Abstract：White-rot fungus(Pleurotus ostreatu) has strong degradation ability of lignin. The experiment was conducted to research effect of different Mn2+ levels on lignocellulose enzyme activity of rape(Brassica campestris L.) straw fermented by white- rot fungus and changes of rape straw tissue structure. The experiment, which was separated into control group(SMc, 0 mmol/L),Test One (SM1, 0.6 mmol/L) and Test Two(SM2, 1.2 mmol/L), selected white-rot fungi P. ostreatu-WY01 to ferment rape straw motionlessly fermented of 40 d on constant temperature of 28℃ in nitrogen-limited mediums which were added Mn2+ of different levels in solid state.The result showed that laccase activity and manganese peroxidase(MnPs) activity of Test One, which reached respectively peak of 211.11 U/g at 6 day and 49 U/g at 10 day, very significantly overtoped other groups(P<0.01); lignin peroxidase(Lips), cellulose enzyme(Cels) and hemicellulase enzyme(Hcels) activity respectively were no difference by adding Mn2+ and tissue structure of straw was accordance with related cellulose enzyme activity. At early period of fermentation, experimental groups Lacs activity reached peak at 6 d and fell fastly until tend to smooth at 10 d while SMc had been living in lower level in process. Lips of SM1 reached peak at 12 d while SM2 and SMc reached peak at 10 d.After peaks,they trended to fall gradually until keep lower level after 20 d. MnPs activity kept low level before 6d of fermentation and ascended suddenly followly. Experimental groups MnPs activity which SM1 and SM2 respectively reached peak at 10 d and 16 d, were greater significantly than SMc. During the fermentation, all treatment groups Cels and Hcels activity had a rising trend and experimental groups were higher than control group. Scanning electron microscopy showed that without any treatment, tissue was very compact and tissue arranged orderly. Empty cavity the arrow refered to the figure might be caused by high temperature sterilization leading to inflation. Processed by the white-rot fungus P. ostreatus-WY01, SMc rape straw tight tissue was destroyed and appeared some loose mesh at 20 d;straw waxy skin arrowed to on left and fibrous tissue was broken down on the right at 40 d; SM1 partly appeared collapsed at 20 d and fibrous tissue was completly decomposed and pulverized at 40 d. SM2 tissue was destroyed in different degree at 20 d and fibrous tissue was completed decomposed at 40 d while it not as effective as SM1. The findings suggested that Mn2+ could induce and benefit degradation of rape straw by white-rot fungus(P. ostreatu-WY01), and comprehensive biodegradation effect was SM1＞SM2＞SMc. The study provides us a basis to develop resources of biological feed using rape straw
