Single and combined eff ects of fertilization,ectomycorrhizal inoculation,and drought on container-grown Japanese larch seedlings

Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus health,vigor,and success of transplantation seedlings used in the forestry by modifying fertilization and promoting mycorrhization.Here,we sowed seeds of Japanese larch(Larix kaempferi)in 0.2-L containers with 0.5 g(low fertilization;LF)or 2 g(high fertilization;HF)of slow-release fertilizer early in the growing season.One month later,we irrigated seedlings with non-sterilized ectomycorrhizal inoculum(ECM)or sterilized solution(non-ECM),and after about 2 months,plants were either kept well watered(WW;500 mL water/plant/week)or subjected to drought(DR;50 mL water per plant/week)until the end of the growing season.HF largely stimulated plant growth and above-and belowground biomass production,eff ects that are of practical signifi cance,but caused a small decrease in stomatal conductance(Gs 390)and transpiration rate(E 390),which in practice is insignifi cant.ECM treatment resulted in moderate inhibition of seedling growth and biomass and largely canceled out the enhancement of biomass and foliar K content by HF.DR caused a large decrease in CO 2 assimilation,and enhanced stomatal closure and induced senescence.DR also largely depleted foliar Mg and enriched foliar K.Although DR caused a large decrease in foliar P content in LF,it moderately increased P in HF.Likewise,DR increased foliar K in HF but not in LF,and decreased foliar P in ECM plants but not in non-ECM plants.Conversely,ECM plants exhibited a large enrichment in foliar P under WW and had a lower water potential under DR when grown in LF.These results indicate that the drought tolerance and health and vigor of Japanese larch seedlings can be modifi ed by soil fertility and soil microorganisms.This study provides a basis for new multifactorial research programs aimed at producing seedlings of superior quality for forestation under climate change.

Ectomycorrhizal diversity at five different tree species in forests of the Taunus Mountains in Central Germany

Ectomycorrhizal fungi were investigated on five different forest tree species growing in pure stands on the south slope of the Taunus Mountains, which are situated at the northern end of the Rhine rift valley in Central Germany. Mycorrhizal fungi accompanying the genus Xerocomus were identified and their frequencies counted. Using ITS markers, 22 different fungal species were identified down to species level and 6 down to genus level. On European beech (Fagus sylvatica) 16 fungal species and 4 genera were identified and on Sessile oak (Quercus petraea) 16 ectomycorrhizal species and 2 genera were determined. On both deciduous trees we observed exclusively: Cortinarius subsertipes, Genea hispidula, Lactarius quietus, Tylopilus felleus and a Melanogaster genus. On Norway spruce (Picea abies) we identified 13 different mycorrhizal species and 3 different genera, on Silver fir (Abies alba) 12 species and 3 genera, and in association with European larch (Larix decidua) 11 species and 3 genera. On these conifers Cortinarius anomalus, Lactarius necator and a Piloderma genus occurred exclusively. Comparisons with published data of ectomycorrhizal diversity on the same five tree species, growing in different areas of Germany and Europe, led to the conclusion that there is relative site specificity for ectomycorrhizal communities. Upper soil compartments of the stands investigated in the Taunus Mountainssuffer from soil acidification (pH-H20 ~3.7 to ~4.8). However, a clear correlation between upper soil pH-values and fungal diversity was not observed. On the other hand, nitrate concentrations in upper soil compartments (~26 to ~91 kgNO3-/ha) were higher in older stands as compared to younger ones. Higher nitrate concentrations in upper soils correlated with lower numbers of mycorrhizal individuals.

The full length <i>PtSRP</i>(<i>Pisolithus tinctorius</i>symbiosis related protein) fungal mRNA encodes a potential marker of ectomycorrhiza formation

The Pisolithus tinctorius symbiosis related protein expressed sequence tag (EST PtSRP) was previously identified in the first hours of the interaction between the fungus Pisolithus tinctorius and sweet chestnut Castanea sativa, and partially characterized as a fungal marker gene of ectomycorrhizal symbiosis formation. We used the 5’ rapid amplification of cDNA ends (RACE) to obtain the PtSRP mRNA 5’ region, and together with our previously reported 3’ mRNA region, the full mRNA sequence was assembled by use of bioinformatics tools and deposited to GenBank (Accession: GU733439). The full-length mRNA sequence (636 bp) revealed the locations of the 5’ and 3’ untranslated regions (UTRs) and contained the Kozak sequence (ccc aag ATG A) in the 5’ UTR. The in silico translated PtSRP open reading frame (ORF) codes for a 127 amino acid protein and contained four putative post-translational modification sites (two N-glycosylation and two phosphorylation). The protein secondary structure is postulated to be composed of one N-terminal hydrophobic transmembrane alpha helix and at least six hydrophilic beta-strands spread across the protein. Sub-cellular localization prediction suggests that the protein is involved in cellular secretory pathway, supported by the presence of a cleavage site motif close to the membrane anchor. The data presented herein indicate the role of PtSRP as a fungal membrane secreted protein involved in early stages of ectomycorrhizal formation, with application as a possible marker for nascent ectomy-corrhiza fungal development.

