原始被子植物八角科和五味子科的生殖生物学研究

The reproductive biology researches of basal angiosperms "ANTIA" (including Amborellaceae, Nymphaeaceae, Illiciaceae, Trimeniaceae, Austrobaileyaceae) indicate that the megagametogenesis of angiosperms could be Amborella type embryo sac(8 cells with 9 nucleus), Schisandra type embryo sac (4 cells with 4 nucleus) and Polygonum type embryo sac (7 cells with 8 nucleus). The new megagmetogenesis type of angiosperms sports the angiosperm phylogeny from molecular biological evidence. Though, the Schisandra type embryo sac was summarized from very limited papers especially Illiciaceae and Schisandraceae. And what's more,the results of megagametogenesis about Illiciaceae and Schisandraceae were some contradictions. The early research described that Illiciaceae were Polygonum type embryo sac, Schisandraceae were Polygonum type embryo sac and bipolar Alllium type embryo sac. Though the resent research described that Illiciaceae was Schisandra type embryo sac. There is not new research about the gemagametogenesis of Schisandraceae. The general reproductive biological researches of basal angiosperms were gemagametogenesis and endosperm. The reproductive biological researches about microgametogenesis, double fertilization and embryo development was scanty. The flower buds and blooming flowers of the basal species of Illiciaceae and Schisandraceae in various development stages will to be collected and fixed in formalin-acetic acid, then to be sectioned and stained,and to be observed carefully. The reproductive biology of Illiciaceae and Schisandraceae will be clarifid, especially the type of embryo sac, the missing link of the basal angiosperms reproductive evolution and biological significance of the endosperm. There will be very important significance about to rebuild the ancestral characters of the basal angiosperms and to perceive the early reproductive evolution of angiosperms.

对原始被子植物"ANITA"类群的最新生殖生物学研究表明，被子植物的雌配子体发生可分为Amborella型（8细胞9核结构）、五味子型（4细胞4核结构）和蓼型（7细胞8核结构），有力地支持了从分子生物学证据得到的被子植物系统。但对五味子型雌配子体的总结是建立在相当有限的文献基础上的，尤其是八角科和五味子科的资料非常缺乏且不乏矛盾之处；其次，对原始被子植物的生殖生物学研究主要集中在雌配子体发育和胚乳发育两个方面，其他如小孢子发生发育、双受精过程、胚发育等方面则较少。本项目通过采集研究材料进行室内各种相关实验，仔细研究两科中位于系统学基部物种及重新研究重要物种的生殖生物学过程，着重论证其胚囊类型、是否具有生殖进化的缺失环节及胚乳发育的生物学意义，完成八角科和五味子科的生殖生物学研究。本研究对重建原始被子植物祖先性状和理解被子植物的生殖早期演化具有重要意义。

原始被子植物"ANITA"类群的生殖生物学研究表明，被子植物的雌配子体发生可分为Amborella型、五味子型和蓼型，其中对五味子型雌配子体的总结是建立在相当有限的文献基础上的，尤其关键类群八角科和五味子科的资料非常缺乏且不乏矛盾之处，大多数研究认为该类群的雌配子体为蓼型胚囊和葱型胚囊，因此八角科和五味子科的生殖生物学值得深入研究。.本项目研究了八角科假地枫皮和五味子科黑老虎和大花五味子的小孢子发生发育、雌配子体的发育过程、胚乳的发育过程，并进行了比较胚胎学研究。发现八角科和五味子科的小孢子减数分裂为四面体型，成熟花粉为2-细胞，花粉绒毡层为腺质绒毡层；雌配子体发育过程为4核4细胞结构，双珠被厚珠心结构，受精为珠孔端受精；细胞型胚乳发育。通过对八角科和五味子科的生殖生物学研究发现，其雌配子体的发育是4核4细胞结构而非蓼型结构，从生殖生物学角度有力地提供了支持原始被子植物类群是一个具有共性类群的证据。对五味子科五味子的雌配子体发育过程进行研究，初步发现其具有4核4细胞胚囊和似蓼型胚囊，比例尚未确定，经比较胚胎学研究，初步确定五味子可能是被子植物雌配子体发育过程中的中间环节，对进一步了解雌配子体发育有重大意义。本项目对重建原始被子植物祖先性状和理解被子植物的生殖早期演化具有重要意义。