Fase assimbiótica, produção, infectividade e efetividade de fungos micorrízicos arbusculares (FMA) em substratos com adubos orgânicos

by Barbosa da, Fábio Sérgio

Abstract (Summary)
Organic fertilizers have low cost and many of them constitute an alternative for production of inoculum of arbuscular mycorrhizal fungi (AMF). However, it is necessary to verify the effects of the organic fertilizers on the propagation of these fungi. The effect of organic fertilizer on AMF and the effect of both on production of seedlings and productivity of sweet passion fruit were investigated. The asymbiotic phase of Gigaspora albida in water agar medium plus glomalin and in soil with organic fertilizer was evaluated in the laboratory. Substrates for production of infective inoculum, mycorrhizal efficiency for production of organic seedlings of sweet passion fruit and the amendment more feasible to increase production of mycorrhizal seedlings and microbial activity were investigated in greenhouse experiments. In the field, the effect of inoculum sources and fertilizer type on production and characteristics of the fruits, and the microbial activity and production of glomalin were determined. The utilization of Tris-HCl buffer stimulated AMF spores formation and the inoculum was still infective after 120 days at 4 ºC. Organic compost and vegetal manure added to the substrate for AMF cultivation increased sporulation, but the benefits were dependent on the diluent substrate (sand or soil) and on the AMF species, however, when the substrate received cattle manure, reproduction of the AMF was reduced. The maintenance of the inocula produced in substrates with organic fertilizer for 120 days, under environmental conditions (28 ºC), did not affect infectivity, although the responses depended on the diluent substrate, source of organic matter and tested AMF. Higher germination rate and mycelial growth of G. albida occurred in soil receiving organic compost (53% and 17.1 mm), followed by vegetal manure (42.8% and 13.9 mm) and cattle manure (23.7% and 5.2 mm). Germination of G. albida was not affected but the mycelial growth was benefited by the addition of 30 amp;#956;g mL-1 of glomalin in the growth medium. Seedlings associated with G. albida (multiplied in substrate with organic fertilizer), cultivated in soil + organic compost, presented higher growth, higher mycorrhizal colonization and 60% reduction of the seedling formation period. Growth of plants cultivated in soil with bovine manure was higher than that maintained in substrate with coconut straw, vegetal manure or soil. The mycorrhization enhanced the development of seedlings and soil enzymatic activity. Use of chemical fertilizers and the inoculation with G. albida produced in soil + organic compost enhanced formation of fruits (64,777 fruits ha-1) with low acidity (0,75 % of citric acid g-1 pulp), high ºBrix/acidity (24.32) and higher productivity (11, 08 t ha-1). Under field conditions, production of glomalin, CO2 evolution and (FDA) diacetate fluorescein hydrolysis activity were benefited by the application of vermicompost, which was modulated by the source of mycorrhizal inoculum used during seedling formation. Organic fertilizers can stimulate the microbial activity, the AMF asymbiotic phase and the production of mycorrhizal inoculum infective and effective in promoting plant growth and formation of high quality sweet passion fruits
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Leonor Costa Maia

School:Universidade Federal de Pernambuco

School Location:Brazil

Source Type:Master's Thesis

Keywords:Micorriza arbuscular Organic amendment Arbuscular mycorrhiza


Date of Publication:02/20/2006

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