‘香榧’雌配子体发育和原胚形成的组织学观察  

Histological studies on megagametophyte and embryogeny development in Torreya grandis‘Merrillii'

作　　者：刘志敏[1,2] 赵宏波[1,3] 黄有军[1,2] 梅丽[1,2] 黄坚钦[1,2] 胡渊渊[1,2] 吴家胜[1,2] 

机构地区：[1]浙江农林大学.亚热带森林培育国家重点实验室培育基地,浙江临安311300 [2]浙江农林大学林业与生物技术学院,浙江临安311300 [3]浙江农林大学风景园林与建筑学院,浙江临安311300

出　　处：《果树学报》2017年第2期231-237,共7页Journal of Fruit Science

基　　金：国家自然科学基金(31570616)

摘　　要：【目的】明确‘香榧’授粉到越冬前雌配子体的发育、受精和原胚形成过程,丰富和完善榧属植物的生殖发育学。【方法】人工授粉后,定期连续采集雌球花,应用常规石蜡切片技术,获得‘香榧’雌球花的纵切片,在光学显微镜下观察。【结果】‘香榧’雌球花由4层鳞片包被,由外向内依次为假种皮、珠被和珠心。珠心中下部分化雌配子体。‘香榧’在授粉期尚处于大孢子母细胞时期;授粉后1周内,完成减数分裂形成功能大孢子;6月初到8月底完成雌配子体的发育,包括游离核时期、细胞化阶段和颈卵器时期;‘香榧’有2个颈卵器母细胞,每个颈卵器分裂形成4个颈细胞和1个卵核,腹沟核很快消失。9月中上旬精卵融合形成合子并发育形成原胚,排列成4层,并以原胚越冬。【结论】‘香榧’的雌配子体发育过程基本上遵循了红豆杉科植物的发育规律,只在原胚类型和颈卵器数目上与其他种类有一定差异。‘香榧’原胚为松型,2个颈卵器,而红豆杉科其他种原胚为标准型,绝大多数仅1个颈卵器。【Objective】The purpose of this research was to determine anatomically the megagametophytedevelopment, fertilization process and proembryo forming in Torreya grandis‘Merrillii＇during the peri-od from pollination to overwintering. It is noteworthy that gymnosperm differs from angiosperm is the inter-val from pollination to fertilization is longer than 3 months. Other characteristics are archegonium and pro-embryo. This is a basic research aim to observe these characteristics and find its special rules to differ fromother gymnosperms. It is also a research for more reproductive biology research, such as cytoplasm inheri-tance, meiosis relevant research.【Methods】Artificial pollination was done on April 24 of 2014 when pol-lination drop appears. Ovules were collected every 3 to 4 days from the middle of April to end Septemberin 2014. Length and diameter were measured and scales were removed. They were fixed in FAA（Vformalin∶Vglacial acetic acid∶V50% ethanol=5∶5∶90） at least 24 h, then hydrated in grated ethanol series, displaced by xyleneand then paraffin. Paraffin filled ovules were sectioned in 8 μm thick and placed in 37 °C about 12 h.Sections were dyed by safranine and fast green and observed with SEM.【Results】Structure of the ovuleincludes aril, integument, nucellus and megagametophyte. The aril develops its length in May mainly tosurround the nucellus for protection and formed micropyle for pollen entering into the ovule. About15 to 20 cells filled with tannins located on the inner side of the integument. Sporogenous tissue locatesbelow the middle of the nucellus. One of these cells differentiates the mega gametophyte and other cellsnourish it. The megagametophyte of T. grandis‘Merrillii＇is still at megasporocyte stage during the polli-nation. One week after pollination, the megasporocyte undergoes meiosis and gives rise to functional mega-spore. Other three megaspores are small in volume and degenerated soon. As the first cell of megagameto-phyte, functional megaspore＇forming

关 键 词：'香榧’ 雌配子体 原胚形成 组织学观察 

分 类 号：S664.5[农业科学—果树学]