Resumo:
To assess seed vigor, it is possible to perform accelerated aging (AA), which consists
of submitting the seeds to high temperature and humidity. In addition, this test makes
it possible to evaluate the behavior of seeds at a physiological, biochemical and
molecular level. The objective of this study was to evaluate the behavior of seeds of
cultivars BRS 188 Paraguaçu and BRS 149 Nordestina of Ricinus communis L. before
and after being submitted to AA regarding the metabolomic, transcriptomic, enzymatic
and physiological profile. The following analyzes were carried out: initial
characterization of seeds, AA standardization, seed moisture contente, germination
test, determination of electrical conductivity and pH exudate, tetrazolium test, lipid
peroxidation (malonaldehyde levels - MDA), determination of the activities of
antioxidant enzymes (superoxide dismutase – SOD, catalase – CAT, ascorbate
peroxidase – APX, monodehydroascorbate reductase – MDHAR, dehydroascorbate
reductase – DHAR, glutathione reductase – GR, glutathione peroxidase – GPX and
glutathione S-transferase – GST). The evaluation of primary and secondary
metabolites by metabolomics, and the production of transcripts through the RNA-seq
test for the seeds of BRS 188 Paraguaçu. In the BRS 188 Paraguaçu seeds after the
AA, there was a loss of vigor, increase in electrical conductivity, alteration in the
production of primary (galactinol, myo-inossitol, melibiose, glyoxylic acid, sorbitol,
inositol, xylose, sucrose and ribitol) and secondary metabolites of the terpene, phenolic
and alkaloid classes, and greater gene expression, especially energy metabolismo. In
response to AA, the increase in MDA concentration and APX and CAT activity was
only significant in the whole seed, while SOD and DHAR were enzymes that showed
a significant increase in activity in the whole seed and in the embryo. The change in
GST and GPX activity was significant only in embryo samples. The cultivar BRS 149
Nordestina, showed after AA a significant reduction in viability, with membrane
damage and increased lipid peroxidation. The increase in SOD activity, APX and
DHAR were significant in whole seeds and the embryo, while CAT activity in the whole
seed. MDHAR, GR and GPX, activity increased significantly only in the embryo. When
analyzing the physiological, biochemical and molecular mechanisms of seeds after AE,
that MDA, SOD and DHAR, and the increase of electrolytes in the exudate are
biochemical biomarkers for the evaluation of seed quality, even as, the genes
important for energy metabolism are suitable biomarkers for evaluating the quality of
seeds of this species.
