Efeito do fósforo sobre a interação das bactérias isoladas da rizosfera de Guandu (Cajanus cajan)
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Data
2002-02-19
Autores
Finger, Giovana Peroni [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Foram isoladas e quantificadas bactérias totais, actinomicetos, bactérias esporuladas aeróbias, bactérias Gram negativas, pseudomonas e bactérias solubilizadoras de fosfato de solo rizosférico de guandu cultivado em células rizosféricas, empregando meios de cultura seletivos e o método de diluição seriada. As células rizosféricas foram utilizadas para separar o solo ao redor das raízes em camadas milimétricas. Do grupo de bactérias totais 50 bactérias foram isoladas por tratamento e submetidas ao teste de aglutinação com exsudato radicular, produzido em solução nutritiva, em estado bruto ou parcialmente purificado em coluna de Sephadex. Os grupos de bactérias totais, actinomicetos e bactérias Gram negativas, sofreram aumentos significativos na presença do guandu, fósforo (P) e na menor distância das raízes. As bactérias esporuladas aeróbias diminuíram com o aumento das doses de P. O grupo das pseudomonas foi o menos representativo no solo rizosférico e as solubilizadoras de fosfato apresentaram um aumento percentual nas doses crescentes de P. O teste de aglutinação mostrou a influência da planta sobre as bactérias com a maior porcentagem de reações positivas. O P não mostrou efeito sobre as reações de aglutinação quando analisado em conjunto com os fatores planta e distância da raiz. O exsudato radicular, produzido em solução nutritiva sem P e purificado, foi o que aglutinou o maior número de bactérias da rizosfera de guandu. Os testes de aglutinação mostraram que houve interações entre as bactérias e as plantas.
Total bacteria, actinomycetes, aerobic sporulated bacteria, Gram negative bacteria, pseudomonas and P-solubilizing bacteria of rhizospheric soil of pigeonpea cultivated in rhizospheric cells were isolated and quantified using selective culture medium and serial dilluition method. The rhizospheric cells were used to separate soil around roots into millimetric layers. From the groups of total bacteria, 50 bacteria were isolated per treatment and submitted to agglutination test using roots exudate produced into nutritive solution, crude solution or partialy purified by Sephadex column. Total bacteria, actinomycetes and Gram negative bacteria presented significative increasing considering the presence of pigeonpea, phosphorus (P) and at smallest root distance. Aerobic sporulated bacteria decreased at increasing doses of P. The pseudomonas group was less representative to rhizospheric soil and those wich solubilized phosphate presented an increased percentage at increasing doses of P. The agglutination test showed the influence of plant over bacteria presenting higher positive reaction percentage. The did not show effect over agglutination when analysed together with plant and root distance factors. The roots exsudate produced into nutritive solution without P and purified agglutinated the highest number of bacteria of rhizospheric of pigeonpea. The agglutination test showed that there were interaction between bacteria and plants.
Total bacteria, actinomycetes, aerobic sporulated bacteria, Gram negative bacteria, pseudomonas and P-solubilizing bacteria of rhizospheric soil of pigeonpea cultivated in rhizospheric cells were isolated and quantified using selective culture medium and serial dilluition method. The rhizospheric cells were used to separate soil around roots into millimetric layers. From the groups of total bacteria, 50 bacteria were isolated per treatment and submitted to agglutination test using roots exudate produced into nutritive solution, crude solution or partialy purified by Sephadex column. Total bacteria, actinomycetes and Gram negative bacteria presented significative increasing considering the presence of pigeonpea, phosphorus (P) and at smallest root distance. Aerobic sporulated bacteria decreased at increasing doses of P. The pseudomonas group was less representative to rhizospheric soil and those wich solubilized phosphate presented an increased percentage at increasing doses of P. The agglutination test showed the influence of plant over bacteria presenting higher positive reaction percentage. The did not show effect over agglutination when analysed together with plant and root distance factors. The roots exsudate produced into nutritive solution without P and purified agglutinated the highest number of bacteria of rhizospheric of pigeonpea. The agglutination test showed that there were interaction between bacteria and plants.
Descrição
Palavras-chave
Agglutination, Phosphate solibilizing bacteria, Guandu, Testes de aglutinação, Bactérias
Como citar
FINGER, Giovana Peroni. Efeito do fósforo sobre a interação das bactérias isoladas da rizosfera de Guandu (Cajanus cajan). 2002. viii, 71 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2002.