خشکی

In order to investigate the effect of pinching and foliar spraying of thidiazuron on improving the tolerance to water-deficit stress in Pelargonium graveolens plants, a factorial experiment was conducted in the form of a completely randomized design with four replications in the research greenhouses of the Faculty of Agriculture of Lorestan University in 2022. The first factor was water deficit stress (80 (control), 50 and 20% available water in the soil (AWC)), the second factor was pinching and non-pinching, and the third one included thidiazoron foliar spraying (zero, 5 and 10 mg/liter). The results showed that water deficit stress had a decrease effect on the indices of plant height, number of lateral branches, total fresh and dry weight, relative water content and essential oil percentage, whereas it had an increase impact on electrolyte leakage, malondialdehyde content and catalase enzyme activity. Pinching of plants and foliar application of thidiazuron in the control level decreased the plant height, number of leaves and the relative water content of the leaves, but increased total fresh and dry weight, root growth, concentration of photosynthetic pigments and electrolyte leakage. However, under the water deficit stress, plant height, number of lateral branches, number of leaves, root growth, total fresh and dry weight, relative leaf water content and essential oil yield increased and electrolyte leakage, malondialdehyde content and catalase enzyme activity decreased. In general, the results showed that the application of pinching and thidiazoron, particularly at a concentration of 5 mg/liter, resulted in a reduction of the adverse effects of water deficit stress by improving the water balance and promoting root growth.

Global warming and recent droughts are one of the main factors in reducing agricultural products. This research was conducted in order to increase the adaptability of ‘Asgari’ grapevine against drought stress in rainfed conditions. In this research, foliar spraying with kaolin (6%) and potassium sources (1.5% and 3% each of potassium nitrate, potassium sulfate and potassium chloride) was done during two seasons on 30-year-old vines located in Shiraz. Kaolin is a highly durable antiperspirant for vineyards, and it is a realistic and attractive strategy to protect grape clusters from excessive heat and sunburn. The results showed that the application of different sources of potassium caused an increase in berry weight, fruit cluster length, soluble solids, chlorophyll, leaf and fruit potassium content, relative leaf water content, and a decrease in the activity of antioxidant enzymes and leaf temperature compared to the control treatment. On the contrary, kaolin treatment decreased these traits and increased the activity of antioxidant enzymes compared to the control treatment. Potassium sources in both concentrations were able to improve the morphological and physiological characteristics of the, resulting in the greater resistance of ‘Asgari grapevine’ to drought and increase in yield compared to the control treatment. But the application of kaolin had no positive effect on studied traits, which may have been due to the inappropriate concentration used in this study.

In order to investigate the effect of animal manure and biochar on the improvement of tolerance to water deficit stress in sweet scented geranium, Pelargonium graveolens, a factorial experiment was conducted in the form of a completely randomized design with four replications in the research greenhouses of the Faculty of Agriculture of Lorestan University in 2021. The first factor included water deficit stress at three levels of 80, 50 and 20% available water in the soil, and the second factor was six levels of planting substrate: control (Sand and agricultural soil in a volume ratio of 1:1), animal manure substrate (soil, sand, animal manure 25% by volume), biochar 5 g kg-1 control bed, biochar 10 g kg-1 control substrate, biochar 5 g kg-1 of manure substrate, and biochar 10 g kg-1 of manure substrate. The results showed that water deficit stress of 20% of available water caused a decrease in the number of leaves, fresh and dry weight of shoot, and dry weight of root (73, 48.9, 55.2, and 46.8%, respectively, compared to the control treatment), the amount of photosynthetic pigments (chlorophyll a, chlorophyll b, and carotenoids decreased to 14.2, 35.7, and 25.6%, respectively compared to the control treatment) and essential oil yield (50% reduction compared to the control treatment). Meanwhile, the content of malondialdehyde, proline, ion leakage, and essential oil percentage increased by 49.3, 188, 222 and 26.3%, respectively, compared to the control treatment. According to the results, the application of animal manure and biochar (5 and 10 g kg-1) reduced the negative effects of water deficit stress and increased the morpho-physiological characteristics of the plant under both stress and non-stress conditions. It also redused the amount of malondialdehyde, proline, and ion leakage, resulting in the improvement in the growth of sweet-scented geranium. Therefore, a combination of animal manure and biochar can be suggested as a suitable substrate for cultivation of sweet-scented geranium.

The Peganum hamala L. medicinal plant belongs to the Nitrariaceae family and is a native species of the Peganum genus in Iran. P. hamala possesses a wide range of unique biological and medicinal properties due to its valuable secondary metabolites like flavonoids, alkaloids, anthraquinones, and volatile oil compounds. Despite the widespread distribution of P. hamala in northern Iran, limited studies were conducted on this plant species adapted to arid and semi-arid ecological conditions. Therefore, in this regard, one of the goals of this research is to evaluate the ecological impact and the effect of fixed latitude and different geographical longitudes of the growing place along with the rhizosphere on some structural and yield traits of P. hamala under nine altitude gradients located in Mazandaran.

To investigate the effect of ecological factors on the structural traits (wet and dry weight of vegetative organs, fresh and dry weight of root, dry matter percentage of vegetative organs, dry matter percentage of root, arch, plant height, plant canopy area, diameter and length of root, and maximum length of stem and crown) and yield traits (fruit diameter, fruit yield, fruit weight, seed weight, average number of seeds, number of fruits, and percentage of seeds in the fruit) of P. hamala, samples of whole plants in the seeding stage were collected from nine different altitude gradients in regions of Khatirkoh (700 and 1000 m), Chahardangeh (1300, 1500, 1700, and 1900 m), and Gadook (2100, 2300, and 2500 m), with three replications along with the substrate soil in a completely random design.

