Navegando por Autor "Sant’Anna-Santos, Bruno Francisco"
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Item Carfentrazone-ethyl and glyphosate drift inhibits uredinial formation of Austropuccinia psidii on Eucalyptus grandis leaves(Pest Management Science, 2019-01) Santos, Samuel Alves dos; Tuffi-Santos, Leonardo David; Tanaka, Francisco André Ossamu; Sant’Anna-Santos, Bruno Francisco; Rodrigues, Fabrício de Ávila; Alfenas, Acelino CoutoThe response to infection of Austropuccinia psidii in resistant (CLR‐383) and susceptible (CLR‐384) Eucalyptus grandis clones, exposed to herbicide drift of carfentrazone‐ethyl, glyphosate and a mixture of these two herbicides, was evaluated at microscopic and physiological levels.Plants of the two clones showed symptoms of phytotoxicity caused by herbicide drift. However, net CO2 assimilation rate, height and shoot dry matter were lower in CLR‐384 than in CLR‐383. At the ultrastructure level, the leaves of both clones exposed to the herbicides showed thylakoid disorganization and accumulation of starch grains in the chloroplasts. Only plants of CLR‐384 were infected by A. psidii, but when exposed to herbicide drift, rust severity was lower than in control plants. Six days after inoculation (dai), plants of this clone exposed to the herbicides had smaller uredinia than control plants. At 12 dai, non‐herbicide treated plants showed normal uredinia, containing abundant urediniospores. By contrast, plants exposed to the herbicides were less colonized by the fungus, and the uredinia were smaller with reduced production of urediniospores, which were sometimes not even detected. Glyphosate and carfentrazone‐ethyl herbicide drift reduce infection and uredinial formation of A. psidii and to some extent induce basal resistance in a susceptible clone of E. grandis.Item Effects of emissions from an aluminium smelter in a tree tropical species sensitive to fluoride(Water, Air, & Soil Pollution, 2014-01) Sant’Anna-Santos, Bruno Francisco; Azevedo, Aristéa Alves; Alves, Thiago Gonçalves; Campos, Naiara Viana; Oliva, Marco Antônio; Valente, Vânia Maria MoreiraFluoride is among the most phytotoxic atmospheric pollutants, commonly linked to the appearance of lesions in susceptible plants around emitting sources. In order to assess the effects of fluoride on leaves of Spondias dulcis Parkinson (Anacardiaceae), plants were examined 78 km (non-polluted area) and 0.78 km (polluted area) from an aluminium smelter. The level of fluoride increased with the exposure time of the plants in the polluted area. On the third day of exposure in the polluted area, necroses with typical colouration were observed. Micromorphological damage began at the abaxial epidermis, mainly associated with the stomata. Starch grain accumulation was more pronounced in the midrib. The cell membranes and chloroplasts were greatly affected by the pollutant. We observed accumulation of phenolic compounds and electron-dense material at the boundaries of the ending veinlets. The microscopic events described precede the appearance of symptoms and are therefore of prognostic value in predicting injury by fluoride and will be useful as biomarkers. The high sensitivity of S. dulcis to fluoride and the specificity of the symptoms confirm, for the first time, in an experiment of active biomonitoring, the potential of this species as a bioindicator.Item Effects of simulated acid rain on the foliar micromorphology and anatomy of tree tropical species(Environmental and Experimental Botany, 2006-12) Sant’Anna-Santos, Bruno Francisco; Silva, Luzimar Campos da; Azevedo, Aristéa Alves; Araújo, João Marcos de; Alves, Ericka Figueiredo; Silva, Eldo Antônio Monteiro da; Aguiar, RosaneIn order to correlate sintomatology with anatomical alterations caused by acid rain in leaves of tropical species, seedlings and saplings of Spondias dulcis Forst. F., Mimosa artemisiana Heringer and Paula and Gallesia integrifolia (Spreng.) Harms were exposed to simulated low-pH acid rain (pH 3.0). Control plants were submitted only to rain with distilled water (pH 6.0). The plants were exposed daily to the acid rain for 20 min for 10 consecutive days. Necrotic spots on the leaf blade occurred and most of the injuries onset on the epidermis in all species studied. S. dulcis displayed epicuticular wax erosion and rupture