Pisolithus tinctorius increases the size of nursery grown red oak seedlings

Inoculation of nursery beds with vegetative mycelia of P. tinctorius (Pt) significantly increased the number of salable 1–0 red oak seedlings produced in two of three years and the average stem height and diameter each year. The percentage of Pt mycorrhizal primary lateral roots on seedlings in the inoculated plots was significantly correlated with stem diameter and weight of lateral roots. The high rates of colonization of short roots by Pt in inoculated plots suggested the test fungus could successfully compete with indigenous fungi in forming mycorrhizae.     

Field survival of containerized red and jack pine seedlings inoculated with mycelial slurries of ectomycorrhizal fungi

Red pine and jack pine seedlings growing in styroblocks were inoculated 8 wk after sowing with mycelium/agar slurries of 3 mycorrhizal fungi (Laccaria bicolor, Scleroderma citrinum, and an unidentified basidiomycete), and one suspected mycorrhizal fungus (Cantharellula umbonata). Seedlings inoculated with L. bicolor developed mycorrhizae earlier and in greater numbers than the other inoculation treatments, with red pine out-performing jack pine in both respects. At 34 wk following sowing, seedlings were outplanted on a cleared xeric site in Baraga Co., in Michigan's Upper Peninsula. Seedlings inoculated with C. umbonata failed to form mycorrhizae and were not outplanted. Inoculation treatments did not affect shoot or root weight at outplanting. Red pine inoculated with L. bicolor averaged 21% and 19% greater survival compared with control seedlings after one and two years in the field, respectively. Other inoculation treatments failed to increase seedling survival for either tree species. Jack pine demonstrated higher overall survival than did red pine for both years in all corresponding inoculation treatments.     

Interactions between Tricholomopsis rutilans and ectomycorrhizal fungi in paired culture and in association with seedlings of lodgepole pine and Sitka‐spruce

Interactions between two isolates (Avondhu and CBS) of Tricholomopsis rutilans and ectomycorrhizal fungi (Hebeloma crustuliniforme, Laccaria laccata and Paxillus involutus) were examined on agar medium in the presence or absence of woodchips. The CBS isolate showed more competitiveness than the Avondhu isolate, when paired with ectomycorrhizal fungi. There was an inhibition of the growth of mycelium of the ectomycorrhizal fungi ranging from overgrowth to avoidance. The ectomycorrhizal fungi exhibited hyphal abnormalities such as discoloration, excessive vacuolation and curling. Formation of mycorrhizas by H. crustuliniforme in Pinus contorta and Picea abies was unaffected by the presence of the CBS isolate, whereas a reduction occurred in the presence of the Avondhu isolate. In non‐mycorrhizal seedlings of both conifers, the Avondhu isolate reduced root and shoot dry mass and number of root laterals and caused a lower number of short roots in lodgepole pine. The significance of these interactions between T. rutilans and ectomycorrhizal fungi in paired culture and during symbiosis is discussed.     

板栗接种食用菌根真菌的菌根化效果及对幼苗促生效应的研究

[目的]通过板栗幼苗人工接种食用菌根菌固体菌剂,分析其对板栗幼苗生长指标和根系菌根化的效果,以验证大红菇(菌株编号2014-10)、红绒盖牛肝菌(菌株编号2014-14)和美味牛肝菌(菌株编号50559)这3种食用菌根菌固体菌剂作为板栗接种体的有效性及其促生效应,为进一步探索"板栗食用菌根菌新型经济林栽培模式"提供基础。[方法]在板栗播种时分别接种上述3种食用菌根菌固体菌剂,并设空白作对照。对当年生幼苗苗高、地径、根系干质量、侧根数、侧根总长、幼苗侵染率、吸收根侵染率等指标进行调查和分析,并制作菌根石蜡切片进行微观结构观察。[结果]表明:(1)上述3种食用菌根菌在人工接种下均能侵染板栗幼苗根系,平均幼苗菌根化率分别达95.8%、87.0%和96.7%,平均吸收根菌根化率分别达57%、53%和50%,达较高的侵染强度;经微观观察,板栗幼苗根系均形成典型的菌根结构——菌丝套和哈蒂氏网。(2)与对照幼苗相比,3个菌种处理幼苗的平均苗高分别提高32.5%、24.0%和22.7%,平均地径分别提高19.4%、14.1%和5.0%,差异显著(P0.05);平均根系干质量分别提高18.9%、25.3%和14.1%,平均侧根数分别提高16.0%、14.1%和12.1%,平均侧根总长分别提高26.8%、28.9%和44.8%,差异极显著(P0.01)。[结论](1)上述供试食用菌根菌均与板栗根系建立了共生关系,幼苗菌根化效果良好,吸收根菌根化强度高,形成了菌根的典型结构,即菌丝套和哈蒂氏网,验证了上述菌种固体菌剂的有效性,认为其可以作为板栗食用菌根菌栽培的接种体而用于生产实践,为探索"板栗食用菌根菌新型经济林栽培模式"提供了基础。(2)上述供试菌种接种后,对板栗幼苗各项主要生长指标均有不同程度的促进作用,说明上述食用菌根菌对板栗幼苗具有显著的促生效应。     

