Canadian Forest Service Publications
Control of pressure-chamber and rehydration-time effects on pressure: volume determination of water-relation parameters. 1993. Zine El Abidine, A.; Bernier-Cardou, M.; Bernier, P.Y.; Plamondon, A.P. Canadian Journal of Botany 71: 1009-1015.
Issued by: Laurentian Forestry Centre
Catalog ID: 16533
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In a study of the seasonal variation of water-relation parameters in four black spruce (Picea mariana (Mill) BSP) populations, the weekly derivation of 32 pressure-volume curves with the sap-expression method between May and October required the simultaneous use of four pressure chambers and variable sample rehydration periods. Pressure chamber had a significant effect on three of the five characteristics studied: symplastic water fraction, maximum modulus of elasticity, and osmotic potential at full turgor. These effects were constant over the growing season. On average, rehydration-time effects were significant for all water-relation parameters except osmotic potential at turgor loss point, but they were not constant over sampling dates. Variations in water-relation parameters due to chambers and rehydration times were controlled and estimated through an experimental design based on the Latin square, which allowed precise comparisons among populations despite the increase in variability due to these two factors. The efficiency of the design varied between 110 and 142% relative to a completely randomized design in which neither chambers nor rehydration times would have been controlled for.