Abstract |
The atmospheric CO2 concentration is increasing. Effects of elevated CO2 on rice production could occur not only through direct impacts to rice, but also indirectly via ecosystem responses. Changed competitiveness with elevated CO2 could occur between rice which has the C3 type of photosynthesis vs. barnyardgrass (a serious weed in rice fields) which exhibits C4 photosynthesis, as has been resported for other plants. Thus, preliminary experiments were conducted to test the hypothesis that the C3 crop rice and the C4 weed barnyardgrass respond differently to CO2, affecting competition between them when grown at different relative densities in the same container. |