Alterações celulares durante o envelhecimento em sementes de Phaseolus vulgaris L. e Senna reticulata (Willdenow) Irwin &Barneby

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

In this work we compaired cytological and biochemical alterations during loss f viability of seeds of P.vulgaris and S.reticulata. Seeds were submitted to accelerated aging treatment during progressively larger time intervals, and both species suffered loss of viability under these conditions, but S.reticulata was more resistant. No seed of P.vulgaris germinated after 384 hours of accelerated aging, but seeds of S.reticulata did. Several cytological changes were detected during this aging process. Cells walls appear equally metachromatic after all the accelerated aging times, but showed a reduction in glycidic radicals. Protein bodies showed an increase in these radicals, and suffered morphological changes. Gel electrophoresis of albumins and globulins showed a decrease in intensity of some fractions and disappearence of others qith the advance of aging. These alterations were more remarkable in S.reticulata than in P.vulgaris. Protein contents, however decrease significantly in P.vulgaris seeds. Xylidine-Ponceau staining also revealed a decrease in protein contents. P.vulgaris quiescent seeds contain some weak reducing compounds, which suffer a alight increase during aging. These compounds are found in S.reticulata, only in the phloem of quiescent seeds, but spread over the entire cotyledon surface of aged seeds. Starch levels remained constant in both species, but in P.vulgaris starch granules became smaller and more numerous. On the oder hand, S.reticulata showed fewer and larger starch granules with increasing accelerated aging time. Condensation of chromatin accompanied aging in P.vulgaris, while non-viable seeds presented picnotic nuclei and loss of nucleoli. None of these nuclear changes were observed in aged S.reticulata seeds

ASSUNTO(S)

citologia sementes - envelhecimento

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