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Previous issue date: 2012-10-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / 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 / A mobiliza??o das reservas nutritivas nos tecidos de armazenamento e a
aloca??o de seus produtos de hidr?lise no eixo em crescimento s?o processos cr?ticos
para o estabelecimento das pl?ntulas ap?s a germina??o das sementes. Assim sendo,
? necess?rio que a mobiliza??o das reservas seja sincronizada com o crescimento do
eixo de forma que a atividade fotossint?tica tenha iniciado antes que as reservas sejam
exauridas. Para isso, abordagens integrativas envolvendo as diferentes reservas, os
diferentes produtos e o interc?mbio entre os tecidos de armazenamento e o eixo em
crescimento, seja por interm?dio de horm?nios ou metab?litos com papel de
sinaliza??o, podem contribuir sobremaneira para o esclarecimento dos mecanismos
que regulam a mobiliza??o de reservas. Neste trabalho, foram levantadas as hip?teses
de que o efeito de horm?nios e de metab?litos sobre a mobiliza??o das reservas ?
diferente e de que deve existir um efeito cruzado de a??cares sobre a mobiliza??o de
prote?nas e de amino?cidos sobre a mobiliza??o de lip?dios e amido em pl?ntulas de
girassol. O presente trabalho foi desenvolvido com sementes de girassol (Helianthus
annuus L.) h?brido Helio 253, utilizando sistema in vitro de cultura. As sementes foram
germinadas em papel Germitest? e crescidas em meio ?gar-?gua 4g/L sem adi??o de
nutrientes durante 9 dias ap?s a embebi??o (DAE) para a curva de crescimento. Para
verificar o efeito de metab?litos e horm?nios, as pl?ntulas foram transferidas ao 2o DAE
para meio ?gar-?gua 4 g/L suplementado com concentra??es crescentes de sacarose
ou L-glutamina, ?cido absc?sico, ?cido giber?lico ou ?cido indolbut?rico. Os resultados
deste trabalho confirmam que a mobiliza??o dos lip?dios e das prote?nas de reserva
ocorre de forma coordenada durante o crescimento p?s-germinativo inicial em girassol,
corroborando a hip?tese de que a aplica??o externa de fontes de carbono (sacarose) e
nitrog?nio (L-glutamina) ? capaz de atrasar a mobiliza??o dessas reservas nutritivas de
forma cruzada. Al?m disso, considerando as mudan?as nos padr?es de mobiliza??o
das reservas e a parti??o dos seus produtos, proporcionadas pela aplica??o externa de
diferentes reguladores do crescimento, ? evidente que os efeitos dos metab?litos e dos
horm?nios devem envolver, pelo menos em parte, mecanismos de a??o distintos
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12599 |
| Date | 17 October 2012 |
| Creators | Galv?o, Thiago Barros |
| Contributors | CPF:93216717991, http://lattes.cnpq.br/2455621187263790, Scortecci, K?tia Castanho, CPF:13451112825, http://lattes.cnpq.br/4808910380593455, Silveira, Joaquim Alben?sio Gomes da, CPF:03258009287, http://lattes.cnpq.br/6073841207993010, Voigt, Eduardo Luiz |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Bioqu?mica, UFRN, BR, Bioqu?mica; Biologia Molecular |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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