The effects of long term nitrogen deposition on extracellular enzyme activity in an Acer saccharum forest soil
The effects of long term nitrogen deposition on extracellular enzyme activity in an Acer saccharum forest soil
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DOI：
10.1016/s0038-0717(02)00074-3
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发表时间：
2002-09-01
影响因子：
9.7
通讯作者：
Zak, DR
中科院分区：
文献类型：
--
作者：
Saiya-Cork, KR;Sinsabaugh, RL;Zak, DR
人为氮沉降通过多种机制影响凋落物分解和土壤有机质（SOM）储存。在1998 - 2000年生长季期间，对密歇根北部一个以糖枫为主的森林中微生物群落对长期氮沉降的响应进行了研究。从三个施肥样地（30千克氮/公顷·年）和三个对照样地收集了凋落物和土壤。对10种胞外酶（EEA）的活性进行了测定。采用方差分析和荟萃分析技术来比较处理响应。凋落物中胞外酶对氮添加的响应大于土壤（凋落物平均效应量[d] = 0.534标准差；土壤d = 0.308）。脲酶、酸性磷酸酶和糖苷酶（β - 葡萄糖苷酶、α - 葡萄糖苷酶、纤维二糖水解酶、β - 木糖苷酶）在土壤和凋落物中的活性均增加；平均响应幅度为7% - 56%。N - 乙酰氨基葡萄糖苷酶活性在土壤中增加了14%，但在凋落物中降低了4%。酚氧化酶活性在土壤中下降了40%，但在凋落物中增加了63%。这些响应表明氮沉降提高了凋落物分解速率，抑制了土壤有机质分解。在先前的研究中，氮沉降导致酚氧化酶活性丧失被归因于木质素降解担子菌受到抑制。然而，这种活性在以细菌为主的土壤中下降表明，氮对难降解有机物分解的抑制可能是一种更普遍的现象。（C）2002爱思唯尔科学有限公司。保留所有权利。
Anthropogenic N deposition affects litter decomposition and soil organic matter (SOM) storage through multiple mechanisms. Microbial community responses to long-term N deposition were investigated in a sugar maple-dominated forest in northern Michigan during the 1998-2000 growing seasons. Litter and soil were collected from three fertilized plots (30 kg N ha(-1) y(-1)) and three control plots. The activities of 10 extracellular enzymes (EEA) were assayed. ANOVA and meta-analysis techniques were used to compare treatment responses. EEA responses to N amendment were greater in litter than in soil (litter mean effect size [d] = 0.534 std. dev.; soil d = 0.308). Urease, acid phosphatase and glycosidase (P-glucosidase, a-glucosidase, cellobiohydrolase, P-xylosidase) activities increased in both soil and litter; mean responses ranged from 7 to 56%. N-Acetylglucosaminidase activity increased 14% in soil but decreased 4% in litter. Phenol oxidase activity dropped 40% in soil, but increased 63% in litter. These responses suggest that N deposition has increased litter decomposition rate and depressed SOM decomposition. In previous studies, loss of phenol oxidase activity in response to N deposition has been attributed to suppression of lignin-degrading basidiomycetes. However, the decline of this activity in bacterially-dominated soil suggest that N inhibition of recalcitrant organic matter decomposition may be a more general phenomenon. (C) 2002 Elsevier Science Ltd. All rights reserved.