The effect of atmospheric carbon dioxide concentrations on the performance of the mangrove Avicennia germinans over a range of salinities. Issue 3 (5th November 2014)

• Record Type: Journal Article
• Authors: Reef, Ruth; Winter, Klaus; Morales, Jorge; Adame, Maria Fernanda; Reef, Dana L.; Lovelock, Catherine E.
• Is Part Of: Physiologia plantarum. Volume 154:Issue 3(2015:Jul.)
• Page Start: 358
• Page End: 368
• Publication Date: 2014-11-05
• Subjects: Plant physiology -- Periodicals; 571.2
• DOI: 10.1111/ppl.12289
• Languages: English
• ISSNs: 0031-9317

Abstract

<abstract abstract-type="main" id="ppl12289-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="ppl12289-para-0001">By increasing water use efficiency and carbon assimilation, increasing atmospheric CO<sub>2</sub> concentrations could potentially improve plant productivity and growth at high salinities. To assess the effect of elevated CO<sub>2</sub> on the salinity response of a woody halophyte, we grew seedlings of the mangrove <italic>Avicennia germinans</italic> under a combination of five salinity treatments [from 5 to 65 parts per thousand (ppt)] and three CO<sub>2</sub> concentrations (280, 400 and 800 ppm). We measured survivorship, growth rate, photosynthetic gas exchange, root architecture and foliar nutrient and ion concentrations. The salinity optima for growth shifted higher with increasing concentrations of CO<sub>2</sub>, from 0 ppt at 280 ppm to 35 ppt at 800 ppm. At optimal salinity conditions, carbon assimilation rates were significantly higher under elevated CO<sub>2</sub> concentrations. However, at salinities above the salinity optima, salinity had an expected negative effect on mangrove growth and carbon assimilation, which was not alleviated by elevated CO<sub>2</sub>, despite a significant improvement in photosynthetic water use efficiency. This is likely due to non‐stomatal limitations to growth at high salinities, as indicated by our measurements of foliar ion concentrations that show a displacement of K<sup>+</sup> by Na<sup>+</sup> at elevated salinities that is not affected by CO<sub>2</sub>. The observed shift in the optimal salinity for growth with increasing CO<sub>2</sub> concentrations changes the fundamental niche of this species and could have significant effects on future mangrove distribution patterns and interspecific interactions.</p> </abstract>