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[1] [3] In the frog Xenopus laevis, the animal pole is heavily pigmented while the vegetal pole remains unpigmented. [4] A pigment pattern provides the oocyte with features of a radially symmetrical body with a distinct polarity. The animal hemisphere is dark brown, and the vegetal hemisphere is only weakly pigmented.
Plant embryonic development, also plant embryogenesis, is a process that occurs after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy and germination . [ 1 ]
In seed plants, the embryo will develop one or more "seed leaves" . By the end of embryogenesis, the young plant will have all the parts necessary to begin its life. Once the embryo germinates from its seed or parent plant, it begins to produce additional organs (leaves, stems, and roots) through the process of organogenesis.
Somatic embryogenesis is an artificial process in which a plant or embryo is derived from a single somatic cell. [1] Somatic embryos are formed from plant cells that are not normally involved in the development of embryos, i.e. ordinary plant tissue. No endosperm or seed coat is formed around a somatic embryo.
Retinoic acid, an important signaling molecule needed throughout embryogenesis, acts through the Hox genes. It was originally postulated that retinoic acid acts to induce the Hoxb-8 gene, [ 11 ] but this hypothesis has not been supported by genetic studies in mouse embryos lacking retinoic acid synthesis that still express Hoxb-8 in the limb. [ 8 ]
Polar auxin transport (PAT) is directional and active flow of auxin molecules through the plant tissues. The flow of auxin molecules through the neighboring cells is driven by carriers (type of membrane transport protein) in the cell-to-cell fashion (from one cell to other cell and then to the next one) and the direction of the flow is determined by the localization of the carriers on the ...
The second mechanism of unequal cleavage involves the production of an enucleate, membrane bound, cytoplasmic protrusion, called a polar lobe. [8] This polar lobe forms at the vegetal pole during cleavage, and then gets shunted to the D blastomere. [7] [8] The polar lobe contains vegetal cytoplasm, which becomes inherited by the future D ...
Late embryogenesis abundant proteins (LEA proteins) are proteins in plants, and some bacteria and invertebrates, that protect against protein aggregation due to desiccation or osmotic stresses associated with low temperature. [1] [2] [3] LEA proteins were initially discovered accumulating late in embryogenesis of cotton seeds. [4]