入侵草坪生态系统的2种蔊菜属植物的竞争效应

The Competition Effect of Two Invasive Rorippa Plants in Turf Ecosystem

外来物种的高竞争能力已被提及是促进其成功入侵的关键因素。研究不同条件下两栖蔊菜(R.amphibian)和欧亚蔊菜(R.sylvestris)形态可塑性及其生物量的变化,明确二者种间竞争在草坪生态系统中优势程度,为合理利用和防控入侵草坪根蘖植物提供依据,并丰富入侵生态学研究。采用模拟草坪中2种蔊菜属植物生态重叠区的方法,通过设置单种和混种的种内和种间竞争的盆栽试验,测定不同处理条件下2种蔊菜的生理生态指标和生物量,分析其相对生长速率和竞争能力。结果表明:在单种处理条件下,两栖蔊菜与欧亚蔊菜的株高、生物量、叶片数、茎粗都显著高于混种条件下,且两栖蔊菜的株高、SPAD值、叶片数、茎粗显著高于欧亚蔊菜,根系活力与生物量无显著性差异;在混种条件下,两栖蔊菜的SPAD值、根系活力、生物量均显著低于欧亚蔊菜,株高与叶片数无显著性差异。两者竞争效应参数相对产量总和(RYT)小于1,欧亚蔊菜的竞争平衡指数大于0。综上,两栖蔊菜与欧亚蔊菜间存在竞争关系,且在单、混种处理条件下,种内竞争显著大于种间竞争。种间竞争对2种入侵植物的生长有显著抑制作用,对两栖蔊菜的抑制作用更强。欧亚蔊菜的相对竞争能力强于两栖蔊菜,欧亚蔊菜可能是通过调节自身生理生化特征以适应种间竞争,并在竞争中处于优势地位。

The high competitiveness of alien species has been mentioned as the key factor to promote their successful invasion.To study the morphological plasticity and biomass changes of R.amphibian and R.sylvestris under different conditions,and clarify the dominance of interspecific competition between them in lawn ecosystem,so as to provide basis for rational utilization and prevention and control of invasive lawn rooting plants,and enrich the research of invasion ecology.Using the method of simulating the ecological overlapping area of two species of Rorippa in the lawn,through the pot experiment of intraspecific and interspecific competition of single species and mixed species,the physiological and ecological indexes and biomass of the two kinds of Rorippa under different treatment conditions were measured,and their relative growth rate and competitiveness were analyzed.The results showed that the plant height,biomass,leaf number and stem diameter of R.amphibian and R.sylvestris were significantly higher than those of mixed species,and the plant height,SPAD value,leaf number and stem diameter of R.amphibian and R.sylvestris were significantly higher than those of R.sylvestris.There was no significant difference in root activity and biomass;Under the mixed treatment,the SPAD value,root activity and biomass of R.amphibian were significantly lower than those of R.sylvestris,and there was no significant difference in plant height and leaf number.The total relative yield(RYT)of the two competitive effect parameters is less than 1,and the competitive balance index of R.sylvestris is greater than 0.In conclusion,there is competition between R.amphibian and R.sylvestris,and the intraspecific competition is significantly greater than the interspecific competition under the conditions of single and mixed species treatment.Interspecific competition significantly inhibited the growth of the two invasive plants,and had a stronger inhibitory effect on R.amphibian.The relative competitiveness of R.sylvestris is stronger than that of R.amphibian.R.sylvestris may adapt to interspecific competition by adjusting its physiological and biochemical characteristics,and be in a dominant position in the competition.