Search results
Results from the WOW.Com Content Network
The endodermis is the boundary between the cortex and the stele. In many seedless plants, such as ferns, the endodermis is a distinct layer of cells immediately outside the vascular cylinder (stele) in roots and shoots. In most seed plants, especially woody types, the endodermis is present in roots but not in stems.
Generally the exoskeleton will have thickened areas in which the chitin is reinforced or stiffened by materials such as minerals or hardened proteins. This happens in parts of the body where there is a need for rigidity or elasticity.
The mycorrhizae of the fungus then uses its extended system to help the plant find the correct area of nutrition, signaling the direction in which the roots should grow. [13] This makes root growth more efficient, preserving energy for other metabolic processes, which in turn benefits the fungus that feeds off those metabolic products.
The discovery of the Casparian strip dates back to the mid-19th century, and advances in the understanding of the endodermis of plant roots. [15] In 1865, the German botanist Robert Caspary first described the endodermis of the root of plants, found that its cell wall was thickened, and named it Schuchtzscheide.
Parenchyma is a versatile ground tissue that generally constitutes the "filler" tissue in soft parts of plants. It forms, among other things, the cortex (outer region) and pith (central region) of stems, the cortex of roots, the mesophyll of leaves, the pulp of fruits, and the endosperm of seeds.
An endodermis generally surrounds the stele. A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhynia. [6] actinostele – a variation of the protostele in which the core is lobed or fluted. [7] This stele is found in many species of club moss (Lycopodium and ...
Earth's outer core is a fluid layer about 2,260 km (1,400 mi) in height (i.e. distance from the highest point to the lowest point at the edge of the inner core) [36% of the Earth's radius, 15.6% of the volume] and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. [31]
Human bones are densely vascularized as in many other mammals. Even though some authors tried to identify a correlation between endothermy and secondary Haversian reconstruction, this feature is absent in many living mammals (e.g. monotremes, Talpa, flying foxes, Herpestes, Dasypus) and birds (Aratinga, Morococcyx, Nyctidromus, Momotus, Chloroceryle) while others possess only scattered ...