Physiological and biochemical performance of sunflower seeds subjected to different osmotic potentials

Abstract

The aim of this study was to evaluate the performance of sunflower seed lots under different osmotic potentials. Four lots of sunflower seeds, cv. Paraíso 33 were used, submitted to different water restrictions 0 (control), -0.10 MPa (1.310 g L -1 of NaCl), -0.20 MPa (2.620 g L -1 of NaCl), -0.30 MPa (3.930 g L -1 of NaCl) and -0.40 MPa (5.240 g L -1 of NaCl), through the use of saline solutions in conducting the tests. The physiological quality was evaluated by: germination, emergence rate index, cold, emergence, accelerated aging, seedling length and seedling dry weight, as well as the enzymatic activity. The results obtained showed that the physiological potential of sunflower seeds is negatively affected in water restrictions -0.30 and -0.40 MPa, and the enzymes superoxide dismutase (SOD) and peroxidase (PO) are activated when sunflower seeds are submitted to saline stress. Key words: Helianthus annuus L., salinity, stressDesempenho fisiológico e bioquímico em sementes de girassol submetidas a diferentes potenciais osmóticos RESUMO O objetivo neste estudo foi avaliar o desempenho de lotes de sementes de girassol submetidas a diferentes potenciais osmóticos. Para isto foram utilizados quatro lotes de sementes de girassol, cv. Paraíso 33, submetidos a diferentes restrições de água 0 (controle); -0,10 MPa (1,310g L -1 de NaCl); -0,20 MPa (2,620 g L -1 de NaCl); -0,30 MPa (3,930 g L -1 de NaCl) e -0,40 MPa (5,240 g L -1 de NaCl) através da utilização de soluções salinas na condução dos testes. A qualidade fisiológica foi avaliada pelos testes: germinação, índice de velocidade de emergência, frio, emergência, envelhecimento acelerado, comprimento e massa seca de plântulas, como também a atividade enzimática. O potencial fisiológico de sementes de girassol é afetado negativamente em restrições de água -0,30 e -0,40 MPa e as enzimas superóxido dismutase (SOD) e peroxidase (PO) são ativadas quando as sementes de girassol são submetidas ao estresse salino.

Genotypic Variation on the Antioxidative Response of Cowpeacultivars Exposed to Osmotic Stress

“…The effect of different water potentials on the physiology and morphology of various species, such as common bean (CUSTÓDIO; SALOMÃO; MACHADO NETO, 2009;YAMAMOTO et al, 2014), wheat (GIROTTO et al, 2012), and sunflower (HÄTER et al, 2014) has been intensively studied in order to elucidate the effects of water deficiency, as well as the mechanisms of response to the water stress. The authors, evaluating the effect of different water potentials during germination and initial growth stages, observed a decrease in growth with an increase in water restriction, a behavior explained by the reduction in cell elongation, with a consequent increase in the synthesis of the secondary wall under water stress (CARVALHO; NAKAGAWA, 2000).…”