Canadian Forest Service Publications
Effect of Water Stress on Photosynthesis, Respiration, and Transpiration of Four Abies Species. 1973. Puritch, G.S. Canadian Journal of Forest Research 3(2): 293-298.
Issued by: Pacific Forestry Centre
Catalog ID: 28702
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The relationship between water stress and rates of net photosynthesis, respiration, and transpiration was determined for four Abies species native to Canada. Net photosynthesis, after an initial optimum rate, declined in three phases as water stress increased, viz. a rapid linear rate of decline, a second more gradual reduction and, finally, a steady rate of zero net photosynthesis. Of the four species, photosynthesis of A. grandis was affected the least by water stress, whereas that of A. balsamea was affected the most. Respiration declined at about the same water stress as photosynthesis, but was only reduced to between 40–75% of the maximum rate, depending on the species. Transpiration declined at similar water stresses to those of photosynthesis and after an initial decline, continued at between 10–30% of the maximum rate at water stresses up to 35 bars.