Abstract Detail

Ecophysiology

Brocious, Caroline [1], Hacke, Uwe G. [2].

Discerning genetic differences in leaf anatomy and leaf hydraulic conductance in hybrid poplar clones.

In a changing climate, meeting the projected global demand for wood products seems daunting. Hybrid poplars, or crosses between two or more Populus species, are valued for their high rates of biomass production, and presently are grown commercially in northern Alberta plantations. The productivity of hybrid poplars is limited in part by their hydraulic architecture, a concept defining the relationship between the vascular architecture in trees (xylem) and the leaves it must supply. As carbon gain in plants occurs only in exchange for water loss, water movement inherently controls overall plant performance. Leaves, in particular, are crucial to growth in trees, serving as both the site of carbon gain (photosynthesis) and water loss (transpiration). Recent research has elucidated the importance of leaves to plant hydraulics, emphasizing the need to understand how vascular structure influences productivity. Our research focuses on a current gap in this field; namely, how does vascular anatomy influence hydraulic conductance in poplar leaves? Can we predict differences in leaf hydraulic traits based on anatomical parameters? For this study, different Populus hybrids and one pure species (P. tremuloides) were grown under ideal greenhouse conditions. The maximum leaf hydraulic conductance (K_leaf) of each poplar clone was measured, as well as various anatomical components of the vascular architecture. Overall, significant differences in K_leaf were found between several of the hybrid clones, including interesting trends between major vein density and leaf area. The hybrid poplars also exhibited variations in leaf mass per area, emphasizing the strong genetic control over certain hydraulic parameters. Ultimately, the data suggests that extra-xylem pathways may dictate overall K_leaf in our hybrid poplars.

1 - University of Alberta, Renewable Resources, University of Alberta 247 Earth Sciences, Edmonton, AB, T6G2E3, Canada
2 - University of Alberta, Renewable Resources, Edmonton, AB, T6G 2E3, Canada

Keywords:
Leaf hydraulic conductance
leaf anatomy
hybrid poplar
plant physiology
hydraulic architecture
extra-xylem pathway.

Presentation Type: Oral Paper:Papers for Topics
Session: 41
Location: Salon 16/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 10:30 AM
Number: 41002
Abstract ID:777
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize