Recherche sur la nutrition azotée de plusieurs souches1 de ĽArmillaria mellea

Investigation of nitrogen nutrition in different strains of Armillaria mellea. I. Utilisation of different sources of nitrogen. The assimilation of different forms of nitrogen - NO₃-, NH₄+ and L-asparagine by isolates of Armillaria mellea from France and Poland was investigated. Both the growth aspect, in which mycelial biomass production was related to the utilisation of nitrogen sources, and the morphological aspect, involving aerial mycelium, sclerotia and rhizomorphs, were studied. Significantly difterent effects were recorded for the influence of nitrogen source, the period of growth and their interaction on the growth of various isolates. Different nitrogen sources significantly affected sclerotial and rhizomorph formation. Isolates of A. mellea, geographically and genetically different, were shown to be also physiologically specialised as was also C. tabescens.     

Yield of dry mycelium of Trichoderma viride Pers. ex Fr. on some carbon and nitrogen sources

This work reports results of mycelial yield of Trichoderma viride from a number of carbon and nitrogen sources and different C:N ratios. The ratios were in two series: first by increasing the carbon content (d-glucose as standard), second – by decreasing the nitrogen content (1-as-paragine as standard). The best mycelium production was found on d-xylose and glucose as C sources and KNO³ and 1-asparagine as N sources. Increase in dosage of both sources caused increase in yield but different changes in pH, according to how nutrients were utilised.     

Effects of <Emphasis Type="Italic">Ips typographus</Emphasis> (L.) damage on litter quality and decomposition rates of Oriental Spruce [<Emphasis Type="Italic">Picea Orientalis</Emphasis> (L.) Link.] in Hatila Valley National Park,Turkey

This study investigated the effects of Ips typographus (L.) damage on initial litter quality parameters and subsequent decomposition rates of oriental spruce tree species [Picea orientalis (L.) Link]. The needle litter was collected from highly damaged, moderately damaged and control stands on two aspects (north and south) and two slope position (top and bottom) on each aspect. The litter was analyzed for initial total carbon, lignin and nutrient (nitrogen, phosphorus, potassium, calcium, magnesium and manganese) concentrations. The variability in nitrogen and calcium concentrations and ratios of C:N, lignin:N and lignin:Ca was significantly affected by the insect damaged levels. While nitrogen concentrations in needle litter increased with increasing insect damage (and consequently the ratios of C:N and lignin:N decreased), calcium concentrations decreased (and consequently the ratio of lignin:Ca increased). Aspect and slope positions explained most of the variability in carbon, lignin, phosphorus, potassium, magnesium and manganese concentrations and lignin:P ratio between all studied stands. Litter decomposition was studied in the field using the litterbag technique. The litter from highly damaged stands showed highest decomposition rates followed by moderately damaged and control stands. The mass loss rates were significantly positively correlated with initial nitrogen concentration and negatively with C:N and lignin:N ratios. The effects of microclimate resulting from canopy damage on litter decomposition was also examined at the same time using standard litter with the same litter quality parameters, but they showed no significant differences among the insect damage levels indicating that alteration of the litter quality parameters produced by I. typographus damage played a more important role than altered microclimate in controlling needle litter decomposition rates. However, changes in microclimate factors due to topography influenced decomposition rates.     

晋西黄土区三种林地土壤养分随林分生长的变化

[目的]研究不同林分类型以及林龄对晋西黄土区土壤养分的改良效应,以期为森林可持续经营提供参考、丰富该区域的生态服务评估资料。[方法]采用林分调查、土壤取样和室内分析方法,于2011年和2016年7—8月对3种不同林龄(山杨中龄林、油松幼龄林、侧柏中龄林)林地内的不同土层有机碳、全氮、全磷含量进行分析,并研究林内各土层间的C、N、P化学计量关系。[结果]表明:各林地土壤养分都有极强的表聚性,0~30 cm土层内有机质、全氮、全磷含量占0~100 cm土层的70%以上;经过5年时间,山杨、油松和侧柏林地0~50 cm土层内平均全氮含量分别增长了9.4%、7.4%、7.5%,全磷含量分别增长了11.6%、12.2%、21.4%;0~100 cm土层内碳储量分别增加了21.17、23.74、2.21 t·hm-2。不同林地之间土壤C:N值随土层深度逐渐减小,而N:P、C:P值随土层变化并没有规律;随着林龄的增加,土壤表层(0~10 cm)的N:P和C:P值明显减小,而C:N值变化不明显。[结论]根据全国土壤养分分级标准,试验林地内碳和氮含量较为丰富,而全磷平均含量为0.36~0.46 g·kg-1、为4~5级标准。在试验林地内,对土壤碳储量、全氮、全磷改良效果相对较好的分别为油松林、山杨林和侧柏林。     

