Cortex, root

The part of the plant, which is used - epigeous part (blossom, stem, leaves, fruit, cortex), roots and rootage (decorticated or nondecorticated). 

Polyhydroxylated piperidines from natural sources, which have structures and shapes resembling monosaccharides have been found as a -glycosidase inhibitors. They competitively inhibit glycosidases whose substrates they most closely resemble. 1-Deoxynojirimycin (moranoline) (98 1), was isolated from Mori Cortex (root bark of the mulberry tree, Morus bombycis (Moraceae)), leaves of Jacobinia suberecta (Acanthaceae)... 

In some cases pectinolytic enzymes have been associated with virulence and it is generally accepted that pectinolysis by these bacteria facilitates their entry and spread in plant tissue. In Rhizohium, these enzymes may play a role in the root infection process that precedes nodule formation (Hubbell et al 1978). A. irakense has never been reported to be pathogenic on plants. It can therefore be speculated that moderate and strictly regulated pectinolysis of A. irakense facilitates entry in the outer cortex of plants roots, since A. irakense has been isolated from surface-sterilized roots. It is likely that breakdown of plant polysaccharides by root colonizing bacteria can provide them with extra carbon source. 

K. Old and T. Nicol.son, The root cortex as part of a microbial continuum. Microbial Ecology (M. Loutit and J. Miles, eds.) Springer-Verlag, New York, 1978. 

Spinal and bulbar cerebellar cortex, brain stem Motor neurons, dorsal root ganglia 11-34 40-62 Androgen receptor NI (n)... 

As discussed, the first-order neuron is the afferent neuron that transmits impulses from a peripheral receptor toward the CNS. Its cell body is located in the dorsal root ganglion. This neuron synapses with the second-order neuron whose cell body is located in the dorsal horn of the spinal cord or in the medulla of the brainstem. The second-order neuron travels upward and synapses with the third-order neuron, whose cell body is located in the thalamus. Limited processing of sensory information takes place in the thalamus. Finally, the third-order neuron travels upward and terminates in the somatosensory cortex where more complex, cortical processing begins. 

In contrast to the exterior localization of cutin, suberin can be deposited in both external and internal tissues. External deposition occurs in the periderm of secondary roots and stems and on cotton fibers, whereas internal deposition occurs in the root endodermis and the bundle sheath of monocots. The Casparian strip of the root en-dodermis contains suberin, which produces a barrier isolating the apoplast of the root cortex from the central vascular cylinder. Suberin also produces a gas-impermeable barrier between the bundle sheath and mesophyll cells in C4 plants. The bark of trees contains periderm-derived cork cells that have a high suberin content. 

A1 adenosine receptors are inhibitory in the central nervous system. A receptors were originally characterized on the basis of their ability to inhibit adenylyl cyclase in adipose tissue. A number of other G-protein-mediated effectors of A receptors have subsequently been discovered these include activation of K+ channels, extensively characterized in striatal neurons [13], and inhibition of Ca2+ channels, extensively characterized in dorsal root ganglion cells [14]. Activation of A receptors has been shown to produce a species-dependent stimulation or inhibition of the phosphatidylinositol pathway in cerebral cortex. In other tissues, activation of A receptors results in synergistic activation of the phosphatidylinositol pathway in concert with Ca2+-mobilizing hormones or neurotransmitters [15]. The effectors of A adenosine receptors and other purinergic receptor subtypes are summarized in Table 17-2. 

The extent of aerenchyma development by the degradation of the primary root cortex. 

In the model, the internal structure of the root is described as three concentric cylinders corresponding to the central stele, the cortex and the wall layers. Diffu-sivities and respiration rates differ in the different tissues. The model allows for the axial diffusion of O2 through the cortical gas spaces, radial diffusion into the root tissues, and simultaneous consumption in respiration and loss to the soil. A steady state is assumed, in which the flux of O2 across the root base equals the net consumption in root respiration and loss to the soil. This is realistic because root elongation is in general slow compared with gas transport. The basic equation is... 

The structure of the rice root is therefore apparently dominated by the need for internal gas transport. On the face of it, this structure may conflict with the needs for efficient nutrient absorption (Kirk and Bouldin, 1991). The development of gas-impermeable layers in the root wall seems likely to impair the ability of those parts of the root to absorb nutrients, and the disintegration of the cortex might impair transport from the apoplasm to the main solute transport vessels in the stele, though these points are uncertain (Drew and Saker, 1986 Kronzucker et al, 1998a). It seems likely that the short fine lateral roots are responsible for the bulk of the nutrient absorption by the root system and compensate for any impairment of nutrient absorption by the primary roots as a result of adaptations for internal aeration. 

The porosity of the cortex, permeability of the root wall and the coverage of the root with laterals vary along the root length, with a much smaller porosity. 

Armstrong W, Beckett PM. 1987. Internal aeration and the development of stelar anoxia in submerged roots. A multishelled mathematical model combining axial diffusion of oxygen in the cortex with radial losses to the stele, the wall layers and the rhizosphere. New Phytologist 105 221-245. 

The ectomycorrhizae form a mat of hyphal tissue (the mantle) surrounding the plant root and have hyphae that radiate away into the soil as well as those that radiate inward to reside between plant cells. The intercellular hyphae usually form a ramifying network in the root cortex (the Hartig s net), and some may have hyphal tips that form a broad pad that makes direct contact with the plant cell (the appressorium) to expedite nutrient transfer, but they usually do not invade the plant cell itself Ectomycorrhizae are often basidiomycete fungi (Basidiomycota). 

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