1:00 pm - 2:00 pm
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Coral Fermaniuk. This seminar is open to the general public to attend.
MSc with Dr. Simon Landhäusser.
Thesis Topic: The phenology and potential constraints on the remobilization of non-structural carbohydrate reserves in matureboreal
The remobilization of non-structural carbohydrate (NSC) reserves among organs is crucial for the survival of trees duringperiods of carbon (C) limitation, however, the framework of reserve allocation and remobilization remains unclear,especially for mature trees. Here, I used mature Betula papyrifera trees to (1) characterize the seasonal fluctuation ofNSC reserves at the whole-tree and organ level, as well as (2) determine the patterns/potential constraints of reserveremobilization when organs (crown, stem, roots) were separated through stem phloem girdling and functioning under C-limitation. Driven mostly by reserves in the branches, seasonal whole-tree NSC storage increased by 72% from itsminimum — greatly exceeding the storage reported for more temperate conspecifics. Further, through girdling I found thatthe storage capacity of the crown can far exceed (double) the seasonal maximum, but that reserves (here stem) may notbe universally available for remobilization to other organs (here roots) under C-limitation. Together, these results suggestthat NSC phenology in large mature boreal B. papyrifera is highly regulated to ensure adequate allocation of reserves tostorage throughout the tree — however, when carbon limited, reserve remobilization may be regulated somewhatautonomously among organs which could potentially limit reserve sharing.