The effects of CO2 and nutrient fertilisation on the growth and temperature response of the mangrove Avicennia germinans.
In order to understand plant responses to both the widespread phenomenon of increased nutrient inputs to coastal zones and the concurrent rise in atmospheric CO2 concentrations, CO2-nutrient interactions need to be considered. In addition to its potential stimulating effect on photosynthesis and growth, elevated CO2 affects the temperature response of photosynthesis. The scarcity of experiments testing how elevated CO2 affects the temperature response of tropical trees hinders our ability to model future primary productivity. In a glasshouse study, we examined the effects of elevated CO2 (800 ppm) and nutrient availability on seedlings of the widespread mangrove Avicennia germinans. We assessed photosynthetic performance, the temperature response of photosynthesis, seedling growth and biomass allocation. We found large synergistic gains in both growth (42 %) and photosynthesis (115 %) when seedlings grown under elevated CO2 were supplied with elevated nutrient concentrations relative to their ambient growing conditions. Growth was significantly enhanced under elevated CO2 only under high-nutrient conditions, mainly in above-ground tissues. Under low-nutrient conditions and elevated CO2, root volume was more than double that of seedlings grown under ambient CO2 levels. Elevated CO2 significantly increased the temperature optimum for photosynthesis by ca. 4 °C. Rising CO2 concentrations are likely to have a significant positive effect on the growth rate of A. germinans over the next century, especially in areas where nutrient availability is high.
Cambridge Coastal Research Unit, The University of Cambridge, Cambridge, CB2 3EN, UK. rr491@cam.ac.uk.|School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia. rr491@cam.ac.uk.|School of Earth, Atmosphere and Environment, Monash University, Clayton, VIC, 3800, Australia. rr491@cam.ac.uk.
Ruth
R
Reef
Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Republic of Panama.
Martijn
M
Slot
Department of Ecology, Evolution and Behavior, Department of Statistics, The Federmann Centre for the Study of Rationality, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel.
Uzi
U
Motro
The David Yellin Academic College of Education, 96342, Jerusalem, Israel.
Michal
M
Motro
Plant Protection and Inspection Services, Ministry of Agriculture and Rural Development, 50250, Beit Dagan, Israel.
Yoav
Y
Motro
Australian Rivers Institute, Griffith University, Nathan, QLD, 4111, Australia.
Maria F
MF
Adame
Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Republic of Panama.
Milton
M
Garcia
Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Republic of Panama.
Jorge
J
Aranda
School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
Catherine E
CE
Lovelock
Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Republic of Panama.
Klaus
K
Winter
D032407:Avicennia / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D018533:Biomass; D002245:Carbon Dioxide / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018526:Plant Transpiration; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D012987:Soil / Q000737:chemistry; D013696:Temperature
D012987:Soil; D002245:Carbon Dioxide; D010758:Phosphorus; D012273:Ribulose-Bisphosphate Carboxylase; D009584:Nitrogen
CO2; Climate change; Eutrophication; Mangrove; Nitrogen; Phosphorus; Photosynthesis; RUBISCO; Temperature response; Tropics