Influence of water stress on water relations and growth of a tropical (C4) grass, Panicum maximum var. trichoglume

Ng , T.T. and Wilson, J.R. and Ludlow, M.M. (1975) Influence of water stress on water relations and growth of a tropical (C4) grass, Panicum maximum var. trichoglume. Australian Journal of Plant Physiology, 2 (4). pp. 581-595.

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The effects of recurring cycles of short-term water stress on the water relations and growth of P. maximum var. trichoglume in pots of soil were investigated under controlled conditions. As soil water content decreased there was an increase in the resistance to water movement in the soil-plant system. Leaf stomatal resistance increased and concomitantly transpiration rate decreased when soil water content fell below 37% (soil water potential of -1.0 bars) and leaf water potentials were less than -6 bars. The leaf water potential at wilting (-8 to -10 bars) and the relation between leaf water potential and relative water content changed with leaf position on the tiller. The death of early-formed leaves on the plants was accelerated by water stress but, in contrast, the later-formed leaves died more rapidly in the unstressed control so that finally the control plants had a higher proportion of dead leaves. Plant growth was reduced at soil water contents above the permanent wilting point. Reduction in NAR was the main determinant of lower RGR of stressed plants over the initial cycles of stress but subsequently, as leaf area expansion was reduced, LAR also had a significant influence. Water stress influenced growth directly, and also indirectly via its effect on plant development (ontogeny). 2 techniques were used to separate the direct from the indirect effects on RGR. Some published data which suggested a stimulation of growth rate after the relief of stress are re-interpreted and the effect was shown to be due mainly to differences in ontogeny between stressed and control treatments

Item Type: Article
Author Affiliation: Department of Agronomy and Soil Science, New England University, Armidale, N.S.W., Australia 2350
Subjects: Plant Physiology and Biochemistry > Plant Physiology
Plant Physiology and Biochemistry > Biochemistry
Divisions: Other Crops
Depositing User: Ms K Syamalamba
Date Deposited: 19 Apr 2012 10:24
Last Modified: 19 Apr 2012 10:24

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