Changes of Photosynthetic Pigment Contents in Soybean under Elevated Atmospheric CO_2 Concentrations

The photosynthetic pigment contents including chlorophyll a,chlorophyll b,total chlorophyll contents and carotennoid contents of soybean were measured under ambient and elevated CO_2concentration,and their responses to elevated CO_2concentration was analyzed.The results showed that photosynthetic pigment contents increased under high CO_2levels. The chlorophyll contents increased by 4.3%,7.4%,12.1% and 14.1% at initial flowering stage under elevated(450,550,650 and 750 μmol/mol) CO_2concentration compared to that under the ambient air CO_2concentration.The carotennoid contents increased by 6.8%~24.6%.It was also found that chlorophyll a and chlorophyll b increased by 3.3%~11.2% and 6.7%~20.4% in soybean leaves.But the ratio of chlorophyll a to b was reduced under four high CO_2 levels.