Mycorrhizae in the Alaska Landscape

This publication explains how mycorrhiza, an important relationship between plant roots and certain types of fungi, can improve the plant's growth and provide protection from certain root diseases.For more information, contact your local Cooperative Extension Service office or Jeff Smeenk, Extension Horticulture Specialist, Agriculture and Horticulture, at 907-746-9470 or [email protected]. Reviewed by Stephen Brown and Robert Gorman, Extension Faculty, Agriculture and Horticulture, and Jodie Anderson, Instructor, School of Natural Resources and Agricultural Science

Pengaruh Trichoderma terhadap Perkembangan Mikoriza pada Akar Pinus Merkusii Jungh. et de Vriese = The Effect of Trichoderma to The Mycorrhizae Development of Pinus merkusii Jungh. et de Vriese Root

The objective of experiment was to determine the effect of introduction Trichoderma on development of mycorrhizae of seedling Pinus merkusii Jungh. et de Vriese. T. Koningii (T,), T. reesei (T]3), and T. harzianum (T27), were introduced into seedling of wood with different time of introduction. The different time was before, together and after inoculation of soil, which had mycorrhizae, or without mycorrhizae. The result of research showed that percentage of infection mycorrhizae, were created in variation according to the kind of Trichoderma and time of introduction. An introduction before inoculation mycorrhizae caused total infection 52,7% in the seedling of T,, 54,32% in T13, and 56,59% in T27. It was smaller than infection value that was introduced together with mycorrhizae (64,36% in T,, 71,03% in T]3, 57,35% on T^,). Introduction after inoculation of mycorrhizae caused infection on T, (67,17%), Tjj (72,88%) and T27 (63,92). Keywords: trichoderma -mycorrhizae -Pinus merkusi

INTERRELATIONS BETWEEN THE MYCORRHIZAL SYSTEMS AND SOIL ORGANISMS

The mycorrhizae are largely spread in natural ecosystems, and the proportion of plants that realise mycorrhizas is overwhelming, this relation involving advantages for both partners. The presence or absence of mycorrhizae, the rate and intensity of mycorrhiza formation are aspects with ecological importance, but also present importance in modern agriculture. The research results published on international literature which views the principal relations between mycorrhizae and soil microbiota, the way in which these relations affect the intensity of mycorrhizae formation and also the efficiency of mycorrhizae under the influence of soil organisms are synthesized and commented in this paper. The relations between mycorrhizae and different categories of bacteria, protozoa or microfungi, as well the influence of invertebrates through interactions of them with microorganisms are also being analyzed

Mycorrhizal Status of Gunnera petaloidea in Hawai'i

Eight collections of the endemic Hawaiian angiosperm Gunnera petaloidea ssp. kauaiensis were examined for mycorrhizae. Soil-inhabiting roots of all specimens possessed extensive vesicular-arbuscular mycorrhizae 01AM). Aerial roots lacked mycorrhizae. Soil from the root zones of the plants contained propagules of VAM fungi, and spores of two species of VAM fungi were found in the soil. The discovery of mycorrhizae in Gunnera adds another symbiont to the Gunnera-Nostoc symbiosis

Epiparasitic plants specialized on arbuscular mycorrhizal fungi

Over 400 non-photosynthetic species from 10 families of vascular plants obtain their carbon from fungi and are thus defined as myco-heterotrophs. Many of these plants are epiparasitic on green plants from which they obtain carbon by 'cheating' shared mycorrhizal fungi. Epiparasitic plants examined to date depend on ectomycorrhizal fungi for carbon transfer and exhibit exceptional specificity for these fungi, but for most myco-heterotrophs neither the identity of the fungi nor the sources of their carbon are known. Because many myco-heterotrophs grow in forests dominated by plants associated with arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota), we proposed that epiparasitism would occur also between plants linked by AMF. On a global scale AMF form the most widespread mycorrhizae, thus the ability of plants to cheat this symbiosis would be highly significant. We analysed mycorrhizae from three populations of Arachnitis uniflora (Corsiaceae, Monocotyledonae), five Voyria species and one Voyriella species (Gentianaceae, Dicotyledonae), and neighbouring green plants. Here we show that non-photosynthetic plants associate with AMF and can display the characteristic specificity of epiparasites. This suggests that AMF mediate significant inter-plant carbon transfer in nature

Arbuscular mycorrhizal fungi

The potential disease suppressiveness of arbuscular mycorrhizal (AM) fungi of various origins on Bipolaris sorokiniana in barley has been investigated. Firstly, a survey considering the occurrence of AM fungi in arable fields in Sweden were conducted with the aim to exploit site specific genetic resources in relation to disease suppressiveness. Arbuscular mycorrhizal fungi were present at all 45 sampling sites surveyed all over Sweden at densities ranging from 3 up to 44 spores per gram air dried soil. The highest spore density was found in a semi-natural grassland and the lowest were found in a cereal monoculture. The AM fungi were then multiplied in trap cultures in the greenhouse with the aim to use these for studying potential disease suppressiveness. Thus, the effects of the AM fungi trap cultures on the transmission of seed-borne B. sorokiniana in barley were investigated, using the trap culture inocula, but also including inocula consisting on spore mixtures. The arbuscular mycorrhizal fungi were able to suppress the transmission of B. sorokiniana in aerial parts of barley plants. The degree of suppression varied with the origin of the AM fungal trap cultures. The trap culture inoculum with the highest suppression of the B. sorokiniana transmission originated from an organically managed barley field with undersown ley. The two spore-inocula with the best suppression of the pathogen originated from fields with winter wheat and spring barley, respectively. Eventually, an in vitro method was developed for studying the effect of AM fungal colonisation of roots on the development of foliar diseases and the reaction of the actual host plant of the disease causing organism. Using the developed method, it was indicated that AM fungal colonisation of barley plant suppressed the development of leaf necroses due to B. sorokiniana. Further in vitro studies on the interaction between B. sorokiniana and arbuscular mycorrhizal fungi showed that B. sorokiniana decrease the germination of the AM fungal spores. In conclusion, AM fungi suppress the development of B. sorokiniana in barley. My data suggest that for biocontrol of B. sorokiniana AM fungi should be considered