ABSTRACT Restoration of degraded sites by using native plants like Plathymenia reticulata Benth. and Melanoxylon brauna Schot. is advisable. However, seedlings of both species, when raised on commercial substrates, may present low survival. This study aimed to evaluate the growth of seedlings under inoculation with arbuscular mycorrhizal fungi (AMF). The seedlings were raised on soil sampled from near an adult plant of the same species. The P. reticulata and M. brauna seedlings were grown with or without the inoculation of a mix of three species of AMF (Rhizophagus clarus, Claroideoglomus etunicatum, and Gigaspora albida), and five doses of P (0, 50, 150, 300, and 450 mg dm-3 of P). All seedlings were inoculated with Bradyrhizobium sp., isolated from each species. After 90 days, P. reticulata inoculated with AMF showed higher growth and nutrient content than those uninoculated, and the maximum plant growth was obtained when received 160 to 280 mg dm-3 of P. On the other hand, no effects of AMF inoculation or phosphate fertilization were observed on M. brauna. For both species, no effect of inoculation was observed on mycorrhizal colonization, and M. brauna, unlike P. reticulata presented a considerable number of nodules. We conclude that inoculation with AMF and P fertilization improves the growth of P. reticulata seedlings but does not promote the growth of M. brauna; presenting the necessity to investigate each species.

ABSTRACT The production of inoculum from arbuscular mycorrhizal fungi (AMF) at a large scale and low cost is essential for establishing methods to assist in producing pineapple plantlets with high nutritional and phytosanitary quality. However, this objective is difficult to accomplish because of the biotrophic nature of these fungi. The on-farm multiplication method for AMF inoculum presents a good alternative to supply the demand for the production of glomerospores. This study aimed to multiply and evaluate AMF inoculum originating from isolated species (including Rhizophagus clarus, Claroideoglomus etunicatum) versus native AMF from pineapple and coffee plantations multiplied by the on-farm method on the colonization in pineapple plantlets. Initially, inocula of R. clarus, C. etunicatum, and native AMF (pineapple and coffee) were multiplied by the on-farm method in Sorghum bicolor. After four months, the number of AMF spores and the percentage of viable spores at the layers of 0.00-0.05 and 0.05-0.10 m were evaluated. There were no differences in spore numbers in relation to the source of the inoculum (R. clarus, C. etunicatum, pineapple, and coffee) and evaluated layers, with an average number of 605 spores per 100 cm3 of soil. The percentage of viable spores was greater at the layer of 0.00-0.05 m (76.32 %) compared to the layer of 0.05-0.10 m (72.05 %), regardless of the inoculum source. The viability of the inoculum obtained from C. etunicatum was higher than that from the coffee crop (77.93 and 68.06 %, respectively). Subsequently, the spores were inoculated in pineapple plantlets to assess the rate of colonization. Pineapple plantlets inoculated with AMF had an average of colonization of 18 and 67.73 % after 50 and 180 days cultivation, respectively, with no significant difference being detected between treatments. Therefore, on-farm inoculum production was effective at multiplying the AMF of both isolates of R. clarus and C. etunicatum, as well as for commercial crops (pineapple and coffee), with spores having high viability. Arbuscular mycorrhizal fungi colonized pineapple plantlets independently of the inoculum utilized and favored its growth.

RESUMO O fungo Pochonia chlamydosporia é um dos mais estudados agentes de controle biológico de fitonematoides. Neste estudo foi demostrado que os isolados Pc-3, Pc-10 e Pc-19 do fungo promovem o crescimento de plântulas de tomate e alface. O isolado Pc-19 colonizou o rizoplano de mudas de tomate em apenas 15 dias e produziu grande quantidade de clamidósporos. O isolado foi capaz de utilizar celulose como fonte de carbono, tanto quanto glicose e sacarose. Em estudos realizados por microscopia eletrônica de varredura (MEV), foi possível observar que hifas do isolado Pc-10 penetraram as células epidérmicas das raízes de tomateiro. Os três isolados de P. chlamydosporia promovem o crescimento de tomateiro e alface.

ABSTRACT The fungus Pochonia chlamydosporia is one of the most studied biological agents used to control plant-parasitic nematodes. This study found that the isolates Pc-3, Pc-10 and Pc-19 of this fungus promote the growth of tomato and lettuce seedlings. The isolate Pc-19 colonized the rhizoplane of tomato seedlings in only 15 days and produced a large quantity of chlamydospores. This isolate was able to use cellulose as a carbon source, in addition to glucose and sucrose. Scanning electron microscopy (SEM) revealed that hyphae of the P. chlamydosporia isolate Pc-10 penetrated the epidermal cells of the tomato roots. These three P. chlamydosporia isolates promote the growth of tomato and lettuce.

