Qualidade fisiológica de sementes de girassol avaliadas por condutividade elétrica

Abstract

INTRODUÇÃOO girassol (Helianthus annuus L.) está entre as cinco maiores culturas produtoras de óleo vegetal comestível do mundo, ficando apenas atrás da soja, algodão, colza e amendoim (Fagundes 2002). A demanda por sementes de girassol tem aumentado, devido à importância econômica do óleo extraído de seus aquênios, utilizado, principalmente, para consumo humano e animal, bem como matéria-prima para a produção de biocombustível (Ungaro 2006). Segundo Scheeren et al. (2010), conhecer a qualidade das sementes antes da semeadura é o procedimento mais correto e seguro para se evitar aumentos no custo da lavoura. Pesquisas com o girassol, principalmente na área de controle de qualidade de sementes, são essenciais para o estabelecimento da cultura e se justificam pela potencialidade da espécie. Logo, torna-se imprescindível ajustar tecnologias para a produção de sementes, que permitam homogeneizar o processo de germinação, bem como reduzir o tempo de germinação entre lotes, facilitan- Physiological quality of sunflower seeds according to electrical conductivity ABSTRACT RESUMOThe seed quality evaluation is essential in quality control programs. Thus, vigor tests have been developed to differentiate seed lots, due to the limitations of the germination test. This study aimed at evaluating the electrical conductivity test efficiency for determining the physiological quality of sunflower seeds. Ten lots of sunflower seeds (Catissol and Multissol cultivars) were used. Initially, the quality of each lot was determined, besides the seeds moisture content, by using tests of germination, first counting and seedling emergence, in a greenhouse. Then, the seeds were submitted to the electrical conductivity test, for four soaking periods (6, 12, 18 and 24 hours), by using disposable plastic cups containing 25 and 50 seeds, in 50 mL and 75 mL of deionized water, at 25°C and 30°C. The experimental design was completely randomized, in a 5x4 factorial scheme (five lots and four soaking periods), separately for each cultivar, with four replications. It was possible to conclude that the electrical conductivity test combining 25°C, 75 mL of deionized water and 50 seeds was sufficiently sensitive to evaluate the physiological quality of sunflower seeds.

Effects of Stenocarpella maydis in seeds and in the initial development of corn

“…This fact was also observed from the first inoculum potential, but less intense. Moreover, the decrease in germination and vigor is directly proportional to the increased release of solutes, indicating that the evaluation of the conductivity by the weight method was also efficient for determine the vigor (Oliveira et al, 2012). …”

Drying process: effects of temperature on the oil of different sunflower genotypes

“…Interaction between exposure time and temperature during drying can alter grain characteristics (Teixeira et al, 2018;Ziegler et al, 2017), since substantial variations in moisture content may damage seed structure and viability (Botelho et al, 2015a;Oliveira et al, 2012;Goneli et al, 2011).…”

“…Reduced grain quality as a function of drying temperature has been reported in peanut (Araújo et al, 2017), sunflower (Oliveira et al, 2012;Smaniotto et al, 2017), soybean (Botelho et al, 2015a), and sorghum (Botelho et al, 2015b), with immediate and latent consequences (Botelho et al, 2015a;Goneli et al, 2011).…”

Desempenho Fisiológico E Qualidade Físico-Química De Grãos De Soja Secados Sob Diferentes Temperaturas

“…Sendo em algodão e café, a deterioração às membranas confirmada através de microscopia eletrônica (BORÉM et al, 2008;SAATH et al, 2010). Em grãos de girassol, os índices da lixiviação de potássio foram, respectivamente, 10, 100 e 95 vezes maiores que de Na, Ca e CE (QUEIROGA; PARRA, 1997), atribuído à perda de sua capacidade seletiva (COSTA et al, 2007) e liberação de solutos (FAVARATO et al, 2011), influenciados pela temperatura da água e volume de grãos (OLIVEIRA et al, 2012).…”