Biomaterial Database

Measuring the osmotic water permeability of the plant protoplast plasma membrane: implication of the nonosmotic volume. 2007

Aniela Sommer, and Georg Mahlknecht, and Gerhard Obermeyer

Molecular Plant Biophysics and Biotechnology, Centre of Biosciences and Health, Division of Allergy and Immunology, Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, 5020 Salzburg, Austria.

Starting from the original theoretical descriptions of osmotically induced water volume flow in membrane systems, a convenient procedure to determine the osmotic water permeability coefficient (P (os)) and the relative nonosmotic volume (beta) of individual protoplasts is presented. Measurements performed on protoplasts prepared from pollen grains and pollen tubes of Lilium longiflorum cv. Thunb. and from mesophyll cells of Nicotiana tabacum L. and Arabidopsis thaliana revealed low values for the osmotic water permeability coefficient in the range 5-20 microm.s(-1) with significant differences in P (os), depending on whether beta is considered or not. The value of beta was determined using two different methods: by interpolation from Boyle-van't Hoff plots or by fitting a solution of the theoretical equation for water volume flow to the whole volume transients measured during osmotic swelling. The values determined with the second method were less affected by the heterogeneity of the protoplast samples and were around 30% of the respective isoosmotic protoplast volume. It is therefore important to consider nonosmotic volume in the calculation of P (os) as plant protoplasts behave as nonideal osmometers.

UI	MeSH Term	Description	Entries
D009995	Osmosis	Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.	Osmoses
D010539	Permeability	Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.	Permeabilities
D011058	Pollen	The fertilizing element of plants that contains the male GAMETOPHYTES.	Male Gametes, Plant,Male Gametophytes,Microspores, Plant,Plant Microspores,Pollen Grains,Gamete, Plant Male,Gametes, Plant Male,Gametophyte, Male,Gametophytes, Male,Grain, Pollen,Grains, Pollen,Male Gamete, Plant,Male Gametophyte,Microspore, Plant,Plant Male Gamete,Plant Male Gametes,Plant Microspore,Pollen Grain
D011523	Protoplasts	The protoplasm and plasma membrane of plant, fungal, bacterial or archaeon cells without the CELL WALL.	Protoplast
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D014026	Nicotiana	A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; the dried leaves of Nicotiana tabacum are used for SMOKING.	Tobacco Plant,Nicotiana tabacum,Plant, Tobacco,Plants, Tobacco,Tobacco Plants
D014867	Water	A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Hydrogen Oxide
D053205	Pollen Tube	A growth from a pollen grain down into the flower style which allows two sperm to pass, one to the ovum within the ovule, and the other to the central cell of the ovule to produce endosperm of SEEDS.	Pollen Tubes,Tube, Pollen,Tubes, Pollen
D027762	Lilium	A plant genus in the family LILIACEAE generally growing in temperate areas. The word lily is also used in the common names of many plants of other genera that resemble true lilies. True lilies are erect perennial plants with leafy stems, scaly bulbs, usually narrow leaves, and solitary or clustered flowers.	Lily,Lilies,Liliums