masterThesis
Regulação coordenada da mobilização de lipídios e proteínas por hormônios, fontes de carbono e nitrogênio durante o crescimento pós-germinativo em Girassol
Fecha
2012-10-17Registro en:
GALVÃO, Thiago Barros. Regulação coordenada da mobilização de lipídios e proteínas por hormônios, fontes de carbono e nitrogênio durante o crescimento pós-germinativo em Girassol. 2012. 73 f. Dissertação (Mestrado em Bioquímica; Biologia Molecular) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Galvão, Thiago Barros
Resumen
The mobilization of food reserves in storage tissues and allocation of their
hydrolysis products in the growing axis are critical processes for the establishment of
seedlings after germination. Therefore, it is crucial for mobilization of reserves to be
synchronized with the growing axis, so that photosynthetic activity can be started before
depletion of reserves. For this, integrative approaches involving different reserves,
different hydrolysis products and interaction between storage and growing axis tissues,
either through hormones or metabolites with signaling role, can contribute greatly to the
elucidation of the regulation mechanisms for reserve mobilization. In this study, was
hypothesized that hormones and metabolites have different actions on reserve
mobilization, and there must be a crossed effect of sugars on the mobilization of
proteins and amino acids on lipids and starch mobilization in sunflower seedlings. This
study was conducted with seeds of sunflower (Helianthus annuus L.) hybrid Helio 253
using in vitro culture system. Seeds were germinated on Germitest® paper and grown on
agar-water 4 g/L without addition of nutrients during 9 days after imbibition (DAI) for
growth curve. To verify the effect of metabolites and hormones, seedlings were
transferred in the 2nd DAI to agar-water 4 g/L supplemented with increasing
concentrations of sucrose or L-glutamine, abscisic acid, gibberellic acid or indolebutyric
acid. The results of this study confirm that the mobilization of lipids and storage proteins
occurs in a coordinated manner during post-germination growth in sunflower,
corroborating the hypothesis that the application of external carbon (sucrose) and
nitrogen (L-glutamine) sources can delay the mobilization of these reserves in a crossed
way. Moreover, considering the changes in the patterns of reserve mobilization and
partition of their products in seedlings treated with different growth regulators, it is
evident that the effects of metabolites and hormones must involve, at least in part,
distinct mechanisms of action