Optimization Of Cultivation Matrix Formula Based On Tobacco Stalk For Pleurotus Eryngii And Evaluations On Sporocarp Quality And Safety

As a large country of tobacco cultivation and production,the disposal of tobacco by-products,tobacco stalk has become one of the thorny issues in the mass production of tobacco leaves.At present,the main treatment of tobacco stalks is burning,discarding or returning to the fields,which not only harmful to soil,groundwater and air,causing serious wasting of resources,and also resulting negative effects on sustainable development of agriculture.This study was to explore the effects of tobacco stalks on the growth of hyphae and the quality and safety of the sporocarp,and tried to find out the optimal formula for the Pleurotus eryngii cultivation with tobacco stalks.Tobacco stalk was chosen as main materials,wheat bran,lime,gypsum and calcium carbonate were used as the supplementar.Six different proportion formula(60%-85%)were designed which respectively containing 60%,65%,70%,75%,80%,85% of tobacco stalks.75% of cotton seed husk was chosen as the control(CK).The main research results were as follows:(1)Tobacco stalks can be a main substitute cultivation matrix for Pleurotus eryngii.The Pleurotus eryngii cultivation experiments of consisting of six tobacco stalks formula(60%-85%)and CK were carried.The results showed that the hyphae in all cultivating bags grew well.There was no significant difference in color and hyphae uniformity between the six formulas(60%-85%)and CK.As the increasing proportion of tobacco stalks,the average daily growth rate was going up.The time that plastic bag was filled with growing hyphae was reduced accordingly.The daily growth rate of the six tobacco stalks formula were all higher than that of the CK.The sporocarp size on cap diameter,stipe length and stipe diameter increased first,then decreased,and reached maximum in the formula 70% and 75%.While there was no significant difference compareing with the CK.The yield and biological tranform efficiency of the sporocarp also increased first and then decreased as the increasing proportion of tobacco stalks.The highest values were appeared in the formula 70% and 75%.They were 180.27g/bag,57.69% and 180.69g/bag,57.82% respectively.No significant difference comparing with the CK.The results showed that tobacco stalks can be substitute matrix for Pleurotus eryngii.The biological efficiency,the hyphae growth condition and the sporocarp agronomic traits were all better in formula 70%,75% than those of in 60%,65%,80%,85% and CK.So,formula 70% and 75% are optimized tobacco stalks cultivation formula for Pleurotus eryngii.(2)Good quality of Pleurotus eryngii when cultivated with tobacco stalks.There were no significant difference in water content of the sporocarp between in tobacco stalks formula(60%-85%)and in CK.The contents of crude fiber,crude fat,crude protein,polysaccharide,reducing sugar,total sugar and ash in the sporocarp increased first and then decreased with the proportion increasing of tobacco stalks in formula.The content of crude fat in sporocarp was significantly lower than that of in CK.The content of ash content was highest in formula 70% and 75%,and all were significantly higher than the CK.The content value of polysaccharide,reducing sugar and the total sugar was highest in formula 70% and 75%.There was no significant difference among traits of reducing sugar,total sugar in formula 70%,75% comparing with CK.While the content of polysaccharide in formula70% was significantly lower than the CK,the value in formula 75% was all most the same to CK.The contents of crude fiber and crude protein were highest in formula 65%,70% and 75%.The content of crude fiber in formula 65%,70% and 75% were significantly higher than the CK.There was no significantly difference in highst values of crude protein content between comparing CK.The results showed that the quality of Pleurotus eryngii cultivated in appropriate tobacco stalk matrix was very excellent.(3)The nicotine content in Pleurotus eryngii cultivated with tobacco stalks was in line with the European Union's highest limit standard.The nicotine content of the sporocarp cultivated in tobacco stalks formula(60%-85%)was from 187.4?g/kg to 453.1?g/kg,and 38.1?g/kg in CK.They were all significantly lower than 1170?g/kg of the European Union's highest limit standard.The results showed that nicotine also existed in Pleurotus eryngii when cultivated in cotton seed husk.Nicotine was not a specific secondary metabolites of Pleurotus eryngii of cultivation with tobacco stalks.Although the nicotine content of the sporocarp would be significantly improved resulting from tobacco stalks,but it was still safe for human food.The regular change trend of the nicotine content in the sporocarp was not observated with the proportion increase of tobacco stalks in cultivation matrix.