Physiological and growth responses of two different salt-sensitive cucumber cultivars to NaCl stress

Abstract

The effect of NaCl stress on the growth, membrane permeability, anti-oxidant enzyme activities and ion content of cucumber seedlings was investigated. Two cultivars (Jinchun No. 2, a relatively salt-sensitive cultivar, and Zaoduojia, a relatively salt-tolerant cultivar) of cucumber were used. Shoot and root dry weights, plant height, stem diameter, leaf area and leaf number of both cultivars decreased when NaCl concentrations increased. The decreases in shoot and root dry weights and leaf area were more significant in Jinchun No. 2 than in Zaoduojia. Meanwhile, the salt injury index, the membrane permeability, malondialdehyde (MDA) contents, superoxide dismutase (SOD) and peroxidase (POD) activities of both cultivars increased significantly with salt stress, and the increases in the salt injury index and MDA were higher in Jinchun No. 2 than in Zaoduojia, whereas the increase in POD activity was lower in Jinchun No. 2 than in Zaoduojia. Free proline content of Zaoduojia increased markedly with increasing concentrations of NaCl, whereas the content of Jinchun No. 2 was unaffected by salt stress. In addition, the contents of Na + in the leaf, stem and root of both cultivars increased significantly, whereas the contents of K + decreased significantly, resulting in an increase in the Na + /K + ratio when NaCl concentrations increased. These results suggest that Zaoduojia exhibits a better protection mechanism against oxidative damage and lipid peroxidation by maintaining higher proline content and POD activity than the salt-sensitive Jinchun No. 2 cultivar.

Beneficial Effects of Exogenous Selenium in Cucumber Seedlings Subjected to Salt Stress

“…2). Zhu et al [39] found that in relatively salt-sensitive cultivar of cucumber, NaCl stress did not provoke the accumulation of free proline, whereas its content increased markedly in relatively salt-tolerant cultivar. It seems, therefore, that cultivar Polan F 1 , used in the present experiment, is relatively salt-sensitive.…”

Crescimento de leguminosas utilizadas na adubação verde em diferentes níveis de sais na água de irrigação

“…Porém os efeitos promovidos por essas plantas podem ser influenciados por fatores abióticos (Alcântara et al, 2000). Desta forma, para o uso de espécies como adubos verdes, especialmente em regiões áridas e semiáridas, deve-se levar em consideração a salinidade do solo, visto que este é um dos fatores ambientais mais limitantes na produtividade das culturas (Zhu et al, 2008 ).…”

“…Altas concentrações de sais na zona radicular provocam alterações nas respostas fisiológicas das plantas (Parida & Das, 2005) como desequilíbrio no balanço osmótico, desorganização das membranas, inibição na divisão e expansão celular (Mahajan & Tuteja, 2005) características que contribuem para a diminuição do crescimento das plantas, evento passível de se manifestar em reduções em altura de planta, no número de folhas e no diâmetro do caule (Zhu et al, 2008;Silva et al, 2009;) na área foliar e na produção de fitomassa Neves et al, 2009;Santos et al, 2010).…”

“…A tolerância à salinidade é variável entre espécies (Kudo et al, 2010) e até mesmo dentro da espécie (Mendonça et al, 2007;Zhu et al, 2008) e depende de diversos fatores, como estádio fenológico (Bustingorri & Lavado, 2011), intensidade e duração do estresse salino (Neves et al, 2009). …”

Alleviation of Salt Stress in Cucumber (Cucumis sativus) through Seed Priming with Triacontanol

“…Salinity stress had a significant effect on growth rate of cucumber, at salinity level higher than 2.5 dS m -1 , which caused decline in yield 13% (Dorota, 1997). Therefore, cucumber has been classified as salt sensitive crop (Wang, 1998;Stepien and Klobus, 2006;Zhu et al, 2008). Between several strategies to tackle the adverse effects of salts on agricultural crops, many shot-gun approaches are used these days.…”