Caracterização física de frutos e putâmens e taxa de ataque por Carmenta sp. a pequizeiros (Caryocar brasiliense Camb.) no norte de Minas Gerais

O pequizeiro é uma espécie nativa do cerrado brasileiro, cujos frutos, explorados de forma extrativista, têm grande importância econômica. O extenso período de oferta dos frutos do pequi, aliado à heterogeneidade das regiões produtoras levam a crer na existência de diferenças entre as suas características físicas. Dessa forma, este trabalho objetivou comparar as características físicas de frutos de pequizeiro coletados em três municípios do norte de Minas Gerais e verificar se a taxa de ataque por Carmenta sp. está diretamente relacionada com as características biométricas. Assim, foram marcados 10 indivíduos e coletados 20 frutos de cada árvore, em Montes Claros, Mirabela e Japonvar, totalizando 200 frutos por área. Foram determinados as variáveis físicas dos frutos e dos putâmens, o número de frutilhos, de putâmens e de sementes e a porcentagem de frutos e de putâmens intactos e danificados. Os resultados indicaram que há diferenças nas características físicas entre as localidades, possuindo a região de Japonvar os putâmens mais vigorosos e com menor taxa de ataque pela broca-do-pequizeiro. Além disso, a porcentagem de ataque por Carmenta sp. relacionou-se com a espessura da casca e o comprimento dos frutos nas localidades de Japonvar e Mirabela, respectivamente. As diferenças encontradas entre as localidades podem estar associadas às influências climáticas e edáficas das regiões, que podem ressaltar certos aspectos de sua composição genética

Hemiparasitism effect on Baccharis dracunculifolia DC. and consequences to its major galling herbivore

ABSTRACTMistletoes obtain nutrients and water from their hosts, with varying effects among those hosts. We assessed the factors that influence the colonization of the mistletoe Struthanthus flexicaulis on Baccharis dracunculifolia and the subsequent effects on host performance. We evaluated the incidence of S. flexicaulis according to size (height classes) and architecture of the host as well as its effects on various physiological parameters of the host. Furthermore, we assessed the occurrence of insect galls induced by Baccharopelma dracunculifoliae(Psyllidae), including the number of leaves infected, and the mortality of infected and non-infected branches. Taller hosts had a higher abundance of mistletoes (60%, p> 0.05). Physiological parameters of hosts were not affected by parasitism, although galling occurred more often (p <0.05) and leaf loss increased (p>0.05) on infected branches. Taller individuals are more colonized by mistletoes and more architecturally complex hosts support a greater number of mistletoes. Mistletoe causes a top-down effect on host-associated organisms on parasitized branches. Mistletoes had a strong top-downeffect on B. dracunculifolia due to a reduction in the number of leaves on parasitized branches and the replacement of the bush crown, as well as an increased incidence of insect galls. Furthermore, the occurrence of a heavy parasite load increased the mortality rate of the host branches

Advances in Arbuscular Mycorrhizal Taxonomy

Taxonomy, the science of classifying organisms, describes names, identifies organisms, and generates tools for taxonomic identification of fungi. The products of taxonomy are used by taxonomists and ecologists. Correct species names are deliberately used for instance on land management systems to compare ecological interactions between the different components. Current classification systems of Arbuscular mycorrhizal fungi (AMF, Glomeromycota) involve both morphological and molecular tools and their progress shows in some measure a natural organization and understanding of the relationships among species. Several research groups have been discussing the taxonomy, systematics, and evolution of AMF. The researchers may propose their classification system; however, most biologists believe that these developing systems only reflect our knowledge at time. This chapter presents an overview of data showing AMF classification, and recent advances are here compiled. Our goal was to provide nonspecialists such as researchers in other fields and land managers with information on historical and recent changes in AMF classification

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq