肖文娅　费菲　刁娇娇　关庆伟

(南京林业大学，南京，210037)



杉木人工林凋落物中微生物数量对间伐的响应1)

肖文娅费菲刁娇娇关庆伟

(南京林业大学，南京，210037)

为了明晰凋落物中微生物数量对间伐强度的响应程度，以南京溧水林场间伐7 a后25年生的杉木(Cunninghamialanceolata(Lamb.) Hook.)人工林为对象，研究了不同间伐强度对凋落物中真菌、细菌、放线菌3类微生物数量季节性变化的影响。结果表明：不同强度间伐杉木人工林下凋落物中微生物的数量随季节变化差异显著，微生物数量在春季期间对间伐响应最为显著。与对照相比，春季内弱度间伐下细菌数量显著减少了61.05%(P<0.01)；而春季内中度间伐下的真菌和细菌数量分别减少了25.32%(P<0.01)和36.14%(P<0.01)，放线菌则增加了30.97%(P<0.05)；春季内强度间伐下真菌量和放线菌数量分别增加了77.64%(P<0.05)和59.35%(P<0.01)，细菌数量减少了42.11%(P<0.01)。其中，凋落物层温度及林下植被层Margalef指数对微生物数量的影响最为显著。微生物数量的影响会导致凋落物向土壤中输送的养分不同，对提高林分生产力有重要意义。

间伐强度；凋落物；真菌；细菌；放线菌；季节变化

In order to clarify the response of the microbial number to thinning intensities in the litter layer, the microorganisms’ number of fungi, bacteria and actinomycetes in litter was determined during season changes in different thinning intensities in a 25-year old Chinese fir (Cunninghamialanceolata(Lamb.) Hook.) plantation. The numbers of microorganisms in the litter were significantly different depending on the season in the different thinning intensity, especially in spring. Compared with the control, the number of bacteria in spring significantly was reduced by 61.05% (P<0.01) in the light intensity thinning. The number of fungi in litter was reduced by 25.32% (P<0.01) in middle intensity thinning in spring, and the number of bacteria was reduced by 36.14% (P<0.01), while the number of actinomycetes was increased by 30.97% (P<0.05). In high intensity thinning, the numbers of fungi and actinomycetes were increased by 77.64% (P<0.05) and 59.35% (P<0.01), respectively. The number of bacteria in spring decreased by 42.11% (P<0.01) in high intensity thinning. Among all the factors, the impact of litter layer temperature and the Margalef index of the forest floor on the numbers of microorganisms is the most significant. The differences of the numbers of microorganisms in litter will lead to different nutrients that delivered to the soil, and improve the forest productivity.

森林凋落物是森林植物在生长发育过程中新陈代谢的产物，在促进生态系统养分循环方面起着重要作用[1]。凋落物分解是生态系统物质循环和能量转换的主要途径，对维持森林土壤肥力有重要作用[2]。而凋落物的分解与其中的微生物种群数量关系密切[3]。

微生物数量及生物量的变化受凋落物质量、树种组成、土壤水热状况等多种因素的影响[4]，与凋落物和土壤中的养分状况[5]和元素周转速率密切相关[6]。物种组成[7-8]不同，凋落物的质和量就不同，适于微生物生长的营养源也不同，因而微生物的种类和数量也不同[9]。凋落物组成类型的增加对凋落物中微生物数量提升作用显著[10]。光、热、水、气的分布以及土壤状况，对凋落物中微生物的结构以及多样性也会产生一定影响[11]。……