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Functional Plant Biology Functional Plant Biology Society
Plant function and evolutionary biology
RESEARCH ARTICLE

Whole-Plant Carbon Balance During Osmotic Adjustment to Drought and Salinity Stress

KJ Mccree

Australian Journal of Plant Physiology 13(1) 33 - 43
Published: 1986

Abstract

The whole-plant daily carbon balance (the 24-h sum of photosynthetic input of substrate carbon per plant and loss of carbon through respiration) is the CO2 exchange measure that relates most closely to crop production rates. Water stress reduces the photosynthetic input, reducing both leaf area and photosynthetic rate per unit leaf area. Respiratory losses are reduced more or less proportionately. A less-than-proportional loss was observed during osmotic adjustment in sorghum (Sorghum bicolor (L) Moench): the metabolic cost of storing photosynthate and using it for osmotic adjustment was less than the cost of converting it to new biomass. A slightly increased metabolic cost is often found under salt stress but, in sorghum plants that were salinized and then water stressed, the adverse effects of salt were mitigated by decreased water loss rates and enhanced osmotic adjustment during water stress. More tests involving combined salt and water stress are needed.

https://doi.org/10.1071/PP9860033

© CSIRO 1986

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