CO 2 assimilation by Dryas integrifolia on Devon Island, Northwest Territories

• Published in: Canadian Journal of Botany
• Main Authors: Mayo, James M., Despain, Don G., van Zinderen Bakker Jr., Eduard M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1973
• Subjects: Plant Science; Northwest Territories; Devon Island
• Online Access: http://dx.doi.org/10.1139/b73-069; http://www.nrcresearchpress.com/doi/pdf/10.1139/b73-069

In situ measurements of CO 2 assimilation by Dryas integrifolia at different stages of development and under different environmental conditions were made on Devon Island, Northwest Territories. Dryas can fix CO 2 in excess of respiration over a 24-h period under conditions of clear nights and cloudy days. The maximum net assimilation rate measured was 4.2 mg g −1 dry weight h −1 . The maximum amount of CO 2 fixed in 24 h was 61.54 mg g −1 dry weight. Maximum net assimilation occurred at 8 to 10 °C leaf temperatures. Positive net assimilation occurred at 1 °C leaf temperature. Light compensation was shown to be less than 0.04 langley min −1 . Leaf temperatures were always greater than ambient. The maximum leaf temperature measured was 39 °C. Net assimilation rates appear to decrease as the season progresses.