两种AMF对巨菌草根际土壤Cd生物可利用性以及Cd积累的影响

Impacts of two kinds of arbuscular mycorrhizal fungi on rhizospheric bio-available Cd and accumulation of Cd for Pennisetum sp.

利用盆栽巨菌草(Pennisetum sp.)实验,研究了不同土壤镉(Cd)浓度(T0:空白;T1:5 mg·kg^(-1);T2:10 mg·kg^(-1);T3:15 mg·kg^(-1))条件下,接种两种丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)[摩西斗管囊霉(Funneliformis mosseae,Fm)和根内根孢囊霉(Rhizophagus intraradices,Ri)]后土壤中Cd的生物有效性、巨菌草生物量、巨菌草Cd积累量等的变化。结果表明:与不施加菌剂(CK)相比,接种AMF显著降低了土壤中Cd的生物可利用性,在5、10、15 mg·kg^(-1)处理下,接种Fm和Ri后可交换态Cd分别降低了18.65%、20.51%、6.53%和12.54%、16.64%、6.66%;在10、15 mg·kg^(-1)处理下,接种Fm和Ri,植物地上部分生物量分别增加了20.98%、36.94%和36.54%、43.88%,地下部分生物量增加了14.31%、21.79%和25.78%、12.83%。接种AMF显著提高了巨菌草对Cd的吸收能力,其中在5 mg·kg^(-1)处理下接种Ri,巨菌草的重金属富集系数(BCF)最高,达到0.77,由于植物地上、地下部分Cd的含量均增加,巨菌草的Cd转移系数(TF)并没有显著变化。

Pennisetum sp. was inoculated with two different types of arbuscular mycorrhizal fungi：Funneliformis mossea（Fm）and Rhizophagus intraradices（Ri）. And the variations of the rhizospheric bio-available Cd, biomass and plant Cd accumulation were investigated. Four treatments of soil Cd contents（T0：the control, T1：5 mg·kg^（-1）, T2：10 mg·kg^（-1）and T3：15 mg·kg^（-1））were carried out by pot experiment. It indicated that the inoculation had significantly decreased the bio-available Cd content. Compared with the control, the ion exchangeable Cd decreased by 18.65%, 20.51% and 6.53% at soil Cd contents of 5 mg·kg^（-1）, 10 mg·kg^（-1）and 15 mg·kg^（-1）, respectively. And the acidic dissoluble-Cd decreased correspondingly by 12.54%, 16.64% and 6.66% respectively. When treated by soil Cd contents of 10 mg·kg^（-1）and 15mg·kg^（-1）, the above-ground biomass of Pennisetum sp. increased by 20.98%, and 36.94% inoculated with Fm, and 36.54% and 43.88% inoculated with Ri, while the below-ground biomass increased by 14.31% and 21.79% inoculated with Fm, and 25.78% and 12.83% inoculated with Ri, respectively. As a result, no obviously variation was observed with the translocation factor（TF）, but the inoculation of AMF had significantly increased the Cd accumulation in Pennisetum sp.. The bio-concentration factor（BCF）could reach 0.77 at soil Cd content of 5 mg·kg^（-1）after inoculating with Ri.