Details

Autor(en) / Beteiligte

• Sant'Anna-Santos, Bruno Francisco
• Silva, Luzimar Campos da
• Azevedo, Aristéa Alves
• Aguiar, Rosane

Titel

Effects of simulated acid rain on leaf anatomy and micromorphology of Genipa americana L. (Rubiaceae)

Ist Teil von

• Brazilian Archives of Biology and Technology, 2006-03, Vol.49 (2), p.313-321

Ort / Verlag

Instituto de Tecnologia do Paraná - Tecpar

Erscheinungsjahr

2006

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• Experiments were conducted in order to characterize the injuries on leaf structure and micromorphology of G. americana and evaluate the degree of susceptibility of this species to simulated acid rain. Plants were exposed to acid rain (pH 3.0) for ten consecutive days. Control plants were submitted only to distilled water (pH 6.0). Leaf tissue was sampled and fixed for light and scanning electron microscopy. Necrotic interveinal spots on the leaf blade occurred. Epidermis and mesophyll cells collapse, hypertrophy of spongy parenchyma cells, accumulation of phenolic compounds and starch grains were observed in leaves exposed to acid rain. The micromorphological analysis showed, in necrotic areas, plasmolized guard cells and cuticle rupture. Epidermal and mesophyll cells alterations occurred before symptoms were visualized in the leaves. These results showed the importance of anatomical data for precocious diagnosis injury and to determine the sensitivity of G. americana to acid rain. Experimentos foram conduzidos para avaliar o grau de susceptibilidade e determinar as injúrias causadas pela chuva ácida simulada na anatomia e micromorfologia foliar de Genipa americana. Plantas foram expostas à chuva com pH 3,0 durante 10 dias consecutivos. No tratamento controle utilizou-se apenas água destilada (pH 6,0). Amostras foliares foram coletadas e fixadas para microscopia de luz e eletrônica de varredura. Foram observados nas folhas expostas à chuva ácida: necroses pontuais intervenais, colapso das células do mesofilo e da epiderme; hipertrofia do parênquima lacunoso e acúmulo de compostos fenólicos e grãos de amido. A análise micromorfológica evidenciou, nas áreas necrosadas, plasmólise das células-guarda e ruptura da cutícula e da crista estomática. Alterações anatômicas ocorreram antes que sintomas visuais fossem observados nas folhas. Estes resultados comprovam a importância de dados anatômicos na diagnose precoce da injúria e na determinação da sensibilidade de G. americana à chuva ácida.