Hydraulic Limits to Photosynthetic Performance in Tropical Dry Forest Trees

Harvard University, Cambridge MA

Investigators

Abstract

This study addresses the degree to which the water transport capacity of plants limits their productivity. Specifically, we focus on the hydraulic properties of tree stems and branches (the "xylem") in relation to the photosynthetic capacity of the leaves. Our goal is to understand the physiological linkages between vascular and photosynthetic capacity. We have chosen to address this fundamental question by examining seasonally dry forest trees. Our rationale for this reflects the important role that seasonal precipitation patterns play in determining the longevity and productivity of leaves in these forests. We will monitor the extent to which vascular tissues become damaged during periods of low water availability (drought) and the effects that this has on the productivity of leaves. Our study will be one of the first to examine directly the link between vascular and photosynthetic capacity in trees. The results of this work will increase our understanding of how plants copy with dramatic changes in soil water availability, and will contribute to our knowledge of factors influencing the productivity and ecology of seasonally dry tropical forests.