菌根真菌侵染对植物生物量累积的影响

为了从生态系统尺度探讨菌根资源与植物生物量累积的关系,调查了鼎湖山不同成熟度的三个森林群落主要优势树种的菌根侵染情况.综合分析各森林群落优势树种的个体数、生物量和菌根侵染率发现：1）菌根侵染率与径向生长速率相关,植物生长迅速的阶段菌根侵染率更高.中径级（胸径15-30 cm）的马尾松（Pinus massoniana）和锥（Castanopsis chinensis）的侵染率比小径级（胸径1-15 cm）个体的侵染率高,而大径级个体（胸径30 cm 以上）的侵染率略低于中径级个体的侵染率.木荷（Schima superba）则表现出侵染率随着胸径增大而增高的趋势.2）树种在群落内的侵染率越高,其对群落生物量的贡献率越大.如马尾松在马尾松林和混交林的侵染率分别为（77.30±18.02）%和（40.50±14.42）%,其对马尾松林群落生物量的贡献率达到87.43%,是对混交林生物量贡献率（17.51%）的5 倍.混交林和阔叶林的共有优势树种锥的侵染率和生物量贡献率也有存在相同规律.3）根系碳储量占群落总碳储量比例较高的群落其优势树种平均侵染率相对较高.马尾松林、混交林和季风常绿阔叶林中,根系碳储量占群落总碳储量的比例分别为55%、54%、42%,群落优势树种平均侵染率分别为（66.73±10.55）%、（46.97±27.28）%、（54.22±25.45）%,马尾松林的根系碳储量和平均侵染率均高于混交林和季风常绿阔叶林.以上结果表明,菌根真菌侵染对于植物个体生长速率以及群落水平的生物量累积具有-定的促进作用.

Influence of mycorrhizal colonization on plant biomass accumulation

To reveal the relations between mycorrhizal resources and biomass accumulation at system scale, we analysed possibleimpact of mycorrhizal colonization on growth rate and biomass accumulation of dominant tree species in three forests at DinghushanNature Reserve. Mycorrhizal infection rate, quantity percentages and biomass of doiminant tree species in a given ecosystem wereinvestigated in this study. Our research shows that： 1） Infection rate changed accordingly with growth rate. Trees that grow morerapidly might have higher infection rate. 2） Plant with higher infection rate turned to have lager biomass ratio in its community. e.g.,infection rate of Pinus massoniana were （77.30±18.02）% and （40.50±14.42）% in PF and MF, respectively, its biomass ratio was87.43% in PF, which was five times of that （17.51%） in MF. This tendency was the same for Castanopsis chinensis, a codominantspecies in MF and BF. 3） Infection rate and root carbon content were relatively higher in PF （pine forest, early successional stage）than that in MF （mixed coniferous and broadleaved forest, middle successional stage） and BF （monsoon evergreen broadleavedforest, late successional stage）. In PF, MF and BF, root carbon storage ratio was 55%, 54% and 42%, mycorrhizal infection rate was（66.73±10.55）%, （46.97±27.28）% and （54.22±25.45）%, respectively. This study thus suggests that mycorrhizal colonization maypromote plant growth and biomass accumulation of forest community.