spermatophyta


Значение термина spermatophyta в knolik


spermatophyta - spermatophyta (spermaphyta)
spermatophyta - Seed plants (formerly Phanerogamia). Division of plant kingdom providing dominant flora of present day, including most trees, shrubs, herbaceous plants, grasses, etc. Possessing a highly organized plant body of stem, leaf and root, with a well developed vascular system. Hetero-sporous plants with dominant sporophyte and much reduced gametophyte generations. The sporophyte generation is the plant itself. The male gametophyte consists of the germinated pollen grain with its pollen tube by which the non-motile gametes are conveyed to the egg. The female gametophyte is retained on the sporophyte, nourished and protected within the ovule, which after fertilization of the egg within it becomes a seed. Within the seed, protected by seed coat, is a young sporophyte plant, the embryo. Including two groups, Gymnospermae, with ovules lying unprotected on the megasporophylls, and Angiospermae, in which the megasporophylls, known here as carpels, enclose the ovules in the ovary. After fertilization, ovary becomes a fruit containing one or more seeds. In gymnosperms, sporophylls are usually arranged in cones; in angiosperms, sporophylls (stamens and carpels) are borne in flowers. These groups are now frequently classified as Classes of Subdivision Pteropsida in Division Tracheo-phyta.

Рядом со словом spermatophyta в knolik


sperm atophoreВ начало
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spermatozoid

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