模拟增温对入侵植物北美车前生长及繁殖投资的影响

Effects of simulated warming on the growth and reproduction investment of invasive plant Plantago virginica

采用开顶式生长室(open-top chamber,OTC)模拟增温的方法,研究了模拟增温对入侵植物北美车前(Plantago virginica)生长及繁殖投资的影响。结果表明:模拟增温不同程度地促进了入侵植物北美车前的生长和繁殖投资。与对照相比,增温促进了北美车前株高生长,增幅达38%;但根长显著减小。其叶片数在生长前期显著增加,生长中期减少至低于对照;而叶片长、叶片宽、单株花序数、单花序长则均显著增加。增温后,北美车前的总生物量、地上生物量增加,叶生物量减少,但差异不显著;根生物量和与根冠比显著降低。增温对北美车前的单花序花数以及花穗生物量影响不显著,但其花序数、总花数、花序生物量和花序梗生物量则分别显著增加了17%、21%、18%和26%,其繁殖投资比提高11%。增温对结实率以及种子大小没有显著差异,但其种子数显著增加,千粒重显著下降。总之,模拟增温显著促进入侵植物北美车前的生长,提高了同化产物向繁殖器官的投资比例以及花和种子数量,繁殖能力和入侵性增强。

By using opentop chamber （OTC）, this paper studied the effects of simulated war ming on the growth and reproduction investment of invasive plant Plantago virginica during its growth season in 2012, with the plant height, root length, leaf number, length, and width, inflorescence number and length, biomass allocation pattern, and reproduction traits investiga ted. As compared with the control, simulated warming increased the plant height of P. virginica significantly by 38% , but decreased the root length. The leaf number of P. virginica in OTC group increased at its early growth stage, but reduced to less than that of the control at medium growth stage. The leaf length and width and the inflorescence number and length in OTC group increased significantly. Simulated warming increased the total biomass and aboveground biomass while decreased the leaf biomass, but no significant differences were observed between the OTC and CK groups. The root biomass and rootshoot ratio in OTC group decreased significantly. Sim ulated warming had little effects on the inflorescence number and spikelet biomass, but increased the inflorescence number, total flower number, inflorescence biomass, and peduncle biomass sig nificantly by 17%, 21%, 18%, and 26%, respectively, with the reproduction investment ratioincreased by 11%, as compared with the control. There were no significant differences in the seed setting rate and seed size between the OTC and CK groups, but the seed number in the OTC group increased significantly while the thousandkernel weight had a significant decrease. In sum, simulated warming could significantly promote the growth of P. virginica, improve its assimilation products allocated to reproductive organs, increase the numbers of flower and seed, and thus, enhance the reproduction capacity and invasiveness of the invasive plant P. virginica.