腾冲红花油茶花芽分化及雌配子体发育的形态学观察

Morphological study on floral bud differentiation and the development of female gametophytes in Camellia reticulate Lindl f.simplex Sealy

[目的]观察腾冲红花油茶花芽分化与雌配子体发育进程,旨在掌握腾冲红花油茶花芽分化整体进程,明确各分化时期的内部结构特征,完善腾冲红花油茶的生殖生物学基础数据,为腾冲红花油茶的栽培管理提供参考依据。[方法]以腾冲红花油茶为研究材料,采用石蜡切片的方法对其花芽分化及雌配子体的发育过程进行解剖观察。[结果]1)腾冲红花油茶的花芽分化经历了分化始期、萼片形成期、花瓣形成期、雌雄蕊形成期、子房花药形成期、雌雄蕊成熟期等6个时期,历时长达8个月,分化期间历经较长时间的低温环境。2)腾冲红花油茶子房有3~4个心室,每个心室多枚胚珠,每枚胚珠发育状况不一致,胚珠为倒生型胚珠,具双层珠被,胚珠发育属于薄珠心型。9月初,珠心中央的薄壁细胞迅速分裂形成孢原细胞,孢原细胞继续发育形成大孢子母细胞,在大孢子母细胞发育过程中珠心组织开始被溶解吸收。3)腾冲红花油茶雌配子体发育由大孢子母细胞进行两次减数分裂形成4个功能大孢子,进而发育成为四核胚囊,四核胚囊通过一次有丝分裂发育形成七细胞八核胚囊。胚囊发育类型为五福花型,胚囊为四孢子胚囊。其胚囊发育类型与普通油茶、攸县油茶的葱型胚囊有明显差异。[结论]腾冲红花油茶花芽分化历经6个时期;子房有3~4个心室;倒生胚珠,薄珠心型;胚囊发育类型为五福花型,胚囊为四孢子胚囊。

【Objective】The flower bud differentiation and female gametophyte development of Camellia reticulate f.simplex were observed to understand the whole process of flower bud differentiation of C.reticulate f.simplex,to clarify the internal structural characteristics of flower buds at different differentiation stages,and to supplement the basic data on the reproductive biology of C.reticulate f.simplex to provide a theoretical basis for cultivation management.【Method】C.reticulate f.simplex was used as the experimental material.The anatomical features of the morphological differentiation of flower buds and the development of female gametophytes were observed using the method of paraffin sectioning.【Result】1)The process of flower bud differentiation could be divided into 6 periods:initial differentiation phase,sepal differentiation phase,petal differentiation phase,stamen and pistil differentiation phase,anther and ovule differentiation phase,and stamen and pistil maturity,which lasted up to eight months,and the differentiation period experienced a long period of low temperature.2)In the ovary of C.reticulate f.simplex,there were 3-4 ventricles with multiple ovules,the developmental stage of each ovule was not uniform.The ovule was anatropous,tenuinucellate and with double-layer integument.At the beginning of September,the parenchyma cells divided rapidly to form archesporium,which continued to develop to form megaspore mother cells in the center of the nucellus,and the nucellar tissue began to be dissolved and absorbed during the development of megaspore mother cells.3)The megasporocyte underwent two meiotic divisions to produce four functional megaspores,which then developed into a four-nuclear embryo sac,and the four-nuclear embryo sac underwent one mitotic division to form seven nuclear and eight embryo sacs.The development type of the embryo sac was adoxa type,and the embryo sac was tetraspore embryo sac,whose embryo sac development type was obviously different from the onion embryo sac of C.oleifera Abel and C.yuhsienensis.【Conclusion】The flower bud differentiation go through 6 stages;there are 3-4 ventricles in ovary;the ovule is anatropous ovule nucellus thin with double-layer integument;the development type of embryo sac is adoxa type,and the embryo sac is tetraspore embryo sac.