Identification of European Armillaria species by analysis of isozyme profiles

Studies were carried out to test the possibility of identifying European Armillaria species by using isozyme patterns. Twenty-two different enzymes were used to analyse the haploid and diploid mycelium extract of Armillaria borealis, Armillaria cepistipes, Armillaria gallica, Armillaria mellea, Armillaria ostoyae and Armillaria tahescens. Tests for fumarase (E.C. 4.2.1.1.), aconitase (E.C. 4.2.1.3.), leucine-amino peptidase (E.C. 3.4.11.1.), isocitrate dehydrogenase (E.C. 1.1.1.42.), shikimic dehydrogenase (E.C. 1.1.1.25), glucose-6-P-dehydrogenase (E.C. 1.1.1.49.), malic enzyme (E.C. 1.1.1.40.), 6-P-gluconic dehydrogenase (E.C. 1.1.4.4.), pectin esterase (E.C. 3.1.1.11.), and pectic lyase (E.C. 4.2.99.3.) did not reveal enzyme activity. Isozyme profiles of acid phosphatase (E.C. 3.1.3.2.), phospho-gluco-isomerase (E.C. 5.3.1.9.), peroxidase (E.C. 1.11.1.7.), polyphenoloxidase (E.C. 1.14.18.), malic dehydrogenase (E.C. 1.1.1.37.), glutamic dehydrogenase (E.C. 1.4.1.3.) and superoxide dismutase (E.C. 1.15.1.1.) were ineffective for species identification. In contrast, esterase (E.C. 3.1.1.1.), glutamic-oxalacetic transaminase (2.6.1.1.), phospho-gluco-mutase (E.C. 2.7.5.1.), alcohol dehydrogenase (E.C. 1.1.1.1.), and polygalacturonase (E.C. 3.2.1.15.) isoenzyme patterns showed enough polymorphism to allow the identification of the different Armillaria species. However, it is necessary to compare several enzyme profiles for a conclusive identification. Intraspecific crosses of A tabescens were confirmed by the presence of a heteromeric isozyme pattern of alcohol dehydrogenase and phospho-gluco-mutase.     

Contrasting impact of whole-tree-harvesting on chemical quality of plant foliage in coastal versus inland forest

Whole-tree-harvesting (WTH) is gaining support as a means to obtain more bioenergy from forests. One aspect that is scarcely addressed is its impact on the chemical quality of post-harvest plant growth, which may initiate ecological cascade effects through, for example, altered patterns of herbivory and decomposition. We measured C:N ratios and phenolic compounds in foliage from birch Betula spp. that had grown naturally after WTH and conventional harvest (CH) on two boreal sites in inland and more coastal Norway, three or five years after harvest. We found that carbon concentrations were higher after WTH compared to CH on the near-coastal site in spring and summer, but not on the inland site. The only observed change in nitrogen concentration after WTH was that it was lower compared to CH on the near-coastal site in autumn. In line with these changes, the C:N ratio was higher with WTH throughout the season on the near-coastal site, ostensibly favouring production or accumulation of plant defence metabolites. Expectedly, we observed altered concentrations of several phenolic compounds with WTH, particularly at the near-coastal site. Further studies are needed to clarify patterns, but our data strongly suggest that sustainability assessments of WTH should not ignore impact on plant chemical quality, and its potential consequences for trophic interactions.     

