Aasamaa, Krõõt , Sõber, Anu .
Stomatal sensitivities to changes in leaf water potential, CO2 concentration and light intensity, and drought tolerance of temperate deciduous tree species.
Stomatal sensitivity to several different environmental factors was measured before and after a drought period (3 weeks). Before the drought period, stomatal sensitivities to rapid decrease in leaf water potential, to any rapid change (increase or decrease) in CO2 concentration and to any rapid change in light environment were the highest in seedlings of slow-growing temperate deciduous tree species and the lowest in the fast-growing temperate deciduous tree species. Stomatal sensitivity to rapid increase in leaf water potential, and also the stomatal conductance and leaf water potential were the highest in the fast-growers and the lowest in the slow-growers. The drought changed all the stomatal sensitivities in all the species. Stomatal sensitivities to an increase in leaf water potential, to a decrease in CO2 concentration and to an increase in light intensity were decreased. Stomatal sensitivities to a decrease in leaf water potential, to an increase in CO2 concentration and to a decrease in light intensity were increased. Thus, not only the stomatal sensitivity to rapid decrease in leaf water potential, but also the stomatal sensitivities to the ‘photosynthetic factors’ that cause stomatal closure, were increased during the drought. And the stomatal sensitivities to all the different factors that cause stomatal opening, were decreased during the drought. All the stomatal sensitivities had changed significantly more in slow-growers than in fast-growers during the drought. But leaf water potential and stomatal conductance were the lowest in fast-growers after the drought. We suggest that the stronger drought response of all the stomatal sensitivities in slow-growers (than in fast-growers) is relevant cause of the higher drought tolerance of slow-growers.
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1 - Estonian University of Life Sciences, Inst Forestry & Rural Engin, Department of Silviculture, Kreutzwaldi 5, Tartu, 51014, Estonia
2 - University of Tartu, Institute of Botany & Ecology, Chair of Ecophysiology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM