Effects of elevated atmospheric CO2 concentration on the nutrient uptake characteristics of Japanese larch (Larix kaempferi)

• Published in: Tree physiology Vol. 27; no. 1; pp. 97 - 104
• Main Authors: Shinano, T, Yamamoto, T, Tawaraya, K, Tadokoro, M, Koike, T, Osaki, M
• Format: Journal Article
• Language: English
• Published: Canada 2007
• Subjects: Atmosphere; carbon dioxide; Carbon Dioxide - pharmacology; climate change; climatic factors; dry matter accumulation; ectomycorrhizae; elevated atmospheric gases; forest trees; Larix - drug effects; Larix - metabolism; Larix kaempferi; leaves; Mycorrhizae - drug effects; Mycorrhizae - metabolism; mycorrhizal fungi; nitrogen; nutrient uptake; phosphorus; plant nutrition; Plant Roots - drug effects; Plant Roots - metabolism; Plant Roots - microbiology; potassium; roots; seasonal variation; shoots; symbiosis; tree growth; Japan
• ISSN: 0829-318X; 1758-4469
• DOI: 10.1093/treephys/27.1.97

We evaluated the response of Japanese larch (Larix kaempferi Sieb. & Zucc.) to elevated atmospheric CO2 concentration (CO2) (689 +/- 75 ppm in 2002 and 697 +/- 90 ppm in 2003) over 2 years in a field experiment with open-top chambers. Root activity was assessed as nitrogen, phosphorus and potassium uptake rates estimated from successive measurements of absorbed amounts. Dry matter production of whole plants was unaffected by elevated CO2 in the first year of treatment, but increased significantly in response to elevated CO2 in the second year. In contrast, elevated CO2 increased the root to shoot ratio and fine root dry mass in the first year, but not in the second year. Elevated CO2 had no effect on tissue N, P and K concentrations. Uptake rates of N, P and K correlated with whole-plant relative growth rates, but were unaffected by growth CO2, as was ectomycorrhizal colonization, a factor assumed to be important for nutrient uptake in trees. We conclude that improved growth of Larix kaempferi in response to elevated CO2 is accompanied by increased root biomass, but not by increased root activity.