皮细胞以开裂的方式与其余表皮细胞脱离而形成贮粉室的开口.大孢子母细胞时期,贮粉室尚未发生;四分体阶段,贮粉室已经开始形成;到雌配子体发育时期,贮粉室已经完全产生.反映大孢子发育和贮粉室发生的同步性.
대은행(Ginkgo biloba L.)배주저분실적조기발육과정이급주심세포사망적세포학궤제진행료연구.DNA전영출현DNA ladder화TUNEL표기설명삼여형성저분실적주심세포사망시정서성사망(PCD)과정,병차현시출재저분실형성중,PCD적발생유일정적공간분포식양.결합소묘전경관찰,저분실적조기발육가분위4개계단:기시사건시위우주공단적3지4층주심세포종향신장;접착,위우주심조직최상부(주공단)적주심세포계시사망;연후,저사이경종향신장적주심세포향기지화측향지축점사망,형성일개공강;최후,주공단주심표피세포이개렬적방식여기여표피세포탈리이형성저분실적개구.대포자모세포시기,저분실상미발생;사분체계단,저분실이경개시형성;도자배자체발육시기,저분실이경완전산생.반영대포자발육화저분실발생적동보성.
The early stage of pollen chamber development in ovule and the cytological mechanism of nucellar cell death were studied in Ginkgo biloba L. DNA ladder appearance and TUNEL assay demonstrated that the nucellar cell death, doomed to bring about pollen chamber formation, was a process of programmed cell death (PCD). A spatial distribution of PCD was visualized during the development of pollen chamber. Together with the observation under the scanning electron microscope, these results have revealed that the early developmental pattern of pollen chamber consists of four phases. Firstly, several layers of the nucellar cells at the micropylar end elongate longitudinally. Thereafter, the uppermost layer of the nucellar cells at the micropylar end initiate PCD; and the nucellar cell death extends in a basally and laterally oriented direction to form a cavity. Finally, the epidermal cells at the micropylar end detach from the other epidermis by dehiscence, bringing about the opening of the pollen chamber. The early development of pollen chamber begins sometime after the stage of megasporocyte and continues by the time of the formation of megaspore tetrad, and finally completes at the stage of development of female gametophyte. This shows a synchronous development of megaspore and pollen chamber.