Effect of electric impulse on sporocarp formation of ectomycorrhizal fungusLaccaria laccata in Japanese red pine plantation

We examined the effect of electric impulses on sporocarp formations of ectomycorrhizal fungus in a Japanese red pine (Pinus densiflora) plantation.Laccaria laccata was the dominant species in this study plantation. Spatial distribution concentrated in the electric impulse treatment zone, and recorded a markedly larger number of sporocarps compared with untreated control plots. The effect of electric impulses was also recognized onL. laccata fruiting with a mycorrhizal sapling in a pot. Sporocarp production ofL. laccata was strongly promoted by the electric impulse in experiments bothin vivo natural plantation stands andin vitro pot saplings. Our work indicates the possibility of enhancement of sporocarp production of the mycorrhizal fungi with electric impulses in the nursery and plantation. This work was partly supported by a grant from the Kyushu Electric Power Company.     

In vitro effects of four ectomycorrhizal fungi, Boletus edulis, Rhizopogon roseolus, Laccaria laccata and Lactarius deliciosus on Fusarium damping off in Pinus nigra seedlings

Species of Fusarium cause damping off of forest seedlings resulting in considerable losses and oftentimes fungicides are used to control the disease. Such chemicals may be detrimental to the environment. Protection of forest seedlings against this disease must be focused on integrated management for in which biological control is one of the most important tools. Mycorrhizal fungi may provide protection against pathogen invasion of seedlings. In this study, the interactions between the mycorrhizal fungi Boletus edulis, Rhizopogon roseolus, Laccaria laccata and Lactarius deliciosus and damping off pathogens (Fusarium oxysporum and F. moniliforme) were investigated in vitro and mechanisms involved in the protection of damping off in P. nigra seedlings are also discussed. The effect of filtrates from mycorrhizal species on spore germination of F. oxysporum varied throughout the tests. At the end of the assay, the inhibitory effect only could be observed in the L.␣deliciosus treatment. None of the filtrates reduced spore germination in F. moniliforme. Finally, three of the four mycorrhizal species grown for 2 months in the substrate, L. laccata, L.␣deliciosus and B. edulis, increased the survival of Fusarium inoculated P.␣nigra seedlings.     

Selection of efficient VA mycorrhizal fungi for Casuarina equisetifolia—second screening

An investigation was carried out to screen and select efficient vesicular arbuscular mycorrhizal (VAM) fungi for inoculating the forest tree species, Casuarina equisetifolia. The seedlings were inoculated with 10 different VAM fungi, obtained from various sources. Inoculated seedlings generally had greater plant height, stem girth, biomass and P content than uninoculated plants. They also had more mycorrhizal root colonization and spore numbers in root zone soil. C. equisetifolia seedlings responded best (in biomass) to inoculation with Glomus mosseae (Nicolson and Gerdemann) Gerdemann and Trappe, closely followed by Acaulospora laevis Gerdemann and Trappe and G. fasciculatum (Thaxter Sensu Gerdemann) Gerdemann and Trappe; all the three being statistically on par with each other.     

