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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11846

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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, Rosane
In 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.
Manganese accumulation and its effects on three tropical aquatic macrophytes: Azolla caroliniana, Salvinia mínima and Spirodela polyrhiza
(Rodriguésia, 2011-10) Lizieri, Claudineia; Aguiar, Rosane; Kuki, Kacilda Naomi
The phytoremediation technique, which consists of using plants to remove ions, has been increasingly chosen over past decades due to its low-cost technology to mitigate contaminated areas. The aim of this study was to evaluate the potential of the aquatic macrophytes, Azolla caroliniana Willd, Salvinia minima Baker and Spirodela polyrhiza (L.) Schleiden, to accumulate manganese (Mn), an element which, at high concentrations, may be toxic to human populations. The three species accumulated Mn in their tissues and the absorption was independent of the metal concentration in the solution. Spirodela polyrhiza accumulated Mn at higher concentrations of the ion (17.062 mg g-1 MS), followed by S. minima (4.283 mg g-1 MS) and A. caroliniana (1.341 mg g-1 MS). Manganese excess reduced total chlorophyll content in all three species. Carotenoid content was reduced in A. caroliniana (27.02 %) and S. polyrhiza (25.34 %). Growth was only significantly reduced (21.34%) in S. polyrhiza. The species A. caroliniana and S. minima were able to tolerate excess Mn, but were inefficient regarding the accumulation of high concentrations of the metal. High accumulated Mn content in the tissues of S. polyrhiza suggests that the species is able to accumulate this element. Therefore, it has potential for use in phytoremediation and provides a new resource for exploring the Mn accumulation mechanism.
Utilização de parâmetros morfoanatômicos na análise da fitotoxidez do flúor em folhas de Magnolia ovata (A. St.-Hil.) Spreng. (Magnoliaceae)
(Revista Árvore, 2007-03-29) Sant'Anna-Santos, Bruno Francisco; Duque-Brasil, Reinaldo; Azevedo, Aristéa Alves; Silveira, Alice de Souza; Araújo, João Marcos de; Aguiar, Rosane
Com os objetivos de avaliar o grau de suscetibilidade e caracterizar as injúrias na morfoanatomia de folhas de Magnolia ovata, mudas foram submetidas à chuva simulada com flúor (10 µg.ml-1 de F-) por 10 dias consecutivos. No tratamento controle, utilizou-se apenas água deionizada. Folhas foram coletadas para quantificação de flúor na matéria seca e fixadas para análises em microscopia de luz e eletrônica de varredura. As folhas apicais apresentaram pequena porcentagem de necroses intervenais e marginais em uma ou ambas as faces e maior acúmulo de flúor, em relação ao controle, quando comparadas com as folhas da porção basal. A análise micromorfológica das folhas aparentemente sadias indicou alterações nas paredes periclinais externas da epiderme e formação de concavidades, além de cristas estomáticas danificadas, erosão de ceras epicuticulares e presença de esporos e hifas de fungos. A caracterização estrutural das injúrias evidenciou retração de protoplasto das células epidérmicas, colapso das células do mesofilo e da epiderme e acúmulo de compostos fenólicos em células das regiões necrosadas. As alterações micromorfológicas das folhas ocorreram antes que sintomas fossem observados, o que comprova a importância da micromorfologia na diagnose precoce da injúria. As plantas de M. ovata apresentaram poucos sintomas visuais em resposta ao flúor, entretanto as alterações morfoanatômicas indicam que essa espécie possui potencial para ser utilizada como bioindicadora.