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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 amphibians, the development of the animal-vegetal axis occurs prior to fertilization. [1] Sperm entry can occur anywhere in the animal hemisphere. [2] The point of sperm entry defines the dorso-ventral axis - cells opposite the region of sperm entry will eventually form the dorsal portion of the body. [1] [3]
From that point, it begins to divide to form a plant embryo through the process of embryogenesis. As this happens, the resulting cells will organize so that one end becomes the first root, while the other end forms the tip of the shoot. In seed plants, the embryo will develop one or more "seed leaves" . By the end of embryogenesis, the young ...
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 ...
This distinction of layers of the bilaminar disc defines the primitive dorso ventral axis and polarity in embryogenesis. [2] The epiblast migrates away from the trophoblast downwards, forming the amniotic cavity in between, the lining of which is formed from amnioblasts developed from the epiblast. The hypoblast is pushed down and forms the ...