Secagem e armazenamento de sementes de sorgo com alto e baixo teor de tanino

Abstract

5rESUMo -o teor de água em que a semente é colhida, bem como a temperatura utilizada para a secagem, é fundamental para garantir a qualidade fisiológica das sementes, principalmente as de sorgo, que podem apresentar dormência secundária, por secagem em altas temperaturas. Com a realização deste trabalho, objetivou-se avaliar a qualidade fisiológica das sementes de sorgo, com alto e baixo teor de tanino e armazenadas após secagem, utilizando diferentes temperaturas. Foram utilizadas sementes das cultivares br 305(2,28 g tanino/100 g) e br 310 (0,52 g tanino/100 g), colhidas com teor de água 18-20%, secas à sombra e em secadores artificiais, nas temperaturas de 35 °C, 45 °C e 35 °45 °C, até atingirem 12% de teor de água. Após a secagem, essas sementes foram armazenadas em câmara fria e seca, por 0, 3 e 6 meses. Em cada época de armazenamento, as sementes foram avaliadas pelos testes de germinação, tetrazólio, condutividade elétrica, índice de velocidade de emergência, teste de frio, microscopia eletrônica de varredura e perfis enzimáticos. Foi quantificada, ainda, a concentração de tanino. Foi observado, em sementes com alto tanino, secas à temperatura de 45 °C e armazenadas durante 6 meses, 88,5% de germinação. houve maior porcentagem de dormência em sementes submetidas à secagem aos 35 °C. houve aumento na concentração de tanino, aos seis meses de armazenamento, para ambos os lotes.Termos para indexação: Sorghum bicolor, armazenamento, umidade. DrYinG AnD STorAGE oF hiGh AnD LoW TAnnin SorGhUM SEEDSAbSTrACT -Water content in harvested seed and the drying temperature are fundamental for ensuring seed physiological quality, especially in sorghum, which may show secondary dormancy when dried at high temperatures. The objective of this study was to evaluate the physiological quality of sorghum seeds, with high and low tannin contents, stored after drying at different temperatures. Seeds of the br 305(2.28 g tannin/100 g) and br 310 (0.52 g tannin/100 g) cultivars were collected with a water content of 18-20% and dried in the shade and in artificial dryers at temperatures of 35 °C, 45 °C and 35/45 °C until water content was 12%. After drying, the seeds were stored in a cold, dry chamber for 0, 3 and 6 months. For each storage period the seeds were evaluated with germination, tetrazolium, electric conductivity, emergence velocity index, cold, scanning electron microscopy and enzyme profile tests. Tannin concentration was also measured. high tannin seeds showed 88.5% germination when dried at 45 °C and stored for 6 months. Dormancy increased in both batches for seeds dried at 35 °C and with increased tannin concentration at six months storage.index terms: Sorghum bicolor, temperature, moisture.

Qualidade fisiológica das sementes de sorgo sacarino submetidas à secagem em diferentes condições de ar

“…Oliveira et al (2011) constataram, para as sementes de sorgo da cultivar BR 305, que o maior valor de germinação ocorreu com sementes secadas sob temperatura de 45 °C, quando estudaram a secagem das sementes à sombra e em protótipos de secadores estacionários, regulados nas temperaturas de 35°, 45° e 35/45 °C.…”

Floral induction, production and seed quality of parsley cultivars as influenced by plants vernalization periods

“…As observed in this research, extreme conditions of temperature have been reported to be able to bring about dormancy in seeds as a defense mechanism to preserve seed viability under adverse conditions (MARCOS-FILHO, 2005;VIVIAN et al, 2008;OLIVEIRA et al, 2011;NAKAGAWA, 2012). This is an important information for parsley seeds, since factors associated with the occurrence of dormancy in parsley seeds have not been clarified and the dormancy of those seeds is a common problem for the production of this species, causing tardiness and low uniformity in seedling emergence (TRINCA, 2007).…”

Extended Storage of Sudangrass Seeds

“…According to this experiment, variations in germination and emergence may be due to overcoming dormancy, which naturally occurs during storage of sorghum seeds (Oliveira et al, 2011 show better quality compared to conservation in dry chamber. On the other hand, Oliveira et al (2011) found that cold temperatures during storage may increase seed dormancy. In any way, it is uncertain if dormancy is accentuated by cold-temperature storage or reducing of phenolic compounds.…”

“…Seeds are one of the most important inputs in agriculture; among all production stages, storage is a mandatory concern, mainly in Brazilian subtropical and tropical conditions (Souza et al, 2009). According to Oliveira et al (2011), studying behavior of seeds during storage, as well as biochemical changes and accumulation of secondary components, may bring relevant information to be applied in quality maintenance.…”