Efeitos da inoculação de Enterobacter sp. ICB481 sobre o crescimento e acúmulo de nitrogênio em plântulas de cana-de-açúcar (Saccharum sp.) submetidas a fertilização orgânica e convencional.

Abstract

Sugarcane has great importance in the Brazilian economy because it is raw material for products such as sugar and alcohol. Most cultivars use conventional fertilization and therefore there is a concern in developing alternatives less aggressive to the environment. Alternatives are the organic fertilization and employment diazotrophic endophytic bacteria. The genus Enterobacter has diazotrophic and plant growth promoters representatives. The objective of this study was to analyze the interaction of Enterobacter sp. ICB481 with seedlings of micropropagated sugarcane submitted to organic and conventional fertilization. The seedlings used were divided into three inoculated and three non-inoculated groups: organic, conventional, no fertilization. The parameters evaluated were: leaf length, root volume, fresh and dried leaf and root matters and concentrations of nitrate, ammonium, amino acids, proteins and soluble sugars. The plants were kept in a greenhouse with a photoperiod controlled by two months. After 60 days, it was found that the organic and conventional fertilizers influenced similarly almost all growth parameters and the chlorophyll concentration in both, the inoculated and uninoculated groups. The exception was fresh mass, where the organic treatments promoted greater increase of biomass. There were no differences between organic and conventional groups (with and without bacteria) in the following parameters: leaf length, fresh leaf matter, root and leaf dry matter. The inoculation of Enterobacter promoted increase root volume and fresh mass in organic and conventional groups. Inoculation of the group without fertilization promoted increases in all growth parameters and chlorophyll content as compared to non-inoculated groups. The measurements of nitrate, free amino acids and total proteins content, show the influence of Enterobacter sp. ICB481 the profile of nitrogen content. The concentrations of free ammonium measured were below the detection limit. The protein content of the three inoculated groups did not differ. The conventional groups, inoculated and uninoculated, were not significantly different. The inoculated groups treated with organic fertilization and not fertilized showed higher protein content compared to the same noninoculated. The test showed that colonization Enterobacter sp. ICB481 at 60 days were still present in root tissue and the population was 10 5 CFU g -¹ in the three inoculated groups. The results show beneficial effects promoting plant growth by increasing several growth parameters when as seedlings were inoculated with sugarcane Enterobacter sp. ICB481, particularly under conditions of deficiency of combined nitrogen.

CRESCIMENTO INICIAL DO FEIJOEIRO EM FUNÇÃO DO VIGOR DE SEMENTES E INOCULAÇÃO COM Bacillus subtilis

“…Uma vez que a redução no uso de produtos químicos constitui uma diretriz a ser seguida frente ao modelo de agricultura atual, o uso de recursos biológicos para produção de alimentos como a inoculação com rizobactérias, torna-se uma alternativa interessante, e que pode gerar benefícios de ordem econômica e ambiental (FREITAS & AGUILAR VILDOSO, 2004;SHAHAROONA, 2008), estimulando o emprego de novas estratégias agrícolas em favor do cultivo sustentável (ICHIWAKI, 2012).…”

INFLUÊNCIA DO Bacillus subtilis NO CONTROLE BIOLÓGICO DE NEMATOIDES E ASPECTOS PRODUTIVOS DO FEIJOEIRO

“…Neste contexto, as rizobactérias, em especial, a espécie Bacillus subtilis, vem tornando-se objeto de estudo (ARAÚJO et al, 2012.;SIDDIQUI et al, 2001.;SAHARAN, 2011), principalmente devido a sua capacidade nematicida e como promotora de crescimento de plantas cultivadas (RAMAMOORTHY, 2001.;MENA-VIOLANTE & OLALDE-PORTUGAL, 2007), o que estimula o emprego de novas estratégias a favor do exercício de uma agricultura mais sustentável (ICHIWAKI, 2012).…”