New isolates of ectomycorrhizal fungi and the growth of eucalypt

Luiz Afonso Borges De Souza,Vetúria Lopes De Oliveira,Pedro Augusto Pinto Bonnassis,Germano Nunes Silva Filho

doi:10.1590/s0100-204x2008000200012

Luiz Afonso Borges De Souza, Vetúria Lopes De Oliveira + Show 2 more

Open Access

https://doi.org/10.1590/s0100-204x2008000200012

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Abstract

The objective of this work was to evaluate the efficiency of ectomycorrhizal isolates on root colonization, phosphorus uptake and growth of Eucalyptus dunnii seedlings. Inocula of ten ectomycorrhizal isolates of Chondrogaster angustisporus, Hysterangium gardneri, Pisolithus spp., and Scleroderma spp. were aseptically produced in a peat-vermiculite mixture supplemented with liquid culture medium. Plants grew in a similar substrate supplemented with macro-and micro-nutrients; treatments were randomly distributed in a greenhouse. After three months, seedlings inoculated with three isolates - UFSC-Sc68 (Scleroderma sp.), UFSC-Ch163 (Chondrogaster angustisporus), and UFSC-Pt188 (Pisolithus microcarpus) - had a phosphorus shoot content and a shoot dry matter higher or equivalent to those of noninoculated controls which had been fertilized with a 16-fold phosphorus amount. These isolates were selected for new studies for establishing inoculum production techniques, in order to be applied in reforestation programmes under nursery and field conditions.

Highlights

The increasing need of forest products has created a worldwide deficit of timber that has to be met using strategies designed to promote a higher productivity
Root colonization was higher in plants inoculated with Pisolithus isolates (Table 1), Universidade Federal de Santa Catarina (UFSC)-Pt22, UFSC-Pt145, UFSC-Pt188 and UFSC-Pt116, which colonized 10 to 12% of the root systems
Plants inoculated with isolates UFSC-Pt132 (Pisolithus microcarpus) and UFSC-Hg93 (Hysterangium gardneri) produced lower colonization rates at 4 and 3%, respectively

Summary

Introduction

The increasing need of forest products has created a worldwide deficit of timber that has to be met using strategies designed to promote a higher productivity. Many Brazilian reforestation programmes have to deal with soil low fertility, which requires the application of very high amounts of fertilizers to maintain the productivity at the present levels This practice contributes to high production costs and has deleterious environmental effects. Ectomycorrhizas contribute to increase water and nutrient uptake, those presenting low mobility in the soil, such as phosphorus (Glowa et al, 2003; Sawyer et al, 2003; Di Pietro et al, 2007) This increase in nutrient uptake is the result of a significant increase in the plant-soil interface due to the growth of the hyphae of the ectomycorrhizal fungus beyond the root zone and to the more intense branching of the colonized roots (Smith & Read, 1997; Zeppa et al, 2005). Ectomycorrhizas can augment hydraulic conductivity inside the plant and the resistance to drought and soil-borne pathogens, and can improve soil

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