Rúbia Santos Fonseca

Microenxertia ex vitro para eliminação do vírus CABMV em maracujá-azedo

O objetivo deste trabalho foi avaliar diferentes meios de cultura, utilizados sobre o ponto da enxertia, na microenxertia ex vitro para a eliminacao do Cowpea aphid-borne mosaic virus (CABMV), em plantas de maracuja-azedo (Passiflora edulis Sims f. flavicarpa Deg.). Apices caulinares, provenientes de plantas infectadas, foram microenxertados em plântulas obtidas pela germinacao de sementes em substrato comercial esterilizado. Foram conduzidos experimentos com a microenxertia realizada no hipocotilo e no epicotilo, e foram utilizados cinco meios de cultura, que diferiam na concentracao de fitorreguladores, aplicados no local da enxertia. O indice medio de microenxertos com folha expandida foi de 27,22 e 32,22%, quando a microenxertia foi realizada no hipocotilo e no epicotilo, respectivamente. Na microenxertia realizada no hipocotilo, nao houve efeito da aplicacao de meios de cultura. Na microenxertia realizada no epicotilo, o meio MS acrescido de 0,1 mg L-1 de AIB e 1 mg L-1 de BAP proporcionou 53,3% de microenxertos com folha expandida, numero superior aos demais tratamentos e maior desenvolvimento das brotacoes. A indexacao realizada pelo teste ELISA indireto, 80 a 100 dias apos a microenxertia, mostrou que 93% das plantas testadas nao apresentavam virus detectavel.

Species richness of anthophilous butterflies of an Atlantic Forest fragment in Southeastern Brazil

The objectives of this study were to identify anthophilous butterflies on psychophilous flowers of four Asteraceae species in an Atlantic Forest fragment in Vicosa, Minas Gerais State, Southeastern Brazil, and to determine whether there are species in common with other lepidopteran inventories of the Southeastern and Midwestern regions of Brazil. It is the first inventory of anthophilous butterflies of a semideciduous forest fragment in Zona da Mata, State of Minas Gerais. A total of 108 species were recorded, representing the fourth lar gest lepidopteran survey in this S tate. The results demonstrated that Asteraceae species may be important tools for monitoring anthophilous butterflies. The similarity with other inventories ranged from 1 to 92.55%. Fifteen species were reported for the first time in the State of Minas Gerais, and among them, Melanis alena and Thisbe irenea were observed in this study only.

Is the pollination efficiency of long-lived orchid flowers affected by age?

The long-lived flowers of orchids increase the chances of pollination and thus the reproductive success of the species. However, a question arises: does the efficiency of pollination, expressed by fruit set, vary with the flower age? The objective of this study was to verify whether the flower age of Corymborkis flava(Sw.) Kuntze affects pollination efficiency. The following hypotheses were tested: 1) the fruit set of older flowers is lower than that of younger ones; 2) morphological observations (perianth and stigmatic area), stigma receptivity test by using a solution of hydrogen peroxide and hand-pollination tests are equally effective in defining the period of stigmatic receptivity. Flowers were found to be receptive from the first to the fourth day of anthesis. Fruit set of older flowers (third and fourth day) was lower than that of younger flowers. Morphological observations, the stigma receptivity test and hand-pollinations were equally effective in defining the period of stigmatic receptivity. However, to evaluate the maximum degree of stigma receptivity of orchid species with long-lived flowers, we recommend hand-pollinations, beyond the period of receptivity.