| 亚热带森林不同土壤类型团聚体酶活性及化学计量特征的差异 |
| 摘要点击 1326 全文点击 121 投稿时间：2024-01-05 修订日期：2024-05-09 |
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| 中文关键词 红壤 石灰性土壤 团聚体 酶活性 酶化学计量比 亚热带森林 |
| 英文关键词 red soil limestone soil aggregates enzyme activity enzyme stoichiometry subtropical forests |
| 作者 | 单位 | E-mail | | 苏芝凤 | 广西师范大学珍稀濒危动植物生态与环境保护教育部重点实验室, 桂林 541006
广西师范大学环境与资源学院, 桂林 541006 | 2411217827@qq.com | | 黄德周 | 广西师范大学环境与资源学院, 桂林 541006 | | | 朱芷仪 | 广西师范大学环境与资源学院, 桂林 541006 | | | 陈荣枢 | 广西师范大学珍稀濒危动植物生态与环境保护教育部重点实验室, 桂林 541006
广西师范大学环境与资源学院, 桂林 541006 | | | 代廷皓 | 广西师范大学环境与资源学院, 桂林 541006 | | | 梁建宏 | 中国地质科学院岩溶地质研究所, 自然资源部/广西岩溶动力学重点实验室, 桂林 541004 | | | 朱婧 | 广西师范大学珍稀濒危动植物生态与环境保护教育部重点实验室, 桂林 541006
广西师范大学环境与资源学院, 桂林 541006
广西生态脆弱区环境过程与修复重点实验室, 桂林 541006 | zhuj@gxnu.edu.cn |
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| 中文摘要 |
| 为揭示我国亚热带森林生态系统不同土壤类型和团聚体土壤微生物养分限制和养分有效性的差异及其驱动因素,以亚热带森林典型酸性红壤和中性石灰性土壤的O/A层（分别为 0~3和0~7 cm）和AB层（O/A层以下至20 cm）为研究对象,分析不同粒径团聚体中碳获取酶[蔗糖酶、淀粉酶、 β-1,4-葡萄糖苷酶（BG）]、氮获取酶[脲酶、乙酰葡糖胺糖苷酶（NAG）、亮氨酸氨基肽酶（LAP）]和磷获取酶[植酸酶、酸性磷酸酶（AP）]的活性,揭示土壤酶化学计量特征的变化规律. 结果表明,石灰性土壤比酸性红壤的氮获取酶活性更高,其中石灰性土壤脲酶、NAG酶和LAP酶活性分别比酸性红壤高38.84%、123.89%和4.06%,而两者的碳和磷获取酶活性差异不大. 红壤与石灰性土壤O/A层土壤酶活性整体上均高于AB层. 土壤总有机碳和pH值是影响土壤酶活性的关键环境因子. 多数碳、氮、磷转化水解酶（BG、脲酶和NAG以及植酸酶）活性在微团聚体（0.1~0.25 mm和<0.1 mm）中活性更高；这凸显了小团聚体在促进有机质的分解,加快土壤养分循环中的作用；相比红壤,石灰性土壤中NAG和植酸酶在不同团聚体中呈现了显著的差异性. 红壤和石灰性土壤及其团聚体的ln（BG）∶ln（NAG+LAP）∶ln（AP）均值分别为1.02∶1∶1.04和0.95∶1∶0.93,总体上符合全球平均水平1∶1∶1. 红壤ln（BG）∶ln（NAG+LAP）及其矢量长度均高于石灰性土壤,表明红壤受到更强的碳限制. 红壤ln（NAG+LAP）∶ln（AP）低于石灰性土壤且矢量角度大于石灰性土壤,表明其磷限制更强. 土壤pH值和总磷是影响酶活性化学计量特征的最主要因子. 红壤有机质和生物有效性磷均低于石灰性土壤,促使微生物通过分泌碳磷获取酶以提高获取磷效率. 高pH的石灰性土壤可能由于自身矿化和硝化速率较高导致硝酸盐淋溶,造成更强的氮限制. 土壤大团聚体（1~2 mm和0.5~1 mm）的微生物受到较强磷限制；而在微团聚体（尤其是0.1~0.25 mm）中受到更强的碳限制. 石灰性土壤大团聚体到微团聚体的微生物养分模式从磷限制转变为氮限制. 研究结果揭示了我国亚热带森林土壤微生物养分限制同时受土壤类型及团聚体结构的影响. |
| 英文摘要 |
| To reveal the differences in soil microbial nutrient limitation and nutrient availability at the aggregate scale of soil types in a subtropical forest in China, the O/A horizon （0-3 cm and 0-7 cm, respectively） and AB horizon （below O/A horizon to 20 cm depth） of typical acidic red soil and neutral limestone soil in Northern Guangxi were studied. The activities of carbon-acquiring enzymes （sucrase, amylase, β-1,4-glucosidase （BG））, nitrogen-acquiring enzymes （urease, β-1,4-N-acetyl-glucosaminidase （NAG）, leucine amino peptidase （LAP））, and phosphorus-acquiring enzymes （phytase and acid phosphatase （AP）） in different aggregate sizes were determined to reveal the variation in soil enzyme stoichiometry characteristics. The results showed that the limestone soil had higher nitrogen-acquiring enzyme activity compared to that in the red soil, with urease, NAG, and LAP activities being 38.84%, 123.89%, and 4.06% higher, respectively. The differences in carbon- and phosphorus-acquiring enzyme activities between the two soils were not significant. The overall soil enzyme activities in the O/A horizon were higher than in the AB horizon for both red soil and limestone soil. Soil total organic carbon and pH were identified as key factors influencing soil enzyme activities. Most enzyme activities （BG, urease, NAG, and phytase） were higher in micro-aggregates （0.1-0.25 mm and <0.1 mm）, emphasizing the role of micro-aggregates in promoting organic matter decomposition and accelerating soil nutrient cycling. Compared to those in red soil, limestone soil exhibited greater differences in NAG and phytase activities among aggregates. The mean values of ln（BG）∶ln（NAG+LAP）∶ln（AP） of red soil and limestone soil as well as their aggregates were 1.02∶1∶1.04 and 0.95∶1∶0.93, respectively, generally conforming to the global average ratio of 1∶1∶1. The ln（BG）∶ln（NAG+LAP） and vector lengths were higher in red soil than in limestone soil, indicating stronger carbon limitation in the red soil. The ln（NAG+LAP）∶ln（AP） ratio was lower in red soil than in limestone soil, with the former having a larger vector angle, suggesting stronger phosphorus limitation. Soil pH and total phosphorus were identified as the primary influencing factors of enzyme activity stoichiometry characteristics, suggesting that the bioavailability of organic matter and phosphorus in acidic soil was lower than in limestone soil, prompting microbes to secrete carbon and phosphorus enzymes to enhance acquisition efficiency. The high pH of limestone soil may lead to nitrogen limitation due to nitrate leaching caused by higher mineralization and nitrification rates. Microbes in the large aggregates （1-2 mm and 0.5-1 mm） of both soils experienced stronger phosphorus limitation, whereas carbon limitation was stronger in micro-aggregates, especially in the 0.1-0.25 mm aggregates. The microbial nutrient pattern in limestone soil aggregates shifted from phosphorus limitation to nitrogen limitation from large to micro-aggregates. This study reveals the influence of soil type and aggregate on the soil microbial nutrient limitation patterns of soil microbial elements in subtropical forest soils of China. |
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