Tham khảo tài liệu 'advances in photosynthesis fundamental aspects part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 322 Advances in Photosynthesis - Fundamental Aspects of the 21st century Baker and Ort 1992 . Rising atmospheric CO2 could benefit many economically important crops especially the C3 however gains may or may not be realized in long-term growth because of the interaction of various environmental factors that complicate the issue Farquhar and Sharkley 1982 . The current CO2 concentration of the atmosphere is increasing by about 1 ppm each year primarily because of the burning of fossil fuels. Since 1958 when systematic measurements of CO2 began at Mauna Loa Hawaii atmospheric CO2 concentrations have increased by more than 17 Keeling et al. 1995 and by 2020 the atmospheric CO2 concentration could reach up to 600 ppm. With the increase in CO2 many crops may be affected either positively or negatively. Oil palm is an industrial perennial plant widely cultivated in Southeast Asia where it plays a major role in the economics of the regional income. Claimed to be the most productive oil bearing plant as compared to coconut olive rapeseed and soybean the crop has contributed about of Malaysian gross domestic products GDP and the second largest economic contributor after exported goods and petroleum. In 2009 large area of about million ha had been cultivated with oil palm. As the concentration of CO2 is expected to increase to 600 ppm by 2020 the productivity of oil palm could also be increased. However the research on oil palm acclimation to increased CO2 issue is still lacking especially in the leaf gas exchange aspects. Net photosynthesis and quantum yield are good indicators of plant acclimation to elevated CO2. The notion of photosynthetic efficiency in the literature involves some different terms including photosynthetic rate quantum yield of carbon assimilation and photochemical efficiency of PSII which is often expressed as a ratio of variable to maximal fluorescence Xu and Shen 2000 . These terms are different but they linked to each other. Both .