Horizontal distribution of ectomycorrhizal infection in Dipterocarpus turbinatus plantations of Bangladesh

Garjan （Dipterocarpus turbinatus Gaertn. F） is a highly ectomycorrhizal tree species growing in hilly areas of Bangladesh. The horizontal distributions ofectomycorrhizas （ECM） in different distances （1, 2, 3 ＆ 4m） from the tree base were determined in 5, 10 and 20-year-old D. turbinatus plantations of Chittagong University Campus （CUC） in 2003, The ECM infection （%） in roots was counted at three hill positions （top, mid and bottom） for each of the plantations. Samples of 1000 cm^3 rhizosphere soil were collected from underneath the trees at different horizontal distances. The percentage of infection at different distances and hill elevations varied considerably. In 5 and 10-year-old plantations, the occurrence of infection （%） was rapidly declined with increasing distances, while in 20-year-old plantation, the infection increased sharply with increasing distances from the tree base. The highest infection （81.33%） was found at 4 m distance from the tree at bottom hill in 20-year-old plantation and the lowest （55.33%） at the same distance at the top of the hill in 5-year-old plantation.

Ectomycorrhiza of Larix sibirica Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar Urals

Siberian larch(Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas(EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors(soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.

Growth of Shorea contorta Vid.Inoculated with Eucalypt Ectomycorrhizal Fungi in the Nursery and in a Logged-Over Dipterocarp Forest in Surigao,Philippines

This study was conducted to determine the compatibility of ectomycorrhizal (ECM) fungi associated with eucalypts on dipterocarps. Two nodal cuttings of Shorea contorta (Vid.) were rooted in a non-mist system for two months, and later inoculated with vegetative mycelia of three strains of Pisolithus collected under eucalypts and a strain of Scleroderma from dipterocarps. Inoculated rooted cuttings were planted in irradiated potting mix and raised in the nursery for five months. Root colonization prior to outplanting ranged from 31% to 38% and ECM fungi did not colonize the uninoculated ones. The cuttings were outplanted in a logged-over dipterocarp forest in Bislig, Surigao Sur following a Randomized Complete Block Design with four blocks;each block was planted with 50 seedlings. Two years after outplanting, Pisolithus strain from New Caledonia (H6394) promoted the highest height (46 cm) and diameter (0.48 cm) increment. Height was increased by 17% and diameter by 7% relative to the uninoculated control. By contrast, Pisolithus strain from the Philippines (H615) gave the shortest (26 cm) height increment and smallest (0.42 cm) diameter. Diameter growth of cuttings inoculated with Scleroderma D01 (from the Philippines) and a Pisolithus strain from Australia (H445) was bigger (0.47 cm) than the uninoculated treated cuttings (0.45 cm). In terms of survival, the uninoculated cuttings gave the highest (90%) percent survival while the lowest (60%) was those inoculated with Pisolithus strain from New Caledonia. It is possible that the indigenous ECM fungi infected easily the roots of the uninoculated cuttings thus contributing to the high survival rate (90%). During outplanting, fruit bodies of S. columnare were present in the field site. The results, however, show that ECM fungi were able to colonize the roots and that some strains promoted the growth and survival of S. contorta planted in a logged-over dipterocarp forest in Bislig, Surigao, Philippines.

Ectomycorrhizal fungi associated with Pinus gerardiana in Kinnaur district of Himachal Pradesh,India

Investigations on the diversity of ectomycorrhizal macrofungi associated with Pinus gerardiana in Kinnaur district of Himachal Pradesh revealed the associations of 22 ectomycorrhizal fungi belonging to 12 genera in 11 families.The dominant genus was Geastrum(4 species),followed by Russula and Suillus(3 species each);Boletus,Ramaria and Scleroderma(2 species each)and rest of the genera were represented by one species each.Among these,Scleroderma polyrhizum had the highest frequency of occurrence and was recorded in most of the sites.Maximum diversity was recorded beyond 2500m above mean sea level.Morpho-anatomical study of mycorrhizal roots revealed typical ectomycorrhizal association exhibiting well-developed mantle and hartig net.

