Root mycorrhizal colonization and plant responsiveness are related to root plasticity, soil fertility and successional status of native woody species in southern Brazil

Abstract

Twelve native woody species were studied to investigate the influences of soil fertility and root morphology on colonization by arbuscular mycorrhizal (AM) fungi during seedling establishment and growth. Seedlings were grown in soils of low and high natural fertility, uninoculated or inoculated with AM fungi, under greenhouse conditions. The mycorrhizal root colonization and plant responsiveness were higher among early successional species than late successional ones. Among early successional species, in both soils, mycorrhizal colonization provided significant increase in total dry mass, growth rates of shoot and root, root length, density of root tissues, root surface area and P concentration and content in the shoot. Early successional species grown with AM fungi displayed significant decreases in carbon allocation to roots, specific root length and the length and incidence of root hairs. Mycorrhizal colonization did not affect the root morphology of the late successional species in either soil. The growth of these woody species was influenced by differences in soil fertility. There was positive correlation between the degree of plant responses to AM inoculation with the percentage of root colonized by AM fungi. In both soils, plant responsiveness and mycorrhizal root colonization correlated positively to root-hair incidence and root-hair length and correlated negatively to fine-root diameter. The results suggest that during the establishment of seedlings, the large responses to the inoculation and colonization of roots by AM fungi are related to both the successional status and root morphological plasticity of the host plant, regardless of soil fertility.

Interactions between diazotrophic bacteria and mycorrhizal fungus in maize genotypes

“…In native woody species, mycorrhiza also decreased the specific root length and increased the root diameter (Zangaro et al, 2005(Zangaro et al, , 2007. The increase of the specific root length in the present work was…”

“…Mycorrhiza increased root hair incidence to values above 92% in the line lg40505-1 and the hybrid C333B. Conversely, previous reports showed reduction of root hair incidence in mycorrhizal maize (Bressan & Vasconcellos, 2002) and seedlings of native woody tropical trees (Zangaro et al, 2005(Zangaro et al, , 2007.…”

Influence of arbuscular mycorrhizal fungi inoculum produced on-farm and phosphorus on growth and nutrition of native woody plant species from Brazil

“…Successfulness of mycorrhizal inoculation depends partially on the mycorrhizal dependency of each woody species (Siqueira & Saggin Junior 2001) which varies accordingly to the successional stage that a species belongs; pioneer and early successional species being more dependent compared to late successional and climax species (Carneiro et al 1996;Siqueira & Saggin-Júnior 2001;Zangaro et al 2007;Pasqualini et al 2007).…”

“…Many studies in Brazil have shown that nutrition and growth of native woody species are improved by the mycorrhizal association and that many species are moderate to very highly dependent on the association (Siqueira & Saggin Júnior 2001;Zangaro et al 2007). Despite this, mycorrhizal inoculation of seedlings under nursery conditions is not a common practice and no inoculant is available commercially.…”

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

“…The seasonal pattern of production and root length may be related to changes in organic matter accumulation (Cuevas and Medina 1988;Aerts et al 1992;Sundarapandian and Swany 1996), nutrient concentration in the soil (Maycock and Congdon 2000; Pregitzer et al 2000;Stewart 2000;Blair and Perfecto 2001), soil moisture (Hook et al 1994;Visalakshi 1994;Makkonen and Helmisaari 1999) and microbial activity (Zangaro et al 2007). …”