The barrier to radial oxygen loss from roots of rice (Oryza sativa L.) is induced by growth in stagnant solution |
| |
Authors: | Colmer T; Gibberd M; Wiengweera A; Tinh T |
| |
Institution: | Faculty of Agriculture, The University of Western Australia, Nedlands, WA 6907, Australia; Prachinburi Rice Research Centre, Ban Sang, Prachinburi 25150, Thailand; Cantho University, 30-4 St, Cantho City, Vietnam |
| |
Abstract: | The present report describes experiments in which the effects of growth in
aerated and stagnant nutrient solutions on adventitious root porosities and
patterns of radial O2 loss (ROL) from the roots of four genotypes of rice
(Oryza sativa L.) were evaluated. The genotypes
studied are usually cultivated in farming systems which differ markedly in
their degree of soil waterlogging and flooding. Rice genotypes were found
to differ in the constitutive porosity (% gas space) of their adventitious
roots when grown in aerated solutions (lowest was 16%, highest was 30%),
and the roots grown in stagnant conditions had porosities between 28% and
38%. ROL from the adventitious roots raised in aerated solution increased
with distance behind the tip in three of the four genotypes; whereas for
roots raised in stagnant solution, ROL decreased with distance behind the
tip which is indicative of a high resistance to diffusion between the
aerenchyma and external medium. For example, at 35 mm behind the root tip
the ROL from roots of the 'deepwater' cultivar grown in stagnant conditions
was 0.7% of the rate of its aerated roots, for the 'lowland' cultivar it
was 5.6%, and for one of the 'upland' cultivars it was 43.6%. Thus, the
barrier to ROL from the adventitious roots in three of the four genotypes
was induced by growth in stagnant nutrient solution. A low rate of ROL from
the basal zones of roots in an O2-free environment is of adaptative value
since longitudinal diffusion of O2 to the root apex would be enhanced
which, in turn, enables greater penetration of roots into anaerobic
soils. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|