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Bybordi A.,East Azarbyjan Agronomy and Natural Resources Research Center | Ebrahimian E.,Khoy University | Ebrahimian E.,Islamic Azad University at Khoy
Asian Journal of Agricultural Research | Year: 2011

Plant exposed to salinity stress exhibit changes in their physiology and metabolism. In general salinity reduces water availability and causes nutritional imbalance in plants. Since there is no enough information about effect of salinity stress on activity of enzymes involved in nitrogen and phosphorous metabolism we studied the effects of different levels of salinity (0, 50, 100, 150 and 200 mM NaCl) on nitrate reductase, acid phosphatase and alkaline phosphatase activity as well as nitrate and phosphate uptake and total nitrogen content in leaves of canola, so a hydroponically experiment was conducted. Canola seeds were sown in an experimental green house under non-saline conditions. After two month, healthy plants were selected for hydroponic culture in Hoagland's nutrient solution supplemented with NaCl. The plants were cultured in plastic pots filled up with perlite and then were put in green house. The plants were watered with fresh nutrient solution made every week. Leaf samples were clipped 0, 7, 14, 21, 30 and 45 days after exposure to salinity stress in order to nitrate reductase, acid phosphatase and alkaline phosphatase assay, measurement of nitrate uptake, phosphate uptake and total nitrogen content. The results showed that nitrate reductase activity was increased in treated plants with 100 mM NaCl, in contrast it was decreased gradually in plants that were exposure to 150 and 200 mM NaCl, in comparison with controls. Decrease of nitrate reductase activity due to salinity stress and nitrate uptake and follow them total nitrogen content were occurred at the same time. Reduction in nitrate reductase activity, nitrate content and total nitrogen content because of high salinity levels may be a physiological response in order to decrease in growth and extra biomass in canola. However, it was observed that salinity stress caused an increase in both acid phosphatase and alkaline phosphatase activity. We monitored phosphate levels in leaves and found that phosphate levels decreased significantly under salinity stress. These results suggest that the induction of acid phosphatase and alkaline phosphatase under salt stress may be due to a phosphorous deficiency. © 2011 Knowledgia Review, Malaysia. Source


Ebrahimian E.,Islamic Azad University at Khoy | Bybordi A.,East Azarbyjan Agronomy and Natural Resources Research Center
Journal of Food, Agriculture and Environment | Year: 2011

The effect of sodium chloride, silicium and different proportions of ammonium and nitrate on photosynthetic rate, antioxidant enzyme activity, chlorophyll content, proline accumulation, relative water content and protein content of sunflower was studied in hydroponical conditions. Salinity was induced by 200 mM NaCl solution. Also, silicium was applied in three levels; 0, 2 and 4 mM. The plants were nourished by different proportions of nitrate and ammonium for supplying nitrogen (NO 3:NH 4 ratios 100:0, 75:25, 50:50 and 25:75). The results showed that salinity stress decreased photosynthesis, chlorophyll content and relative water content while it increased antioxidant enzyme activity and soluble protein content. Silicium application increased photosynthesis, enzyme activity, chlorophyll and protein content but it had no significant effect on relative water content. The highest photosynthesis was observed in plants treated with 25:75 ratios. Moreover, this ratio increased enzyme activity; while it had no significant effect on chlorophyll, relative water content and soluble protein. Source


Ebrahimian E.,Islamic Azad University at Khoy | Bybordi A.,East Azarbyjan Agronomy and Natural Resources Research Center
Journal of Food, Agriculture and Environment | Year: 2011

Sunflower is a major oil seed crop worldwide and it is also an important crop in Mediterranean areas where salinity is an increasing problem. Although seed oil of standard cultivated sunflower is considered to be of good quality for edible purposes, the development of cultivars with oil high in oleic acid is an important breeding objective for this crop. In this paper, the effect of the salinity, silicium and different nitrate and ammonium ratios were evaluated on growth, sodium and potassium content, nitrate reductase activity and fatty acid composition. Sunflower plants were grown in a pot hydrological system. The results revealed that salinity significantly decreased plant growth, potassium accumulation, K/Na ratio and linolenic acid percentage while increased sodium content and oleic acid percentage. Also, silicium increased plant growth, oleic acid and linolenic acid percentage, potassium content, K/Na ratio and silicium content. Silicium prevented sodium accumulation in plants. Among different nitrate and ammonium ratios 25:75 ratio was the best treatment in respect of plant growth. Source


Ebrahimian E.,Islamic Azad University at Khoy | Bybordi A.,East Azarbyjan Agronomy and Natural Resources Research Center
Journal of Food, Agriculture and Environment | Year: 2011

In order to study the effect of salinity stress, silicium nourishment and foliar application of zinc on growth, antioxidant enzyme activity and fatty acid profile of sunflower an experiment was conducted under controlled conditions. The sunflower plants were grown in a hydroponical system and nourished with Hoagland's solution. Silicium was added to Hoagland's solution at three levels: 0, 1 and 2 mM. Furthermore, salinity stress was induced by NaCl solution at three levels: 0, 100 and 200 mM. Zinc foliar application was performed at two levels: 0 and 0.04%. The results demonstrated that salinity stress significantly increased antioxidant enzyme activity, proline accumulation and oleic and linoleic acid while decreased weight of plants, chlorophyll content and euresic acid percentage. Also, silicium application increased fresh and dry weight of plants, proline accumulation and oleic acid but decreased euresic acid percentage. Zinc foliar application increased fresh and dry weight, catalyses, super oxide dismutase, glutathione s-transferase activity and proline accumulation. Finally, it can be suggested that silicium application is useful under conditions of salt stress, especially in hydroponical systems. Source


Ebrahimian E.,Islamic Azad University at Khoy | Bybordi A.,East Azarbyjan Agronomy and Natural Resources Research Center
Journal of Food, Agriculture and Environment | Year: 2012

Water stress is one of the most important environmental factors that reduce growth, development and production of plants, thus, the effects of water deficit stress and foliar application of ascorbic acid were studied on chlorophyll a and b, flavonoids and anthocyanin contents and soluble sugar composition (glucose, xylose and mannose) in leaves of sunflower. A factorial pot experiment based on completely randomized design was used with three replications. Stress levels were consist, -0.03 (control), -0.6 and -1.2 MPa as the first factor and ascorbic acid concentrations namely 0, 50, 100 and 150 mM were allocated to the second factor. The results showed that water deficit stress decreased chlorophyll content while increased flavonoids, anthocyanin and soluble sugars contents. Ascorbic acid foliar application had significant effect on decrease of flavonoids, anthocyanin and soluble sugars content in stressed plants. All these results suggest that ascorbic acid foliar application increases water stress resistance and we can use it on stressed plants in order to decrease adverse effect of water deficit stress. Source

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