氮素增加条件下丛枝菌根真菌对陆稻和无芒稗相互作用的调节

Regulation effects of arbuscular mycorrhizal fungi on the interactions between barnyard grass and upland rice under enhanced nitrogen supply

采用盆栽方法研究了增氮条件下丛枝菌根真菌(AMF)对无芒稗(Echinochloa crusgallivar.mitis L.)和陆稻(Oryza sativa L.)相互作用的调节.结果表明:在单种条件下,无芒稗的菌根侵染率增加,陆稻的菌根侵染率降低;无AMF和接种AMF处理陆稻的生物量分别提高13.48%和42.35%,总磷吸收分别提高2.55%和4.07%,总氮吸收分别提高62.09%和30.35%;无芒稗的生物量分别提高15.65%和20.24%,总磷吸收分别提高4.06%和3.88%,总氮吸收分别提高30.35%和15.10%.在混种条件下,无芒稗的菌根侵染率增加,而陆稻无显著变化;无AMF和接种AMF的无芒稗与陆稻的生物量比值降低,总氮吸收比值无显著变化,无AMF处理的总磷吸收比值增加,而接种AMF处理降低.表明增氮条件下AMF提高了无芒稗对陆稻的竞争.

A pot experiment was conducted to study the regulation effects of arbuscular mycorrhizal fungi （AMF） on the interactions between Echinochloa crus-galli var. mitis L. and Oryza sativa L. under enhanced N supply （4.0 g N · m^-2 · a^-1）. The results showed that under monoculture condition, the AMF colonization on E. crus-galli increased but that on O. sativa decreased. In the treatments with and without AMF inoculation, upland rice biomass and its P and N uptake increased by42.35% and 13.48%, 4.07% and 2.55%, and 30.35% and 62.09%, respectively, and barnyard grass biomass and its P and N uptake increased by 20.24% and 15.65% , 3.88% and 4. 06% , and 15.10% and 30. 35% , respectively. Under mixed cropping, the AMF colonization on E. crus-gaUi increased but that on O. sativa had little change. In the treatments with and without AMF inoculation, the biomass ratio of O. sativa to E. crus-galli decreased, but N uptake ratio changed a little. The P uptake ratio of O. sativa to E. crus-galli increased in treatment without AMF inoculation but decreased in treatment with AMF inoculation. It was suggested that AMF tended to enhance the competition of E. crus-galli to O. sativa under enhanced N supply.