Scaling of Plant Hydraulic Architecture
Joshua Weitz (Department of Ecology & Evolutionary Biology, Princeton University)
(April 27, 2006 10:30 AM - 11:30 AM)
An important component of plant water transport is the design of the vascular network, including the size and shape of water conducting elements, or xylem conduits. Despite the development of a number of competing theories of hydraulic design, empirical data have rarely been assembled to assess whole-plant hydraulic architecture of woody plants as they age and grow. In this talk, I present analysis of the scaling of plant hydraulic architecture within a single white ash tree over 18 years of growth and 12 meters in height. The qualitative form for the scaling of vessel radii agrees remarkably well with simple power laws, implying the existence of an ontogenetically stable hydraulic design, i.e. a design that scales in the same manner as a tree grows in height and diameter. I discuss the implications of the present finding for optimal theories of hydraulic design, its relevance to work on cavitation, and comparison to recent empirical findings on other species.