Activities of selected soil enzymes (invertase, acid phosphatase, proteinase,catalase, peroxidase and polyphenoloxi-dase) were determined under different spruce forests withrestoration histories of 5, 13, 18, 23, 27 y...Activities of selected soil enzymes (invertase, acid phosphatase, proteinase,catalase, peroxidase and polyphenoloxi-dase) were determined under different spruce forests withrestoration histories of 5, 13, 18, 23, 27 years and an old growth forest over 400 years old in theeastern Qinghai-Tibetan Plateau, China, and their possible use as indicators of ecosystems healthwere analyzed. Plots 10 X 10 m with 4 replications were established to investigate three hypotheses:soil enzyme activities a) would increase with the restoration process; b) would be greater insurface soils than at lower depths; and c) would be correlated to selected physicochemicalproperties. Results showed that as the forests developed after restoration, invertase and peroxidaseactivities usually increased up to the 23 year point. Also soil enzyme activities were associatedwith surface soils and decreased with depths, suggesting that in earlier restoration stages surfaceaddition of organic fertilizer to soils might be more effective than additions at depth. In the 0-20cm soil, there were significant correlations (P < 0.01 or < 0.05) between some soil enzymeactivities and some selected chemical properties. Therefore, temporal changes in enzyme activitiesshould be included as an indicator when evaluating sustainable forest management practices.展开更多
树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量...树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量部分树木的树高，缺失的树高则通过不同树种的树高曲线来预测（S6nehez—Gonzalez et al．，2007）。展开更多
Class Ⅲ secretable plant peroxidases occur as a large family of genes in plants with many functions and probable redundancy. In this review we are concentrating on the evidence we have on the catalysis of lignin poly...Class Ⅲ secretable plant peroxidases occur as a large family of genes in plants with many functions and probable redundancy. In this review we are concentrating on the evidence we have on the catalysis of lignin polymerization by class Ⅲ plant peroxidases present in the apoplastic space in the xylem of trees. Some evidence exists on the specificity of peroxidase isozymes in lignin polymerization through substrate specificity studies, from antisense mutants in tobacco and poplar and from tissue and cell culture lines of Norway spruce （Picea abies） and Zinnia elegans. In addition, real time （RT-）PCR results have pointed out that many peroxidases have tissue specific expression patterns in Norway spruce. Through combining information on catalytic properties of the enzymes, on the expression patterns of the corresponding genes, and on the presence of monolignols and hydrogen peroxide in the apoplastic space, we can show that specific peroxidases catalyze lignin polymerization in the apoplastic space of Norway spruce xylem.展开更多
Background： Coarse woody debris （CWD） is an important element of forest structure that needs to be considered when managing forests for biodiversity, carbon storage or bioenergy. To manage it effectively dynamics o...Background： Coarse woody debris （CWD） is an important element of forest structure that needs to be considered when managing forests for biodiversity, carbon storage or bioenergy. To manage it effectively dynamics of CWD decomposition should be known. Methods： Using a chronosequence approach, we assessed the decomposition rates of downed CWD of Fagus sylvatica, Picea obies and Pinus sylvestfis, which was sampled from three different years of tree fall and three different initial diameter classes （〉10 - ≤20 cm, 〉20 - ≤40 cm, 〉40 cm）. Samples originating from wind throws in 1999 were collected along a temperature and precipitation gradient. Based on the decay class and associated wood densities, log volumes were converted into CWD mass and C content. Log fragmentation was assessed over one year for log segments of intermediate diameters （〉20 - 40 cm） after 8 and 18 years of decomposition. Results： Significantly higher decomposition constants （k） were found in logs of F. sylvotica （0.054 year^-1） than in P. abies （0.033 year^-1） and P. sylvestris （0.032 year^-1）. However, mass loss of P. sylvestris occurred mainly in sapwood and hence k for the whole wood may be overestimated. Decomposition rates generally decreased with increasing log diameter class except for smaller dimensions in P. obies. About 74 % of the variation in mass remaining could be explained by decomposition time （27 %）, tree species （11%）, diameter （17 %）, the interactive effects between tree species and diameter （4 %） as well as between decomposition time and tree species （3 %） and a random factor （site and tree; 9.5 %）, whereas temperature explained only 2 %. Wood fragmentation may play a more important role than previously thought. Here, between 14 % and 30 % of the decomposition rates （for the first 18 years） were attributable to this process. Carbon （C） density （mgC· cm ^-3）, which was initially highest for F. sylvatico, followed by P. sylvestris and P. obies, decr展开更多
基金Project supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (Nos. KZCX3-SW-339 and KSCX1-07) the Ministry of Science and Technology of China (No. 2001CCB00600).
