© 1995 Heron Publishing—Victoria, Canada
Foliar absorption of dew influences shoot water potential and root growth in Pinus strobus seedlings
J.-F. Boucher (1), A. D. Munson (1) and P. Y. Bernier (2)
1. Centre de Recherche en Biologie Forestière, Université Laval, Faculté de Foresterie et de Géomatique, Laval, Québec G1K 7P4,
Canada / 2. Forestry Canada, Quebec Region, C.P. 3800, Sainte-Foy, Québec G1V 4C7, Canada / Received April 26, 1995
Summary
We investigated the effects of foliar absorption of dew by eastern white pine (Pinus strobus L.) seedlings on midday shoot water potential, as well as on other water relations variables and growth. Two-year-old container-grown
eastern white pine seedlings were subjected to contrasting watering regimes (normal and deficient) and three frequencies of
artificial dew (none, once and three times per week) for 10 weeks in a greenhouse. Midday shoot water potential was measured
on four occasions during the study. Other water relations variables (relative water content, stomatal conductance, pressure-volume
curves) and growth (hypocotyl diameter, aboveground dry mass, root dry mass) were also measured. Artificial dew significantly
increased shoot water potential, stomatal conductance and seedling root growth, with greater responses observed for seedlings
subjected to a deficient watering regime than for well-watered seedlings. Because dew can be a frequent microclimatic event
in some areas, this finding has practical implications for field studies of water relations of eastern white pine and possibly
of other coniferous species.
Keywords:
drought stress, eastern white pine, microclimate, pressure-volume curves, stomatal conductance.
