Integuments


Also found in: Dictionary, Thesaurus, Medical.
Related to Integuments: integumentary

Integuments

 

the external tissues that protect plants from unfavorable influences and perform the functions of absorption and excretion. Gas exchange between the plant and the environment occurs through the integuments. Primary integuments—epidermis and epiblem—arise from the protoderm, which consists of cells of primary meristem of the growing point of a stem or root. Exodermis becomes differentiated from the basal meristem of the growing point.

The epidermis covers the shoot, parts of the flower, the fruit, and the seed. Usually the outer walls of the epidermal cells of leaf and stem are thickened and impregnated with wax and cutin which, upon emerging to the cell surface, form the cuticle. Gas exchange and evaporation are accomplished through the stoma-tal apertures in the epidermis. The epiblem is formed just below the root apex, which is covered by the root cap. The cells of the epiblem absorb water and dissolved mineral matter from the soil; they also effect gas exchange and the excretion of metabolic products. The cells form root hairs, which significantly increase soil contact. After atrophy of the epiblem, the external cells of the primary cortex—the exodermis—take on a protective function. The primary integument is often replaced by a secondary one, or cork, which is a component of the periderm. The protective properties of cork are increased by the deposition of a sub-erin lamella on the internal surface of the cell membranes. Cork contains areas of loosely arranged cells known as lenticels, through which gas exchange and evaporation occur.

M. A. GULENKOVA

References in periodicals archive ?
Another possible synapomorphy is single-layered endoreticulate endotesta (derived from the inner epidermis of the outer integument), as in Ascarina, Sarcandra, and Chloranthus, but this is equivocal because this layer is unspecialized in Hedyosmum-, the character is inapplicable in Ceratophyllum because it has only one integument.
The effect of calcium ion on texture is due to the hardening of the integument and cell wall cotyledons by the formation of [Ca.sup.++] complexes and pectin (BALASUBRAMANIAN et al., 2000).
May 4 ~ May 7###Microspore tetrad stage###Inner and outer integument initiation to elongation
alata confirms the statement of Tokuoka and Tobe (2003) that the ovules of the subtribe Dalechampiinae, including Dalechampia, presents a vascularized outer integument, which is unknown in the subtribes Plukenetiinae and Trigiinae.
Extraction of Embryos from The Ovul: Open ovules at the end opposite to that of the micropyle were cut and embryos from the ovular integuments were carefully excised.
The blood clot represents a potential barrier to entry to the internal milieu across wounds to the integument, both by capturing bacteria as the clot is forming and by physically blocking entry after clotting is complete.
Chaetotaxy, the presence and arrangement of setae and other sensory structures on the integument of arthropods, has been widely used for systematic and taxonomic studies in a variety of groups, including insects (e.g.
In contrast, three types of ovules were observed in ovaries of vc genotypes: (i) normal megagametophyte except that the nucellus was exposed and frequently extruded from the integuments, (ii) normal megagametophyte except inner integuments and nucellus were shorter than normal, and (iii) no internal development of a megagametophyte.
The subversive move is to reveal within the very integuments of "whiteness" the agonistic elements that make it the unsettled, disturbed form of authority that it is - the incommensurable "differences" that it must surmount; the histories of trauma and terror that it must perpetrate and from which it must protect itself; the amnesia it imposes on itself; the violence it inflicts in the process of becoming a transparent and transcendent force of authority.
For people even to conceive of the state, or of its active intervention in altering the social distribution of wealth or property relations, they are required to share a cognitive map which includes a view of a wider world beyond locality, and of the integuments which hold it together.