作 者 ：ZHANG Zhong-Ming, CUI Ke-Ming, LI Zheng-Li
期 刊 ：植物分类学报 2000年 2期
Keywords:Ginkgo biloba, Pollen, Male gametophyte, Lateral germination,
Abstract:
The four-celled mature pollen of Ginkgo biloba L. just shed from the microsporangia,
was round in shape and contained a very large germination area with monosulcate sulcus walled with
two semicircular and nearly perpendicular parts of exine, and the pollen was coated with a compact
irregular striations and spinules in parts other than the germination area. The pollen became boat-
shaped and was bilaterally symmetrical when it was in air or under cold storage, but rapidly rounded
off in cultural solution. Studies on early morphogenesis of the male gametophyte in vitro and in vivo
revealed that the tube nucleus turned a certain degree of angle, and was followed by lateral germina-
tion, while the non-active pollen maintained its round shape. The results suggest that the internal
feature of the pollen tube could be a determinant factor contributing to the expression of the charac-
teristic events of lateral germination of the male gametophyte in G. biloba. Furthermore, this biolog-
ically consistent character, together with the characteristic pollen morphology, is quite different from
those of other groups in gymnosperms such as Cycas and Pinus. This might be a critical character
relevant to the systematic position of G. biloba.