Effect of an ectomycorrhizal fungus,Laccaria laccata,on Fusarium damping-off in Pinus banksiana seedlings

Damping-off caused by Fusarium oxysporum Schlecht in Pinus banksiana Lamb, was reduced significantly when inoculated with an ectomycorrhizal fungus, Laccaria laccata (Scop. ex Fr.) Berk. and Br. In paired culture, growth of F. oxysporum was significantly reduced by L. laccata. The number of colony forming units of F. oxysporum was reduced significantly in the rhizosphere of P. banksiana seedlings when inoculated with L. laccata. Spore germination and germ tube length of F. oxysporum was inhibited strongly by culture filtrate of L. laccata and root exudate of P. banksiana inoculated with L. laccata. Mycorrhizal seedlings had significantly higher amount of total soluble phenols than nonmycorrhizal ones.     

Seed source and vesicular-arbuscular mycorrhizal symbiont affects growth of Juglans nigra seedlings

Seedlings of Juglans nigra from three seed sources were grown in fumigated soil without vesicular-arbuscular mycorrhizal (VAM) fungi or inoculated with Gigaspora margarita, Glomus deserticola or Glomus etunicatum. Vesicular-arbuscular mycorrhizal development varied significantly between fungal symbionts within a black walnut source. Glomus deserticola and G. etunicatum produced the highest levels of root colonization in all sources. Significant differences in seedling shoot and root growth were attributed to root colonization by specific VAM fungi in each black walnut source. Glomus deserticola stimulated seedling leaf area and root weight 26 and 52%, respectively, in one seed source. Seedling leaf N, P and K concentrations were significantly improved by VAM in two seed sources. Juglans nigra seedlings respond favorably to VAM colonization. However, differences between seed sources suggest a strong host-symbiont interaction.     

Growth stimulation of young oak plantations inoculated with the ectomycorrhizal fungus Paxillus involutus with special reference to summer drought

Nursery-grown Quercus petraea and Q. robur seedlings were inoculated with the ectomycorrhizal fungi Paxillus involutus, Hebeloma crustuliniforme or Laccaria laccata. At the end of the first growing season, the seedlings with roots colonized with the inoculated fungi were outplanted at two sites in northeastern France in 1985 or 1988. P. involutus was found to be the most competitive and efficient of the three fungi tested; its mycorrhizas were present 7 yrs after outplanting and it markedly improved the growth of both oak species. In the case of Q. robur, the growth stimulation was more marked on years with a dry summer. These results are discussed in terms of water relations and of competitiveness of the introduced versus resident symbiotic fungi.     

Growth, nitrogen fixation and mineral acquisition of Alnus sieboldiana after inoculation of Frankia together with Gigaspora margarita and Pseudomonas putida

The role of tetrapartite associations among Frankia, Gigaspora margarita (an arbuscular mycorrhizal fungus), Pseudomonas putida (rhizobacterium), and Alnus sieboldiana in growth, nitrogen fixation, and mineral acquisition of A. sieboldiana was investigated. Seedlings of A. sieboldiana were inoculated with Frankia isolated from root nodules of alder, followed by inoculation of G. margarita and P. putida, and were grown for 5 months in a greenhouse. The seedlings inoculated with Frankia and G. margarita together produced the highest biomass of shoots and root nodules. Nitrogen-fixation activity, measured by acetylene reduction assay, was observed when Frankia was inoculated. The activity, on a per-nodule gram basis, decreased after G. margarita inoculation, but on a per-plant basis there was no significant difference in the activity among inoculation treatments. The mineral content in the seedlings changed after inoculation with Frankia, but not after inoculation with P. putida and/or G. margarita. The results showed a synergistic interaction among Frankia, the mycorrhizal fungus, and the rhizobacterium on the growth of A. sieboldiana.     

Colonization of Pedunculate oak by the Burgundy truffle fungus is greater with natural than with pelletized lime

European black truffles can be profitable agroforestry crops outside their native ranges. Truffle fungi grow symbiotically as ectomycorrhizae on the roots of host trees, notably hazels and oaks. Conditions in the central USA appear conducive to cultivation of the Burgundy truffle (Tuber aestivum Vitt. syn. T. uncinatum Chatin), but research is needed to determine effects of management practices on truffle establishment and fruiting. In a greenhouse study we tested the effect of lime type, inoculation technique, and two truffle sources on Pedunculate oak (Quercus robur L.) growth and mycorrhizal colonization. We found that the type of lime used to raise potting mix pH can differentially affect the growth rate of root systems inoculated with different selections of Burgundy truffle inoculum. Seedlings inoculated with one selection of the truffle and grown in potting mixes amended with natural crushed dolomitic limestone developed larger root systems with more truffle mycorrhizae compared with potting mix amended with high-calcium pelletized quick-release lime. Seedlings inoculated with a second truffle selection were not affected by lime source and developed root systems as large as those developed with the first truffle source grown with natural lime. Supplemental root dip inoculation did not improve levels of colonization beyond those accomplished by potting mix infestation with truffle ascospores. Use of a hygroscopic polymer to maintain ascospore suspension in the inoculum slurry used to infest the potting mix had no effect on root system development or mycorrhiza formation.     

