-Although mango is one of the tropical fruits of greater interest in world trade, literature concerning their rootstocks (characteristics and utilization) is scarce. This study aimed to characterize mango plants from cv. Imbú, widely used as rootstock in the Zona da Mata region, Minas Gerais (MG), Brazil. Though fruits of this cultivar do not present desirable commercial characteristics, this study allowed us to characterize part of plant morphology and fill a gap in the literature, providing subsidies for future investigations. For such, 'Imbú' plants (≈ 4-years old) from the collection of the Universidade Federal de Viçosa, located in Viçosa -MG were evaluated. The descriptors were: (i) leaf blade division;(ii) leaf composition; (iii) petiole length in relation to leaf blade; (iv) phyllotaxis, (v) leaf position in relation to the branch insertion; (vi) leaf shape; (vii) leaf apex and base angles; (viii) leaf margin category; (ix) venation; (x) leaf length and thickness; (xi) leaf length/thickness ratio; (xii) leaf texture; (xiii) leaf fragrance; (xix) leaf color. The leaves were depicted as lanceolate, with entire margins and sharp angles at the base and apex of the leaf blade. The intensity of the green color of the leaf blade was considered intermediate and the abaxial surface staining showed less intense than that observed in the upper side. The fruits were processed and separated into peel, pulp and seeds in order to evaluate the flesh color, fresh weight and percentage of seeds, peel and pulp. Was determined the soluble solids content, starch concentration, the peel and the pulp color, the cerosity, the percentage evaluation of peel, pulp and seed and the pulp firmness. The average number of germinated seedlings per seed was estimated for 230 sown seeds. Index terms: Rootstock, Mangifera indica, morphology CARACTERIZAÇÃO DE FOLHAS E FRUTOS DA MANGUEIRA(Mangifera indica L.) CV. IMBÚ RESUMO -Apesar de a manga ser uma das frutas tropicais de maior interesse no comércio mundial, a literatura sobre os seus porta-enxertos (características e utilização) é escassa. Este estudo teve como objetivo caracterizar as mangueiras da cv. Imbu, amplamente utilizada como porta-enxerto na região da Zona da Mata de Minas Gerais (MG), Brasil. E, embora frutos dessa cultivar não apresentem características comerciais desejáveis, este estudo permitiu caracterizar parte da morfologia da planta e preencher uma lacuna na literatura, fornecendo subsídios para futuras investigações. Para tal, folhas completamente expandidas da porção mediana de ramos expostos à luz solar e frutos plenamente desenvolvidos foram coletados de plantas da cv. 'Imbu' (≈ 4 anos de idade) da coleção da Universidade Federal de Viçosa, localizada no município de Viçosa -MG. Os descritores foram: (i) divisão lâmina de folha; (ii) a composição da folha; (iii) comprimento do pecíolo em relação à lâmina de folha; (iv) filotaxia, (v) a posição das folhas em relação à inserção do ramo; (vi) a forma de folha; (vii) ângulos do vértice da folha e de base; (viii...

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Caused by the vascular fungus Ceratocystis fimbriata, mango wilt is considered to be one of the most serious threats in mango-producing regions worldwide. However, changes in leaf gas exchange level and the mechanisms underlying host responses to this fungal infection remain poorly described. This study aimed to evaluate potential changes in the leaf gas exchange of different mango cultivars (Ubá, Espada, Haden and Tommy Atkins) in response to two Brazilian isolates of C. fimbriata (CEBS15 and MSAK16) to non-invasively assess cultivar variability in relation to the basal level of resistance to mango wilt. Both isolates, regardless of the cultivar, caused reductions in stomatal conductance and, thus, a reduction in CO 2 assimilation via diffusive limitations. Taking into account the full length of the internal lesion and the radial colonization of the stem tissues, both isolates showed equivalent aggressiveness when inoculated into the Haden and Tommy Atkins cultivars. Conversely, when compared to the CEBS15 isolate of C. fimbriata, the MSAK16 isolate was more aggressive in cv. Espada and less aggressive in cv. Ubá.

Brown spot (BS), caused by the fungus Bipolaris oryzae, is one of the most important diseases contracted by rice. We investigated the effect of magnesium (Mg) on the development of BS, caused by Bipolaris oryzae, and the effects of disease development on the photosynthetic performance of rice (Oryza sativa L.) plants (cv. Metica-1) grown in nutrient solutions containing 0.25 or 4.0 mM of Mg. Assessments of BS severity, leaf Mg and pigment concentrations (total chlorophylls and carotenoids), were carried out at 120 h after inoculation, in addition to gas Across the range of studies involving the mitigation of diseases through the use of agricultural practices with nutrition, there are reports of a nonspecific role for Mg, since its influence may either reduce or enhance the severity of disease. Jones and Huber (2007) reported 22 diseases where severity was decreased by supplying additional Mg, 17 where it was increased and 6 that showed a variable effect, depending on the environment. However, few studies relate the effects of Mg also to the physiological traits of the host species.Given the importance of Mg in plant nutrition and the differential evolution of disease symptoms observed in plants exposed to Mg in other pathosystems, the objective of the authors in the present study was to investigate the effects of Mg on BS development relative to the associated alterations in the photosynthetic performance in rice. It was hypothesized that Mg could influence the physiology of rice plants through B. oryzae, and thus enhance the production of substrates available to the production of defense compounds,which favor the mitigation of disease development. Materials and Methods Plant materialRice plants (cv. Metica-1) were grown in Hoagland and Arnon (1950) in a modified nutrient solution consisting of: 1.0 mM KNO 3 , 0.25 mM NH 4 H 2 PO 4 , 0.1 mM