Influence of saturation deficit on leaf production and expansion in stands of groundnut (Arachis hypogaea L.) grown without irrigation
1985
Ong, C.K. | Black, C.R. | Simmonds, L.P. | Saffell, R.A.
The response of leaf area expansion to atmospheric saturation deficit (SD) and soil moisture deficit was examined in terms of leaf water potential (ψ1) and turgor potential (ψp), as part of a wider study of the effects of SD on groundnut growth. Stands of plants were grown at four levels of SD and without irrigation in controlled environment glasshouses. A fifth stand was grown at low SD on soil kept irrigated to field capacity. Large saturation deficits accelerated the depletion of soil moisture reserves in the unirrigated stands and greatly reduced leaf area index, particularly in the driest treatment. Leaf number per plant and leaf size both decreased as SD increased, but the effect on leaf size was greater than on number. SD had less effect than soil water deficit on leaf production. Turgor potential and leaf extension rate (R) were both reduced at high saturation deficits and R was linearly related to ψp between 0900 and 1600 h. However, leaf extension rate and turgor potential were poorly correlated between 0400 and 0700 h in the driest treatment.
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