Ectomyeorrhiza formation in Eucalyptus. V. A tuberculate ectomycorrhiza of Eucalyptus pilularis

The structure of mature tubercles collected from a Eucalyptus pilularis forest in Queensland, Australia, is described. The smooth, pale yellow tubercles (5‐20 mm diam.) consisted of a rind (200‐250 μm thick) enclosing a dense coralloid mass of ectornycorrhizas (150‐300 μm diam.) and rhizomorphs (200‐300 μm diam.). The outer rind region was cemented together with an interhyphal matrix of carbohydrate containing embedded lipid deposits. Dolipores were common in the inner rind indicating the fungal component to be a basidiomycete. Mycorrhizas had thin mantles and well‐formed Hartig nets. Protein and lipid reserves were present in mantle hyphae. Rhizomorphs formed around non‐mycorrhizal roots inside the tubercles. The central zone of rhizomorph tissue contained thick‐walled hyphae which stained positively for lignin‐like material. The tubercles are similar to structures formed in associations between Rhizopogon and conifers in the northern hemisphere

Ectomycorrhiza formation in Eucalyptus.. IV. Ectomycorrhizas in the sporocarps of the hypogeous fungi Mesophellia and Castorium in Eucalypt forests of Western Australia

Mesophellia and Castorium are common hypogeous macrofungi in the karri (Eucalyptus diversicolor F. Muell.) and jarrah (Eucalyptus marginata Donn ex Sm.) forests of south‐western Australia. Sporocarps of Mesophellia and Castorium develop 5‐20 cm below the soil surface in close association with eucalypt roots. During differentiation of the sporocarps, eucalypt roots become trapped within the peridium where they branch profusely and form a dense ectomycorrhizal layer. Mature sporocarps of M. trabalis nom. ined. contain approximately S m of roots of 45 cm2 surface area. Anatomical studies have shown that these roots have Hartig nets penetrating to the hypodermis and are similar to the superficial eucalypt ectomycorrhizas formed in soil and litter. The association of Mesophellia and Castorium sporocarps with tree roots suggests that these are important mycorrhizal fungi in forests of southern Australia

Nutrient disorders in plantation eucalypts

Summary. The purpose of this manual is to illustrate the symptoms associated with essential nutrient deficiencies of those species of eucalypts which are now widely established in plantations. The manual focuses on three tropical/subtropical species (Eucalyptus grandis, E. pellita and E. urophylla) and one temperate species (E. globulus). Other plantation species are included where illustrations were available. Techniques for identifying nutritional disorders are explained and deficiency symptoms are described in detail for twelve elements. These symptoms can be used to help determine deficiencies in nurseries or young plantations. However, symptoms are a guide to nutrient deficiencies and should be used with other diagnostic tools. For this reason leaf analysis standards are included

Ectomycorrhizal formation by micropropagated clones of Eucalyptus marginata inoculated with isolates of Pisolithus tinctorius

Eucalyptus marginata Donn ex Sm. and Pisolithus tinctorius (Pers.) Cok and Couch were co-cultured to obtain ectomycorrhizal formation in vitro. One isolate of P. tinctorius formed mycorrhizas with aseptic seedlings of a juvenile clone derived from a 4-month-old seedling, and four clones derived from crowns of mature trees. A second P. tinctorius isolate formed mycorrhizas with only the clones from mature trees. Successful combinations resulted in formation of a mantle followed by a Hartig net and epidermal cell elongation. The fungal/seedlings or fungal/seedling clone combinations which did not produce ectomycorrhizal roots, were characterized by a mantle but lacked a Hartig net, and formed an abundance of polyphenols throughout the root. Genotype, maturity and fungal specificity are key factors influencing successful ectomycorrhizal formation on E. marginata by P. tinctorius in vitro

Field performance of Eucalyptus urophylla inoculated with an introduced and idigenous strains of Pisolithus at three sites in the Philippines

The effectiveness of an isolate of Pisolithus from Australia was compared with a Philippine Pisolithus isolate in promoting the growth of Eucalyptus urophylla on three acid (pH 4.1-5.9, 0.005M CaCl2) sites in the Philippines (Pangasinan, Bukidnon and Surigao). Isolates of Pisolithus were taken from basidiocarps collected under eucalypts growing in Western Australia and from the Philippines. Generally, the introduced Pisolithus promoted greater wood volume of E. urophylla planted in dry marginal land (Pangasinan) and in moist logged-over area (Surigao) in the Philippines than the Philippine Pisolithus isolate. Root colonization by the two fungi did not vary but there was a difference in the root colonization levels between sites implying that the prevailing microclimatic conditions on each site had affected the performance of the ECM inoculants. In this study, the number of isolates tested was limited, thus, future field trials should include a wider range of ectomycorrhizal fungi. Further work is required to determine whether the growth responses measured at the two sites (Pangasinan and Surigao) are maintained until the trees are harvested

Mycorrhization of fagaceae forests within mediterranean ecosystems

Mediterranean Fagaceae forests are valuable due to their ecological and socioeconomic aspects. Some profitable plant species, such as Castanea (timber and chestnut), Quercus (timber and cork), and Fagus (timber), encounter in this habitat the excellent edaphoclimatic conditions to develop. All Fagaceae plants are commonly associated to ECM fungal species, which are found in these forests in quite stable communities, mainly enriched in Russulaceae and Telephoraceae species. Currently, the Mediterranean Basin is considered as one of the global biodiversity hotspots, since many of their endemic plant species are not found elsewhere and are now under threat. Due to climate changing and introduction of disease agents, Fagaceae forests are facing an adaptation challenge to both biotic and abiotic threats. Although ECM communities are highly disturbed by climate factors and tree disease incidence, they could play an important role in increasing water availability to the plant and also improving plant tree defense against pathogens. Recent advances, namely, on genomics and transcriptomics, are providing tools for increasing the understanding of Fagaceae mycorrhization process and stress responses to biotic and abiotic stresses. Such studies can provide new information for the implementation of the most adequate management policies for protecting threaten Mediterranean forests.info:eu-repo/semantics/publishedVersio

Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops