Production and antioxidative metabolism in bell pepper grown with saline water in hydroponic system

Abstract

A B S T R A C TThis study aimed to evaluate the effect of salt stress on production and antioxidative defense metabolism of two bell pepper cultivars (Capsicum annuum L.) grown hydroponically. The experimental design was in randomized blocks, with treatments arranged in a 5 x 2 factorial scheme with five replicates. The treatments consisted of five salinity levels of the nutrient solution (2.0, 3.5, 4.5, 5.5 and 6.5 dS m -1 ) with two bell pepper cultivars, 'Bruno' and 'Rúbia' . Biomass and yield were reduced with increasing salinity. The contents of chlorophyll a, b and total decreased with increasing salinity. There was an increase in proline content and activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), showing the activation of the antioxidant defense mechanism. The higher yield in the cv. 'Rúbia' , as well as the greater activity of the APX and the lower levels of chlorophyll content, reflect the best acclimatization of this cultivar to saline stress. The estimated yield of the cv. 'Rúbia' , 39.9 t ha -1 when grown with ECs of up to 3.5 dS m -1, indicates the feasibility of its commercial cultivation in hydroponic conditions. Produção e metabolismo antioxidativo em pimentão cultivado com água salina em sistema hidropônico R E S U M O Este trabalho foi realizado com o objetivo de avaliar o efeito do estresse salino sobre a produção e o metabolismo de defesa antioxidativa de duas cultivares de pimentão (Capsicum annuum L.), cultivadas em sistema hidropônico. O delineamento experimental foi em blocos casualizados, com os tratamentos arranjados em esquema fatorial 5 x 2, com cinco repetições. Os tratamentos consistiram da combinação de cinco níveis de salinidade da solução nutritiva (2,0; 3,5; 4,5; 5,5 e 6,5 dS m -1 ) com duas cultivares de pimentão (Bruno e Rúbia). A biomassa e a produção foram reduzidas com o incremento da salinidade. Os teores de clorofila a, b e total, diminuíram com o aumento da salinidade. Houve aumento no teor de prolina e na atividade das enzimas superóxido dismutase (SOD), catalase (CAT) e ascorbato peroxidase (APX), evidenciando a ativação do mecanismo de defesa antioxidativo. A maior produção de frutos na cv. Rúbia, bem como a maior atividade da APX e os menores teores de clorofilas refletem a melhor aclimatação desta cultivar ao estresse salino. A produtividade estimada da cv. Rúbia, 39,8 t ha , indica a viabilidade de seu cultivo comercial em condições hidropônicas.

Bell pepper production under saline stress and fertigation with different K+/Ca2+ ratios in a protected environment

“…These results agreed with those reported by various authors who studied the bell pepper crop under saline stress conditions, cultivated in either soil (Leonardo et al, 2007;Lima et al, 2016) or substrate (Arruda et al, 2011;Rubio et al, 2011;Nunes et al, 2013;Furtado et al, 2017;Lima et al, 2017). Reductions in fruit size and weight due to saline stress and, consequently, in the economic performance of the crop, are caused by physiological and biochemical changes in the cells or at the molecular level (Munns & Tester, 2008).…”

“…In bell peppers, saline stress causes a reduction in photosynthetic activity, photosynthesis, transpiration, stomatal conductance, gas exchange and photosystem II efficiency, culminating in yield losses (Lima, Morais, Silva, Camara, & Willadino, 2017;Nunes, Dias, Moura, Souza Neto, & Costa, 2013;Amirinejad, Sayyari, Ghanbari, & Kordi, 2017).…”

Assessment of Morpho-Physiological, Biochemical and Antioxidant Responses of Tomato Landraces to Salinity Stress

“…CAT activity increased in Hail 548, with a maximum increase close to 7.6% when treated with 75 mM NaCl. The increase in CAT activity favors the elimination of H 2 O 2 , both generated by SOD and produced in photorespiration [ 53 ]. Abdelaal et al [ 23 ] found that in sweet pepper, an increase in malondialdehyde (MDA) content under the salinity condition and the antioxidants SOD and CAT activities increased salt stress and were higher in the tolerant cultivar.…”

Alterações fisiológicas do pimentão sob soluções nutritivas preparadas com águas salobras e concentrações de H2O2

“…pigments apparently involved in the protection against photoinhibition(Freire et al, 2013) Lima et al (2017). observed a linear reduction in the contents of Cl b and Cl T in bell pepper plants by increasing the salinity of…”