Osmotic water permeability of isolated protoplasts. Modifications during development

Citation
T. Ramahaleo et al., Osmotic water permeability of isolated protoplasts. Modifications during development, PLANT PHYSL, 119(3), 1999, pp. 885-896
Citations number
49
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT PHYSIOLOGY
ISSN journal
00320889 → ACNP
Volume
119
Issue
3
Year of publication
1999
Pages
885 - 896
Database
ISI
SICI code
0032-0889(199903)119:3<885:OWPOIP>2.0.ZU;2-R
Abstract
A transference chamber was developed to measure the osmotic water permeabil ity coefficient (P-os) in protoplasts 40 to 120 mu m in diameter. The proto plast was held by a micropipette and submitted to a steep osmotic gradient created in the transference chamber. P-os was derived from the changes in p rotoplast dimensions, as measured using a light microscope. Permeabilities were in the range 1 to 1000 mu m s(-1) for the various types of protoplasts tested. The precision for P-os was less than or equal to 40%, and within t his limit, no asymmetry in the water fluxes was observed. Measurements on p rotoplasts isolated from 2- to 5-d-old roots revealed a dramatic increase i n P-os during root development. A shift in P-os from 10 to 500 mu m s(-1) o ccurred within less than 48 h. This phenomenon was found in maize (Zea mays ), wheat (Tuiticum aestivum), and rape (Brassica napus) roots. These result s show that early developmental processes modify water-transport properties of the plasma membrane, and that the transference chamber is adapted to th e study of water-transport mechanisms in native membranes.