Bio-Mobilization of Potassium from Clay Minerals: I. By Ectomycorrhizas

A pot experiment was carried out to investigate effect of ectomycorrhizal fungi on eucalyptus growth and K bio-mobilization from soils and clay minerals. In the experiment, sands mixed with soil, KCI-saturated vermiculate and mica, respectively, were used to nurse eucalyptus seedlings which were nonectomycorrhized or ectomycorrhized by an ectomycorrhizal fungus Pisolithus tinctorius strain XCI (Pt XC1) isolated from a forest soil from Xichang, Sichuan Province, China, and a worldwide well-known ectomycorrhizal fungus Pisolithus tinctorius strain 2144 (Pt 2144) obtained in Australia. More depletion of HCl-soluble K by mycorrhizas from the soil and minerals than nonmycorrhizas suggested that mycorrhizas had a great ability to mobilize K present in the interlayer and feldspar. Mycorrhizal seedlings depressed greatly K digested with HF-HCIO4 from substrates after consecutive extractions of soils and minerals by water, ammonium cetate and boiling HCl, while nonmycorrhizal seedlings reduced it little if any, showing that the mycorrhizal seedlings could mobilize and then utilize the structural K in mineral lattice. Ectomycorrhizal fungi played a very important role not only in promoting the growth of eucalyptus seedlings but also in mobilizing K in soils and minerals. The infection of Pt XC1 led to a better growth of eucalyptus seedlings and more K accumulation in the seedlings than that of Pt 2144. The large differences in K accumulation by the seedlings might be due to different abilities of the two ectomycorrhizal fungi to mobilize K in interlayer and lattice pools in the clay minerals.

Ectomycorrhizal and Saprotrophic Fungal Communities Vary Across mm-Scale Soil Microsites Differing in Phosphatase Activity

To understand nutrient cycling in soils, soil processes and microorganisms need be better characterized. To determine whether specific trophic groups of fungi are associated with soil enzyme activity, we used soil imprinting to guide mm-scale sampling from microsites with high and low phosphatase activities in birch/Douglas-fir stands. Study 1 involved sampling one root window per site at 12 sites of different ages(stands);study 2 was conducted at one of the stem-exclusion stands, at which 5 root windows had been installed. Total fungal and ectomycorrhizal(EM) fungal terminal-restriction fragment length polymorphism(TRFLP)fingerprints differed between high-and low-phosphatase activity microsites at 8 of 12 root windows across 12 sites. Where differences were detected, fewer EM fungi were detected in high-than low-phosphatase activity microsites. Using 5 root windows at one site,next-generation sequencing detected similar fungal communities across microsites, but the ratio of saprotrophic to EM fungal reads was higher in high-phosphatase activity microsites in the two windows that had low EM fungal richness. In windows with differences in fungal communities, both studies indicated that EM fungi were less successful than saprotrophic fungi in colonizing fine-scale,organic matter-rich microsites. Fine-scale sampling linked with in situ detection of enzyme activity revealed relationships between soil fungal communities and phosphatase activity that could not be observed at the scales employed by conventional approaches, thereby contributing to the understanding of fine-scale phosphorus cycling in forest soils.

Formation of Mycorrhiza-like Structures in Cultured Root/Callus of Cathaya argyrophylla Chun et Kuang Infected with the Ectomycorrhizal Fungus Cenococcum geophilum Fr.

An in vitro system was used for ectomycorrhizal synthesis of Cenococcum geophilum Fr. with Cathaya argyrophylla Chun et Kuang, an endangered species. Calli initiated from stem segments and adventitious roots differentiated from young seedlings were removed and cocultured with Cenococcum geophllum on a modified Murashlge-Skoog medium. Fungal hyphae were visible within intercellular spaces of the callus 4 weeks after inoculation, but definite and well-developed Hartig net structures did not form in the calU 8 weeks after inoculation. The typical ectomycorrhizal structures （i.e. hyphal mantle and Intracortical Hartig net） were observed in root segments 8 weeks after inoculation. This is the first report of aseptic ectomycorrhlzal-like formation/infection between root organ/callus of Cathaya argyrophylla and the ectomycorrhizal fungus Cenococcum geophflum. This culture system is useful for further investigation of mycorrhizal synthesis in Cathaya trees.

种植方式和菌根类型对吸收根性状的影响

[目的]通过分析种植方式对两种菌根类型树种吸收根性状的影响,揭示物种共存的适应条件。[方法]本研究选择8个树种(5个AM树种和3个EM树种)的单种和所有树种混种的样地,分析不同种植方式(单种vs混种)下两类型菌根(AM vs EM)树种吸收根(1~2级根)的主要形态性状(根直径、比根长、根组织密度、单根长)和构型性状(根分支强度、根分支比)及菌根侵染率的差异。[结果]菌根类型极显著影响吸收根的形态和构型性状(p<0.001),显著影响菌根侵染率(p<0.05);种植方式仅显著影响吸收根的组织密度和根构型性状(p<0.05);菌根类型和种植方式对所有性状均无交互影响(p>0.05)。AM树种根性状间的相关程度高于EM树种,混种大幅度降低AM树种根性状间的相关性。混种降低AM树种根形态性状的可塑性(比根长除外),增大其构型性状的可塑性;混种降低EM树种根组织密度的可塑性,增大根直径、构型性状及侵染率的可塑性。[结论]AM和EM树种的根形态和构型性状均有显著差异。混种对AM和EM树种根性状的可塑性有不同程度的影响,主要增大AM树种的分支强度,降低EM树种的根组织密度。可见,不同菌根树种可以通过调节不同根性状变化来实现物种共存。

中华网柄牛肝菌培养基组分优化及其对黑松菌根合成及内源激素的影响

该研究以中华网柄牛肝菌(Retiboletus sinensis)菌丝体干质量为响应值,采用Plackett-Burman试验、最陡爬坡试验及响应面试验对中华网柄牛肝菌的液体发酵培养基进行优化,并探究其对共生黑松(Pinus thunbergii)植物内源激素含量的影响。结果表明,中华网柄牛肝菌的最优培养基组分为:KH_(2)PO_(4)0.5 g/L,Mg SO_(4)·7H_(2)O 0.5 g/L,ZnSO_(4)3 g/L,酒石酸铵0.75 g/L,柠檬酸铁10 g/L,硫胺素50μg/L,酪蛋白水解物0.99 g/L,酵母浸粉1.35 g/L,葡萄糖18.2 g/L。在此优化条件下,中华网柄牛肝菌菌丝体干质量最大,为3.43 g/L。黑松经过接种中华网柄牛肝菌形成菌根后,菌根苗根部为二叉分支结构并且显微结构具有明显哈氏网。黑松菌根菌生长素吲哚-3-乙酸(IAA)、玉米素(ZT)及赤霉素(GA)含量分别提高33.0%、42.5%、102.0%,脱落酸(ABA)含量降低29.0%。

Influence of Ectomycorrhizal Fungi on Absorption and Balance of Essential Elements of Pinus tabulaeformis Seedlings in Saline Soil

Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xerocomus chrysenteron and Gomphidius viscidus) and two P treatments (with or without extra P). Growth and mineral nutrition of pine seedlings were stimulated by three EMF under salinity stress. Na concentrations were changed and plant K and P concentrations were increased significantly by EMF. Adding extra P made no difference in accumulation of seedlings biomass, and did not assist element absorption of plants. Although three strains of EMF can all enhance the tolerance of pine seedlings to salinity stress, they may utilize different mechanisms because of different performance in absorption of elements. The increased P and K accumulation and the balance of ion concentrations might be due to the enhanced tolerance of EMF-inoculated plants to saline conditions.

Application and Research Development of Ectomycorrhizae on Forest Disease Resistance

Ectomycorrhizae (ECM) is becoming the research hotspot because it can improve plant nutrientcycling and storage and strengthen plant resistance to adversity and disease. It is well known that ECMcan enhance plant resistance to soil-borne and stem diseases. The mechanisms mainly include: plant tenderroots will be protected well by sheath; ECM can facilitate uptake and transport capacity of nutrition andwater to roots and increase plants vigor; ECM can control or block pathogens to invade trees; ECM canactivate resistance-related enzymes of the hosts; it also can form rhizosphere microbial colony and establishroot-rhizosphere micro-ecological environment. So mycorrhizal technology has become one of the mostimportant methods of ecological control and biological control of plant diseases. This paper summarizesthe application and development of ECM in forest disease control and also raises some ideas on theirtheory and application researches in the future.

