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首页> 中文期刊> 《生态学报》 >磷添加对中亚热带米槠和杉木细根分解及其酶活性的影响

磷添加对中亚热带米槠和杉木细根分解及其酶活性的影响

         
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摘要

为深入探讨磷(P)有效性对中亚热带地区林木细根分解及其胞外酶活性的影响,选取福建省三明格氏栲自然保护区内米储天然林为分解的实验样地,采用网袋法以该区域较为典型且底物P含量有显著差异的米槠和杉木细根为研究对象,进行P添加试验.各施P水平分别为高磷(HP,360 kg P hm-2 a-1)、中磷(MP,240 kg P hm-2 a-1)、低磷(LP,120 kg P hm-2 a 1)和对照(CT,0kgPhm-2a-1).结果显示:在2 a分解期内,米槠细根分解快于杉木细根,呈先快后慢的变化趋势;P添加提高了细根的分解速率,对分解起促进作用,且对P含量较低的杉木细根促进作用更强,但未随施P水平的提高分解呈加速的现象.总体上,米槠细根分解各种酶活性及总的累积酶活性均显著高于杉木细根;主要降解纤维素的水解酶活性呈先升后降,主要降解木质素的氧化酶活性呈增长趋势;P添加降低了酸性磷酸酶(AP)活性,而提高了β-葡萄糖苷酶(βG)、纤维素水解酶(CBH)、β-N-乙酰氨基葡萄糖苷酶(NAG)、酚氧化酶(PhOx)和过氧化物酶(PerOx)活性;回归分析显示细根的分解速率与水解酶呈显著的二次函数关系,与氧化酶呈显著的指数关系.研究表明,P是影响中亚带林木细根分解的主要因素之一,分解过程中酶活性的变化可用于解释细根的分解速率.对土壤P有效性低的中亚热带地区林木细根分解的机理探讨,有助于进一步了解森林生态系统的养分循环并为森林经营提供决策参考.%It is well known that phosphorus (P) is one of the most important elements frequently limiting primary productivity in tropical and subtropical ecosystems.However,the effect of P availability on the decomposition rate of fine roots has yet to be confirmed by experimental manipulation.In order to examine fine root decomposition in response to P addition,we conducted litterbag experiments using the fine roots of Castanopsis carlesii and Cunninghamia lanceolata,which are two tree species typical of subtropical forests.The experimental site is located in Sanming Castanopsis Kawakamii nature reserve of Fujian.We examined the effects of four levels of P addition:high P (HP,360 kg P hm-2 a-1),medium P (MP,240 kg P hm-2 a-1),low P (LP,120 kg P hm-2 a-1),and control (CT,0 kg P hm-2 a-1).During the 2-year experimental period,it was found that C.carlesii fine roots decomposed faster than those of C.lanceolata,and that the decomposition rates were relatively rapid during the initial phase and slow during the later phase.P addition increased the fine root decomposition rates in both species,although it had a greater stimulatory effect on C.lanceolata fine roots.However,the decomposition rates did not accelerate with increasing P addition level.During the decomposition process,the enzyme and accumulated enzyme activities in C.carlesii fine roots were significantly higher than those in C.lanceolata.The pattern of cellulose-degrading enzyme activity showed an initial increase,but subsequently decreased after reaching a peak.In contrast,degradation of recalcitrant lignin gradually increased during the decomposition process.There was a significant correlation between hydrolase activity and the fine root decomposition rate (P ＜ 0.05),and an exponential relationship between oxidase activity and the fine root decomposition rate.P addition decreased acid phosphatase activity,but significantly increased the activities of β-1,4-glueosidase,cellobiohydrolase,β-1,4-N-acetylglucosaminidase,phenol oxidase,and peroxidase during fine root decomposition.The results show that P is one of the main factors affecting subtropical tree fine root decomposition,and that changes in enzyme activities during the decomposition process can explain the observed decomposition rates.The present study reveals the mechanism of fine root decomposition in a subtropical forest with low soil phosphorus availability,which is conducive to both understanding nutrient cycling and decision making in forest management.

著录项

  • 来源
    《生态学报》 |2017年第1期|136-146|共11页
  • 作者

    洪慧滨; 林成芳; 彭建勤; 陈岳民; 魏翠翠; 杨玉盛;

  • 作者单位

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

    福建师范大学地理科学学院,福州 350007;

    福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福州350007;

  • 原文格式 PDF
  • 正文语种 chi
  • 中图分类
  • 关键词

    磷; 细根; 分解; 酶活性; 中亚热带;

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