Production, morphologic and ultra-structural analyses of Passiflora spp. callus. / ObtenÃÃo, anÃlises morfolÃgicas e ultra-estruturais de calos de Passiflora spp.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Brazil occupies a position of prominence in the passion fruit plant culture, being the largest world producer of passion fruit. In the last years, the increasing demand resulted in a expansion of the planted area resulting in the expansion and appearance of many diseases. Some species not cultivated, as Passiflora gibertii N. E. Brown and Passiflora edulis edulis, present important contributions for plant breeding, for having pests and diseases resistance, longevity, larger adaptation to adverse climatic conditions, enlarged flowering period, larger concentration of interesting chemical components for the pharmaceutical industry and other potentialities, almost unexplored. The objective of this work was to analyze in vitro regeneration and germination aspects, as well as to characterize, at morphologic and ultra- structural levels, callus of Passiflora spp. The results allow to affirm that the native species P. gibertii has mechanical extra-embryonic dormancy, that is overcome with seed tip scarification using a scalpel. Fresh seeds present larger germination percentage than the dry seeds, however, larger germination percentage for dry seeds are obtained using tip scarification. The P. gibertii species respond better to the callus formation than native P. edulis edulis; the use of 8,88 μM BAP promotes larger callus percentage from leaf segments; root segments of P. gibertii and native P. edulis edulis do not form callus and there is no difference between leaf and nodal segments in the formation of native Passiflora species callus; P. gibertii leaf and nodal segments, after transferred to MSM medium containing GA3, form bud; callus from dark conditions are more responsive to MS medium contain half of its salt concentration is the most inducated for organogenesis; the addition of coconut water to the culture medium is essential for callus induction and bud formation in P. gibertii. The picloram and kinetin addition to the culture medium promotes larger callus formation in cotyledonary leaf explants of P. gibertii than 2,4-D and kinetin. Different callus colors, from the cotyledonary leaf explants, are observed in treatments using picloram and kinetin. P. gibertii leaf explants inoculated in MS culture medium and maintained in the dark in the presence of BAP (8,88 μM) and coconut water (5%) for 30 days, induce callus formation, which, later transferred to MS medium, in the presence of light and BAP (2,22 μM) turned organogenic, whose ultra-structural and morphologic parameters associated were of isodiametric cells, presenting organized cellular system, nucleus with prominent nucleolar, presence of starch grains and dense cytoplasm rich in endoplasmic reticulum. The growth regulator 2,4-D provides the obtaintion of callus with embryogenic characteristics (cells with isodiametric format, small and with small intercellular space, organized cellular system and predominance of round format mitochondria), while negative results (predominance of prolonged format cells, larger cells with intercellular spaces, disorganized cellular system and predominance of prolonged format mitochondrias) are observed when picloram is used. Translucent and yellow-clear callus present no-morfogenic characteristics, like cells of different formats, disorganized cellular system, larger cells and absence or reduced starch content. Callus of yellow-darkness and white-brown coloration presented embryogenic characteristics with the following morphologic and ultra-structural parameters: predominance of isodiametric format cells, organized cellular system, small cells, dense cytoplasm rich in mitochondria and endoplasmic reticulum.

ASSUNTO(S)

in vitro germination germinaÃÃo in vitro morphologic and ultra-structural analyses fisiologia vegetal maracujazeiro nativo calogenesis anÃlises morfolÃgicas e ultra-estruturais native passion fruit plant calogÃnese

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