广宁红花油茶花器官发生

利用扫描电镜观察了山茶科Theaceae山茶属Camellia红山茶组广宁红花油茶Camellia semiserrata Chi.的花器官发生过程.广宁红花油茶花被片呈螺旋形发生,心皮原基发生于环状分生组织,4～5枚心皮原基同时发生,在后来的发育过程中,心皮原基发育成合心皮雌蕊,心皮原基纵向伸长发育成合生花柱,柱头布满乳凸状细胞,柱头浅裂,一般3～5裂;雄蕊原基分为内轮雄蕊原基和外轮雄蕊原基,内轮雄蕊原基一般15～21枚同时发生于环状分生组织,外轮雄蕊原基也发生于环状分生组织,外轮雄蕊原基分为3～5层,其基部1/3～1/2合生,外轮雄蕊原基中同层的同时发生,不同层的雄蕊原基发生次序不同;广宁红花油茶的花器官发生与山茶科厚皮香亚科Ternstroemi-oideae杨桐属Adinandra Jack的阔叶杨桐Adinandra latifolia L.K.Ling和猪血木Euryodendron excelsun H.T.Chang明显不同.该研究为山茶属甚至于山茶科的系统发育与演化提供了花器官方面的依据.

Floral Organogenesis in Camellia semiserrata

The floral development of the Theaceae species, Camellia semiserrata Chi. was observed under scanning electron microscope (SEM) for the first time up to date. Both perianth were initiated spirally and centripetally; in the species four to five carpel primordial arose from a ring meristem; in the flowering developmental process the carpels in C. semiserrata Chi. developed nearly into syncarpous gynoecium, and the carpels developed into connate stylus. The surface of stigma had a lot of papilla cells, and it was divided into 3-5 clefts. The stamen was divided into two wheels, and the internal stamen primordia all developed on a ring meristem; 15-21 stamen primordia in the inner whorl first arose simultaneously; the outer whorl of stamen primordia was divided into 3-5 layers; the same layer developed simultaneously on a ring meristem; different layers irregularly initiated; in the flowering development process the outer stamen primordia developed nearly into 1/3-1/2 of based connate stamens. The floral development of C. semiserrata Chi. is distinctly different from those of Adinandra latifolia(Theaceae) and Euryodendron excelsun(Ternstroemioideae, Theaceae). This study provides evidence from floral organogenesis about the further study on the phylogeny of Camellia and even of Theaceae.