New isolates of ectomycorrhizal fungi and the growth of eucalypt

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. Index terms: Chondrogaster, Pisolithus, Eucalyptus dunnii, efficiency, inoculation, plant growth. Novos isolados de fungos ectomicorrízicos e o crescimento de eucaliptoResumo -O objetivo deste trabalho foi avaliar a eficiência de isolados fúngicos ectomicorrízicos na colonização radicular, na absorção de fósforo e no crescimento de mudas de Eucalyptus dunnii. Os inóculos de dez isolados de Chondrogaster angustisporus, Hysterangium gardneri, Pisolithus spp. e Scleroderma spp. foram produzidos em uma mistura turfa-vermiculita suplementada com meio de cultura líquido. As plantas foram cultivadas em substrato semelhante com macro e micronutrientes. Os tratamentos foram distribuídos em casa de vegetação em delineamento inteiramente casualizado. Após três meses, as plântulas com inoculação dos isolados -UFSC-Sc68 (Scleroderma sp.), UFSC-Ch163 (Chondrogaster angustisporus) e UFSC-Pt188 (Pisolithus microcarpus) -tiveram os maiores valores de matéria seca e de fósforo na parte aérea. Esses valores foram superiores ou equivalentes aos observados nas plantas sem inoculação, adubadas com 16 vezes mais fósforo. Esses isolados foram selecionados para futuros estudos, a fim de se estabelecerem técnicas de produção de inoculantes, para serem usados em programas de reflorestamento em condições de viveiros e campo.Termos para indexação: Chondrogaster, Pisolithus, Eucalyptus dunnii, eficiência, inoculação, crescimento vegetal.

Growth and Nutrition of Eucalypt Rooted Cuttings Promoted by Ectomycorrhizal Fungi in Commercial Nurseries

“…The increase in inoculated plant P content for three out of four EMFs used, according to inoculum application rates and their differential ability in promoting P uptake (Figures 2a, 2b) corroborates with some results reported in the literature (Alves et al, 2001;Chen et al, 2006b;Souza et al, 2008). E. dunnii seedlings inoculated with P. microcarpus (UFSC-Pt188) accumulated nine times more P (528 μg per plant) than non-inoculated seedlings (60 μg per plant) (Souza et al, 2008).…”

“…The increase in eucalypt CD, SH, and SDM promoted by inoculation with increasing application rates of different EMF species (Figures 1a, 1b, 1c) was also observed by other authors in eucalypt seedlings (Alves et al, 2001;Souza et al, 2004Souza et al, , 2008. E. dunnii seedlings had greater CD (1.4 times), SH (1.3 times), and SDM (1.7 times) levels when inoculated with Pisolithus sp.…”

“…Ectomycorrhizal fungi species differed in their capacity to increase leaf P concentration and content ( Figures 2a, 2b); however, they did not differ in terms of growth promotion (Figures 1a, 1b, 1c) and root colonization ability (Figure 1d), and they also raised leaf K and N concentration and content (Figures 2c, 2d, 2e, 2f). This similar behavior among EMF species observed in growth promotion, root colonization, and plant nutrition for some nutrients differs from most studies found in the literature (Alves et al, 2001;Silva et al, 2003;Souza et al, 2004Souza et al, , 2008Chen et al, 2006c).…”

“…inoculum produced in a vermiculite-peatculture medium (Alves et al, 2001). Root length colonization of 16 %, observed at the highest application rate of inoculum (15 beads), was higher than the highest percentage observed in E. dunnii inoculated by 10 species and, or, EMF isolates (Souza et al, 2008). However, it was lower than that reported in eucalypt by other authors (Alves et al, 2001;Chen et al, 2006c).…”

“…E. dunnii seedlings had greater CD (1.4 times), SH (1.3 times), and SDM (1.7 times) levels when inoculated with Pisolithus sp. (UFSC-Pt24) (Souza et al, 2008), with P. microcarpus (UFSC-Pt116) isolate (1.2 times), and with C. angustisporus (UFSC-Ch163) isolate (1.3 times) (Souza et al, 2004). These results are greater than or equal to the CD and SDM observed in this study, which were 1.1 and 1.2 times higher respectively, always at the highest application rate without reaching a maximum (Figures 1a, 1b, 1c).…”