Determination of the permeability of plant cells (mass wall separation method)

plant cells are a permeable system, when they are in a high seepage solution, cells lose water, the volume of protosites shrinks, and mass wall separation occurs. Conversely, if the cells that have already been isolated by the mass wall are transferred to a low seepage solution, the cells will re-absorb water and the mass wall will be isolated and restored. The penetration potential of plant cells can be determined by using the mass wall separation of plant living cells. The permeability of plant cells mainly depends on the solute concentration of the cell fluid, so it is also known as the solute potential. Permeability is closely related to plant moisture metabolism, growth and resistance.
It is known that under drought, salinization and other conditions, some plants often actively accumulate solutes in cells to reduce their permeability and increase their water absorption capacity, while maintaining puffing pressure to a certain extent to ensure cell growth and the opening of pores, a phenomenon known as osmosis regulation. The size of the osmosis regulation ability can be expressed by the decrease of the permeability of the cells under adversity regulation, which is often needed in the study of moisture physiology and resistance physiology.
, principle
Plant cells absorb water is related to the permeability of their cell fluid, but it is not entirely determined by the permeability, but by the water potential of the cells. Because there are cell walls on the periphery of the protosite and cell wall restriction of the expansion of protosites, while the hydroelol collosite in the cell has the ability to absorb water, so the typical cell water potential consists of three parts: ψw ψπ and ψp ψM
of which ψπ is permeability, that is, the water potential of the solution, is due to the presence of the solution particles caused by the reduction of its own energy, generally negative value, mainly depends on the total number of particles (ions or molecules ψp) in the solution; ΨM Is the pressure potential, is due to the presence of cell wall pressure and increase the water potential, generally positive, in special circumstances will be equal to zero (when the mass wall is separated) or negative value (when intense steaming);
to determine the permeability of plant cells, plant
tissue
can be placed in a series of different concentrations of sucrose solution, over time, plant cells and sucrose solution will reach the permeable balance. If the cell dehydrates into balance in a solution and is in a critical wall separation state, the pressure potential of the cell will drop to zero.
the lining potential is negligible, at this time the permeability of the cell fluid is equal to the osmosis potential of the outer liquid ψπo that is, ψπ ψπo. This solution is called the osmosis solution of the tissue, and its concentration is called the iso-permeable concentration of the tissue to calculate the permeability potential (ψπ).
the actual determination, because the critical mass wall separation state is difficult to be directly observed under
microscope
, so the initial mass wall separation is generally used as a criterion to judge iso-permeable concentration. The cell volume in the initial mass wall separation state is slightly smaller than when the absorbent is saturated, so the permeability potential of cell fluid concentration and penetration is slightly lower than that of absorbent saturation.
II, materials,
instruments
and
reagents
(i) Materials: onions or scallion bulbs, wheat leaves
(ii) Instruments: microscopes, slides and cover slides each several,
thermometers
, pointed tweezers, blades, 12 vials with
penicillin, test bottles,
beech
,
capacity bottle
, volume barrel,
straw
, etc., absorbent paper appropriate amount
(iii) reagents:
(1) 1mol/L sucrose water solution. It is said that 34.2g of sucrose dried in advance at 60-80 oC is dissolved in 70 ml distilled water, and the capacity bottle is fixed to 100 ml, i.e. 1M sucrose solution.
(2)0.03% neutral red solution.
。