Kneeshaw, D. | Search bioRxiv

bioRxiv2021

Interactions between xylem traits linked to hydraulics during xylem development optimize growth performance in conifer seedlings

O_LIClimate change has threatened forests globally, challenging tree species ability to track the rapidly changing environment (e.g., drought and temperature rise). Conifer species face strong environmental filters due to climatic seasonality. Investigating how conifers change their hydraulic architecture during xylem development across the growing season may shed light on possible mechanisms underlying hydraulic adaptation in conifers. C_LIO_LILaser microscopy was used to assess the three-dimensional hydraulic architecture of balsam fir (Abies balsamea (Linnaeus) Miller), jack pine (Pinus banksiana Lambert), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Miller) Britton, Sterns & Poggenburgh) seedlings. We measured hydraulic-related xylem traits in different regions (from early to latewood), during four years of plant growth. C_LIO_LIThe xylem development of jack pine seedlings contrasts with the other species by maintaining torus overlap (a hydraulic safety-associated xylem trait), relatively constant across the season (from early to latewood), and over the years studied. The expansion of tracheids and torus was positively associated with plant growth. C_LIO_LIPit aperture-torus covariance is central to the seasonal dynamics of jack pine xylem development, which jointly with a rapid tracheid and pit expansion is consistent with strong growth performance. Linking xylem structural changes during xylem development with hydraulics is a major issue for future research to assess conifers vulnerability to climate change. C_LI

ecology↗

bioRxiv2018

The Gut-Associated Microbiome of the Eastern Spruce Budworm Does Not Influence Larval Growth or Survival

Microbial communities have been shown to play an important role for host health in mammals, especially humans. It is thought that microbes could play an equally important role in other animal hosts such as insects. A growing body of evidence seems to support this, however most of the research effort in understanding host-microbe interactions in insects has been focused on a few well-studied groups such as bees, cockroaches and termites. We studied the effects of the gut-associated microbial community on the growth and survival of the eastern spruce budworm Choristoneura fumiferana, an economically important lepidopteran forest pest in eastern Canada and the northeastern United States. Contrary to our expectations, the gut microbial community of spruce budworm larvae does not appear to influence host growth or survival. Our results agree with the hypothesis that lepidopteran larvae lack resident microbial communities and are not nutritionally dependent on bacterial symbionts.

microbiology↗