增温对喜旱莲子草入侵和竞争力的影响

随着全球气候的变暖,外来入侵植物对温度的升高可能会做出积极的响应,其危害程度也随之增加,因此需要采取积极有效的措施对其进行控制。本研究以入侵植物喜旱莲子草(Alternanthera philoxeroides)为研究对象,黑麦草(Lolium perenne)和白三叶(Trifolium repens)为其竞争对象(替代植物)进行单种、纯种和混种试验并配合增温处理,探讨喜旱莲子草对增温和竞争的响应以及黑麦草和白三叶作为喜旱莲子草替代物种的可能性,以期为气候变暖条件下喜旱莲子草的入侵趋势和生物替代提供理论依据。结果表明:1)增温条件下,喜旱莲子草通过提高叶片和茎对光能的获取,将更多的生物量分配在地上部分。同时,增温还加剧了喜旱莲子草与黑麦草和白三叶的种间竞争强度。这些响应表明温度的增加会增强喜旱莲子草的入侵。2)种间竞争抑制了喜旱莲子草的生长,但随着竞争密度的增大,抑制作用没有显著变化(P> 0.05)。黑麦草和白三叶都对喜旱莲子草的生长有明显的抑制作用,通过对不同竞争条件下喜旱莲子草相对产量的分析,发现黑麦草的抑制作用相较于白三叶更加显著(P <0.05)。3)增温促进了...

Warming affects the invasion ability and competitiveness of the invasive plant Alternanthera philoxeroides

Invasive plants may positively adapt to temperature increases caused by global warming,and these changes could promote their harmful effects.Therefore,it is important to control invasive plants in order to decrease the harm they cause.In this study,we focused on the invasive plant Alternanthera philoxeroides and chose Lolium perenne and Trifolium repens as its competition plants.There were three treatments.These were one plant of each species per pot(no competition),two plants of the same species in one pot(intraspecific competition),and two plants from different species in one pot(interspecific competition).Half the pots were placed under warming conditions.The results showed that(1)under warmer conditions,A.philoxeroides allocated more biomass to the growth of aboveground parts through improvements to light energy capture by its leaves and stems.Warming also increased the competition between A.philoxeroides and L.perenne or T.repens.Both responses indicated that warming will enhance invasion by A.philoxeroide.(2)Interspecific competition inhibited the growth of A.philoxeroides,but the inhibition did not significantly change(P>0.05)as the competition density increased.The results showed that L.perenne and T.repens significantly inhibited A.philoxeroides growth,and an analysis of the A.philoxeroide relative yield under the different competition conditions showed that L.perenne inhibition of A.philoxeroide was more significant(P<0.05)than inhibition due to T.repens.(3)Warming generally promoted L.perenne growth.However,growth was inhibited by interspecific competition under warming conditions,but there was no significant(P>0.05)inhibition under non-warming conditions.In contrast,warming had no significant effect(P>0.05)on T.repens growth,but its growth was considerably inhibited by interspecific competition.Furthermore,interspecific competition decreased A.philoxeroide aboveground biomass by 89.5%,L.perenne by 55.8%,and T.repens by 82.5%.The results suggest that L.perenne could be used as a competitive plant to control A.philoxeroide.