Growth, Nutrient Status and Some Oxidases Enzyme Activity of Cucumber Plants as Affected by Sodium Chloride Salinty (original) (raw)
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Salt stress-induced responses in cucumber plants
Journal of Plant Physiology, 1997
A previous study of the formation and removal of reactive oxygen species (ROS) in plants in relation to salt stress gave heterogeneous results that depended upon the mode of plant treatment, the age of the plant tissue and organs, and the experimental setup. This repon demonstrates the relationship between ROS scavenging activities and the degree of damage sustained by cucumber plants under salt stress, in a standardized assay system.. Cucumber seedlings were grown in a hydroponic solution for 1 to 2 weeks prior to salt treatment. NaCl or KCI was added to the solution at a final concentration of 100 mmollL, with root exposure to the salt being direct and homogeneous. Plant treatment with NaCl for 4 days resulted in reduced growth, increased leakage of solutes from the leaf tissue and modification of chloroplast structure. NaCl treatment increased the activities of the antioxidative enzymes catalase and glutathione reductase, and the content of the antioxidants ascorbic acid and reduced glutathione, but did not affect the activity of superoxide dismutase (SOD). The distribution of Na + and K+ ions in the plant suggests that the salt-derived injuries and the effects on antioxidative systems reflect a response to osmotic stress.
Applied Ecology and Environmental Research
The potential of cucumber (Cucumis sativus L.) genotypes for salt tolerance was investigated in a pot experiment under a lath house conditions. Salt stress substantially reduced plant growth and physiological traits in cucumber plants. On other hand, increase in accumulation of organic solutes i.e., proline as well as activity of anti-oxidant enzymes like SOD, POD and CAT were also observed. However, salinity also caused ionic imbalancement in studied genotypes and lead towards high leaf sodium and chloride (Na + , Cl-) content along with a significant reduction in leaf K + and Ca + levels. On the behalf of percent increment or reduction in observed, cucumber genotypes Marketmore & Green long were found to be salt resistant, while Summer green and 20252 catagerized as salt sensitive. Tolerant genotypes effectively maintained better dry biomass and high Ca + and K + content with least Na + and Clin their leaves exposed to salt stress. Furthermore, maximum accumulation of proline contents and greater activity of antioxidants (SOD, POD and CAT) results in improved tolerance under salinity which indicate that salt tolerance induced in cucumber is greatly connected with level of organic osmolytes and antioxidant defense system.
A glasshouse experiment was carried out at Sultan Qaboos Univeristy, Oman, to evaluate the performance of cucumber grown at varying salt stress levels viz; 0, 2, 3, 4, and 5 dSm -1. The results revealed that salinity adversely affected the morphological, physiological and biochemical attributes of cucumber. The results exhibited that stem length and number of leaves per plants was substantially reduced at 5 dSm -1. Moreover, the highest weakening in shoot and root dry weights were noted at 5 dSm -1 NaCl level in contrast to control treatment. The data set further narrated that the electrolyte leakage was enhanced remarkably with the increasing NaCl levels; however, substantially maximum electrolyte leakage was noted at 5 dSm -1. Moreover, the same salinity level also decreased total chlorophyll contents than any other salinity level. Water potential of cucumber plant was decreased with increasing NaCl levels and maximum lower water potential was observed at 5 dSm-1 NaCl level. In co...
Plants
Exogenous antioxidant applications enable salt-stressed plants to successfully cope with different environmental stresses. The objectives of this investigation were to study the effects of sequential treatments of proline (Pro), ascorbic acid (AsA), and/or glutathione (GSH) on 100 mM NaCl-stressed cucumber transplant’s physio-biochemical and growth traits as well as systems of antioxidant defense. Under salinity stress, different treatment of AsA, Pro, or/and GSH improved growth characteristics, stomatal conductance (gs), enhanced the activities of glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) as well as increased contents of AsA, Pro, and GSH. However, sequential application of antioxidants (GSH-Pro- AsA) significantly exceeded all individual applications, reducing leaf and root Cd2+ and Na+ contents in comparison to the control. In plants grown under NaCl-salt stress, growth characteristics, photosynthetic efficiency, membra...
Acta Physiologiae Plantarum, 2009
A pot experiment with 17 diverse genotypes of cucumber with four levels of salt stress viz., 0, 2, 4 and 6 dS m-1 was carried out during 2006. ANOVA revealed significant differences amongst genotypes and genotype 9 salt stress interaction indicating the genetic variability and differential response of the genotypes to different salt stress levels. The salt stress adversely affected the biochemical parameters; effects were severe under 4 dS m-1. No genotype could survive at 6 dS m-1. Sodium content, Na ?-K ? ratio, proline, reducing sugars, phenol and yield reduction (%) increased significantly as the salt stress increased. Potassium, chlorophyll, membrane stability index and fruit yield decreased significantly under salt stress in all genotypes. However, the genotypes CRC-8, CHC-2 and G-338 showed lower accumulation of sodium, lesser depletion of potassium, lower Na ?-K ? ratio and higher accumulation of proline, reducing sugars, phenols, better membrane stability and lower yield reduction (%) under salt stress, while CH-20 and DC-1 were sensitive to salt stress. Thus, a combination of traits such as higher membrane stability, lower Na ?-K ? ratio, higher osmotic concentration and selective uptake of useful ions and prevention of over accumulation of toxic ions contribute to salt stress tolerance in cucumber. These traits would be useful selection criteria during salt stress breeding in cucumber. Keywords Cucumber Á Salt stress Á Na ?-K ? ratio Á Chlorophyll Á Membrane stability Á Osmolyte Á Phenol
Photosynthesis, water relations and leaf growth of cucumber exposed to salt stress
Cucumber (Cucumis sativus L., hybrid 'Pepinex') was grown in soil culture over a range of NaCl concentrations (0-190 mM) in a glasshouse and the effects on gas exchange, water relations, ion content and leaf growth were examined. Salinity at 8.5 mM had no effect on plant performance, but exposure to higher salinities (25, 50, 120 and 190 mM) caused stomatal closure and a significant decrease in photosynthetic rate. Leaf water potential, osmotic potential and turgor potential were also lower with increasing salinization. Leaf expansion rate and final leaf size declined linearly with an increase in external NaCI. These differences were associated with 22%, 49% and 80% reduction in relative growth rate. The results suggest that salinity influences cucumber growth through a reduction in photosynthesis and photosynthesizing area.
