Plasmolysis


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plasmolysis

[plaz′mäl·ə·səs]
(physiology)
Shrinking of the cytoplasm away from the cell wall due to exosmosis by immersion of a plant cell in a solution of higher osmotic activity.

Plasmolysis

 

the loosening of the protoplast from the cell cover when a cell is immersed in a hypertonic solution. Plasmolysis is characteristic mainly of plant cells, which have a sturdy cellulose cover. Animal cells contract when transferred to a hypertonic solution. Plasmolysis may be convex, concave, convulsive, or mitriform. These variations are determined by the viscosity of the protoplasm, the difference between the osmotic pressure of the cell and that of the external solution, and the speed and degree of water loss by the protoplasm. Sometimes plasmolyzed cells remain alive; when such cells are immersed in water or a hypotonic solution, deplasmolysis occurs.

There are two methods for comparative evaluation of plasmolysis: borderline plasmolysis and the plasmometric method. The first method, developed by H. de Vries in 1884, consists of immersing tissues in solutions with various concentrations of KNO3, sucrose, or other osmotically active substances and establishing the concentration at which 50 percent of the cells are plasmolyzed. With the plasmometric method, the relative volumes of the cell and the protoplast are measured after plasmolysis, and the osmotic pressure of the cell is calculated according to appropriate formulas from the concentration of the solution.

V. V. KABANOV

References in periodicals archive ?
This trend could also be attributed to the initial occurrence of plasmolysis in the canned products leading to leaching of its tissue mass into the processing medium as explained by Prescott et al.
Nonetheless, when the salinity increased to 35 g x [L.sup.-1], the higher osmotic stress would cause an outward flow of intracellular water, leading to cell dehydration and eventually plasmolysis and loss of activity of the cells for these microorganisms [20].
Soil salinity prevents plant growth and development with adverse effects such as osmotic stress, [Na.sup.+] and [Cl.sup.-] toxicity, ethylene production, plasmolysis, nutrient imbalance and interference with photosynthesis (Sairam and Tyagi 2004).
Larger amounts of mineral salts (KCl, NaCl) evoke plasmolysis inside the cells of microorganisms as a result of which microorganisms are destroyed.
The midrib shows cellular plasmolysis and consequent formation of large intercellular spaces, as well as hypertrophy of the parenchyma cells and intense coloration caused by fuchsine in the affected areas (Figures 2b and 2c).
This process is called plasmolysis and is, of course, disastrous for the cell.
Cell plasmolysis and aberrations of or coalescence of LB were evident in seed harvested at MC >400 g [H.sub.2]O [kg.sup.-1] fw and dried in the fluidized bed without PC (Fig.
When applied too close to seed or foliage, high-index materials may cause plant injury by plasmolysis.
This concept of controlled release, would aid in preventing plasmolysis in plant root systems during the dry intervals in the growing season or in arid soils.
The light plasmolysis and shape alteration were demonstrated by the dashed arrows.
This may be attributed to the inhibition of bacteria at high salt concentration due to plasmolysis or loss of activity of cells [35].