Spore Density and Arbuscular Mycorrhizal Colonization in Sunflower Grown in Campo Verde (Brazil)
Dryelle Sifuentes Pallaoro *
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Dayana Aparecida de Faria
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Daniela Tiago Silva Campos
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Aluisio Brigido Borba Filho
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Joadil Gonçalves de Abreu
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Elisangela Clarete Camili
Department of Agronomy and Zootechny, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Márcia Helena Scabora
SENAITechnology College, Cuiabá, Mato Grosso, Brazil.
*Author to whom correspondence should be addressed.
Abstract
The objective of this study was to evaluate the number of spores and the mycorrhizal root colonization in a Cerrado soil (Red-Yellow Latosol) cultivated with different sunflower genotypes. The sampling of the rhizospheric soil was performed at three growth stages: Sowing, flowering, and harvest. The experimental design was in completely randomized blocks with four replications. Three different sunflower hybrids were tested in the 2009 and 2010 cropping seasons. The collected data comprised the total number of spores per 50 g of soil at the three growth stages, along with arbuscular mycorrhizal fungi (AMF) colonization. It was verified that the mycorrhizal colonization was not influenced by the sunflower genotypes, and the mean spore densities were equivalent to 4.94 and 4.64 g soil-1 in 2009 and 2010, respectively. More importantly, AMF colonization was enhanced by lower soil phosphorus levels. The maximum spore production was obtained at flowering, with mycorrhizal colonization rates ranging from 21 to 28% and from 28 to 48% in 2009 and 2010, respectively. The number of spores also varied from 153 to 342 and from 147 to 320 in 2009 and 2010, respectively.
Keywords: Helianthus annuus L., soil phosphorus, plant nutrition, symbiosis