白毛新木姜子[Neolitsea aurata var.glauca]胚胎学研究

应用光学显微镜对白毛新木姜子的胚胎学特征进行了研究,首次在非寄生性樟科植物中发现了细胞型胚乳。对樟科8属进行了胚胎学特征的比较。花药四室,药室壁的发育属于"基本型",周原质团型绒毡层。小孢子母细胞连续型分裂。等四面体型四分体。二细胞成熟花粉,无孔沟。雌孢原多个,一般仅一个能继续发育。蓼型胚囊。助细胞具丝状器。反足细胞宿存。大孢子母细胞和合子具极性。宿存的一个助细胞具有吸器功能。细胞型胚乳,胚胎发育属于柳叶菜型的三叶变型。种皮源于外珠被,内表皮细胞壁螺旋状加厚。胚胎学特征表明,新木姜子属与木姜子属有密切的亲缘关系。较多的双胚囊异常现象,支持樟科与Monimiaceae具有紧密关系的推测。胚胎学特征不支持将无根藤属独立为科的观点。

THE EMBRYOLOGAL STUDY ON NEOLITSEA AURATA VAR.GLAUCA

The embryological features of Neolitsea aurata(Hay.) Koidz. var, glauca Yang have been investigated with the light microscope, The cellular type endosperm was found firstly in nonparasitic plants of Lauraceae. The embryological comparison of the eight genera in Lauraceae has been made.Each anther has four sporangia The anther wall formation conforms with the basic type. Periplasmodial tapetum is formed by binueleate cells. The microspore mother cells divide successively and the tetrad is tetrahedral in shape, rarely isobilateralo Mature pollen grain is two-celled, acalpate and atreme.The archesporium in the ovule is multicellular, but only one embryo-sac is formed Polygonum type in general The synergid shows filiform appara tus, and the antipodals are persistent The fact that the megaspore mother cell and zygote are polarized has been proved by biochemical reaction and the persistent synergid functions as a haustorium.The endosperm is of the cellular type Theembryo development conforms to the Onagrad type and keys out to the Trifolium variation. The seed coat is derived from the outer integument and the inner epidermis shows helical thickening of wallComparative embryology shows the close relationship between Neolitsea and Litsea. Assigning Cassytha to a subfamily of Lauraceae is more suitable than to a separate family. The fact of twin embryo sacs per ovule supports the conclution that Lauraceae probably most closely related to Monimiaceae