论文部分内容阅读
孟加拉东南部土壤中的砷含量很高,不仅威胁人的健康,而且对土壤也有破坏作用.云南石梓(Gmelina arborea)在孟加拉是个快速生长的树种,也是含砷土壤中的潜力树种.研究评价了含砷试验土中丛枝菌根真菌对云南石梓(Gmelina arborea)生长的影响.播种前,四种不同浓度的砷(10 mg.kg-1、25 mg·kg-1、50 mg·kg-1和100 mg·kg-1)被加入到试验土中.记录生长参数,如,植物的根、苗鲜重、干重、冠幅径、根长和苗高、根瘤菌和孢子菌群落.菌根植株较非菌根植株生长好.与其它含砷量高的土壤中植株的生长情况相比,在含砷量为10-mg·kg-1的土壤中,菌根植株和菌根生长效果最佳,菌根植株生物量最高.随着砷浓度的增加,种苗生长,根瘤菌和孢子菌群落均明显降低(P<0.05).与非菌根植株比较,菌根植株高生长增加了40％,生物量增加了2.4倍.研究表明,根瘤菌接种可以减少有害土壤中的云南石梓(Gmelina arborea)的初生长的影响.“,”Arsenic (As) in the soils of South-Eastern Bangladesh is not only a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has also a potential to be planted in arsenic contaminated areas. This study assessed the role of arbuscular mycorrhizal (AM) fungi on the growth of G. arborea in arsenic amended soils at nursery stage. Before sowing seeds, soils were treated with four different concentrations (10 mg·kg-1, 25 mg·kg-1, 50 mg·kg-1, and 100 mg·kg-1) of Arsenic. Growth parameters (length of shoot and root, collar diameter, fresh and dry weight of shoot and root) of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal seedlings. Mycorrhizal seedlings planted in soil with 10-mg·kg-1 arsenic showed best performance in terms of growth, biomass and mycorrhizal colonization, compared to other treatments with higher concentration of arsenic. With increasing arsenic concentration, growth of seedlings, mycorrhizal infection rate and spore population, all decreased significantly (p<0.05). The mycorrhizal seedlings had as much as 40%higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.