Transient resistance to root growth inhibition by moderate water stress: A possible explanation

摘要

Root growth is dependent on a continuous supply of water and organic solutes needed to maintain cell expansion. It might therefore seem obvious that water stress inhibits root growth. However, some reports indicate that root growth can be maintained or even stimulated during exposure to moderate water stress. This phenomenon was investigated in rice (Oryza sativa L) seedlings grown hydroponically in a controlled environment. Seedlings were exposed for fixed periods to defined levels of water stress induced by PEG 6000 at external water potentials ranging from 0 to - 0.6 MPa. Effects of water stress on rates of root and leaf elongation, as compared to controls without PEG, were determined for 2 cultivars:-