callus


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callus:

see corns and callusescorns and calluses,
thickenings of the outer layer of skin where there is irritation or constant pressure. Corns are cone-shaped with their points protruding into the dermis, or inner layer of skin. They usually have hard, shiny surfaces surrounded by red, painful areas.
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Callus

 

(1) Tissue formed in plants on the surface of a wound (cracks, taps, the bases of cuttings, and areas of concrescence of stock and scion). A callus promotes the healing of wounds. Consisting of thin-walled parenchymal cells, a callus develops when there is cell division of any living tissue of the plant (cambium or phloem) in the peripheral zone of the pith, lying next to the protoxylem. Adventitious roots and buds, particularly with grafting, often develop in the callus. (2) Corpus callosum, an accumulation of callóse that obstructs the sieve plate when the sieve tubes of the phloem age. Use of the term in this sense is obsolete.


Callus

 

a thickening of the horny layer of skin as a result of constant pressure or friction. Calluses usually appear on the palms, soles, and other parts of the body that are in constant contact with tough surfaces. The cracks formed on the surface of a callus may hinder one’s ability to work, and they can also be portals of entry for pyogenic microbes, resulting in such conditions as erysipelatous inflammations and phlegmons.

callus

[′kal·əs]
(botany)
A thickened callose deposit on sieve plates.
A hard tissue that forms over a damaged plant surface.
(medicine)
Hard, thick area on the surface of the skin.

callus

1. an area of skin that is hard or thick, esp on the palm of the hand or sole of the foot, as from continual friction or pressure
2. an area of bony tissue formed during the healing of a fractured bone
3. Botany
a. a mass of hard protective tissue produced in woody plants at the site of an injury
b. an accumulation of callose in the sieve tubes
4. Biotechnology a mass of undifferentiated cells produced as the first stage in tissue culture
References in periodicals archive ?
In embryogenic callus, a small proportion of cells divided to give rise to an organogenesis (figure 1a, 1b and 1c).
The success of regeneration protocols is subject to limitations associated with the genotype, somaclonal variation, low frequencies of callus induction and the very process of in vitro plant regeneration (TOMES; SMITH, 1985).
Age of Number Shoot bud Induction response explant (range) (d) 3 5-10 Development of callus and shoot buds at cotyledonary nodal ring region was poor.
The yellow callus showing small clusters (Figure 2B) had isodiametric cells, and those having large yellow clusters were isodiametric in shape (Figure 2C).
Data were analyzed after four weeks of culture and the analysis showed that callus induction frequency, callus growth rate and nature of callus were affected by the type and concentration of the plant growth regulators.
After 15 days, the in vitro raised seedlings were used as the plant material source for callus induction.
They were named callus hairs because of their resemblance to the cells that make up the white velvety tufts--sometimes mistaken for fungus--which develop around the seeds in some apple varieties.
Next, a vascular spindle forms, initiating the vascular phase of fracture callus formation.
Bone and cartilage formation was quantified on ABH/OG-stained slides by outlining the perimeter of the fracture callus under the 2x objective.
MY kitten recently broke her leg and she is about to have a second operation to have the pin removed, I have been told there is a callus on her leg.
Callus type and co-cultivation period absolutely influenced the transformation efficiency.