Effect of nitrogen and carbon sources on lignin and cellulose degradation by Armillaria ostoyae

Lignin has been hypothesized to be the primary mechanism of resistance to fungal pathogens in plant tissue. Degradation of lignin and cellulose by Armillaria ostoyae cultured for six weeks in Melin-Norkrans medium containing various nitrogen and carbon sources was measured radiometrically. No consistent pattern of lignin or cellulose degradation was found, regardless of A. ostoyae isolate, nitrogen source and concentration, or carbon concentration. More lignin was degraded as the concentration of glucose and fructose increased but not when the concentration of sucrose increased.     

Effects of elevated nitrogen deposition on soil microbial biomass carbon in major subtropical forests of southern China

2003

Wallenstein M D.McNulty S.Fernandez I J.Boggs J Schlesinger W H Nitrogen fertilization decreases forest soil fungal and bacterial biomass in three long-term experiments [其它论文] 2006

Wang X F.Li S Y.Bai K J.Kuang T Y Influence of doubled CO2 on plant growth and soil microbial biomass C and N 1998(12)

Xue J H.Mo J M.Li J.Li D J The short-term response of soil microorganism number to simulated nitrogen deposition 2007(02)

Yao W H.Yu Z Y The nutrient content of throughfall inside the artificial forests on downland 1995

Yi Z G.Yi W M.Zhou L X.Wang X M Soil microbial biomass of the main forests in Dinghushan Biosphere Reserve 2005(05)

Zhou G Y.Yan J H The influence of region atmospheric precipitation characteristics and its element inputs on the existence and development of Dinghushan forest ecosystems [其它论文] -Acta Ecologica Sinica2001

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地形因子对思茅松人工林土壤有机碳储量的影响

[目的]以思茅松人工中龄林为研究对象,探讨不同坡向、坡度和坡位对思茅松人工林SOC储量的影响,为精确评估思茅松人工林碳储量提供科学依据。[方法]对不同坡向、坡度和坡位不同土壤层次的SOC含量、全氮、土壤密度、C:N和SOC储量进行T检验和单因素方差分析,对不同土层的SOC储量和全氮、土壤密度、C:N之间进行Pearson相关分析。[结果]思茅松人工中龄林,SOC含量、全氮和C:N随着土层加深而减少,土壤密度随着土层加深而增加。不同的坡向和坡度显著影响SOC储量大小,阳坡的SOC储量要显著高于阴坡,坡度为20 30°的SOC储量要显著低于10 20°和0 10°,坡位对SOC储量大小无显著影响。在0 100 cm土层中,随着土层深度的增加,不同立地条件的思茅松人工中龄林的SOC储量呈减小趋势,不同坡向、坡位和坡度0 20 cm土层SOC储量均显著高于其它土层。坡向和坡度显著影响0 20 cm土层的SOC储量(P0.05);坡位对各层SOC储量均无显著影响(P0.05)。0 20 cm土层中SOC储量和土壤密度呈极显著负相关,和坡向、坡度呈显著负相关关系;除2040 cm土层外,其它土层的SOC储量与全氮之间呈极显著正相关;SOC储量和坡位与C:N在任一土层均无显著相关关系。[结论]立地条件差异影响SOC储量的大小与分布,尤其是坡向和坡度的不同会造成思茅松人工中龄林SOC储量的差异。     

Effects of metals and pH on in vitro growth of Armillaria ostoyae and other root and butt rot fungi of red spruce

