EAPSI: Quantifying Pore Characteristics and Leaf Water Transport Conduits in Three Australian Evergreen Tree Species

Riley Megan L, Moscow ID

Investigators

Abstract

In plants, water is transported from the soil through a complex network of conduits from roots to trunks, branches and leaves. As soils dry, water columns in the plant can break, resulting in a reduced water transport capacity and eventual death if the dry conditions persist, as with drought. We know that the physical characteristics of the pores, which link adjacent water transport conduits in trees, relate to drought tolerance in roots, trunks and branches, but little research has focused on these pores in leaves, despite their being the gateway to plant photosynthesis and therefore overall growth and survival. In this project, the Fellow will work with Dr. Brendan Choat ? an expert in plant water transport at the Hawkesbury Institute for the Environment at Western Sydney University, Australia ? to measure these interconnecting pores in leaves of three economically vital evergreen tree species using laser-based and electron-based high resolution imaging systems. Analyzing the anatomical structure of the pores will increase foundational knowledge and help to enhance accuracy of drought-induced forest dieback predictions. Although leaves are the gateways of overall plant growth and productivity, their hydraulic function has been studied much less than other plant organs. Research has shown that there is a correlation between bordered pit/torus-margo morphology and drought resistance in roots, stems and branches, but these structures remain largely unquantified in leaf xylem. In this project, the Fellow will work with Dr. Brendan Choat ? an expert in plant hydraulics at the Hawkesbury Institute for the Environment at Western Sydney University, Australia ? to image and quantify numerous aspects of pit and torus-margo morphology in leaf tracheids and transfusion tracheids in three economically vital conifer species using confocal laser scanning microscopy and electron scanning microscopy. Anatomical characteristics are necessary components of leaf and soil-plant-atmosphere models; understanding bordered pit morphology may contribute to enhanced predictions of altered plant function and species distributions under changing climate regimes. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Australia Academy of Science.