AM真菌和铅处理对镧胁迫下玉米生长和镧吸收的影响

为探讨AM真菌和重金属Pb对稀土La胁迫下玉米生长及La吸收的影响,采用盆栽试验方法,在La胁迫下(500 mg·kg^-1)研究接种AM真菌G.versiforme和不同浓度Pb处理(0、50 mg·kg^-1和400 mg·kg^-1)对玉米菌根侵染率、生物量、营养元素吸收、稀土La和重金属Pb吸收、转运的影响。结果显示,在稀土La胁迫下,随着Pb浓度的增加(La500Pb0、La500Pb50、La500Pb400),接种G.versiforme的玉米根系平均菌根侵染率为20.8%~35.9%,400 mg·kg^-1Pb处理使菌根侵染率显著降低42%。不接种AM真菌时,La500Pb400处理与La500Pb0相比使总干质量、地上部La浓度和转运率分别降低24.4%、73.3%和83.5%,根部La浓度显著增加101.2%。接种AM真菌时,与La500Pb0相比,La500Pb50处理使总干质量和La转运率分别显著增加26.4%和55.5%,La500Pb400处理使总干质量显著降低26.1%。与不接种CK相比,接种AM真菌使3种处理玉米总干质量和营养元素含量分别显著增加70.7%~128.2%和30.2%~467.1%;接种AM真菌使La500Pb0处理地上部La浓度和转运率分别显著降低52.8%和59.2%,使La500Pb50处理La转运率显著降低28.6%,使La500Pb400处理地上部La浓度和转运率分别显著增加110.5%和147.2%,根部La浓度显著降低41.9%,地上部和根部Pb浓度分别显著降低42.6%和28.2%。AM真菌和Pb的交互作用对玉米总干质量、地上部和根部La浓度、地上部Pb浓度以及La的转运率有显著影响。结果表明,重金属Pb可显著影响玉米对稀土La的吸收、转运和La的植物毒性,并与Pb浓度和AM真菌共生有关。

Effects of arbuscular mycorrhizal fungi and Pb on the growth and La uptake of maize grown in La-contaminated soil

Here, a greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal fungi(AMF; G. versiforme, genus Glomus, a species of AMF)and Pb(0, 50 mg·kg^-1 and 400 mg·kg^-1)on AMF colonization rate, biomass, nutrient uptake, and metal uptake and translocation in maize(Zea mays L.)grown in soil spiked with lanthanum(La)at a concentration of 500 mg·kg^-1. The results indicated that the average AMF colonization rate in maize inoculated with G. versiforme ranged from 20.8% to 35.9%, and it decreased with the increase in Pb concentration in soils under La stress. The root colonization rate was significantly decreased by 42% under La500Pb400 (La500Pb400, the soil spiked with 500 mg·kg^-1La and 400 mg·kg^-1 Pb, the same below)compared with that under La500Pb0. Without AMF inoculation, La500Pb400 decreased the total dry weight, shoot La concentration, and La translocation rate in maize by 24.4%, 73.3%, and 83.5% compared with La500Pb0. The root La concentration in maize was significantly increased by 101.2% under La500Pb400 compared with that under La500Pb0. With AMF inoculation, La500Pb50 significantly increased the total dry weight and La translocation rate in maize by 26.4% and 55.5% compared with La500Pb0. The total dry weight of maize was significantly decreased by 26.1% under La500Pb400 compared with that under La500Pb0. Compared with no inoculation treatment, AMF significantly increased the total dry weight and mineral nutrient content in maize by 70.7%~128.2% and 30.2%~467.1% under the three treatments, respectively. Furthermore, AMF significantly decreased the shoot La concentration and La translocation rate in maize by 52.8% and 59.2% under La500Pb0, and significantly decreased the La translocation rate by 28.6% under La500Pb50 compared with no inoculation treatment. AMF also significantly increased the shoot La concentration and La translocation rate by 110.5% and 147.2% and significantly decreased the root La concentration, and shoot and root Pb concentration by 41.9%, 42.6%, and 28.2% under La500Pb400 compared with no inoculation treatment, respectively. The interaction between AMF and Pb had significant effects on the biomass, shoot and root La concentrations, shoot Pb concentrations, and La translocation rate from the root to shoot in maize. The results demonstrated that Pb could significantly influence the uptake and translocation of La(a rare earth element)by plants and its toxicity on plants; it was related to the concentration of heavy metals and AMF symbiosis with plants.