Seed germination and light quality action on vegetative development and phytochemistry aspects of Catharanthus roseus (L.) G. Don. / GerminaÃÃo de sementes e aÃÃo da qualidade da luz sobre o desenvolvimento vegetativo e aspectos fitoquÃmicos de Catharanthus rosesus (L.) G. Don

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Periwinkle (Catharanthus roseus (L.) G. Don), Apocynaceae, is recognized by its medicinal importance as producer alkaloids with anticancer action (vinblastine and vincristine). This work aimed to evaluate the temperature and light effects on imbibition and seed germination aspects, plant vegetative development features of this species shaded by different color nets (black, blue and red), and the influences of light provided by fluorescent colored lamps and the plant age on alkaloid profile of two different Catharanthus roseus cultivars. The imbibition behavior of this species was altered by the GA3 treatment, which, in comparison with untreated seeds, increased the imbibition rate and the final germination percentage. Seeds presented a preferentially photoblastic negative germination, with a lower cumulative germination and germination percentage, and lower GVI in presence of light in all tested temperatures. The red net increased total dry matter and total leaf area of plants in relation to blue net, black net and the full sun treatment, and lower foliar nitrogen and pigments content in comparison to blue and black nets. The irradiance showed most prominent effect than spectral alteration on root/aerial part, chlorophyll a/b ratios, leaf area and leaf dry weight ratios of plants growth under full sun in relation to shaded plants Treatments with colored lamps altered the morphological aspect of seedlings. Seedlings developed under red lamp showed higher stem length in comparison to other light treatments, prostrated aspect and reduced cotyledons. A m/z 793 (vinblastine) peak, as well as its monomeric precursors vindoline (m/z 457) and catharanthine (m/z 337) were detected in significantly intensity only in the 180 daysâ plant extract. For the cultivar Victory Pure White, the relative intensities of vindoline were very lower than that presented by the cultivar Pacifica White under all light treatments.

ASSUNTO(S)

coloured nets agronomia alkaloids catharanthus roseus germinaÃÃo catharanthus roseus malhas coloridas germination vegetative development alcalÃides desenvolvimento vegetativo

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