Acta Scientiarum: Biological Sciences (Apr 2009)
Efeitos da radiação ultravioleta-C sobre a simetria e morfoanatomia foliar de Rapanea ferruginea (Ruiz et. Pav) Mez. (Myrsinaceae) = Effects of ultraviolet-C radiation on symmetry and morphoanatomy of Rapanea ferruginea (Ruiz et. Pav) Mez. (Myrsinaceae) leaves
Abstract
Neste estudo, analisaram-se os efeitos da radiação UV-C sobre odesenvolvimento de folhas de Rapanea ferruginea. Plantas jovens foram selecionadas com seis meses de idade identificando-se as folhas já diferenciadas do 3º, 4º, 6º, 8º e 9º nó. Posteriormente, as plantas foram divididas em três grupos e submetidas à radiação UV-Cpor 30, 60 ou 120 min. seguidos. Para o estudo anatômico, foram utilizadas técnicas usuais de corte e coloração. As análises morfométricas foram realizadas determinando-se três pontos ao longo da nervura central da folha, medindo-se das bordas esquerda (E) e direita (D) até cada um desses pontos. Determinaram-se também os desvios de simetria, o comprimento e a largura máxima do limbo, submetendo os valores à Anova e ao teste de Tukey (p This study analyzed the effects of UV-C radiation on the development of Rapanea ferruginea leaves. Young plants were selected at six months of age, previously identifying the leaves that had already differentiated on the 3rd, 4th, 6th 8th and 9th nodes. After the selection, the plants were divided into three groups and subjected to UV-C radiation for 30, 60 or 120 minutes. The anatomic study wasmade by using usual techniques of cut and coloration. The morphometric analyses were made by determining three points on the midvein of the leaf, measuring from left (L) and right (R)borders to each of those points. The symmetry deviations, maximum length and width of the limb were measured and the values were submitted to Anova and the Tukey-test (p < 0.05). The responses of R. ferruginea to the UV-C were expressed by variations in the symmetry aswell as morphoanatomic injuries, mainly in the palisade parenchyma and mesophyll. The differentiation of leaves did not follow a morphometric pattern, characterizing no directional asymmetry, i.e., fluctuating asymmetry. This study emphasizes the importance of multiscale observations for the determination of plant responses under stress, since several leaves showed anatomic injuries but no morphologic injuries.