Armillaria ostoyae, Perenniporia subacida, Resinicium bicolor and Scytinostroma galactinum, root and butt rot fungi found on red spruce, Picea rubens, were tested, in vitro, for their sensitivity to metals typically found in high elevation forest soils where red spruce grows. Rhizomorph production by A. ostoyae from woody inocula in soils from red spruce stands at three elevations at each of five mountainous sites in the eastern United States was inhibited completely in the mineral soil from all elevations at all sites, and was also reduced significantly in the organic horizon from the upper two elevations at three of the sites. Inhibition was correlated with concentrations of metal ions in the soil. Growth of rhizomorphs into an agar medium containing lead and other heavy metals was inhibited for isolates of A. ostoyae from red spruce, but not for an isolate of Armillaria gallica from sugar maple; aluminium inhibited rhizomorph growth of isolates of both species. Mycelial growth of all four root and butt rot fungi was inhibited by lead, aluminium and other heavy metals depending on the solubility and concentration of metal and pH of the medium; growth inhibition was usually greater at an initial pH of 3.5 than at pH 4.5. Metal ions inhibited radial growth of Armillaria species more than that of the other three fungi. Rhizomorph growth of Armillaria was inhibited more than radial growth. Because local spread of A. ostoyae occurs frequently by means of rhizomorph growth between near roots, increases in lead, aluminium and other metals in the forest floor may contribute to this fungus' scarcity in high elevation soils and reduced incidence of infection at these sites in the eastern United States.     

The influence of carbon nutrition on Armillaria ostoyae growth and phenolic degradation

Concentrations of 1, 5 and 25 g C L^?1 as glucose, fructose and sucrose were added to basal media containing 0 or 1.0 mM catechol orwa-hydroxybenzoic acid. Media were poured in petri dishes and inoculated with one of three isolates of Armillaria ostoyae(Romagn.) Herink. Armillaria ostoyae isolates usually had greater colony size and biomass yield when glucose was the carbon source as compared to fructose or sucrose. When compared to A. ostoyae growth on basal media alone, 1.0 mM catechol and /wvi-hydroxybenzoic acia added to basal media inhibited A. ostoyae growth. In a second experiment, catechol andpara-hydroxybenzoic acid degradation by three A. ostoyae isolates growing on 1, 5 and 25 g C L^?1 glucose, fructose or sucrose were measured radiometrically. Carbon source and concentration had no effect on the degradation of pzra-hydroxybenzoic acid or catechol by Armillaria ostoyae. Results of these experiments suggests that A. ostoyae can grow faster when at high carbon concentration but cannot more effectively degrade catechol or para-hydroxybenzoic acid.     

Do multipurpose companion trees affect high value timber trees in a silvopastoral plantation system?

Establishment of native timber trees on deforested land may contribute to the livelihood of farmers, to improved ecosystem services and to increased greenhouse gas uptake. Here, we present a new silvopastoral planting design to assess species performance and interspecific competition or facilitation effects among native timber and multipurpose trees in Central America. Two timber species, Tabebuia rosea and Cedrela odorata, were established in three low-density planting regimes allowing combined tree and future livestock production: (1) solitary planting, (2) companion planting with Guazuma ulmifolia, and (3) companion planting with the nitrogen-fixing Gliricidia sepium. We quantified survival, growth and reforestation potential of the two timber species subjected to the different planting regimes for the first 2 years after establishment. Nitrogen concentration as well as stable nitrogen and carbon isotope composition (δ¹⁵N, δ¹³C) of leaves of the timber saplings were determined. T. rosea showed higher survival and better growth than C. odorata under varying environmental conditions (soil, concomitant vegetation). Performance of the timber saplings was unaffected by either companion species. Planting regimes had no effect on foliar nitrogen concentration and δ¹⁵N of the two timber species, although δ¹⁵N values indicated nitrogen fixation activity in G. sepium trees. Planting regimes affected foliar δ¹³C values in T. rosea. δ¹³C values were significantly higher in solitarily growing individuals, suggesting lower exposition to water stress conditions in saplings surrounded by companion species. As we found positively correlated growth traits among timber and multipurpose trees, a combined planting may benefit farmers by providing additional goods and services.     