蓝桉和尾叶桉混合菌根研究 Ⅱ.混合菌根的接种效应

接种苗木在生长量和生物量上均表现出极其显著的生长优势,ＥＣＭ真菌蜡蘑菌单接种及其与４种ＶＡ菌根菌剂混合接种,对苗木生长的促进作用尤为显著。在接种后１６周时,与对照苗相比,蓝桉和尾叶桉接种苗木的高生长量最大增幅分别为２８．８６％（ＬＳ）和８６．６５％（ＬＧ）;两种桉树地上部分平均干质量最大增幅分别为１２９．９３％（ＬＳ）和１３３．３４％（Ｌ）,地下部分分别为１１９．９３％（ＬＦ）和１７４．８３％（Ｌ     

Inoculation effects ofSuillus grevillei on Larch seedlings

A large areas of Larch seedlings, including container and bare-root seedlings (new and transplanted seedlings) were inoculated pure inocula that were cultivated by usingSuillus grevillei. Compared with those of control area, all growth indices as rate of emergence, growth(in seedling height, collar diameter and number of lateral branch-root), rate of mycorrhiza inoculum, rate of survival and content of nutrient elements were greatly increased. Therefore,Suillus grevillei is a better and suitable mycorrhizal fungus to larch seedling either in the severe cold mountain area or in the plain region. It should be spread and used in larch cultivation and planting.     

Economically profitable post fire restoration with black truffle (Tuber melanosporum) producing plantations

Cultivating black truffle (Tuber melanosporum Vittad.) is highly profitable in sites suitable for its development. Land use history is an important factor when choosing suitable habitat, and lands with non-ectomycorrhizal host species are recommended when introducing T. melanosporum-inoculated seedlings in order to reduce competition from native, soil-borne ectomycorrhizal (ECM) inoculum. Nearly every year Mediterranean wildfires cause the loss of forested lands where soil and climatic characteristics are suitable for truffle cultivation. Introducing T. melanosporum-inoculated seedlings in these sites could promote reforestation with a native ECM fungus and, in addition, may provide economic incentives. We tested the viability of burnt forest lands for truffle cultivation by introducing T. melanosporum-inoculated Quercus ilex seedlings in burnt forest sites with and without resprouting forest species which act as repositories for native ECM fungi. We also evaluated the role of the ECM host plants, which resprout after a forest fire, in the maintenance and dynamic processes of the ECM fungal community. The study followed a factorial design with two levels: (1) T. melanosporum-inoculated and non-inoculated Q. ilex seedlings and (2) presence and absence of ECM host plants resprouting after the fire. We established 10 experimental plots with 360 holm oaks. After four and a half years, the truffle-inoculated holm oaks maintained 36?% of their root tips colonized with T. melanosporum, and 10?years after plantations, 26.2?% of the surviving inoculated holm oaks displayed a “truffle burn” area. A greater ECM morphotype richness was associated with seedlings planted in plots with the presence of ECM host plants, whereas the T. melanosporum mycorrhizal ratio was constant. These results suggest that reforestation with T. melanosporum-inoculated seedlings can be successful following forest fires and highlights the competitiveness of this fungus within the ECM community in these soils.     

Growth and Mycorrhizal Dependency of Acacia mangium Willd. Inoculated with Three Vesicular Arbuscular Mycorrhizal Fungi in Lateritic Soil

Three VA-mycorrhizal fungi; Glomus occultum, Glomus aggregatum (local isolates) and G. mosseae (strain from Bangalore, India) were inoculated to assess their effect on growth of Acacia mangium in lateritic soil. All inoculations enhanced growth with respect to shoot height, root diameter, leaf area, chlorophyll content and biomass of A. mangium significantly compared to uninoculated control seedlings. G. occultum proved most efficient among the three. The mycorrhizal dependency factor indicated that the growth of A. mangium was 57% dependent on G. occultum, 47% on G. mosseae and 46% on Glomus aggregatum.     

