© 1990 Heron Publishing—Victoria, Canada
Response of five temperate deciduous tree species to water stress
T. G. Ranney (1), T. H. Whitlow (2) and N. L. Bassuk (2)
1. Mountain Horticultural Crops Research and Extension Center, Department of Horticultural Science, North Carolina State University,
2016 Fanning Bridge Road, Fletcher, NC 28732, USA / 2. Department of Floriculture and Ornamental Horticulture, Cornell University, Ithaca, NY 14853, USA / Received October 23, 1989
Summary
Gas exchange, tissue water relations, and leaf/root dry weight ratios were compared among young, container-grown plants of
five temperate-zone, deciduous tree species (Acer negundo L., Betula papyrifera Marsh, Malus baccata Borkh, Robinia pseudoacacia L., and Ulmus parvifolia Jacq.) under well-watered and water-stressed conditions. There was a small decrease (mean reduction of 0.22 MPa across species)
in the water potential at which turgor was lost (Ψtlp) in response to water stress. The Ψtlp for water-stressed plants was –1.18, –1.34, –1.61, –1.70, and –2.12 MPa for B. papyrifera, A. negundo, U. parvifolia, R. pseudoacacia, and M. baccata, respectively. Variation in Ψtlp resulted primarily from differences in tissue osmotic potential and not tissue elasticity. Rates of net photosynthesis declined
in response to water stress. However, despite differences in Ψtlp, there were no differences in net photosynthesis among water-stressed plants under the conditions of water stress imposed.
In A. negundo and M. baccata, water use efficiency (net photosynthesis/transpiration) increased significantly in response to water stress. Comparisons
among water-stressed plants showed that water use efficiency for M. baccata was greater than for B. papyrifera or U. parvifolia. There were no significant differences in water use efficiency among B. papyrifera, U. parvifolia, A. negundo, and R. pseudoacacia. Under water-stressed conditions, leaf/root dry weight ratios (an index of transpiration to absorptive capacity) ranged from
0.77 in R. pseudoacacia to 1.05 in B. papyrifera.
