Etude Comparée de la Formation de l'Exine au Cours de la Microsporogénèse Chez une Gymnosperme (Taxus baccata) et une Préphanérogame (Ginkgo biloba)
1977 年 42 巻 1 号 p. 157-167
詳細
1977 年 42 巻 1 号 p. 157-167
In both genus, the nuclear envelope and the golgi bodies show a particular activity which is probably related to the exine depositing. This phenomenon occurs in the eraly tetrad stage.
Sexine and nexine are simultaneously elaborated in Taxus. The nexine, which is constituted by strata with lamellar structure is produced by the microspore. The sexine which is only composed of sporopollenin bodies is formed outside the microspore.
The exine layers of Ginkgo microspore are successively deposited: -firstly the sexine (tectum and bacula)-secondly the nexine 1-finally the nexine 2 the structure of which is similar to the Taxus nexine.
Inside the longitudinal slit of the dehydrated pollen grain of Ginkgo the sexine is lacking, the only components of the sporoderm are the two nexine layers. During the germinating process the pollen tube bursts out of this thinned area of the male gametophyte.
