Abstract Detail

Physiology & Ecophysiology

Savage, Jessica [1], Montgomery, Rebecca [2], Primack, Richard [3], Rothendler, Matthew [4], Mosher, Kennedy [5].

Hydraulic constraints on the timing of leaf out in angiosperms.

In seasonally cold environments, spring is often a time of recovery, when plants have to re-activate their vascular system and repair freezing-induced damage. This re-activation needs to occur before resources can be mobilized to support new growth and before plants can support a full canopy. It is for this reason that it has been proposed that leaf phenology in seasonally cold climates might be tied to the timing of xylem recovery. The idea being that plants that experience low levels of freezing-induced embolism (e.g. species with narrow vessels) could leaf out early in the spring, while species that experience high levels of freezing-induced embolism (e.g. species with wide vessels) would have to wait until after they have made new vessels through xylogenesis. If this is the case, then we would expect a strong relationship between leaf out time and vessel diameter. To test for this relationship, we studied wood anatomy and leaf phenology in three different common garden experiments: (1) a phylogenetically diverse group of fifty-five species at the Arnold Arboretum, (2) a phylogenetically constrained group of eighteen species from the family Salicaceae that were grown in a greenhouse common garden, and (3) a geographically constrained group of fifteen Minnesotan tree and shrub species that are native to the same climate. In all three of these data sets, we found evidence for a relationship between vessel diameter and leaf out time. We only failed to find a relationship when examining annual variation within individual plants over time. These data suggest that wood anatomy and spring hydraulic capacity constrain the timing of leaf out at a large-scale. However, there is still considerable variation in leaf phenology that cannot be explained by this trait alone, indicating wood structure may only be one of many traits important in determining the timing of leaf out in plants.

1 - University Of Minnesota - Duluth, Biology, 1035 Kirby Drive, 207 Swenson Science Buildling, Duluth, MN, 55812, United States
2 - 1530 Cleveland Ave N., Green Hall 115, St. Paul, MN, 55108, United States
3 - DEPARTMENT OF BIOLOGICAL SCIENCES, 5 Cummington Mall, Boston, MA, 02215, United States
4 - Boston University, Department of Biological Sciences, 5 Cummington Mall, Boston, MA, 02215
5 - University Of Minnesota - Duluth, Biology, 1035 Kirby Drive, 207 Swenson Science Buildling, Duluth, MN, 55812

Keywords:
phenology
xylem
Leaf
Freezing
xylem hydraulics.

Presentation Type: Oral Paper
Session: 39, Ecophysiology
Location: 114/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 8:30 AM
Number: 39003
Abstract ID:666
Candidate for Awards:None