思茅松人工林土壤有机碳和氮储量变化

以思茅松人工林中龄林、近熟林和过熟林及附近区域思茅松天然林和常绿阔叶林为研究对象,探讨造林对思茅松人工林土壤有机碳和氮储量大小与空间分布的影响。结果表明:各林地类型土壤有机碳、氮含量与C:N随着土层厚度增加而减少,过熟林土壤有机碳和氮含量随土层加深则显著高于其它林地类型,近熟林土壤表层有机碳和氮含量显著低于中龄林和过熟林。思茅松人工林乔木层碳储量随林龄增大而增加,过熟林乔木层碳储量最高。造林对思茅松人工林土壤氮储量的影响不显著,而土壤有机碳储量随林龄增大先减少后增加至过熟林恢复至常绿阔叶林和思茅松天然林水平,土壤有机碳与氮储量随土层加深而减少。与常绿阔叶林和思茅松天然林相比,思茅松人工林的中龄林与过熟林土壤有机碳和氮储量的年变化量高于近熟林,近熟林年变化量呈净减少;在思茅松天然林中,人工更新与在常绿阔叶林中造林相比,思茅松人工林可以累积更多的土壤有机碳和氮储量。此外,土壤含水量越大,土壤有机碳储量则越高。     

Changes in soil properties of Abies holophylla and Quercus-dominated stands 4 years after trenching

Abstract

Few studies tried to isolate the influence of plant roots on the soil characteristics including soil carbon (C) and nitrogen (N) storage. We evaluated the impact of root trenching on soil characteristics of coniferous (Abies holophylla) and deciduous (Quercus spp.) stands 4 years after trenching. Trenching treatment significantly increased the soil water content and nitrate concentration in both stand types. Soil pH, cation exchange capacity, soil C and N pools and isotopic compositions of C and N were significantly different between two stands, but trenching was not found to have significant impact on these soil properties. Our results indicated that root trenching in coniferous and broad-leaved deciduous forests of temperate region could significantly alter soil moisture regime and inorganic N levels, but not C and N stabilization in soils.     

Sexual behaviour of Armillaria heimii and A. mellea isolates from Africa

Thirty isolates of Armillaria heimii from western, eastern and southern Africa were cultured for fruit body production in the laboratory. Most isolates fruited easily. Investigation of single-spore progenies revealed that all the isolates do not have the same sexual behaviour: some are heterothallic and unifactorial while others are homothallic. Two African isolates belonging to the species Armillaria mellea also appeared homothallic. Unifactorial heterothallism has not previously been described in Armillaria, species. Homothallic behaviour has been reported only in a rare European species Armillaria ectypa and in the Japanese subspecies Armillaria mellea ssp. nipponica.     

Ecology and distribution of Armillaria species in Norway

The occurence of Armillaria species was assessed in Norway, enabling the northern‐most distribution of this genus to be determined in Europe. Four Armillaria species were found in Norway. Armillaria borealis was the most common species occurring on woody vegetation to the permafrost zone (ca. 69°N). Armillaria cepistipes was present in southern and central Norway, but was not found further than 66°N. Armillaria solidipes and Armillaria gallica were rare, found at only one locality each; 59°40′ and 59°32′, respectively. Armillaria species were found on 14 hosts, but there was no significant difference between occurrence of A. borealis and A. cepistipes on declining and dead trees. Phylogenetic analyses separated each species into separate clades. All isolates of A. borealis, except one, and most isolates of A. solidipes were in separate clades. However, a subclade within the A. borealis clade was formed of two A. ostoyae and one A. borealis isolates. Two small A. cepistipes genets were found in a declining oak stand.     

Biomass and net primary production of a <Emphasis Type="Italic">Pinus densiflora</Emphasis> forest established on a lava flow of Mt. Fuji in central Japan

We assessed the above- and below-ground biomass and net primary production (NPP) in a mature (85-year-old) Pinus densiflora forest established on a lava surface of Mt. Fuji in central Japan. The nitrogen (N) concentration of the forest soil was low (1.25%), and the mean soil carbon/nitrogen (C/N) ratio was 34.2; therefore, both plants and microorganisms would compete for N in our research forest. The total biomass was 192.62Mgha^–1, of which 67.28% was in the stems and 25.71% was in the roots. The fine-root biomass was 1.12% of the total biomass. The total NPP of the forest reached 11.89Mgha^–1 year^–1, which fell within the values reported for other cool temperate P. densiflora forests established on non-volcanic-related substrata. The below-ground production was about 39% of the total NPP; the value was relatively small under the conditions of low total N concentration and high soil C/N ratio. Our study suggested that P. densiflora could recruit and grow on geologically new substrata without increasing the allocation of its annual carbon budget to below-ground organs (i.e., roots).     