A test of the mycorrhizal-associated nutrient economy framework in two types of tropical rainforests under nutrient enrichments

Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), and tested it using nutrient addition experiments conducted in two tropical rainforests. We selected two tropical rainforests dominated by arbuscular mycorrhizal(AM) and ectomycorrhizal(ECM) trees, and established eighteen20 m×20 m plots in each rainforest. Six nitrogen(N) and phosphorus(P) addition treatments were randomly distributed in each rainforest with three replicates. We examined the differences in soil carbon(C) and nutrient cycling, plant and litter productivity between the two rainforests and their responses to 10-year inorganic N and P additions. We also quantified the P pools of plants, roots, litter, soil and microbes in the two rainforests. Overall,distinct MANE frameworks were applicable for tropical rainforests, in which soil C, N and P were cycled primarily in an inorganic form in the AM-dominated rainforest, whereas they were cycled in an organic form in the ECMdominated rainforest. Notably, the effects of mycorrhizal types on soil P cycling were stronger than those on C and N cycling. The intensified N and P deposition benefited the growth of AM-dominated rainforests instead of ECMdominated rainforests. Our findings underpin the key role of mycorrhizal types in regulating biogeochemical processes, and have important implications for predicting the ecological consequences of global changes.

模拟氮沉降和接种外生菌根真菌对马尾松(Pinus massoniana)幼苗营养元素的影响

量化植物地上部和地下部元素含量对于理解和预测植物养分平衡如何响应大气氮沉降的变化至关重要。通过盆栽试验研究了氮沉降增加背景下外生菌根真菌对马尾松幼苗营养元素的影响。对马尾松幼苗进行了接种两种外生菌根真菌:(彩色豆马勃(Pisolithus tinctorius,Pt)与厚环乳牛肝菌(Suillus grevillei,Sg))以及4种氮素浓度添加:0 kg N hm^(-2)a^(-1)(N0)、正常氮沉降30 kg N hm^(-2)a^(-1)(N30)、中度氮沉降60 kg N hm^(-2)a^(-1)(N60)、重度氮沉降90 kg N hm^(-2)a^(-1)(N90),共12个处理,测定了马尾松地上部和地下部大量元素和微量元素的含量。结果表明:施氮改变了营养元素在马尾松幼苗地上部和地下部的含量,马尾松幼苗磷(P)、钙(Ca)、铁(Fe)、锰(Mn)等元素均在N60时达到临界值,而当输入的量超过了马尾松对氮的需求时,氮沉降会使马尾松营养元素含量较最适浓度时降低,地上部碳(C)随施氮浓度的升高先升高后降低,N随施氮浓度的升高而升高,根系和叶片钾(K)、Ca、镁(Mg)均随施氮浓度的升高而降低,施氮也降低了根系C及微量元素的含量。但在同一施氮浓度下,接种外生菌根真菌(EMF)后能够提高大多数元素的含量,N90时接种厚环乳牛肝菌(Sg)和彩色豆马勃(Pt)的叶片N含量与对照相比分别提高112.6%和138.6%,根系N含量分别提高73.1%、71.6%;N60时接种Sg和Pt的植株叶片P含量比不施氮未接种对照分别提高了166.3%、132.9%,根系P含量分别提高了40.8%、38.5%。EMF能够维持植物养分平衡,从而降低高施氮量对植物的影响效果。这为未来气候变化情景中氮沉降增加下接种EMF可以调节植物元素含量,从而达到更适应环境的元素平衡来促进生长提供理论依据。

