© 1992 Heron Publishing—Victoria, Canada
The impact of water and nutrient deficiencies on the growth, gas exchange and water relations of red oak and chestnut oak
Karl W. Kleiner (1), Marc D. Abrams (2) and Jack C. Schultz (1)
1. Department of Entomology, The Pennsylvania State University, Pesticide Research Laboratory, University Park, PA 16802, USA / 2. School of Forest Resources, The Pennsylvania State University, Ferguson Building, University Park, PA 16802, USA / Received December 20, 1991
Summary
Red oak (Quercus rubra), a mesic species, and chestnut oak (Quercus prinus), a xeric species, were grown in a greenhouse with and without fertilizer (F+ and F–, respectively) and subjected to a 10-week
drydown (W–) or kept well watered (W+). In both species, fertilized seedlings exhibited greater reductions in mean net photosynthesis
(A), leaf conductance (gwv), leaf water potential (Ψleaf) and water use efficiency (WUE) during the drydown than unfertilized seedlings. In the W– treatments, red oak showed greater
reductions in A, gwv and Ψleaf than chestnut oak. Differential fertilization of the seedlings of both species had a greater effect on tissue water relations
than differential watering. During the latter weeks of the drydown, there was no osmotic adjustment in red oak, but chestnut
oak in the F+/W– treatment had significantly lower osmotic potentials at full and zero turgor than seedlings in any of the
other treatments. The results indicate that high nutrient availability does not improve the drought tolerance of these two
oak species.
