Controlled-environment studies on net assimilation and water relations of Dryas integrifolia

• Published in: Canadian Journal of Botany
• Main Authors: Hartgerink, Antoinette P., Mayo, James M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1976
• Subjects: Plant Science; Arctic; Devon Island
• Online Access: http://dx.doi.org/10.1139/b76-203; http://www.nrcresearchpress.com/doi/pdf/10.1139/b76-203

Net CO 2 assimilation and water relations of Dryas integrifolia from Devon Island, N. W. T., were studied under controlled-environment conditions. Maximum net CO 2 assimilation rate for single leaves was 18.7 mg g −1 h −1 . The optimum leaf temperature for net CO 2 assimilation was between 9 and 14 °C. Positive net CO 2 assimilation occurred at −5 °C. Respiration and net CO 2 assimilation decreased with the onset of dormancy. Dark respiration was generally equal to or greater than that of other arctic and alpine species. The mean leaf water potential of actively growing plants was −11.4 bars. Values higher than −7 bars were found only infrequently. Turgor pressure was maintained at high values (+6 to +10 bars) over a wide range of water potentials, suggesting osmotic adjustment to soil moisture deficit.