氮添加对水稻与入侵杂草空心莲子草种间竞争力的影响

Effects of Nitrogen Addition on Interspecific Competitive Ability Between Oryza Sativa and Invasive Weed Alternanthera Philoxeroides

为明确水稻(Oryza sativa)与空心莲子草(Alternanthera philoxeroides)在氮添加条件下竞争力的变化,采用de Wit取代法盆栽实验比较了2种植物各自的生物量及光合生理等指标的差异性及施氮对其差异的影响。结果表明:混播处理中,水稻的最大茎长、根长、根面积和叶面积均显著高于空心莲子草;且水稻的生物量及相对产量均显著高于空心莲子草;空心莲子草整体的氮平衡指数、叶绿素指数、类黄酮指数、暗适应后最小荧光和暗适应后最大荧光均显著高于水稻。施氮导致混播处理中水稻的总氮含量显著高于空心莲子草,但使得空心莲子草的稳态荧光衰减率和光化学淬灭系数显著上升、水稻的稳态荧光衰减率显著下降。综上,水稻具备较高的形态及生物量优势,而施氮提升了空心莲子草在光合生理等方面的竞争力。

In order to examine the variations of interspecific competitive abilities of the Oryza sativa and its coexisted invasive weed Alternanthera philoxeroides under nitrogen additions,the differences of biomass and fluorescence parameters between these two plant species were compared by using the de Wit instead pot experiment,as well as the impacts of nitrogen additions on them.The results showed that the maximum stem length,root length,root area and leaf area of O.sativa were significantly higher than A.philoxeroides in the mixed cultures,and the biomass and relative yield of O.sativa were also significantly higher than A.philoxeroides at the whole.But the nitrogen balance index,chlorophyll index,flavonoid index,minimum fluorescence and maximum fluorescence after dark adaptation of A.philoxeroides were all significantly higher than those of O.sativa.Nitrogen additions made the total nitrogen content of O.stiava be significantly higher than A.philoxeroides.However,nitrogen additions significantly increased the steady-state fluorescence decay rate and photochemical quenching coefficient of A.philoxeroides but decreased the steady-state fluorescence decay rate of O.stiava.In conclusion,O.stiava had the higher morphological and biomass advantages,while nitrogen additions improved the competitiveness of A.philoxeroides in photosynthetic physiology.