Seasonal changes of nutrient levels and nutrient resorption in Avicennia marina leaves in Yingluo Bay,China

Avicennia marina is a typical mangrove species of subtropical coastlines of China. However, little is known about the retention of nutrients by this species in oligotrophic, coastal environments. In this study, seasonal changes in nitrogen (N) and phosphorus (P) concentrations, N:P ratio and total phenolic concentration in A. marina leaves during senescence were studied. Avicennia marina leaves had high N and P concentrations but the seasonal pattern of N concentration was different from that of P concentration. The A. marina forest was N-limited as the N:P ratio of mature leaves was less than 14. Nitrogen resorption efficiency was higher than P resorption efficiency, and the concentrations of N and P in senescent leaves indicated that N resorption was mostly complete whereas P resorption was incomplete. Avicennia marina leaves contained low tannin concentrations, particularly condensed tannins, as the leaf extracts did not react with acid butanol. Total phenolic concentrations were not correlated with N concentrations in mature and senescent leaves of A. marina. These findings suggest that the high N resorption efficiency and low nutrient losses play an important role in nutrient conservation strategies for A. marina forests, whereas low tannin concentations have limited effects on nutrient cycling.     

Soil Carbon and Nitrogen Dynamics Followed by a Forest-to-pasture Conversion in Western Mexico

Gains and losses of soil carbon (C), have been reported when tropical forests are converted to pastures. Regional studies are crucial for setting regional baselines and explaining each particular trend, in order to solve this controversy. Tropical deciduous forest (TDF) is under high deforestation pressure, mainly for conversion to pastures. The present study compared soil organic C (SOC) and nitrogen (SON) in the surface layer (0–5 cm) of forest and pasture soils in a TDF of western Mexico. SOC and SON concentrations were 18 and 60% lower in pasture soils than in forest soils, and C:N ratio increased in pasture soils. Furthermore, pasture soils had lower labile C and available inorganic nitrogen (N) than forest soils. These results can be explained as a reduction in C inputs to pasture soils and management-induced disruption of soil aggregates. In forest soils, macroaggregates (> 250 μm) were predominant (85%), whereas in pasture soils they were reduced to 35% of dry sand-free soil mass. The estimated SOC and SON losses from the top 5 cm of soil were 3 Mg C ha⁻¹ and 0.9 Mg N ha⁻¹, respectively.     

不同种植年限尾巨桉人工林叶片-凋落物-土壤碳氮磷化学计量特征

[目的]为了解雷州半岛尾巨桉速生人工林生态系统的C、N、P分配格局及化学计量特征。[方法]采用空间换时间的方法,选取雷州半岛4种不同林龄(1、3、5、7 a)的尾巨桉人工林为研究对象,对尾巨桉叶片、凋落物及土壤的C、N、P含量及化学计量特征进行测定分析。[结果]表明:C、N含量表现为叶片凋落物土壤,P含量表现为叶片土壤凋落物,且3个库间差异显著;土壤的C含量随林龄增加而增加,N、P含量差异不显著,土壤C∶N随林龄的增加而增加,说明土壤有机质分解速率逐渐下降;凋落物的C∶N为54. 07 92. 18 ( 25),表明尾巨桉林下凋落物分解速率较慢,N元素成为主要限制凋落物分解的元素,凋落物的C∶N随林龄的增加先增加后下降,凋落物分解速度先降低后升高;叶片的N∶P为10. 80 12. 98,说明中幼林龄尾巨桉受N限制较明显。相关性分析表明:凋落物养分元素含量受叶片限制,土壤养分含量受凋落物限制,表明生态系统内部C、N、P元素在植物、凋落物与土壤之间实现了运输和转换。[结论]雷州半岛尾巨桉中、幼林龄时期土壤有机质及凋落物分解速率较慢;随林龄的增加,土壤有机质、凋落物分解速率下降,N元素成为其主要分解限制性元素,林分生长受N限制明显。