× Capsella gracilis Grenier

Capsella embryogenesis: the central cell.

The central cell is the binucleate cell of the angiosperm megagametophyte which contains the polar nuclei and participates in double fertilization. The structure of the mature central cell, the fusion of the polar nuclei and the primary endosperm nucleus were studied with the electron microscope. The central cell cytoplasm appears very active and has an extensive ER, many mitochondria, dictyoso...

Signal propagation modeling In Urban Environment Emmanuel Grenier

Capsella embryogenesis: the chalazal proliferating tissue.

Electron-microscope and histochemical procedures were used to study the development and breakdown of the chalazal proliferating tissue in Capsella. This tissue is formed by the enlargement of several layers of nucellar cells at the chalazal end of the embryo sac. When the embryo reaches the early globular stage these enlarged cells start to disintegrate, beginning with those immediately borderi...

Recent speciation of Capsella rubella from Capsella grandiflora, associated with loss of self-incompatibility and an extreme bottleneck.

Flowering plants often prevent selfing through mechanisms of self-incompatibility (S.I.). The loss of S.I. has occurred many times independently, because it provides short-term advantages in situations where pollinators or mates are rare. The genus Capsella, which is closely related to Arabidopsis, contains a pair of closely related diploid species, the self-incompatible Capsella grandiflora an...

The Gracilis-Semitendinosus Indeks

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