The development associated with the research field involving crystalline inorganic lamellar titanium hydrogenphosphate, Ti(HPO4).H2O, synthesized as alpha or gamma forms, is directly linked to the huge number of reactions, that occur inside the free interlamellar space. Two distinguishable well-characterized features such as ion-exchange and intercalation reactions are explored here. From the interactive point of view, the acidic OH centres distributed on the lamella can interact with cations or with basic polar molecules to exchange or to intercalate them. These chemical reactions are normally followed by an expansion of the interlamellar space, proportional to the amount intercalated, reflecting in ion radii or organic molecule size lengths used in ion-exchange or insertion processes, respectively. The effectiveness of the exchange increased when the original matrix has the proton of OH group previously ion-exchanged by an alkaline or an alkylammonium cations. Monoalkyl-, dialkyl- and heterocyclic amines are focused in this revision as clear and elucidative examples of acid-base interactive processes, that come out inside of the well-formed infinite sequence of inorganic lamellar structure.

O objetivo deste trabalho foi identificar os biótipos de Bemisia tabaci (Genn.) presentes no estado do Paraná e determinar sua distribuição geográfica e plantas hospedeiras. Cerca de 50 adultos foram coletados em diversas culturas hospedeiras, plantas daninhas e ornamentais, nas regiões Norte, Noroeste, Nordeste, Oeste e Centro do estado, de janeiro a maio, durante os anos de 1998 e 1999. As espécies foram identificadas por meio de RAPD-PCR, usando-se o primer Operon H-16. Populações de mosca branca foram detectadas a partir do mês de fevereiro em ambos os anos, raramente atingindo níveis superiores a um adulto por folha. O inseto foi encontrado em somente 66% das áreas amostradas e o mosaico dourado do feijoeiro praticamente não foi detectado durante o período. Ambos biótipos A e B de B. tabaci foram coletados no estado do Paraná, sendo o biótipo B mais restrito à Região Norte. Apesar de este biótipo ter sido encontrado colonizando uma faixa maior de plantas hospedeiras, ele não ainda não se encontra amplamente distribuído nas diversas regiões e a maior parte dos espécimes coletados foram identificados como biótipo A. Um padrão de bandas distinto daqueles obtidos para os biótipos A e B de B. tabaci foi obtido exclusivamente com as populações coletadas em mandioca, indicando a possível presença de um biótipo específico para essa cultura.

This work was carried out in order to identify Bemisia tabaci (Genn.) biotypes present in the state of Paraná and to determine their geographical distribution and host plants. About 50 adults were collected in several host crops, weeds and ornamental plants in North, Northwest, Northeast, West and Central areas of the state, from January to May, 1998 and 1999. The species were identified by means of RAPD-PCR, using the primer Operon H-16. Whitefly populations were detected mainly from February on, in both years, seldom achieving more than one adult per leaf. The insect was found in only 66% of the sampled areas. Bean golden mosaic was almost never observed during the period. Both biotype A and biotype B of B. tabaci were found in the State of Paraná, the last one being more restricted to the north region. Although biotype B was found colonising a wider range of host plants, it has not spread out in all the state and most of the whitefly specimens found are still the biotype A. A banding pattern distinct of those obtained for A and biotype B of B. tabaci was obtained exclusively with the populations collected from cassava, thus indicating the possible presence of a biotype specific for this crop.