© 2007 Heron Publishing—Victoria, Canada
Physiological and phenological responses of oak seedlings to oak forest soil in the absence of trees
Ian A. Dickie (1, 2, 4), Rebecca A. Montgomery (1), Peter B. Reich (1) and Stefan A. Schnitzer (1, 3)
1. University of Minnesota, Department of Forest Resources, St. Paul, MN, USA / 2. Present address: Landcare Research, Lincoln, New Zealand / 3. Present address: University of Wisconsin–Milwaukee, Department of Biological Sciences, Milwaukee, WI, USA / 4. Corresponding author (dickiei@landcareresearch.co.nz) / Received February 13, 2006; accepted April 18, 2006; published online October 2, 2006
Summary
Established trees influence the growth and physiology of seedlings by altering above- and belowground conditions; however,
tree influences on seedling physiology via belowground interactions are not well understood. We used soil transfers to an
open field to examine the belowground influences of a Quercus ellipsoidalis E.J.Hill dominated forest on Q. ellipsoidalis seedling mycorrhizal infection, nutrient uptake, growth and photosynthesis over three years. After two years, seedlings planted
with large quantities of forest soil (HF treatment) had greater leaf mass and foliar N concentrations than seedlings receiving
smaller quantities of forest soil (LF) and control treatments. Mycorrhizal infection was greater in the HF treatment after
one year compared with the LF and control treatments, with a positive correlation of foliar N and mycorrhizal infection in
Year 2. There were marked effects of treatments on seedling spring phenology with HF seedlings breaking bud up to 17 days
earlier than seedlings in the other treatments. The HF seedlings also had more rapid leaf expansion and larger leaves, and
an increase in net photosynthetic rates. These results highlight complex linkages between above- and belowground physiology:
forest soil had substantial effects on seedling physiology, including traits such as phenology that have previously been considered
to be under aboveground control. Belowground influences of trees on conspecific seedlings may play a critical role in early
seedling establishment.
Keywords:
mycorrhiza, phenology, photosynthesis, Quercus ellipsoidalis, tree-seedling interactions.
