Showing 5 results for Osmotic Adjustment
M. Heidari, H. Nadeyan, A.m. Bakhshandeh, Kh. Alemisaeid, G. Fathi,
Volume 11, Issue 40 (7-2007)
Abstract
The influence of Nitrogen (N) rates on mineral nutrient uptake in stem and seeds, proline and carbohydrate in flag leaves of Wheat (Triticum aestivum L . Var Chamran) under saline conditions was studied in a field experiment in 2003 and 2004. The experiment was conducted using a split plot design with three replications. The treatments comprised five levels of salinity: 1.5, 5, 10, 15 and 20 ds/m in main plot and three nitrogen levels: 50 , 100 and 150 kg N/ha in sub plot. Salinity treatments were applied in a clay–loam soil by water with NaCl and CaCl2 (5:1 by wt ). The results showed, the nutrient uptake was influenced by both salinity and N treatments. With the Exception of magnesium in seed, salinity increased nitrogen, calcium and magnesium concentrations in seed and stem in both years. By increasing salinity levels, the concentration of potassium in stem and seed decreased and Sodium concentration increased. In the stem the concentration of Sodium in the 20 ds/m was about 17 and 22 times more in the first and second year, respectively. In these experiments, by increasing salinity and nitrogen treatments, proline concentration in flag leaves increased in the two stages (flowering and milky stages) in both years. Salinity had similar effect on carbohydrate accumulation in both stages, but nitrogen treatment had two different effects on carohydrate concentration. In flowering stage, by increasing nitrogen application, carohydrate concentration increased but in milky stage decreased.
S Bazi, M Haydari, N Mehdinejad, F Abasi,
Volume 12, Issue 46 (1-2009)
Abstract
To evaluate effects of different salinity levels on activity of antioxidant enzymes (CAT, APX and GPX) and osmotic components (carbohydrate and proline) in two sorghum genotypes, an experiment was conducted as completely randomized factorial design with three replications in Zabol university in 2007. Three levels of salinity control (0), 100 and 200 mM NaCl and two sorghum genotypes (Payam and Sistan) were compared. Results showed that by increasing salinity levels from 0 to 200 mM NaCl, the activities of these three antioxidant enzymes were significantly increased and the highest level of activity was observed in 200 mM salinity. Payam cultivar had the highest level of APX and GPX enzyme activity in these experiments. salinity significantly changed two osmotic adjustment concentrations (Carbohydrate and proline) and increased their concentrations. The highest proline and carbohydrate were showN in Sistan and Payam, respectively. In this study we found positive correlation between osmotic components and antioxidant enzyme activity. The results showed that in these two sorghum cultivars the two mechanisms help with salinity tolerance. A direct relationship between activity of the antioxidant- enzymes and accumulation of osmotic regulators (carbohydrate and proline) was observed. In Payam genotype, as the activity of the enzymes and accumulation of osmotic regulators increased, the weight of the plants decreased. The decrease in weight could mean some of plant energy is allocated to the production of antioxidant enzymes and osmotic regulators.
M Babaeian, M Haydari, A Ghanbari,
Volume 12, Issue 46 (1-2009)
Abstract
In order to study the effects of foliar micronutrient application under water stress at three stages of growth on proline and carbohydrate concentrations, grain yield and yield components of sunflower (Alster cultivar), a field experiment in split plot design with three replications was conducted in 2007. Alster cultivar was considered under water stress at three stages of growth (heading, flowering and grain filling) as main plot and seven micronutrient treatments, Fe, Zn, Mn, Fe+Zn, Fe+Mn, Zn+Mn and Fe+Zn+Mn, as sub plots. Results showed, water stress at three stages of growth significantly decreased grain yield, biological yield, 1000 weight seeds, cap diameter and cap weight of sunflower (Alster cultivar). The impact of water stress was more pronounced when applied at grain filling. Use of foliar micronutrient increased grain yield in water stress. On the other hand, use of Mn foliar application had the highest positive effect on yield components and grain yield. Free proline and total soluble carbohydrate concentration were increased under water stress at all of the three stages of growth. The highest concentration of these two components was found on the flowering stage. Foliar micronutrient also increased accumulation of the two components.
Sh. Javanmardi , R. Fotovat , J. Saba,
Volume 14, Issue 53 (10-2010)
Abstract
Osmotic adjustment is generally regarded as an important adaptation of wheat to drought. Because it helps to maintain turgor and cell volume, osmotic adjustment is often thought to promote growth, yield, or survival, of plants in dry soils. However, a physiological rationale for such views is lacking. This study was conducted to determine the effect of osmotic adjustment and some of its components on the wheat yield. Ten bread wheat cultivars were grown in pots under different watering levels using a split plot design. During grain filling stage, RWC, leaf sugar content, proline content and osmotic regulation were estimated by sampling flag leaf under normal and stress conditions. Main stem was used for measuring sugar content of different parts of stem. Although there were some differences in osmotic regulation in wheat lines, there were no relationships between yield and osmotic regulation. It was shown that these components probably have a little share in wheat osmotic regulation.
H. R. Fanaei, M. Galavi, M. Kafi, A. Ghanbari Bonjar, A. H.shirani-Rad,
Volume 15, Issue 57 (10-2011)
Abstract
In order to assess the effect of drought stress and various levels of potassium on solutes accumulation and chlorophyll of canola and Indian mustard, a field experiment was conducted in a factorial design based on randomized complete block design with three replications including three irrigation regimes (I1=irrigation after 50% depletion of soil water(control),I2 =irrigation after 70% water depletion and I3 =irrigation after 90% water depletion), two species (Hyola 401 hybrid of canola and landrace cultivar of mustard) and three levels of potassium fertilizer (K1=0 ,K2=150 and K3= 250 kg.ha-1 K2SO4 ) at Agricultural and Natural Resources Research Center of Sistan in 2008-2009 cropping season. Water stress increased proline and soluble carbohydrate accumulation in the leaves of Brassica sp. In non stressed condition (control) in different growth stages, proline was lower than water-stressed plants and Leaf proline content decreased significantly after irrigation. Mustard landrace showed higher capability for accumulating assimilates such as proline, soluble carbohydrates and potassium than hybrid Hyola 401. Water stress decreased the amount of chlorophyll a, b and total leaf chlorophyll, but Potassium application caused an increase in the mentioned parameters. The highest content of chlorophyll pigments was observed at flowering stage. Potassium application caused a decrease in proline and an increase in soluble carbohydrates concentration in the leaf under water stress condition. There was a negative correlation between grain yield and proline content and soluble carbohydrates, but grain yield was positively correlated with chlorophyll, a, b. It was concluded that osmotic adjustment can be an important mechanism for Brassica species under water stress conditions and that organic and inorganic compounds such as proline, soluble carbohydrates and potassium play key roles in this regard.
