title: Relationships between hydraulic architecture, leaf photosynthetic capacity and water-use efficiency in forest trees
reg no: ETF6617
project type: Estonian Science Foundation research grant
subject: 1.14. Ecology
status: accepted
institution: TU Faculty of Biology and Geography
head of project: Arne Sellin
duration: 01.01.2006 - 31.12.2009
description: Relationships between plant water relations, gas exchange and hydraulic characteristics of forest trees will be examined under natural and laboratory (on detached shoots) conditions depending on light availability, temperature and water supply. We shall focus the study on regulation of hydraulic conductance at the leaf level, sampling both shade tolerant (Tilia cordata Mill. or Picea abies (L.) Karst.) and intolerant tree species (Betula pendula Roth or Populus tremula L.). We are going to test the hypothesis that short-term dynamics of whole-tree hydraulic conductance (GT) is determined mainly by leaf hydraulic conductance (GL), and regulation of GL under non-droughty conditions (i.e. without significant cavitation of xylem conduits) is governed by other factors than leaf water status. Ultimately, we address the question about the role of hydraulic constraints in variation of leaf photosynthetic traits within a crown. To realize the tasks set up, we seek answers to the following questions:
a) What are main environmental factors controlling liquid phase conductance of the extra-vascular compartment of leaf?
b) How big is the contribution of symplastic vs. apoplastic compartment to leaf hydraulic conductance?
c) Do plant inner hydraulic constraints limit net photosynthesis (i.e. stomatal limitation of photosynthesis due to hydraulic constraints) in lower-canopy foliage, and whether they have any effect on leaf water-use efficiency?

project group
no name institution position  
1.Priit Kupper 
2.Märt Rahi 
3.Arne SellinTartu Ülikool