A method for observing and manipulating roots and root associated fungi on plants growing in nonsterile substrates

Standard 14‐cm plastic‐petri dishes were used as root substrate chambers allowing controlled inoculation, regular inspection under the dissecting microscope, and manipulation of root infections with pathogens and mycorrhizal fungi under nonsterile conditions. Roots of young pine seedlings were placed on the root substrate and, especially those growing on the substrate surface under the lid, were very easy to manipulate. Mycorrhizal species and inoculation methods were compared and the infection process followed continuously under various conditions. The air pockets formed between the lid and the substrate favoured mycorrhiza formation. Brief, periodic flooding prevented formation of mycorrhizas in two mycorrhizal species having hydrophobic hyphae but did not prevent it in less hydrophobic species. IAA treatment of roots led to heavy production of mycorrhizas. Fruiting body formation in Lacearia laccata was induced and followed in the dish cultures. Pure mycorrhizal stock cultures were able to be revitalized in the dish cultures and reisolated in pure culture. The infection strategy of a weak root pathogen, Cylindrocarpon destructans, was studied with the same technique, which was also used for investigating treatments predisposing seedlings to pathogen infection.     

Effect of inoculation with ecto- and arbuscular mycorrhizae and Rhizobium on the growth and nitrogen fixation by black locust,Robinia pseudoacacia

Experiments were made to determine the effect of inoculation withRhizobium, the ectomycorrhizal fungus Hebelomamesophasem and the arbuscular mycorrhizal fungus Glomuscaledonium on the growth and nitrogen fixation of black locust(Robinia pseudoacacia Linn.) seedlings grown invitro and in pot culture. The results showed that both mycorrhizalfungi and Rhizobium stimulated the growth and nitrogenfixing ability of inoculated seedlings. Inoculation with all three microbestogether produced the most beneficial effects on nitrogen fixation, mycorrhizaldevelopment and seedling growth.     

Application of mycorrhizal roots improves growth of tropical tree seedlings in the nursery: a step towards reforestation with native species in the Andes of Ecuador

Most tree species in tropical mountain rain forests are naturally associated with arbuscular mycorrhizal fungi. Previous studies in southern Ecuador of 115 tree species revealed that only three species were not associated with arbuscular mycorrhizal fungi. Seedlings of tropical tree species raised in the nursery may need to be associated with arbuscular mycorrhizal fungi to survive transplantation shock in higher numbers. Methods for establishing plantations with native tree species are not yet established for Ecuador. Thus, we investigated the feasibility of using mycorrhizal roots of seedlings of Inga acreana, Tabebuia chrysantha, Cedrela montana and Heliocarpus americanus that had trapped mycorrhizal fungi from forest humus in the nursery to inoculate C. montana and H. americanus with native arbuscular mycorrhizal fungi. Inoculation with either a mixture of mycorrhizal roots from the four species or only with mycorrhizal roots from the same tree species were compared with effects of moderate fertilization. Assessment of plant growth and mycorrhizal status of 6-months-old Cedrela montana and Heliocarpus americanus revealed an improvement in growth and diverse associated fungi through mycorrhizal root inoculation in comparison with moderate fertilization. Moderate fertilization did not suppress mycorrhization.     

Pisolithus tinctorius fails to improve plantation performance of inoculated conifers in southwestern Oregon

Bare-root stock of Douglas-fir, lodgepole pine, white fir, and grand fir, inoculated with Pisolithus tinctorius and handled by standard nursery, cold storage and planting practices performed no better than stock which was not intentionally inoculated but which had formed mycorrhizae with indigenous, nursery fungi on a variety of different outplanting sites in southwestern Oregon. Climate, planting sites and nursery practices in the Pacific Northwest differ drastically from those in the southeastern United States, where P. tinctorius has increased plantation survival and growth. Before P. tinctorius can be recommended for nursery inoculation in the Pacific Northwest, its reaction to each phase of the nursery and planting process needs to be carefully analyzed to determine where the problems lie.This article was written and prepared by US Government employees on official time, and is therefore in the public domain.