Carboxylation capacity is the main limitation of carbon assimilation in High Arctic shrubs.

Autor: Paillassa J; Département des Sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada.; Chaire en Écologie Fonctionnelle Arctique, Centre d'études nordiques, Université du Québec à Trois-Rivières, Trois Rivières, Quebec, Canada.; Centre d'études nordiques, Université Laval, Québec, Quebec, Canada.; Département des sols et de génie agroalimentaire, Université Laval, Québec, Quebec, Canada., Pepin S; Département des sols et de génie agroalimentaire, Université Laval, Québec, Quebec, Canada., Ethier G; Département de phytologie, Université Laval, Québec, Quebec, Canada., Lamarque LJ; Département des Sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada.; Chaire en Écologie Fonctionnelle Arctique, Centre d'études nordiques, Université du Québec à Trois-Rivières, Trois Rivières, Quebec, Canada.; Centre d'études nordiques, Université Laval, Québec, Quebec, Canada., Maire V; Département des Sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada.; Chaire en Écologie Fonctionnelle Arctique, Centre d'études nordiques, Université du Québec à Trois-Rivières, Trois Rivières, Quebec, Canada.; Centre d'études nordiques, Université Laval, Québec, Quebec, Canada.
Jazyk: angličtina
Zdroj: Plant, cell & environment [Plant Cell Environ] 2024 Dec; Vol. 47 (12), pp. 5315-5329. Date of Electronic Publication: 2024 Aug 27.
DOI: 10.1111/pce.15097
Abstrakt: Increases in shrub height, biomass and canopy cover are key whole-plant features of warming-induced vegetation change in tundra. We investigated leaf functional traits underlying photosynthetic capacity of Arctic shrub species, particularly its main limiting processes such as mesophyll conductance. In this nutrient-limited ecosystem, we expect leaf nitrogen concentration to be the main limiting factor for photosynthesis. We measured the net photosynthetic rate at saturated light (A sat ) in three Salix species throughout a glacial valley in High-Arctic tundra and used a causal approach to test relationships between leaf stomatal and mesophyll conductances (g sc , g m ), carboxylation capacity (Vc max ), nitrogen and phosphorus concentration (N area , P area ) and leaf mass ratio (LMA). Arctic Salix species showed no difference in A sat compared to a global data set, while being characterized by higher N area , P area and LMA. Vc max , g sc and g m independently increased A sat , with Vc max as its main limitation. We highlighted a nitrogen-influenced pathway for increasing photosynthesis in the two prostrate mesic habitat species. In contrast, the erect wetland habitat Salix richardsonii mainly increased A sat with increasing g sc . Overall, our study revealed high photosynthetic capacities of Arctic Salix species but contrasting regulatory pathways that may influence shrub ability to respond to environmental changes in High Arctic tundra.
(© 2024 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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