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.

This study was carried out in the General Commission for Scientific Agricultural Research (GCSAR) at Der Ez Zour Agricultural Research Center, during 2009- 2010 growing seasons. The role of Na+, K+, Na+/K+, carbohydrates accumulation of leaves, and sugar content of roots on the OSMOTIC ADJUSTMENT was studied in 10 sugar beet genotypes (five were monogerms and five were multigerms), under salinity stress. Sugar beet plants were irrigated with saline water, with the electrical conductivity (EC) ranging from 8.6-10 dS.m-1 in the first year and 8.4-10.4 dS.m-1 in the second year. A randomized complete block design (RCBD) with three replicates was used. The results showed that Na+ content in leaves and roots of all genotypes was increased in salinity stress, but the increment in leaves was higher than in roots. K+ contents in leaves and roots were decreased in all genotypes, but this reduction was lower in roots as compared with leaves. This may be due to the substitution of Na+ with K+ in such condition. However, under salinity stress concentrations of inorganic solutes (Na+, and K+) in leaves was higher than those in roots. Kawimera (multigerm) was considered the most tolerant genotype because of high Na+ content in its leaves and roots, whereas the most sensitive genotype was Tigris (multigerm), which had the lowest content of Na+ in leaves and roots. Generally, the accumulation of soluble sugars in leaves was higher in tolerant genotypes as compared with non-tolerant ones. The results exhibited no correlation between sugar content in roots and salinity stress. Correlation analysis showed Na+ content followed by soluble sugars as the main solutes for OSMOTIC ADJUSTMENT in sugar beet leaves under salinity conditions. Moreover, both sucrose and Na+ contents in beet root could be considered the main solutes for OSMOTIC ADJUSTMENT.

Acer velutinum Boiss. (Persian or velvet maple) is one of the industrial and important species of Hyrcanian (Caspian) forests with wide distribution. This species is rarely seen in the forests of other parts of the world and has only been reported from the forests of the Caucasus. Therefore the information about this species is very limited. This research aims to investigate  the response of A. velutinum seedlings to drought stress as one of the consequences of climate change. Seedlings of velvet maple were analyzed in terms of height, basal diameter, leaf area (LA), specific leaf area (SLA), biomass, photosynthesis pigments, relative water content RWC), free proline, malondialdehyde (MDA), superoxide dismutase(SOD), and peroxidase(POD) activities to drought stress. One year old of Potted plants were exposed to four water supply regimes (100, 75, 50, and 25% field capacity (FC); performed as a control, mild, moderate, and severe water stress. The results showed that drought reduced all aspects of growth in the velvet maple. It negatively affected on growth and reduced plant height, stem diameter, biomass, and leaf area, but SLA significantly increased under moderate treatment. Drought stress reduced chlorophyll content, however, no significant difference was found for carotenoids. RWC reduced significantly just under severe drought stress. Proline and MDA content increased significantly when plants were exposed to moderate and severe drought stress. Drought stress induced POD and SOD activity under drought treatments, although the highest activities were measured under mild and moderate treatments. Our data demonstrate that A. velutinum seedlings have relative drought resistance. They used drought avoidance and tolerance mechanisms through changes in morpho-physiological characteristics. The results of this research briefly showed the mechanisms of drought tolerance in A. velutinum and will provide essential information for more research in the future.

Ajowan is one of the most important medicinal plants in Zahedan region. Salinity and drought are the main causes of yield reduction of plants in Sistan and Balochestan. To evaluate the effect of salinity on yield and quality of ajowan a factorial experiment with randomized complete block design with three replications was conducted at the greenhouse of the Payam Noor University of Agriculture in Zahedan in 2016. Treatments were two populations of ajowan: C1: local and C2: Pakistani which were considered as the first factor and five salinity levels 0, 2, 4, 6 and 8 d/ms as the second. The results of this experiment showed that highest root length, stem height, plant fresh weight and plant dry weight and yield of essence belonged to local population under saline condition. Increasing salinity levels beyond 4 ds/ms decreased quantitative traits significantly but increased essential oil content and concentrations of OSMOTIC regulants (prolin and carbohydrate) as compared to that of control. This may indicate that ajowan is tolerant to salinity.

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.

The effect of four levels of salinity (0, 50, 100 and. 150mM Nacl) on growth, photosyn the- sis and water relations in three grasses "Lolium multitlorum, Lolium perenne and Festuca arundinacea" was studied.  We report a differential response of Lolium and Festuca species to Nacl salinity where Festuca was found to be more resistant than Lolium species. Nacl induced more reduction in dry weight and photosynthetic rate Lolium species than F. arundinacea. The F. arundiacea and L. multiflorum was able to adjust OSMOTIC partially. But L. perenne was failed in such a mechanism. This disability might be reduced growth of L. perenne drastically. The differences between Festucaand L. multiflorum might be related to Na+ exclusion that need further experiment.

Drought one of the most important global threats against bread wheat production. In order to identify physiological traits associated with drought tolerance, 52 bread wheat varieties were cultured under two normal and drought stress condition in a randomized complete block desigen with three replications. RWC (in three independent times), leaf rolling, leaf silvering, days to flowering, days to maturity and stem reserve remobilization were investigeted. Also in a pot experiment OSMOTIC ADJUSTMENT of the varieties were measured at seedling stage. varieties Star and Bezostaya had the highest RWC (0.79 and 0.78, respectively). OSMOTIC ADJUSTMENT in Rasol and Unknown11 were highest (0.58 and 0.56, respectively). Varieties Tipik, Unknown11 and Azar2 showed the least decrease in thousand grain weight after spraying with KI (4.8, 5.5 and 5.5, respectively). Also varieties Dez, Gaspard and MV-17 have the highest degree of leaf silvering and varieties Niknejad, Star and Kohdasht under drought stress were able than the other varieties bring their leaves to form a rolling and cope with water deficit. Under drought stress, Varieties Alborz, Zagros and Inia were observed premature than the other varieties and Gaspard and Kaslojen varieties were observed late mature than the other varieties. Altogetehr varieties Kohdasht, Star and Bezostaya can be used as genetic resources for leaf water retention under drought stress condition for imjproving other varieties. Also as Azar2 and Unknown11 had highest amount of thousand grain weight under normal condition and simoultanously showed high ability in stem reserves remobilization they can be selected as parents in crosses for improving these traits.