光强对三叶鬼针草生长特征的影响

利用温室盆栽试验,研究了不同光强100%、40%、20%和5%下三叶鬼针草营养生长期和繁殖期的生长特征。结果表明:中度遮荫有利于三叶鬼针草支持结构的生长和营养期的物质积累,重度遮荫下仍能生长良好。在两个生长时期,相对生长速率(RGR)、净同化速率(NAR)均在100%光强下最大,5%光强下最小;总生物量在营养期和繁殖期分别在40%光强和全光照下最大,在3%光强下最小;株高、总叶面积(TLA)、根生物量比(RMR)、根冠比(R/C)、叶生物量比(LMR)、比叶面积(SLA)、叶面积比(LAR)、平均叶面积比(LARm)在3%光强时均大于全光照下的;支持结构生物量比(SBR)在40%光强、20%光强下大于3%光强和全光照处理。这说明三叶鬼针草在形态、生物量分配及生长特性上对光因素具较强的可塑性,这可能是其分布范围广、具有强入侵性的因素之一。

Effect of light intensity on the growth characteristics of Bidens pilosa

The growth characteristics of invasive species Bidens pilosa in vegetative and reproductive periods under four different relative irradiance 5%,20%,40% and 100% were studied in the green house.The results showed that moderate shading was favorable for the growth of the weed’s supporting organs and biomass accumulation in vegetative period.However,the weed could grow well under severe shading condition.In the two growth periods,the maximum value of RGR and NAR were found under the full exposure and the minimum value under 5% light intensity;The total biomass was the highest under 40% light intensity in vegetative period and under 100% light intensity in reproductive period respectively,and the lowest one was found under 5% light intensity in both periods;The seedling height,TLA,RMR,R/C,LAR,SLA,and the LARm were more higher under 5% light intensity than that under 100% light intensity;The SBR were higher under 40% and 20% light intensity than that under 5%k and 100% light intensity.The results indicated that B.pilosa had strong plasticity to light in morphology,biomass allocation and growth characteristic,which may be one of the reasons why the weed spread extensively and had strong invasiveness