Temporal and Spatial Changes in Host Defense Enzymes in Response to Fusarium Wilt in Pigeonpea (Cajanus cajan (L.) Millspaugh)

Fusarium wilt caused byFusarium udumButler(Fud) is a constant threat to pigeonpea productivity in several parts of the world. Understanding the molecular basis of pigeonpea-Fudinteraction is necessary to improve resistance to Fudand thereby the productivity of pigeonpea. Temporal and spatial changes were studied in defense enzymes namely catalase, peroxidase (PO), polyphenol oxidase (PPO), Phenylalanine ammonia lyase (PAL), ?-1,3-glucanase and chitinase at pre-initiation (S1), disease initiation (S2) and severe diseased (S3) stages in root, stem and leaf tissues of 2 susceptible and 2 resistant cultivars of pigeonpea inoculated with Fud. Comparison of various treatment combinations revealed that all the defence enzymes showed temporal and spatial variation in activity/expression pattern. PO increased in all the tissues of all the varieties from S1 to S2 and declined thereafter in S3 stage, and induction was higher in resistant cultivars. Catalase and PPO were induced highly in resistant cultivars inoculated with Fud, and the pattern was stage-specific and tissue-specific in nature. Catalase induction occurred at S2 in uninoculatedplants whereas it started at S1 in Fudinoculatedplants. PPO level diminished from S2 to S3 stage, and in susceptible varieties, it reached even below the control. PAL, ?-1,3-glucanase and chitinase activity were induced at S1, and S2 and values at S3 decreased progressively. Induction of chitinase was significantly high in leaves whereas ?-1,3-glucanase activity was high in stem tissues. Both control and challenged plants had a higher level of ?-1,3-glucanase activity at later stages of disease development, but the proportionate increase was much higherin resistant cultivars. The activity/expression pattern of these defence enzymes reveals their use as biochemical markers for resistance and provides scope for manipulating their expression and development of wilt-resistant transgenic pigeonpea

Uso de entrevistas on-line no método de explicitação do discurso subjacente (MEDS) / Use of online interviews in the underlying discourse unveiling method (UDUM)

Tradicionalmente, tal como outros métodos qualitativos que usam entrevistas, a coleta de dados do MEDS é realizada em encontros presenciais que têm como modelo as conversas cotidianas em contextos informais. Com o advento da Internet, grande parte dessas conversas migrou para os ambientes de troca instantânea de mensagens on-line, que se popularizaram rapidamente. O argumento central deste trabalho é o de que, desde então, a coleta de dados por meio de entrevistas on-line, baseadas no modelo das conversas cotidianas informais que também ocorrem on-line, se tornou um procedimento de pesquisa sério e viável. São, portanto, discutidas as especificidades, requisitos, vantagens e desvantagens desta nova forma de entrevista. São, ainda, revelados o histórico, os raciocínios e as necessidades que a legitimam.

Traditionally, as in other qualitative methods that use interviews, data collection in UDUM is done in face-to-face encounters based on the model of daily conversations in informal contexts. With the advent of the Internet, a large part of such conversations migrated to online environments of instant message exchanges, which soon became widely popular. The main argument of this paper is that, since then, data collection through informal online interviews, which have equally informal online daily conversations as a model, has become a serious and viable research procedure. Specificities, requisites, advantages and disadvantages of this new form of interview are, therefore, discussed. The history, reasoning and needs that legitimate it are also revealed.

O campo da pesquisa qualitativa e o Método de Explicitação do Discurso Subjacente (MEDS) / The field of qualitative research and the Underlying Discourse Unveiling Method (UDUM)

Desde o final do século XX, uma revolução qualitativa vem ocorrendo nas ciências sociais e humanas. Impelidos pela necessidade de explorar a fundo novos fenômenos humanos e sociais, inúmeros pesquisadores abandonaram o positivismo e abraçaram metodologias qualitativas. O campo da pesquisa qualitativa passou a abranger uma variedade tão grande de métodos que a discussão das especificidades de qualquer um deles requer a identificação dos pontos em que o método em questão se aproxima ou se distancia dos outros métodos que compõem o campo. Neste trabalho, tal procedimento é usado para a discussão das especificidades do Método de Explicitação do Discurso Subjacente (MEDS).

Since the end of the 20th century, a qualitative revolution has been going on in the social and human sciences. Prompted by the need to attain deeper knowledge of new human and social phenomena, several researchers abandoned positivism and embraced qualitative methodologies. The field of qualitative research has become so vast that a discussion of the specificities of any particular method requires the identification of the similarities and differences that exist between such method and the various other methods in the field. In the present paper, this procedure is used for the discussion of the specificities of the Underlying Discourse Unveiling Method (UDUM).