Effects of drought and changes in vapour pressure deficit on water relations of Populus deltoides growing in ambient and elevated CO2
| Autor: | Katherine G. Rascher, Ramesh Murthy, Edward G. Bobich, Greg A. Barron-Gafford |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Stomatal conductance
Vapor Pressure Physiology Vapour Pressure Deficit Plant Science Environment Soil chemistry.chemical_compound Coppicing Magnoliopsida Transpiration biology fungi Water food and beverages Xylem Carbon Dioxide biology.organism_classification Wood Droughts Plant Leaves Horticulture Populus chemistry Agronomy Carbon dioxide Woody plant |
| Zdroj: | Tree Physiology. 30:866-875 |
| ISSN: | 1758-4469 0829-318X |
| Popis: | The means by which growth CO(2) concentration ([CO(2)]) affects anatomy and water relations responses to drought and vapour pressure deficit (VPD) were studied for yearly coppiced, 4-year-old Populus deltoides clones that were grown in either 400 mumol mol(-1) (ambient) or 800 mumol mol(-1) (elevated) CO(2) for 3 years. It was hypothesized that, during drought, trees growing in elevated [CO(2)] would have a lower volume flux density of water (J(V)), stomatal conductance (g(s)) and transpiration per leaf area (E), as well as a lower stomatal density and a greater stomatal response to drought and changes in VPD than would trees in ambient [CO(2)]. Trees in elevated [CO(2)] actually had higher J(V) values throughout the study, but did not differ from trees in ambient [CO(2)] with respect to g(s) or E under saturating light or E scaled from J(V) (E(scaled)), all of which indicates that the higher J(V) in elevated [CO(2)] resulted from those trees having greater leaf area and not from differences in g(s). Furthermore, although plants in elevated [CO(2)] had greater absolute leaf loss during the drought, the percentage of leaf area lost was similar to that of trees in ambient [CO(2)]. g(s) and E under saturating light were affected by changes in VPD after the first 9 days of the experiment, which coincided with a large decrease in water potential at a soil depth of 0.1 m. Trees in elevated [CO(2)] had a greater stomatal density and a lower wood density than trees in ambient [CO(2)], both traits that may make the trees more susceptible to xylem cavitation in severe drought. Drought and VPD effects for the P. deltoides clone were not ameliorated by long-term growth in elevated [CO(2)] compared with ambient [CO(2)], and plants in elevated [CO(2)] possessed anatomical traits that may result in greater stress associated with long-term drought. |
| Databáze: | OpenAIRE |
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