Carbon balance in a monospecific stand of an annual herb Chenopodium album at an elevated CO2 concentration
- 141 Downloads
Elevated CO2 enhances carbon uptake of a plant stand, but the magnitude of the increase varies among growth stages. We studied the relative contribution of structural and physiological factors to the CO2 effect on the carbon balance during stand development. Stands of an annual herb Chenopodium album were established in open-top chambers at ambient and elevated CO2 concentrations (370 and 700 μmol mol−1). Plant biomass growth, canopy structural traits (leaf area, leaf nitrogen distribution, and light gradient in the canopy), and physiological characteristics (leaf photosynthesis and respiration of organs) were studied through the growing season. CO2 exchange of the stand was estimated with a canopy photosynthesis model. Rates of light-saturated photosynthesis and dark respiration of leaves as related with nitrogen content per unit leaf area and time-dependent reduction in specific respiration rates of stems and roots were incorporated into the model. Daily canopy carbon balance, calculated as an integration of leaf photosynthesis minus stem and root respiration, well explained biomass growth determined by harvests (r 2 = 0.98). The increase of canopy photosynthesis with elevated CO2 was 80% at an early stage and decreased to 55% at flowering. Sensitivity analyses suggested that an alteration in leaf photosynthetic traits enhanced canopy photosynthesis by 40–60% throughout the experiment period, whereas altered canopy structure contributed to the increase at the early stage only. Thus, both physiological and structural factors are involved in the increase of carbon balance and growth rate of C. album stands at elevated CO2. However, their contributions were not constant, but changed with stand development.
KeywordsCarbon balance Chenopodium album Elevated CO2 concentration Photosynthesis Respiration Stand
We thank Kenichi Sato, Niels Anten, Yusuke Onoda, Toshihiko Kinugasa, Yuko Yasumura, Shimpei Oikawa, Muller Onno, Shinjiro Ishizaki, and Teruyuki Takashima for advice and technical assistance in the experiment. This work was partly supported by Grant-in-aid from the Japan Ministry of Education, Culture, Sports, Science and Technology, and the National Natural Science Foundation of China (30800125).
- Amthor JS (1984) The role of maintenance respiration in plant growth. Plant Cell Environ 7:561–569Google Scholar
- Amthor JS (1989) Respiration and crop productivity. Springer-Verlag, New YorkGoogle Scholar
- Hirose T, Ackerly DD, Traw MB et al (1996) Effects of CO2 elevation on canopy development in the stands of two co-occurring annuals. Oecologia 108:215–223Google Scholar
- Hirose T, Ackerly DD, Traw MB et al (1997) CO2 elevation, canopy photosynthesis, and optimal leaf area index. Ecology 78:2339–2350Google Scholar
- Imai K, Coleman DF, Yanagisawa T (1985) Increase in atmospheric partial pressure of carbon dioxide and growth and yield of rice (Oryza sativa L.). Jpn J Crop Sci 54:413–418Google Scholar
- IPCC (2001) Climate change 2001: synthesis report. In: Watson RT, The core writing team (eds) A contribution of working groups I, II, and III to the third assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- Monsi M, Saeki T (1953) Über den Lichtfaktor in den Pflanzengesellschaften und seine Bedeutung für die Stoffproduktion. Jpn J Bot 14:22–52Google Scholar
- Nijs I, Impens I, Behaeghe T (1988) Effects of rising atmospheric carbon dioxide concentration on gas exchange and growth of perennial ryegrass. Photosynthetica 22:44–50Google Scholar
- Saeki T (1960) Interrelationships between leaf amount, light distribution and photosynthesis in a community. Bot Mag 73:5–63 Google Scholar