土壤养分异质性对入侵植物节节麦与小麦竞争关系的影响

【目的】土壤养分异质性在自然界中广泛存在，会对植物间的竞争关系造成影响。分析土壤养分异质性对入侵植物竞争能力的影响，可为其入侵危害研究提供参考。【方法】以入侵杂草节节麦Aegilops tauschii及其主要危害作物小麦Triticum aestivum为试材，设置同质性及异质性养分条件，结合de Wit取代实验方法，依据株高、叶面积及生物量等指标，探讨了土壤养分异质性对节节麦生长发育及其与小麦竞争关系的影响。【结果】(1)土壤养分异质性促进了小麦和节节麦幼苗株高、叶面积及单株分蘖数的增加，2种植物总生物量增加显著(P<0.05)。(2)种间竞争条件下，异质性土壤中节节麦的根冠比降幅最大，表明节节麦通过将更多的生物量分配至地上以加大对小麦的竞争抑制作用。(3)从竞争平衡指数可知：异质性土壤中节节麦的竞争平衡指数大于0，并较同质性土壤中略有增加，表明土壤养分异质性一定程度上促进了节节麦对小麦的竞争作用。【结论】土壤养分异质性促进了节节麦幼苗的生长发育，并提高了其对小麦的竞争抑制作用。因此认为，土壤养分异质性会进一步加剧节节麦对小麦的危害程度。图5表1参46

Effects of soil nutrient heterogeneity on competition between Aegilops tauschii and Triticum aestivum

  Objective  Soil nutrient heterogeneity widely exists in nature, and affects competition among different plant species. This study aims to explore the effects of soil nutrient heterogeneity on competitiveness of invasive plants, so as to provide reference for the study of invasion hazards.   Method  The invasive plant Aegilops tauschii and its main endangered crop Triticum aestivum were used as test materials. Under the conditions of homogenous and heterogeneous nutrients, de Wit substitution experiment was carried out to investigate the impact of soil nutrient heterogeneity on the growth and development of A. tauschii and its competition with T. aestivum, based on plant height, leaf area and biomass.   Result  (1) Soil nutrient heterogeneity promoted the increase of plant height, leaf area and tiller number per plant of A. tauschii and T. aestivum seedlings. In particular, the total biomass of the two plants increased significantly (P＜0.05). (2) Under the condition of interspecific competition, the root-shoot ratio of A. tauschii in heterogeneous soil decreased the most, indicating that A. tauschii increased its inhibition on T. aestivum competition by allocating more biomass to the ground surface. (3) Competition balance index showed that the competitiveness of A. tauschii in heterogeneous soil was above 0, and slightly increased compared with that in homogeneous soil, indicating that soil nutrient heterogeneity enhanced the competition of A. tauschii on T. aestivum.   Conclusion  Soil nutrient heterogeneity promotes the growth of A. tauschii seedling, and enhances its competitive inhibition on T. aestivum. [Ch, 5 fig. 1 tab. 46 ref.]