文摘Activities of selected soil enzymes (invertase, acid phosphatase, proteinase,catalase, peroxidase and polyphenoloxi-dase) were determined under different spruce forests withrestoration histories of 5, 13, 18, 23, 27 years and an old growth forest over 400 years old in theeastern Qinghai-Tibetan Plateau, China, and their possible use as indicators of ecosystems healthwere analyzed. Plots 10 X 10 m with 4 replications were established to investigate three hypotheses:soil enzyme activities a) would increase with the restoration process; b) would be greater insurface soils than at lower depths; and c) would be correlated to selected physicochemicalproperties. Results showed that as the forests developed after restoration, invertase and peroxidaseactivities usually increased up to the 23 year point. Also soil enzyme activities were associatedwith surface soils and decreased with depths, suggesting that in earlier restoration stages surfaceaddition of organic fertilizer to soils might be more effective than additions at depth. In the 0-20cm soil, there were significant correlations (P < 0.01 or < 0.05) between some soil enzymeactivities and some selected chemical properties. Therefore, temporal changes in enzyme activitiesshould be included as an indicator when evaluating sustainable forest management practices.
文摘树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量部分树木的树高，缺失的树高则通过不同树种的树高曲线来预测（S6nehez—Gonzalez et al．，2007）。
基金supported by the Finnish Centre of Excellence in Plant Signal Research granted by the Academy of Finland(grant number 213509)
文摘Class Ⅲ secretable plant peroxidases occur as a large family of genes in plants with many functions and probable redundancy. In this review we are concentrating on the evidence we have on the catalysis of lignin polymerization by class Ⅲ plant peroxidases present in the apoplastic space in the xylem of trees. Some evidence exists on the specificity of peroxidase isozymes in lignin polymerization through substrate specificity studies, from antisense mutants in tobacco and poplar and from tissue and cell culture lines of Norway spruce （Picea abies） and Zinnia elegans. In addition, real time （RT-）PCR results have pointed out that many peroxidases have tissue specific expression patterns in Norway spruce. Through combining information on catalytic properties of the enzymes, on the expression patterns of the corresponding genes, and on the presence of monolignols and hydrogen peroxide in the apoplastic space, we can show that specific peroxidases catalyze lignin polymerization in the apoplastic space of Norway spruce xylem.
基金funded by a German Science Foundation grant to Jürgen Bauhus(DFG-BA 2821/4-1)
文摘Background： Coarse woody debris （CWD） is an important element of forest structure that needs to be considered when managing forests for biodiversity, carbon storage or bioenergy. To manage it effectively dynamics of CWD decomposition should be known. Methods： Using a chronosequence approach, we assessed the decomposition rates of downed CWD of Fagus sylvatica, Picea obies and Pinus sylvestfis, which was sampled from three different years of tree fall and three different initial diameter classes （〉10 - ≤20 cm, 〉20 - ≤40 cm, 〉40 cm）. Samples originating from wind throws in 1999 were collected along a temperature and precipitation gradient. Based on the decay class and associated wood densities, log volumes were converted into CWD mass and C content. Log fragmentation was assessed over one year for log segments of intermediate diameters （〉20 - 40 cm） after 8 and 18 years of decomposition. Results： Significantly higher decomposition constants （k） were found in logs of F. sylvotica （0.054 year^-1） than in P. abies （0.033 year^-1） and P. sylvestris （0.032 year^-1）. However, mass loss of P. sylvestris occurred mainly in sapwood and hence k for the whole wood may be overestimated. Decomposition rates generally decreased with increasing log diameter class except for smaller dimensions in P. obies. About 74 % of the variation in mass remaining could be explained by decomposition time （27 %）, tree species （11%）, diameter （17 %）, the interactive effects between tree species and diameter （4 %） as well as between decomposition time and tree species （3 %） and a random factor （site and tree; 9.5 %）, whereas temperature explained only 2 %. Wood fragmentation may play a more important role than previously thought. Here, between 14 % and 30 % of the decomposition rates （for the first 18 years） were attributable to this process. Carbon （C） density （mgC· cm ^-3）, which was initially highest for F. sylvatico, followed by P. sylvestris and P. obies, decr
