Interação de Ilex paraguariensis com migrorganismos benéficos
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Data
2015-12-08
Autores
Santos, Karen Cristine Gonçalves dos
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A erva mate (Ilex paraguariensis St. Hil) é uma planta muito importante para vários países da América do Sul, entretanto seu cultivo, realizado principalmente por pequenos e médios agricultores, apresenta diversos problemas, dentre eles a necessidade de ser iniciado com plântulas vigorosas. Buscando a solução deste problema, nesta pesquisa foram inoculadas plântulas de I. paraguariensis com três microrganismos promotores de crescimento vegetal com diferentes estilos de vida e características biológicas: a bactéria diazotrófica e de vida livre Azospirillum brasilense, a bactéria diazotrófica endofítica Gluconacetobacter diazotrophicus e o fungo micoparasítico Trichoderma harzianum. Foram inoculadas 50 plantas por tratamento submergindo as raízes em água ou no inóculo microbiano por 15 minutos. O crescimento vegetal foi avaliado 150 dias após a inoculação aferindo-se o comprimento e a massa fresca das plantas inteiras e separadamente dos sistemas radicular e aéreo. A homogeneidade das variâncias foi verificada com o teste Levene2 e os tratamentos foram comparados com o teste ANOVA, ambos foram realizados com o software OriginPro 8.6. Foi verificado que, mesmo que os três microrganismos supracitados sejam considerados benéficos, a promoção de crescimento vegetal foi visualizada somente nas plantas inoculadas com a bactéria G. diazotrophicus. É possível que a erva-mate seja seletiva em relação aos organismos com os quais interage, já que os organismos aqui estudados já foram registrados em interações benéficas com diversas plantas filogeneticamente distantes. Além disso, a bactéria G. diazotrophicus pode ter desenvolvido uma interação mais íntima com as plântulas por ter um caráter endofítico obrigatório, assim a bactéria pode crescer melhor pela menor competição com microrganismos e a planta pode aproveitar mais os nutrientes e os reguladores de crescimento vegetal secretados pela bactéria. A descoberta da promoção de crescimento de I. paraguariensis sem o uso de fertilizantes químicos representa um grande avanço na pesquisa desta planta, entretanto ainda é necessário compreender os mecanismos que promovem tanto a interação quanto o crescimento da erva-mate nessa relação mutualística com G. diazotrophicus. Para iniciar essa investigação, busca-se no futuro avaliar o papel da fixação de nitrogênio e da síntese de auxinas por G. diazotrophicus no crescimento de I. paraguariensis.
Yerba mate (Ilex paraguariensis St. Hil) is a very important plant for several countries of South America, however its culture, made mostly by small and medium farmers, shows many problems, among them is the necessity of initiating it with vigorous seedlings. Seeking for a solution to this problem, in this research we inoculated seedlings of I. paraguariensis with three plant growth-promoting microorganisms of different lifestyles and biological features: the diazotroph and free-living bacterium Azospirillum brasilense, the diazotroph and endophytic bacterium Gluconacetobacter diazotrophicus and the mycoparasite fungus Trichoderma harzianum. We inoculated 50 plants by treatment sinking the roots in water (control) or in the microbial inoculum for 15 minutes. We evaluated the plant growth 150 days after the inoculation by measuring the length and fresh weight of the whole plants and separately of the root and shot systems. We verified the homogeneity of the variances with Levene 2 test and we compared the treatments with ANOVA test, both with the software OriginPro 8.6. We verified that, although the three organisms aforementioned are considered beneficial organisms, the plant growth promotion was visualized only in those plants inoculated with the bacterium G. diazotrophicus. It is possible that I. paraguariensis is selective in relation to the organisms with which it interacts, since all the microorganisms here studied have been registered in beneficial interaction with several plants phylogenetically distant. Furthermore, the bacterium G. diazotrophicus may have developed a more intimate interaction with the seedlings for having an obligate endophytic character, so the bacterium population could grow better for the lower competition with microorganisms and the plant could utilize more of the nutrients and plant growth regulators secreted by the bacterium. Finding the growth promotion of I. paraguariensis without the use of chemical fertilizers represents a great advance in the research of this plant, however it is still necessary to comprehend the mechanisms that promote both the interaction and the growth of the I. paraguariensis in this mutualistic relation with G. diazotrophicus. To initiate this investigation, we seek in the future to evaluate the role of the nitrogen fixation and the synthesis of auxins by G. diazotrophicus in the growth of I. paraguariensis.
Yerba mate (Ilex paraguariensis St. Hil) is a very important plant for several countries of South America, however its culture, made mostly by small and medium farmers, shows many problems, among them is the necessity of initiating it with vigorous seedlings. Seeking for a solution to this problem, in this research we inoculated seedlings of I. paraguariensis with three plant growth-promoting microorganisms of different lifestyles and biological features: the diazotroph and free-living bacterium Azospirillum brasilense, the diazotroph and endophytic bacterium Gluconacetobacter diazotrophicus and the mycoparasite fungus Trichoderma harzianum. We inoculated 50 plants by treatment sinking the roots in water (control) or in the microbial inoculum for 15 minutes. We evaluated the plant growth 150 days after the inoculation by measuring the length and fresh weight of the whole plants and separately of the root and shot systems. We verified the homogeneity of the variances with Levene 2 test and we compared the treatments with ANOVA test, both with the software OriginPro 8.6. We verified that, although the three organisms aforementioned are considered beneficial organisms, the plant growth promotion was visualized only in those plants inoculated with the bacterium G. diazotrophicus. It is possible that I. paraguariensis is selective in relation to the organisms with which it interacts, since all the microorganisms here studied have been registered in beneficial interaction with several plants phylogenetically distant. Furthermore, the bacterium G. diazotrophicus may have developed a more intimate interaction with the seedlings for having an obligate endophytic character, so the bacterium population could grow better for the lower competition with microorganisms and the plant could utilize more of the nutrients and plant growth regulators secreted by the bacterium. Finding the growth promotion of I. paraguariensis without the use of chemical fertilizers represents a great advance in the research of this plant, however it is still necessary to comprehend the mechanisms that promote both the interaction and the growth of the I. paraguariensis in this mutualistic relation with G. diazotrophicus. To initiate this investigation, we seek in the future to evaluate the role of the nitrogen fixation and the synthesis of auxins by G. diazotrophicus in the growth of I. paraguariensis.
Abstract
Descrição
Trabalho de Conclusão de Curso apresentado ao Instituto Latino-Americano de Ciências da Vida e da
Natureza da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Bacharel em Ciências Biológicas – Ecologia e Biodiversidade. Orientador: Prof. Dr. Cristian Antonio Rojas.
Palavras-chave
Ilex paraguariensis, Gluconacetobacter diazotrophicus, Endofíticos, Promoção de crescimento vegetal
Citação
SANTOS, Karen Cristine Gonçalves dos. Interação de Ilex paraguariensis com microrganismos benéficos. 2015. 44p. Trabalho de Conclusão de Curso (Graduação em Ciências Biológicas – Ecologia e Biodiversidade) – Universidade Federal da Integração Latino-Americana. Foz do Iguaçu, 2015.