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本研究采用盆栽试验法,研究了不同浓度Cd胁迫下,接种外生菌根菌——褐环乳牛肝菌(Suillus luteus)对樟子松(Pinus sylvestris var.mongolica)苗期植株的生长及叶绿素含量、抗氧化酶(CAT、POD和SOD)活性、细胞渗透调节物质(可溶性糖、MDA和游离脯氨酸)含量和根际土壤酶(过氧化氢酶、脲酶和碱性磷酸酶)活性的变化。结果表明:1年生樟子松苗木在Cd胁迫1个月后,接菌处理组无论在苗木生长、抗氧化酶活性方面均高于对照组,且大部分指标达到显著差异水平(P<0.05)。各接菌处理组菌根侵染率达48.0%以上。抗氧化酶活性方面,CAT和POD活性呈现出随着胁迫程度的加深,先下降后上升的变化趋势,SOD活性则呈现出地上与地下部分“上下对称”的变化趋势。同时,通过对各处理组苗木细胞渗透调节物质的定量测定,接菌处理组的细胞受破坏程度显著低于不接菌处理组。对苗木根际土壤酶分析结果表明,Cd胁迫下,施加外生菌根菌可以有效提高樟子松根际土壤酶的活性(尤其是脲酶),进而起到增加樟子松根际土壤生物活性作用。综上,接种外生菌根真菌对樟子松缓解重金属Cd胁迫具有明显的促进作用。Cd胁迫下,外生菌根可以有效正向调节樟子松的生长、抗氧化胁迫能力并提高苗木细胞渗透调节作用,进而提高苗木对重金属的耐受性和提高苗木根际土壤生物活性。本研究可以为重金属污染土地的有效治理和利用木本植物修复改良重金属污染土壤提供参考。
In this study, pot experiments were conducted to study the effects of different concentrations of Cd on the growth of Pinus sylvestris var. Mongolica seedlings and inoculation of Supactomycetes Suillus luteus, (CAT, POD and SOD), the contents of osmolyte (soluble sugar, MDA and free proline) and the activity of rhizosphere soil enzymes (catalase, urease and alkaline phosphatase) Variety. The results showed that the 1-year-old Pinus sylvestris var. Mongolica seedlings were significantly higher in the seedling growth and antioxidant enzyme activities than those in the control group after 1 month of Cd stress, and most of the indexes reached significant differences (P <0.05) . The mycorrhizal infection rate of each inoculation group reached 48.0%. In terms of antioxidant enzyme activities, CAT and POD activities showed a trend of decreasing first and then increasing with the deepening of the degree of stress, while SOD activity showed a tendency of “up and down symmetry” above and below ground. At the same time, through the quantitative determination of osmotic adjustment substances in the seedlings of each treatment group, the damage degree of the cells in the inoculation group was significantly lower than that in the non-inoculation treatment group. The results of rhizosphere soil enzyme analysis showed that the application of ectomycorrhizal fungi could increase the activity of soil enzymes (especially urease) in rhizosphere of Pinus sylvestris var. Mongolica under Cd stress, and then increase the rhizosphere soil bioactivity of Pinus sylvestris var. Mongolica. In summary, inoculation of ectomycorrhizal fungi on Pinus sylvestris mitigation of heavy metal Cd stress has a significant role in promoting. Under Cd stress, the ectomycorrhizal fungi can positively regulate the growth of Pinus sylvestris var. Mongolica, enhance the ability of anti-oxidative stress and enhance the osmotic adjustment of seedling cells, thereby increasing the tolerance of seedlings to heavy metals and increasing the bioactivity of rhizosphere soil. This study can provide reference for the effective treatment of heavy metal contaminated land and the use of woody plant to improve the soil polluted by heavy metals.