不同优势菌根类型转变对土壤团聚体组成及性状的影响

【目的】马尾松Pinus massoniana林向阔叶林转变驱动优势菌根类型由外生菌根(ectomycorrhiza,ECM)转向丛枝菌根(arbuscular mycorrhiza,AM)。不同类型菌根由于其菌丝生物量和分泌物的不同,对土壤团聚体的影响可能存在差异,研究优势菌根类型转变对土壤团聚体组成的影响具有重要的生态学意义。【方法】通过野外调查采样,分析了不同优势菌根类型林分土壤不同粒级团聚体的占比及碳氮质量分数、菌根真菌生物量和胞外酶活性等。【结果】与ECM占优势的马尾松林相比,AM占优势的阔叶林在土壤团聚体的组成、稳定性及碳氮质量分数上存在显著差异,大团聚体(直径d>250μm)比例和平均质量直径显著升高(P<0.05),而粉黏粒(d<53μm)占比显著降低(P<0.05)。此外,大团聚体碳氮比显著降低(P<0.05),所有粒级团聚体中β-葡萄糖苷酶活性与β-N-乙酰氨基葡萄糖苷酶活性均显著降低(P<0.05)。大团聚体中易提取态球囊霉素相关土壤蛋白和总球囊霉素相关土壤蛋白趋于升高,微团聚体(d为53~250μm)和粉黏粒中易提取态球囊霉素相关土壤蛋白、总球囊霉素相关土壤蛋白和麦角固醇质量分数则显著降低(P<0.05)。随机森林结果显示:团聚体有机碳质量分数主要与易提取态球囊霉素相关土壤蛋白、总球囊霉素相关土壤蛋白、ECM生物量和酶活性的变化有关(P<0.05)。【结论】在ECM占优势的马尾松林转变为AM占优势的阔叶林的过程中,土壤团聚体的稳定性显著升高,菌根生物量是团聚体有机碳质量分数变异的重要影响因子。

不同菌根类型植物生物量分配对干旱的响应

基于干旱对全球植物生物量分配影响的数据库,选择丛枝菌根(AM)、外生菌根(ECM)和二者兼生型菌根(AM+ECM)3种最常见的菌根类型,研究3种菌根类型植物应对干旱时各器官生物量分配的变化,采用一般线性模型模拟分析器官间的相对生长速率,探索不同菌根类型植物生物量分配对干旱的响应。结果表明:在干旱条件下,AM和AM+ECM植物根系生物量(M_(R))的分配率分别增加了8.2%和7.6%,而ECM植物对M_(R)的分配则无显著变化;干旱导致AM植物茎生物量(M_(S))分配率降低了7.7%,ECM和AM+ECM植物对M_(S)的分配则无显著变化;干旱使得AM+ECM植物和ECM植物叶生物量(M_(L))的分配率分别下降了9.4%和6.5%,AM植物M_(L)则无显著变化;不同菌根类型植物遭受干旱时,AM和AM+ECM植物根、茎、叶的生物量积累速率依次降低,ECM植物茎、叶、根的生物量积累速率依次降低;不同菌根类型植物对干旱响应的策略不同,AM植物通过降低茎和生殖器官的生物量分配来提高对根的生物量分配;AM+ECM植物则更倾向于通过降低叶片生物量的分配来增加对根系的分配;ECM植物则仅仅是降低了叶片的生物量,根和茎生物量无显著变化。在考虑植物对干旱响应策略时,菌根应是重要的考虑因素。

不同外生菌根真菌对紫椴幼苗的促生作用

紫椴(Tilia amurensis)是著名的蜜源树种,也是国家二级保护植物.选取土生空团菌(Cenococcum geophilum)、厚环乳牛肝菌(Suillus grevillei)和米黄丝膜菌(Cortinarius multiformis)3种外生菌根真菌,通过单一和组合接种,探究不同接种处理对紫椴幼苗的促生效应.结果表明,3种真菌及其组合均能与紫椴幼苗根系形成外生菌根,其中接种土生空团菌和厚环乳牛肝菌组合的紫椴幼苗株高、地径、地上部分生物量和地下部分生物量与对照组相比分别增加了60.9%,83.3%,38.9%,31.1%.接种土生空团菌和厚环乳牛肝菌组合的幼苗氮和磷质量浓度显著高于其他处理,接种厚环乳牛肝菌的幼苗钾质量浓度显著高于其他处理.接种土生空团菌和厚环乳牛肝菌组合提升幼苗根系活力效果最明显,相比对照组提高了118.6%.

甘肃太子山林区红桦和落叶松外生菌根真菌多样性研究

为了明确甘肃太子山林区红桦和落叶松外生菌根真菌多样性,选取分子生物学方法开展红桦和落叶松外生菌根真菌多样性的研究。研究结果表明,甘肃太子山林区红桦外生菌根真菌重要值排名前五的分别为青霉、拟青霉、毛霉、犁头霉以及毛壳菌;甘肃太子山林区红桦外生菌根真菌重要值排名前五的分别为青霉、茎点霉、轮枝孢、犁头霉以及指轮枝孢。甘肃太子山林区的幼龄以及阳坡的红桦和落叶松树种,更容易被外生菌根侵染,真菌多样性更高。红桦外生菌根真菌多样性高于落叶松外生菌根真菌多样性,树龄和坡向对红桦和落叶松外生菌根真菌多样性影响明显。研究结果可为甘肃太子山林区人工造林提供理论指导。