开放式空气CO2浓度增高条件下C3作物(水稻)与C4杂草(稗草)的竞争关系

通过田间试验，研究了FACE（开放式空气CO2浓度升高）条件下C3作物水稻（Oryza sativa）和C4杂草稗草（Echinochloa crusgalli）的生长和竞争关系，结果表明，FACE条件下C3植物水稻生物量和产量增加，吉片数增加，分蘖数增加，叶面积系数（LAI）增大；而C4植物稗草相反，FACE条件下水稻和稗草中面积均减少，而净同化率（NAR）均增加；FACE条件下水稻-稗草比例为1：1时，水稻与稗草的生物量比率、产量比率、LAI比率、茎蘖比率和NAR比率均增加，水稻-稗草的竞争关系发生变化，水稻（C3植物）竞争能力增加，稗草（C4植物）竞争能力下降。

Effect of FACE on competition between a C3 crop (rice,Oryza sativa) and a C4 weed (barnyardgrass,Echinochloa crusgalli)

The growth and competition of a C3 crop rice and a C4 weed, barnyardgrass under FACE(free-air carbon dioxide enrichment) conditions were studied by field experiment. The results showed that under FACE condition, the biomass and yield, leaf number, tiller number, and leaf area index of rice increased, while those of barnyardgrass decreased. Both of the leaf area indexed of rice and barnyardgrass were decreased, while their net assimilation rate increased. When the ratio of planting density of rice and barnyardgrass was 1:1, all of the ratio of biomass, yield, leaf area index, tiller and net assimilation rate were increased under FACE condition. It indicated that the competition between rice and barnyardgrass changed under FACE condition. The competition ability of rice(C3 crop) was enhanced relatively, while that of barnyardgrass weakened.