Chin J Plant Ecol ›› 2012, Vol. 36 ›› Issue (5): 438-446.DOI: 10.3724/SP.J.1258.2012.00438

• Research Articles • Previous Articles     Next Articles

Effects of doubled CO2 concentration on leaf photosynthesis, transpiration and water use efficiency of eight crop species

WANG Jian-Lin1, WEN Xue-Fa2,*(), ZHAO Feng-Hua2, FANG Quan-Xiao1, YANG Xin-Min1   

  1. 1Qingdao Agricultural University, Qingdao 266109, China
    2Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • Published:2012-05-04
  • Contact: WEN Xue-Fa

Abstract:

Aims Our objective was to elucidate the response of crop photosynthesis, transpiration and water use efficiency to atmospheric CO2 concentration. This has great significance to predicting crop productivity and water-demand changes under increasing atmospheric CO2 concentration.
Methods The photosynthesis rate, transpiration rate and water use efficiency of eight crops (soybean (Glycine max), sweet potato (Ipomoea batatas), peanut (Arachis hypogaea), rice (Oryza sativa), cotton (Gossypium hirsutum), corn (Zea mays), sorghum (Sorghum vulgare) and millet (Setaria italica)) were studied under natural CO2 concentration, doubled CO2 concentration and natural CO2 concentration after doubled CO2 conditions.
Important findings Doubled CO2 concentration increased the photosynthesis rate and decreased the transpiration rate, and therefore water use efficiency was more significantly increased. The increase of water use efficiency showed greater dependence on the increase of photosynthesis rate than the decrease of transpiration rate. The variations of photosynthesis rate and water use efficiency of C3 crops were larger than those of C4 crops. The effect of photosynthesis rate of C3 crops on the water use efficiency was larger than that of C4 crops. The photosynthesis rate under natural CO2 concentration after doubled CO2 concentration was lower than that under natural CO2 concentration, but no significant difference was found for the transpiration rate. The photosynthetic capacity under natural CO2 concentration after doubled CO2 concentration was decreased mainly by the decreasing of some non-stomatal factors, including the protein content, activation levels and specific activity of the enzyme Rubisco.

Key words: crop, doubled CO2 concentration, photosynthesis rate, transpiration rate, water use efficiency