特异性适应稻作系统的稗草种群生活史特性

Life history traits of an Echinochloa crus-galli var.crus-galli population with extreme adaptations to rice planting systems

长期进行除草剂药效试验可能会导致田间杂草种群发生适应性进化。本研究在安徽南陵县除草剂药效试验专用稻田中采集了1个稗草种群A,并以从常规稻田采集的3个稗草种群为对照,开展同质园栽培试验。结果表明:与3个对照种群相比,A种群稗草植株的单株种子产量显著减少,种子千粒重显著增加,幼苗生长速率显著加快,结实分蘖数显著增多,生育期显著缩短;A种群稗草成株的株高、生物量及对除草剂五氟磺草胺的敏感性均显著降低。A种群稗草幼苗3~4叶期时经五氟磺草胺推荐剂量2倍量(有效成分60 g·hm^(-2))处理后,其株高、生物量及成熟种子产量(平均每株1066粒)显著降低,而抽穗期、结实分蘖数、单个总状花序的种子数及种子千粒重无显著差异。因此,种子较重、生活史周期短、植株矮小、结实分蘖多及对除草剂五氟磺草胺具有抗药性,使得A种群稗草对稻作系统具有特异适应性,应防止此类种群扩散至常规稻田。

Long-term herbicide application may facilitate the adaptive evolution of weed populations.With Echinochloa crus-galli var.crus-galli population A from a rice field used for the experiment of effectiveness of herbicide in Nanling County,Anhui Province,we conducted common garden experi-ments with seeds of population A and three control populations collected from normal rice fields.Compared with the three control populations,population A had significantly lower seed production for individual plant,but higher 1000-seed weight.Population A had faster in seedling growth,higher in number of reproductive tillers,shorter life span,lower in height and biomass of individual plant,as well as lower in sensitivity to herbicide penoxsulam.Individuals from population A survived from 2×label dose(60 g·hm-2)of penoxsulam treatment at the three-to four-leaf stage showed significantly reduction in plant height,biomass,and mature seed production(1066 seeds per plant),but no difference in heading period,number of reproductive tillers,number of seeds per raceme and 1000-seed weight.The short lifespan,heavy seeds,dwarf architecture,more reproductive tillers and penoxsulam resistance made E.crus-galli var.crus-galli population A extremely adapting to rice planting systems,which should be prevented to spread to normal rice fields.