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Botanists define vascular plants by three primary characteristics: Vascular plants have vascular tissues which distribute resources through the plant. Two kinds of vascular tissue occur in plants: xylem and phloem. Phloem and xylem are closely associated with one another and are typically located immediately adjacent to each other in the plant.
Selaginella moellendorffii, remnant of an ancient lineage of vascular plants that is key to understanding the evolution of land plants. It has a small genome size (~110Mb) and its sequence was released by the Joint Genome Institute in early 2008.
Placental growth factor (PGF) is a member of the VEGF (vascular endothelial growth factor) sub-family - a key molecule in angiogenesis and vasculogenesis, in particular during embryogenesis. The main source of PGF during pregnancy is the placental trophoblast. PGF is also expressed in many other tissues, including the villous trophoblast. [7]
In researching human disease, model organisms allow for better understanding the disease process without the added risk of harming an actual human. The species of the model organism is usually chosen so that it reacts to disease or its treatment in a way that resembles human physiology, even though care must be taken when generalizing from one ...
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium. All ...
Among living plants, this type of stele is found only in the stems of ferns. Most seed plant stems possess a vascular arrangement which has been interpreted as a derived siphonostele, and is called a eustele – in this arrangement, the primary vascular tissue consists of vascular bundles, usually in one or two rings around the pith. [12]
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A botanist, plant scientist or phytologist is a scientist who specialises in this field. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants, including some 391,000 species of vascular plants (of which approximately 369,000 are flowering plants) [2] and approximately 20,000 bryophytes. [3]