of epidermis. The abaxial surface of M. artemisiana was colonized by a mass of fungi hyphae and stomatal outer ledge rupture occurred. Some epidermal cells of G. integrifolia showed appearance similar to plasmolysis. The plants accumulated phenolic compounds in necrotic areas. Afterwards, leaves presented injuries in the mesophyll and collapsed completely. Cells surrounding the injured areas accumulated starch grains in S. dulcis. M. artemisiana showed more drastic symptom intensity in response to acidic rain. S. dulcis displayed visual symptoms similar to G. integrifolia, however, anatomical alterations were more severe.Item Morphological responses of different eucalypt clones submitted to glyphosate drift(Environmental and Experimental Botany, 2007-01) Santos, Leonardo David Tuffi; Meira, Renata Maria Strozi Alves; Ferreira, Francisco Affonso; Sant’Anna-Santos, Bruno Francisco; Ferreira, Lino RobertoThis work aimed to evaluate the effects of simulated glyphosate drift on leaf growth and micromorphology of Eucalyptus spp. clones, using subdoses. A factorial scheme consisting of three clones, Eucalyptus urophylla, E. grandis and the hybrid E. urophylla × E. grandis (E. urograndis) and five sub-rates (0; 43.2; 86.4; 172.8 and 345.6 g e.a. ha^−1 of glyphosate) were used in a randomized block design, with four repetitions. The herbicide was applied on the plants so as not to reach the superior third, 23 days after seedling planting. At 7 and 15 days after application (DAA), the leaves collected from the first basal branch of the plants were processed according to the conventional methodology used for micromorphological studies. The effects of glyphosate drift were proportional to the rates tested, with E. urophylla being more tolerant to the herbicide than E. grandis and E. urograndis. Glyphosate symptoms were the same for the different clones tested, being characterized by wilting, chlorosis and leaf curling, and, at higher rates, by necrosis, foliar senescence and death of the eucalypt plants. Plants submitted to 172.8 and 345.6 g ha^−1 of glyphosate had severe injuries in the aerial part, affecting their development, resulting in reduced height, stem diameter and dry mass at 50 DAA. The micromorphological damages occurred prior to the appearance of visible symptoms, with erosion of the epicuticular waxes and fungal hypha infestation in plants exposed to glyphosate drift being observed in the three clones. No marked difference in leaf micromorphology was observed that could explain the differential tolerance among the three clones studied. The results show that further studies on wax and cuticle constitution of Eucalyptus spp. are needed for the elucidation of the mechanisms of differential tolerance of eucalypt species and clones to glyphosate.Item Toxicidade e acúmulo de flúor em hortaliças nas adjacências de uma fábrica de alumínio(Acta Botanica Brasilica, 2010-10) Sant’Anna-Santos, Bruno Francisco; Azevedo, Aristéa Alves(Toxicidade e acúmulo de flúor em hortaliças nas adjacências de uma fábrica de alumínio). Com o objetivo de avaliar o potencial de acumulação de flúor e o percentual deste elemento removido pela lavagem, quatro espécies de hortaliças foram expostas em área poluída. Spondias dulcis foi utilizada como bioindicadora de reação e apresentou sintomas típicos em resposta ao poluente. Somente a salsa apresentou sintomas. Apesar de aparentemente sadias, as folhas das outras espécies utilizadas para estudos microscópicos, exceto da cebolinha, evidenciaram alterações na superfície, principalmente associa- dos aos estômatos. Houve redução na espessura do limbo, mais acentuada no manjericão e na cebolinha, havendo formação de tecido de cicatrização na couve e condensação do conteúdo das células epidérmicas na salsa. As folhas subuladas e eretas da cebolinha favoreceram o menor acúmulo do poluente; já na salsa, as folhas laminares, recortadas e paralelas ao solo contribuíram para a maior retenção. A lavagem das folhas removeu 34,1 e 73,9% do flúor na cebolinha e na salsa, respectivamente, indicando que a maior parte do poluente encontrava-se internamente na cebolinha e externamente na salsa. O cultivo destas hortaliças em áreas poluídas por flúor é inadequado, pois os teores do poluente estão acima do recomendado para o consumo, mesmo após a lavagem das folhas.