摘要
以金针菇和杏鲍菇菌为试材,在平板培养基和液体发酵培养基中添加不同浓度梯度Pb、Cd、As、Hg重金属,通过测量菌丝日均生长速度、菌丝体干质量、菌丝体及发酵液中重金属含量等指标,进行重金属富集模型建模,研究不同菌类对不同种类重金属耐受及富集特征,以期为菌类富集重金属机理提供参考依据。结果表明:重金属Pb、Cd、As、Hg对菌丝生长及菌丝球量表现为低浓度(低于1mg·L~(-1))促进、高浓度(高于5mg·L~(-1))抑制,适宜浓度(1~5mg·L~(-1)浓度)的重金属Pb、Cd、As对菌丝的生长有一个明显前期抑制后期菌丝恢复正常生长的现象。金针菇和杏鲍菇菌丝体均表现为对重金属Cd和Pb高度富集,最大富集量分别达到Cd 619、424mg·kg~(-1) DW以及Pb 449、844mg·kg~(-1) DW,对重金属As和Hg富集量较小,最大富集量分别为As 49、21 mg·kg~(-1) DW以及Hg 44、40mg·kg~(-1) DW。不同菌类菌丝体对同一种重金属的富集饱和点不同,如金针菇菌丝体对Pb的富集饱和点是452 mg·kg~(-1) DW,杏鲍菇菌丝体对Pb的富集饱和点是902mg·kg~(-1) DW。同一菌类对不同重金属的富集饱和点差异较大,如杏鲍菇对Cd的富集饱和点为429mg·kg~(-1) DW,对As的富集饱和点为22.4mg·kg~(-1) DW。
The experiment of heavy metal tolerance and accumulation in Flammulina velutipes and Pleurotus eryngii mycelium was carried out through externally adding different concentration gradients of Pb,Cd,As,Hg to the plate medium and liquid fermentation medium.The tolerance and accumulation characteristics of different kinds of heavy metals in different fungi were studied by measuring the average growth rate of mycelium,the dry weight of mycelium,as well as the heavy metal concentration in mycelium and fermentation broth.Based on this,the heavy metal accumulation model was established,on the purpose of providing fundamental data for the heavy metal accumulation mechanism in fungi.The results showed that Pb,Cd,As,Hg,at lower concentration(below1mg·L~(-1)),promoted the growth of mycelium and increased the amount of mycelium ball,while the heavy metals,at higher concentration(above 5mg·L~(-1)),had an inhibitory effect.And Pb,Cd and As,at the medium concentration(1-5 mg·L~(-1)),had an obvious inhibitory effect at the former stage,but the mycelium recovered to normal growing speed at the latter stage.The mycelium of Flammulina velutipes and Pleurotus eryngii accumulated high amount of Cd and Pb with Cd reaching619mg·kg~(-1) DW,424mg·kg~(-1) DW and Pb reaching 449mg·kg~(-1) DW,844mg·kg~(-1) DW,but low amount of As and Hg was accumulated,with As only reaching 49mg·kg~(-1) DW,21mg·kg~(-1) DW and Hg reaching 44 mg·kg~(-1) DW,40 mg·kg~(-1) DW.Different myceliums had different accumulation saturability for the same heavy metal.The accumulation saturation point of Pb in Flammulina velutipes mycelium was 452mg·kg~(-1) DW,while that of Pb in Pleurotus eryngii mycelium was as high as 902 mg·kg~(-1) DW.Meanwhile,the same species also had different saturability for different fungi,and the difference was large.The accumulation saturation point of Cd in Pleurotus eryngii mycelium was 429mg·kg~(-1) DW,but that of As was 22.4mg·kg~(-1) DW.
引文
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