Estudos sobre a ecologia de organismos envolvidos no processo de produção são necessários para o desenvolvimento de uma agricultura sustentável, e hoje, a sustentabilidade está intimamente ligada à rentabilidade de produção. Objetivou-se com este trabalho verificar a ocorrência de fungos micorrízicos arbusculares em plantas daninhas de lavouras brasileiras e avaliar o potencial de solubilização de fosfato inorgânico da microbiota associada. 36 espécies de plantas daninhas foram avaliadas quanto à ocorrência de micorrizas, e 11 foram selecionadas para avaliação do potencial de solubilização total e relativa de fosfato. Todas as espécies apresentaram colonização por micorrizas, inclusive um exemplar da família Brassicaceae, geralmente enquadrada como não micorrizada. Na maioria das espécies, os tipos morfológicos de arbúsculos e enovelados de hifas foram observados, sendo os enovelados mais comuns entre as gramíneas. Fungos endofíticos do tipo dark septate foram visualizados na maioria das plantas. As plantas daninhas apresentaram distintos potenciais de solubilização de P na rizosfera. Amaranthus retroflexus, Bidens pilosa e Leonotis nepetaefolia apresentaram elevados valores de solubilização relativa de fosfato. Este é o primeiro relato de micorrizas e da atividade de solubilização de fosfato em plantas daninhas no Brasil.

Studies on the ecology of the organisms involved in the production process are necessary for the development of sustainable agriculture, and sustainability is currently closely linked to the profitability of production. The objective of this study was to verify the occurrence of arbuscular mycorrhizal fungi in weeds infesting Brazilian crops and to evaluate the inorganic phosphate solubilization potential of the associated microbiota. A total of 36 weed species were evaluated for the occurrence of mycorrhizae; of these, 11 were selected to evaluate their potential for total and relative phosphate solubilization. All of the species demonstrated mycorrhizal colonization, including a member of the Brassicaceae family, which is usually assumed to be non-mycorrhizal. In most of the species, morphological types of arbuscular and coiled hyphae were observed, with the coiled hyphae being the most common in the grasses. Dark septate endophytic fungi were observed in most of the plants. The weeds presented different potentials for P solubilization in the rhizosphere; Amaranthus retroflexus, Bidens pilosa and Leonotis nepetaefolia showed high values of relative phosphate solubilization. This is the first report on the mycorrhizae and phosphate solubilization activity in weeds in Brazil.

The mushroom Pleurotus ostreatus has nutritional and medicinal characteristics that depend on the growth substrate. In nature, this fungus grows on dead wood, but it can be artificially cultivated on agricultural wastes (coffee husks, eucalyptus sawdust, corncobs and sugar cane bagasse). The degradation of agricultural wastes involves some enzyme complexes made up of oxidative (laccase, manganese peroxidase and lignin peroxidase) and hydrolytic enzymes (cellulases, xylanases and tanases). Understanding how these enzymes work will help to improve the productivity of mushroom cultures and decrease the potential pollution that can be caused by inadequate discharge of the agroindustrial residues. The objective of this work was to assess the activity of the lignocellulolytic enzymes produced by two P. ostreatus strains (PLO 2 and PLO 6). These strains were used to inoculate samples of coffee husks, eucalyptus sawdust or eucalyptus bark add with or without 20 % rice bran. Every five days after substrate inoculation, the enzyme activity and soluble protein concentration were evaluated. The maximum activity of oxidative enzymes was observed at day 10 after inoculation, and the activity of the hydrolytic enzymes increased during the entire period of the experiment. The results show that substrate composition and colonization time influenced the activity of the lignocellulolytic enzymes.

Plantas daninhas e microrganismos do solo se interagem na interface solo/raiz promovendo vantagens para o desenvolvimento e estabelecimento de ambos. Objetivou-se com este trabalho avaliar o crescimento e o acúmulo de nutrientes em oito espécies de plantas daninhas (Ageratum conyzoides L., Bidens pilosa L., Cenchrus echinatus L., Conyza bonariensis L., Echinochloa crus-galli L., Eleusine indica L., Ipomoea grandifolia L. e Lolium multiflorum L.) e nas culturas de feijão e milho, cultivadas, por 50 dias, em substrato fumigado com brometo de metila. Avaliações referentes à altura, área foliar, número de folhas, matéria seca da parte aérea e das raízes e teor relativo dos nutrientes, foram realizados aos 50 dias após emergência das plântulas. Observou-se efeito positivo da fumigação do substrato no crescimento, número de folhas, área foliar, altura de plantas e acúmulo de nutrientes nas plantas daninhas gramíneas em relação às dicotiledôneas. Conyza bonariensis foi a mais afetada pela fumigação do solo, apresentando índices de matéria seca, número de folhas, área foliar, altura e acúmulo de nutrientes em torno de 50% menores em relação às plantas crescidas em solo normal. A fumigação influenciou também o ciclo vegetativo das plantas, sendo este menor para as espécies B. pilosa, E. indica e C. echinatus. Observou-se, ainda, acúmulo de fósforo 20 e 30% menor em plantas de Bidens pilosa e Conyza bonariensis, respectivamente, quando cultivadas em solo esterilizado. As culturas de feijão e milho foram menos afetadas pela fumigação do solo em comparação às plantas daninhas.

