Qualidade fisiológica de sementes de soja pós câmara fria: choque térmico, aclimatação e tratamento de sementes

Abstract

In the storage of soybean seeds, humidity and temperature control are essential to guarantee the longevity and physiological n the storage of soybean seeds, humidity and temperature control are essential to guarantee the longevity and physiological quality of the seeds. Reducing seed temperature is a viable technique to preserve its physiological quality since it reduces seed metabolism during off-season storage. After the period of storage in a cold chamber and transport to the producer, the seed faces variations in temperature that can affect its performance in the field. Therefore, the objective of this work was to verify how changes in temperature and periods after cold storage and acclimatization affect seed quality and biochemistry. Seeds of the cultivar M6410IPRO were used, which were stored in a cold chamber for 6 months at a controlled temperature and humidity of 10 °C and 50%. The experimental design used was completely randomized and two tests were carried out separately, one with seeds with chemical treatment, carried out after acclimatization, and the other without, in each experiment a 2 x 6 factorial arrangement was used, with 2 post-cold chamber acclimatization processes (with and without acclimatization) and six periods after storage in a chamber at 25°C (0, 7, 14, 28, 35 and 42 days). Acclimatization was performed at 20°C for a period of 72 hours after storage in a cold chamber. The following parameters were evaluated: moisture content, first germination count, germination between paper, germination between paper and vermiculite, seedling emergence, accelerated aging, capture and computational processing of high resolution images and enzymatic analysis of antioxidant metabolism e. Acclimatization at 20°C for 72 hours after storage of soybean seeds in a cold and dry chamber alleviates the effects of thermal shock and favors the maintenance of the physiological quality of the seeds, especially for seeds that will be treated after removal from the cold chamber. For non-acclimatized seeds, a longer period at 25°C, over 28 days, after storage in a cold chamber attenuates problems with thermal shock and, consequently, effects on physiological quality. Post-cold chamber acclimatization affects the formation of reactive oxygen species and the performance of antioxidant systems, this technique favors the expression of antioxidant enzymes such as SOD.