Study On The Effect Of Four Heavy Metals On The Growth And Development Of Pleurotus Ostreatus

Pleurotus ostreatus is the most widely cultivated edible fungi in China.As for rich in protein,low fat cntent and dietary fiber,P.ostreatus has become the most popular edible fungi.However,edible fungi,including P.ostreatus are reported to enrich heavy metals,which lead to urgence of the product safety issue.As(Ⅲ)、Cd(Ⅱ)、Pb(Ⅱ)、Hg(Ⅱ)is the most common type of heavy metal contamination,therefore,study on physio-biochemical response of P.ostreatus to four heavy metals is not only important heoretical significance but also provide theoretical basis for the genetic modification of P.ostreatus.The main conclusions are summarized as follows:(1)The effect of the heavy metals As(Ⅲ)on P.ostreatus growth were measured,Results showed that(1)As(Ⅲ)inhibited growth of mycelia,declined the biomass,and increased the number of tip branching along with concentration elevating;(2)Under plate culture conditions,when As(Ⅲ)concentration was lower than 400 μmol/L can increase mycelia protein content,enzyme activity of superoxide dismutase(SOD)and peroxidase(POD)and cause membrane lipid peroxidation the membrane lipid peroxide index-malondialdehyde(MDA)ware evaluated;(3)In liquid culture conditions,The content of protein,SOD and POD is highest when As(Ⅲ)concertration is 0,150,200 μmol/L;(4)Low concentration of As(Ⅲ)showed increasing effect on the activities of extracellular enzymes,while high concentration of As(Ⅲ)decreased the extracellular enzyme activities.The activities of CMCase and Protease showed highest peak at the fruiting body stage and primordial initiation stage,laccase activities went down along with the growth and development stage;(5)TRABS contents showed “W”trend under As(Ⅲ)concentrations;(6)The adsorption of P.ostreatus on As(Ⅲ)was increase with concentration elevating and the content of heavy metal in cap was higher than the stalk.(2)The effect of the heavy metals Cd(Ⅱ)on P.ostreatus growth were measured,Results showed that(1)Cd(Ⅱ)inhibited growth of mycelia,declined the biomass,and increased the number of tip branching along with concentration elevating;(2)In plate culture conditions,when Cd(Ⅱ)concertration is 40,80,80 μmol/L,the content of protein,SOD and POD enzyme activity is highest then dropped slowly and cause membrane lipid peroxidation index MDA content was evaluated;(3)Under liquid culture conditions,the content of protein,SOD and POD enzyme activity is largest when Cd(Ⅱ)concertration was 10,25,20 μmol/L;(4)CMCase showed tendency was same as As(Ⅲ),Protease and Laccase activities went down along with the growth and development stage;(5)TRABS contents went up first and then went down;(6)Concentration of Cd(Ⅱ)in the substrates was lower than 100 mg/kg,the adsorption of P.ostreatus on As(Ⅲ)was increase with concentration elevating then decrease slowly and heavy metal in cap was higher than the stalk.(3)The effect of the heavy metals Pb(Ⅱ)on P.ostreatus growth were measured,Results showed that(1)60-240μmol/L Pb(Ⅱ)could promote the mycelia growth,but higher concentrations caused a decrease in mycelium growth and pellets mass,but an increase in tip branching;(2)In plate culture conditions,when Pb(Ⅱ)concentration was respectivly lower than 120,60,60μmol/L can increase mycelia protein content and enzyme activity of SOD and POD cause membrane lipid peroxide index MDA was evaluated;(3)Under liquid culture conditions,the content of protein,SOD and POD enzyme activity is largest when Pb(Ⅱ)concertration was 60,120,60 μmol/L;(4)CMCase showed two peaks at full-bag stage and the fruiting body stage,Protease activities went down first and went up afterward,then repeated the going down and up pattern,Laccase activities and TRABS contents went down along with the growth and development stage;(5)Adsorption of P.ostreatus on Pb(Ⅱ)showed tendency with that under As(Ⅲ)treatment.(4)The effect of the heavy metals Hg(Ⅱ)on P.ostreatus growth were measured,Results showed that(1)Hg(Ⅱ)inhibited growth of mycelia,declined the biomass,and increased the number of tip branching along with concentration elevating;(2)Under plate culture conditions,when Hg(Ⅱ)concertration is 40,8,80 μmol/L,the content of protein and SOD,POD enzyme activity is highest then dropped slowly and cause membrane lipid peroxidation index MDA content was evaluated;(3)In liquid culture conditions,the content of protein,SOD and POD enzyme activity is largest when Hg(Ⅱ)concertration was 10,25,20 μmol/L;(4)Extracellular matrix degrading enzymes and adsorption of P.ostreatus on Hg(Ⅱ)showed tendency with that under As(Ⅲ)treatment,however,TRABS contents showed tendency with under Cd(Ⅱ)treatment.