散斑壳菌对华山松凋落针叶的室内分解

为了探明散斑壳菌(Lophodermium spp.)分解利用针叶时的各纤维素酶酶解的作用机制和了解该菌的腐生性能,以华山松(Pinus armandii)新近凋落针叶为底物进行纯培养分解试验。试验以针叶为唯一碳源,采用试管培养液法,对Lophodermium conigenum、L. pinastri、L. kumaunicum、L. sichuanense 和L. erlangshanense 5种散斑壳菌进行纯培养试验,同时测定针叶失重率和纤维素酶酶活大小。相关性分析表明,内切纤维素酶(Endoglucanase, EG)、外切纤维素酶(Cellobiohydrolase, CBH)与β-葡萄糖苷酶(β-glucosidase, BGL)三者之间存在一定协同效应(L. pinastri与L. erlangshanense除外),特别是CBH与EG之间。各酶类活性大小是制约针叶纤维素分解的主要因素,协同效应强酶活高凋落针叶分解就越快。5种菌引起针叶质量损失率在8.5%～11.8%之间,各菌株引起针叶质量损失依次为L. pinastri>L. sichuanense>L. kumaunicum>L. conigenum>L. erlangshanense。5种菌均能分泌纤维素酶,对凋落针叶有一定分解能力,且EG、CBH与BGL之间存在不同程度的协同作用,属于兼性寄生物,但其腐生性不强。

Laboratory decomposition research of Lophodermium on the litter needles from Pinus armandii

In order to study the saprophytic ability of Lophodermium spp. and mechanism of each cellulase produced in the process of decomposing litters, newly litter needles from Pinus armandii were used as the decomposition material to conduct a decomposition experiment in pure culture. Five species of Lophodermium(L. conigenum, L. pinastri, L. kumaunicum, L. sichuanense, L. erlangshanense)were cultivated, in which the needles were used as the sole carbon source. The weight loss rate of the needles and the cellulase enzyme activities(Filter paper activity(FPA), Endoglucanase(EG), Cellobiohydrolase(CBH), β-glucosidase(BGL))were determined in the test. The correlation analysis showed that there was a certain synergistic effect among EG, CBH and BGL(except L. pinastri and L. erlangshanense), especially among CBH and EG. Cellulose decomposition was restricted by each enzyme activity, the litter needles could be decomposed faster with higher synergistic effect and high enzyme activity. The mass loss rates caused by five Lophodermium spp. was between 8.5%-11.8%, and which declined in the following order: L. pinastri>L. sichuanense>L. kumaunicum>L. conigenum>L. erlangshanense. The five kinds of Lophodermium spp. can produce cellulase, and they have different levels of synergistic effect among EG, CBH and BGL. They all had certain ability to decompose the needles, and they are facultative parasites, but they have weak saprophytism.