Role of Plasma Membrane NADPH Oxidase in Response to Salt Stress in Cucumber Seedlings
Antioxidants
Plasma membrane NADPH oxidases (RBOHs, EC 1.6.3.1) are known as the main ROS generators involved in plant adaptation to stress conditions. In the present work, regulation of NADPH oxidase was analyzed in cucumber (Cucumis sativus L. var. Krak) seedlings exposed to salinity. RBOH activity and gene expression, as well as H2O2 content, were determined in the roots of plants treated with 50 or 100 mM NaCl for 1 h, and 50 mM NaCl for 1 or 6 days. It was found that enzyme activity increased in parallel with an enhancement in the H2O2 level in roots exposed to 100 mM NaCl for 1 h, and to 50 mM NaCl for 1 day. The expression of some CsRboh genes was induced by salt. Moreover, an increase in the activity of G6PDH, providing the substrate for the NADPH oxidase, was observed. In seedlings subjected to salinity for a longer time, antioxidant enzymes—including superoxide dismutase, catalase, and ascorbate peroxidase—were activated, participating in maintaining a steady-state H2O2 content in the ...
Cucumber (Cucumis sativus L., hybrid 'Pepinex') was grown in soil culture over a range of NaCl concentrations (0-190 mM) in a glasshouse and the effects on gas exchange, water relations, ion content and leaf growth were examined. Salinity at 8.5 mM had no effect on plant performance, but exposure to higher salinities (25, 50, 120 and 190 mM) caused stomatal closure and a significant decrease in photosynthetic rate. Leaf water potential, osmotic potential and turgor potential were also lower with increasing salinization. Leaf expansion rate and final leaf size declined linearly with an increase in external NaCI. These differences were associated with 22%, 49% and 80% reduction in relative growth rate. The results suggest that salinity influences cucumber growth through a reduction in photosyn-thesis and photosynthesizing area.
Brazilian Journal of Plant Physiology, 2010
The salt stress effect in root growth and antioxidative response were investigated in two cowpea cultivars which differ in salt tolerance in terms of plant growth and leaf oxidative response. Four-day-old seedlings (establishment stage) were exposed to 100 mM NaCl for two days. The roots of the two cultivars presented distinct response in terms of salt-induced changes in elongation and dry weight. Root dry weight was only decreased in Pérola (sensitive) cultivar while root elongation was mainly hampered in Pitiúba (tolerant). Root relative water content remained unchanged under salinity, but root Na + content achieved toxic levels as revealed by the K + /Na + ratio in both cultivars. Then, root growth inhibition might be due to ionic toxicity rather than by salt-induced water deficit. Although electrolyte leakage markedly increased mainly in the Pérola genotype, lipid peroxidation decreased similarly in both saltstressed cultivars. APX and SOD activities were reduced by salinity in both cultivars reaching similar values despite the decrease in Pitiúba had been higher compared to respective controls. CAT decreased significantly in Pitiúba but did not change in Pérola, while POX increased in both cultivars. The salt-induced decrease in the CAT activity of Pitiúba root is, at principle, incompatible to allow a more effective oxidative protection. Our results support the idea that the activities of SOD, APX, CAT and POX and lipid peroxidation in cowpea seedling roots were not associated with differential salt tolerance as previously characterized in terms of growth rate and oxidative response in plant leaves.
Emirates Journal of Food and Agriculture
Salinity is expected to be the major destructive abiotic stress that causes ionic and oxidative damage leading to growth reduction and ultimately plant death. Glutamic acid (GA) is an α-amino acid that is used by almost all living beings in the biosynthsis of proteins. Therefore, in the present study, we tried to investigate the effect of foliar application of glutamic acid (GA) on cucumber (Cucumis sativus L.) under altered salinity levels. Cucumber seedlings were grown in plastic pots under greenhouse conditions by applying four levels of salinity (0, 3 dS/m, 6 dS/m and 12 dS/m) and two levels of foliar applied GA (0, 10 mM). Salinity was induced by mixing the salt and soil before seed sowing; however, exogenous GA was applied when the vine length was reached up to maximum height. Morphological characters showed disruptive response under saline conditions especially in indigenous cultivar (local cucumber represented as V1). Enhanced activities of superoxide dismutase (0.29 u g-1 F...