| 水稻不同生育期根际与非根际土壤胞外酶对施氮的响应 |
| 摘要点击 2423 全文点击 917 投稿时间：2017-01-15 修订日期：2017-03-02 |
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| 中文关键词 水稻土 水稻生育期 根际土壤 施氮 胞外酶活性 |
| 英文关键词 paddy soil rice growth period rhizosphere soil nitrogen application extracellular enzyme activity |
| 作者 | 单位 | E-mail | | 魏亮 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
中国科学院大学, 北京 100049 | weiliang16@mails.ucas.ac.cn | | 汤珍珠 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
湖北大学资源环境学院, 武汉 430062 | | | 祝贞科 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125 | zhuzhenke@isa.ac.cn | | 蔡观 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
湖南农业大学资源环境学院, 长沙 410128 | | | 葛体达 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125 | | | 王久荣 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125 | | | 吴金水 | 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125 | |
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| 中文摘要 |
| 与稻田土壤碳氮循环（矿化、转化等）密切相关的酶活性可以反映微生物的生长和代谢过程. 为明确水稻不同生育期根际与非根际土壤胞外酶对施氮的响应，采用根际袋法区分水稻根际和非根际土壤，利用96 微孔酶标板荧光分析法，测定其碳氮过程关键酶β-1，4-葡萄糖苷酶（BG）和β-1，4-N-乙酰氨基葡萄糖苷酶（NAG）活性，探讨根际效应、施氮和生育期对土壤酶活的影响及其调控机制. 结果表明，施氮使拔节期土壤BG酶活性相对于不施氮处理降低了7.4~13.5 nmol·（g·h）-1，而使成熟期BG酶活性增大了7.0~31.4 nmol·（g·h）-1，同时根际与非根际土壤中BG酶活性也随水稻的生育期而发生相应的变化. 与不施氮处理相比，施氮使水稻成熟期非根际土壤NAG酶活性增加了1.1倍，根际土壤降低了0.3倍. 施氮和生育期显著影响土壤BG酶活性，而水稻生育期、施氮和根际效应及其交互作用均对NAG酶活性有极显著影响. RDA分析表明土壤微生物生物量碳（MBC）和可溶性有机碳（DOC）含量主要影响水稻根际土壤胞外酶活性；而非根际土壤中酶活性的变化主要受微生物生物量氮（MBN）和铵态氮（NH4+-N）的影响. 土壤酶活性与多种因素存在复杂关系，需要综合考虑植物生理特征、土壤酶活性和土壤特征，分析N添加对微生物群落组成的影响. |
| 英文摘要 |
| Ecological enzyme activities are closely relevant to the carbon and nitrogen decomposition and mineralization of paddy soils, which can reflect the growth and metabolism of microorganisms. In order to clarify the response to nitrogen application by different enzymes in the rhizosphere and bulk soil of rice, the rhizosphere and bulk soil were identified using a rhizosphere bag. In addition, the β-1,4-glucosidase (BG) enzyme; β-1,4-N-acetylglucosaminidase (NAG) enzyme; and the effects of the rhizosphere, nitrogen application, and growth period on soil enzyme activities were analyzed. The results showed that the activity of the BG enzyme decreased by 7.4-13.5 nmol·(g·h)-1 in the jointing stage and increased by 7.0-31.4 nmol·(g·h)-1 in the maturity stage, and the activity of the BG enzyme in the rhizosphere and bulk soil also changed with the growth period of rice.compared with no nitrogen fertilizer, nitrogen application increased NAG enzyme activity by 1.1 times and rhizosphere soil by 0.3 times in the bulk soil in the maturity stage. Nitrogen application and growth period had significant effects on soil BG enzyme activity, whereas the interaction within rice growth stage, nitrogen application, and rhizosphere effect had significant effects on NAG enzyme activity. The result of RDA showed that the soil microbial biomass carbon (MBC) and dissolved organic carbon (DOC) contents mainly affected the activity of extracellular enzymes in the rice rhizosphere soil, whereas the activities of enzymes in the rhizosphere soil were mainly affected by microbial biomass nitrogen (MBN) and NH4+-N. The relationships between soil enzyme activity and various factors are complex, and the effects of nitrogen addition on microbial community composition needs to be considered after accounting for plant physiological characteristics, soil enzyme activity, and soil characteristics. |
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