Navegando por Autor "Saggin Júnior, Orivaldo José"

Agora exibindo 1 - 3 de 3

Arbuscular mycorrhiza in Coffea arabica L.: review and meta-analyses
(Editora UFLA, 2017-07) Cogo, Franciane Diniz; Guimarães, Paulo Tácito Gontijo; Rojas, Enrique Pouyú; Saggin Júnior, Orivaldo José; Siqueira, Jose Oswaldo; Carneiro, Marco Aurelio Carbone
Coffee, a plant of global economic importance, presents a high degree of micotrophy for nutrients absorption, especially phosphorus, whose sources are scarce, and extremely required in tropical soils. Arbuscular mycorrhizal fungi (AMF) and coffee crop (Coffea arabica) have been studied for more than three decades, and therefore, analyzing and gathering these studies in a quantitative and qualitative way by means of meta-analysis and critical review of advances and trends is of great relevance. In this review, aspects such as geographic distribution, ecology, effects on plant growth, mineral nutrition, myotrophism, and symbiotic efficiency and its applications were discussed, with special emphasis on the researches carried out in Brazil. By applying the electronic databases Cab Abstracts, Springerlink, Science Direct, Scielo, Scopus, ISI, Lilascs, Woldcat, 73 studies were analyzed, including papers, dissertations and theses. The meta-analysis showed the importance of AMF for growth, plant nutrition and grain yield. Nevertheless, a gap is still evident in the evaluation of the different management strategies adopted in coffee crop and their effects on AMF. The need to extend the research under field conditions was also detected, in order to confer the real contribution of AMF in coffee biocontrol, and their action as biofertilizers and biostimulants.
Arbuscular mycorrhizal fungi community in coffee agroforestry, consortium and monoculture systems
(Academia Brasileira de Ciências, 2022-06-27) Barros, Welluma T.; Barreto-Garcia, Patrícia A. B.; Saggin Júnior, Orivaldo José; Scoriza, Rafael N.; Silva, Maicon S. da
Understanding the effects of different production systems on arbuscular mycorrhizal fungi (AMF) can help to interpret interactions between their components and to define management strategies. As a result, our study was conducted on soils under three coffee production systems (one homogeneous and two heterogeneous) and in a native forest located in the Bahia state, Brazil. This study aimed to answer the following questions: 1) Does the organization and management of the coffee production system affect the occurrence and diversity of AMF?; and 2) Is the seasonality effect similar between systems? To do so, soil samples (0-10 cm depth) were collected at two times of the year (rainy and dry). Number of spores (NS) and average richness did not show differences between the systems, only between seasons. There was a reduction in NS in the dry season (1.4 and 2.7 spores g-1 soil) in relation to the rainy season (3.8 to 12.5 spores g-1 soil). The influence of coffee production systems was observed in the presence and absence of some AMF species. The AMF community was shown to be related to the plant species composition of the system, which was reflected in the dissimilarity of heterogeneous systems in relation to the coffee monoculture system.
High rates of agricultural gypsum affect the arbuscular mycorrhiza fungal community and coffee yield
(Instituto Agronômico (IAC), 2020) Cogo, Franciane Diniz; Saggin Júnior, Orivaldo José; Guimarães, Paulo Tácito Gontijo; Siqueira, José Oswaldo; Carneiro, Marco Aurélio Carbone
High rates of agricultural gypsum, above the recommended levels, have been used on a regular basis to deepen plant roots and to alleviate recurrent water stress in Cerrado areas. However, very little is known about the consequences of this practice to arbuscular mycorrhizal fungi (AMF). Therefore, the objective of this study was to evaluate whether or not applying high rates of agricultural gypsum affects the mycorrhizal fungi community, glomalin content and coffee yield. The study rates were: 0; 3.5; 7.0; 14 and 56 t·ha-1 of agricultural gypsum applied in the planting row of the coffee plantation on top of the previous recommended gypsum application. Samples were collected for analysis at the depths of 0-20, 20-40 and 40-60 cm at the end of dry and rainy seasons of the year. In the coffee plantation, 16 AMF species were identified. Gigaspora sp. and Glomus macrocarpum were dominant in all situations. The rate of 7 t·ha-1 favored greater diversity of AMF species and the rate of 56 t·ha-1 reduced AMF diversity and mycorrhizal colonization in deeper layers. In the rainy season, there was a linear decrease of easily extractable glomalin-related soil protein (EE-GRSP) levels as the agricultural gypsum rate was increased. Coffee yield was reduced with the highest gypsum rate (56 t·ha-1), even though the coffee plantation had higher phosphorus contents in beans and leaves. This may have resulted from a number of reasons, including a negative effect on the AMF community.