1.\uffe2\uff80\uff82The Amazon region may experience increasing moisture limitation over this century. Leaf dark respiration (R) is a key component of the Amazon rain forest carbon (C) cycle, but relatively little is known about its sensitivity to drought.
2.\uffe2\uff80\uff82Here, we present measurements of R standardized to 25\uffe2\uff80\uff83\uffc2\uffb0C and leaf morphology from different canopy heights over 5\uffe2\uff80\uff83years at a rain forest subject to a large\uffe2\uff80\uff90scale through\uffe2\uff80\uff90fall reduction (TFR) experiment, and nearby, unmodified Control forest, at the Caxiuan\uffc3\uffa3 reserve in the eastern Amazon.
3.\uffe2\uff80\uff82In all five post\uffe2\uff80\uff90treatment measurement campaigns, mean R at 25\uffe2\uff80\uff83\uffc2\uffb0C was elevated in the TFR forest compared to the Control forest experiencing normal rainfall. After 5\uffe2\uff80\uff83years of the TFR treatment, R per unit leaf area and mass had increased by 65% and 42%, respectively, relative to pre\uffe2\uff80\uff90treatment means. In contrast, leaf area index (L) in the TFR forest was consistently lower than the Control, falling by 23% compared to the pre\uffe2\uff80\uff90treatment mean, largely because of a decline in specific leaf area (S).
4.\uffe2\uff80\uff82The consistent and significant effects of the TFR treatment on R, L and S suggest that severe drought events in the Amazon, of the kind that may occur more frequently in future, could cause a substantial increase in canopy carbon dioxide emissions from this ecosystem to the atmosphere.
", "keywords": ["tropical forest", "0301 basic medicine", "Through-fall exclusion experiment", "moisture transfer", "03 medical and health sciences", "Specific leaf area", "Amazonia", "Tropical forest", "Keywords: carbon cycle", "Climate change", "Para [Brazil] Climate change", "Caxiuana National Forest", "0303 health sciences", "leaf area index", "Night-time foliar carbon emissions", "exclusion experiment", "15. Life on land", "6. Clean water", "Leaf dark respiration", "forest canopy", "Moisture deficit", "climate change", "13. Climate action", "Leaf area index", "carbon emission", "throughfall", "rainforest", "Brazil"]}, "links": [{"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/79379/5/f5625xPUB7833.pdf.jpg"}, {"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/79379/7/01_Metcalfe_Impacts_of_experimentally_2010.pdf.jpg"}, {"href": "https://doi.org/10.1111/j.1365-2435.2009.01683.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Functional%20Ecology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2435.2009.01683.x", "name": "item", "description": "10.1111/j.1365-2435.2009.01683.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2435.2009.01683.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-04-08T00:00:00Z"}}, {"id": "10.1111/plb.12400", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:18:05Z", "type": "Journal Article", "created": "2015-09-25", "title": "Light Compensation Points In Shade-Grown Seedlings Of Deciduous Broadleaf Tree Species With Different Successional Traits Raised Under Elevated Co2", "description": "AbstractWe measured leaf photosynthetic traits in shade\uffe2\uff80\uff90grown seedlings of four tree species native to northern Japan, raised under an elevated CO2 condition, to investigate the effects of elevated CO2 on shade tolerance of deciduous broadleaf tree species with different successional traits. We considered Betula platyphylla var. japonica and Betula maximowicziana as pioneer species, Quercus mongolica var. crispula as a mid\uffe2\uff80\uff90successional species, and Acer mono as a climax species. The plants were grown under shade conditions (10% of full sunlight) in a CO2\uffe2\uff80\uff90regulated phytotron. Light compensation points (LCPs) decreased in all tree species when grown under elevated CO2 (720\uffc2\uffa0\uffce\uffbcmol\uffc2\uffb7mol\uffe2\uff88\uff921), which were accompanied by higher apparent quantum yields but no photosynthetic down\uffe2\uff80\uff90regulation. LCPs in Q.\uffc2\uffa0mongolica and A.\uffc2\uffa0mono grown under elevated CO2 were lower than those in the two pioneer birch species. The LCP in Q.\uffc2\uffa0mongolica seedlings was not different from that of A.\uffc2\uffa0mono in each CO2 treatment. However, lower dark respiration rates were observed in A.\uffc2\uffa0mono than in Q.\uffc2\uffa0mongolica, suggesting higher shade tolerance in A.\uffc2\uffa0mono as a climax species in relation to carbon loss at night. Thus, elevated CO2 may have enhanced shade tolerance by lowering LCPs in all species, but the ranking of shade tolerance related to successional traits did not change among species under elevated CO2, i.e. the highest shade tolerance was observed in the climax species (A.\uffc2\uffa0mono), followed by a gap\uffe2\uff80\uff90dependent species (Q.\uffc2\uffa0mongolica), while lower shade tolerance was observed in the pioneer species (B.\uffc2\uffa0platyphylla and B.\uffc2\uffa0maximowicziana).
", "keywords": ["0106 biological sciences", "CO2 enrichment", "photosynthesis", "Acclimatization", "Acer", "Carbon Dioxide", "15. Life on land", "650", "01 natural sciences", "Carbon", "Apparent quantum yield", "Trees", "shade tolerance", "Plant Leaves", "Quercus", "Phenotype", "Japan", "Seedlings", "Sunlight", "Photosynthesis", "dark respiration", "Betula"]}, "links": [{"href": "https://doi.org/10.1111/plb.12400"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/plb.12400", "name": "item", "description": "10.1111/plb.12400", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/plb.12400"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2015-10-11T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+respiration&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+respiration&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+respiration&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+respiration&offset=2", "hreflang": "en-US"}], "numberMatched": 2, "numberReturned": 2, "distributedFeatures": [], "timeStamp": "2026-09-22T19:50:36.186986Z"}