Avaliação citoquímica durante a germinação de sementes de sorgo envelhecidas artificialmente e osmocondicionadas, sob salinidade

Abstract

The aim of this study was to evaluate the rate of water absorption and cytochemical changes in primed and aged seeds of sorghum during germination under absence or presence of 100 mM NaCl. The initial batch of seeds of sorghum cv. IPA-1011, was divided into two batches of different levels of vigor, by the accelerated aging of half seeds, with half of each batch also referred to the priming of polyethylene glycol 6000 at -0.86 MPa for 48 hours. Four replicates of 50 seeds from each batch were placed on two sheets of filter paper, blotting paper saturated with distilled water and placed inside gerboxes (11 x 11 x 3.5 cm) transparent lids, which were kept in a germination chamber under continuous darkness and 25 ºC for 72 hours. The cytochemical analysis characterization was measured in the soaking times of 0; 24; 48 and 72 hours. The sorghum seeds cells showed irregular shapes, ranging from elliptical to rounded, and the staining with the toluidine blue also revealed the presence of nuclei, especially in primed seeds, indicating that some cells showed high cellular activity. The presence of protein was detected mainly in protein bodies on cytoplasm of cotyledon cells, while the starch was identified in the form of granules at endosperm. The accelerated aging treatments and seed priming, associated to salt stress resulted in little morphological and cytochemical visible changes during the experimental period analyzed.