Weeds and soil microorganisms interact with each other in the soil/root interface, promoting the development and establishment of both. The objective of this study was to evaluate the growth and nutrient accumulation in eight species of weeds (Ageratum conyzoides L., Bidens pilosa L., Cenchrus echinatus L., Conyza bonariensis L., Echinochloa crus-galli L., Eleusine indica L. Ipomoea grandifolia L. and Lolium multiflorum L.) and in bean and corn crops grown for 50 days in a substrate fumigated with methyl bromide. Assessments relating to the height, leaf area, leaf number, dry weight of shoots and roots and relative content of nutrients were carried out 50 days after seedling emergence. A positive effect of soil fumigation was observed on the growth, leaf number, leaf area, plant height and accumulation of nutrients in monocot weeds in relation to dicots. Conyza bonariensis was the most affected by soil fumigation, with levels of dry matter, leaf number, leaf area, height and accumulation of nutrients approximately 50% lower than plants grown in normal soil. Fumigation also influenced the growth cycle of the plants, which was lower for B. pilosa, E. indica and C. echinatus. We also observed a 20 and 30% lower phosphorus accumulation in Bidens pilosa and Conyza bonariensis, respectively, when grown in the sterilized soil. Overall, the bean and corn crops were less affected by soil fumigation than the weeds.

A associação micorrízica é advinda da associação simbiótica entre alguns fungos do solos e da maioria das raízes das plantas. O eucalipto possui a capacidade de se associar com dois tipos de micorrizas, a micorriza arbuscular e a ectomicorriza, o que depende muito da sua idade. Este trabalho objetivou avaliar a taxa de colonização por fungos micorrízicos arbusculares (MA) e ectomicorrízicos (ECM) e o número de esporos de fungos micorrízicos arbusculares em plantios comerciais de Eucalyptus grandis e Eucalyptus urophylla, com diferentes idades e manejos, no período de dezembro de 2002 a fevereiro de 2004, na região leste de Minas Gerais, Brasil. Em todas as coletas e em todas as idades dos plantios, foram encontradas MA, e ECM e a média geral da colonização por fungos micorrízicos arbusculares (FMA) foi de 26%. O número médio de esporos desses fungos de 374,7 por 100 g de solo e a colonização por fungos ectomicorrízicos (FECM) de 20,2%. As maiores porcentagens de colonização por FECM foram observadas em áreas de plantios mais jovens, mas a sua maior diversidade foi observada nas áreas de plantios mais velhos. Conclui-se que a época de coleta, a idade do plantio e o manejo do solo afetam a colonização micorrízica e também a diversidade de fungos ECM e que a sucessão de eucalipto com FMA-FECM não é regra e é muito influenciada pelo tipo de manejo.

Mycorrhyzal association is the symbiotic association among some soil fungus and most plant roots. Eucalyptus has the capacity of associating with two types of mychorrizal, arbuscular and ectomycorrhizal mycorrhizal,depending of its age. The objective of this work was to evaluate colonization rates by arbuscular mycorrhizal fungi (AM) and ectomycorrhizal fungi (ECM) and the number of spores of arbuscular mycorrhizal fungi in in commercial plantations of Eucalyptus grandis and Eucalyptus urophylla, at different ages and managements practices, from December 2002 to February, 2004, in eastern region of Minas Gerais, Brazil. In all periods of sampling and at all ages of the plant, it was found both AM and ECM and the colonization general mean by arbuscular mycorrhizal fungi (AMF) was 26%. The average number of spores of those fungi was 374.7 per 100 g of soil and colonization by ectomycorrhizal fungi (EMF) was 20.2 %. Most percentages of colonization by EMF were observed in areas with younger plantations, but it greatest diversity was observed in older plantation areas. It can be concluded that sampling period, age of the plantation and soil management practices affect mycorrhizal colonization and also ECM fungi diversity and succession of eucalyptus with AM-ECM is not a rule and it is strongly affected by management.