Based on the results of the analysis, yield traits show a positive correlation with atmospheric Based on the analysis, yield traits are positively correlated with atmospheric factors. Furthermore, among the structural traits, stem vegetative traits are positively correlated with precipitation, evaporation, and radiation at the probability level of 5%. They also have a negative correlation with relative humidity at 1%. The increase in height above sea level causes an increase in humidity and a decrease in temperature in the Gadook and Khatirkoh areas. In contrast, it causes decreased humidity and temperature in the Chahardangeh area. Also, crop yield decreases with increasing altitude in all three regions. The maximum yield of the product is observed at 2100 m and 1500 m altitudes. The increase is due to increased silty materials, moisture, EC, and pH. The altitude slope shows a positive correlation with grain yield at 1%. In each region, as height above sea level increases, the root length and diameter increase and decrease, respectively. Stem and root vegetative traits show a negative correlation with seed traits. Also, canopy level with plant height and maximum plant stem arch were positively correlated with plant yield at the 1% probability level. In general, based on the results, by increasing the height gradient from sea level, decreasing the temperature, and increasing the humidity and nutrients of the soil, there is a decrease in vegetative growth and an increase in crop yield. According to the performance feature regression model, as elevation increased, the amount of sand and clay, organic matter, and evaporation increased. This led to an increase in yield with a 60% determination factor. According to the regression model used, the effect of soil factors is higher than weather and climate. Therefore, climate factors change for this plant at a fixed latitude.

According to the results of examining the structural and yield traits of the collected P. hamala ecotypes, yield traits increase with the increase in altitude gradient, the amount of sand and clay, organic substances, evaporation, and decrease in temperature. On the other hand, vegetative traits decrease. Therefore, the Gadook region population is introduced as the superior ecotype with maximum yield traits among these studied regions in Mazandaran province.

Drought is one of the most important abiotic stresses limiting the survival, growth, and production of plants in many regions of the world including Iran. Genetically, different species adopt different strategies to confront with drought. One of the mechanisms that plants have evolved to adapt to the environmental changes is stress memory. In this study, different genotypes of smooth bromegrass were evaluated to investigate the drought stress memory and drought stress tolerance based on a greenhouse pot experiment. Thirty three genotypes of smooth bromegrass were evaluated in three moisture environments: control (C), once drought-stressed (D2), and twice drought-stressed (D1D2) in a factorial arrangement according to the randomized complete blocks design with two replications. The dry matter yield decreased by 45 and 36% in the one-stress and two-stress treatments compared to the control, respectively. These results indicated the role of drought stress memory in modulating drought stress through the influence on forage dry yield and root dry weight. The root dry weight reduced in the once stress and twice stress conditions by 32 and 19%, respectively, compared to the control environment. This finding shows the significant effect of stress memory on the root growth. Based on the principal component analysis, superior genotypes were identified for future researches. Overall, the results suggested that smooth bromegrass is capable to activate some drought stress memory mechanisms related to morphological and root traits.

Smooth bromegrass is particularly adapted to areas with medium and low annual precipitations and has a high drought tolerance when compared with the other grasses. Drought is one of the most important environmental factors with adverse effects on plant growth and development and affects all morphological, physiological, biochemical and metabolic aspects of plants (Farooq et al., 2009). Therefore, it is necessary to identify drought-tolerant genotypes (Saeidnia et al., 2017b). The term stress memory was first proposed by Trewavas (2003), as the plant's ability to access past experiences to better respond to future stresses. In open-pollinated species that are difficult to develop inbred lines, such as smooth bromegrass, the main breeding method is to create synthetic varieties that are obtained through the crossing of suitable parents. Besides, half-sib matting is one of the most common methods for obtaining genetic information such as estimating the additive effects and dominance of genes (Nguyen and Sleper, 1983). Saidnia et al. (2017a) in a study on the genotypes of orchardgrass species found superior genotypes for hay production. They also examined the genetic parameters and heritability of dry matter yield and introduced the superior genotypes for the further researches. Hence, this study was designed to investigate stress memory and its effect on improving drought tolerance in a smooth bromegrass germplasm.

This research was carried out from February 2017 to June 2018 in the research greenhouse located at the Isfahan University of Technology as a pot experiment. A sandy loam soil with bulk density, field capacity, and wilting point of 1.57 g cm-3, and 12.5 and 7.4 %w/w, respectively, was used for filling the pots. The genetic materials included 33 genotypes of smooth bromegrass that were collected from different regions of the country and some foreign gene banks. The genotypes were investigated in three moisture environments including control (C), once drought-stressed (D2) and twice drought-stressed (D1D2) as a factorial experiment in the form of a randomized complete blocks design with two replications.

The analysis of variance showed that drought treatments had a significant effect on most of the traits. A significant difference was observed between the genotypes regarding the measured traits indicating high genetic diversity among the genotypes. The secondary drought stress significantly reduced most of the traits. The dry matter yield decreased by 45 and 36% in the once-stress and twice-stress treatments compared to the control, respectively. These results indicated the role of drought stress memory through the effect on dry yield of forage and root dry weight. Also, the root dry weight was reduced by 32 and 19% in the conditions of one stress and two stress compared to the control environment, respectively, which shows the significant effect of stress memory on the root system. Multivariate analysis showed that under the twice stress condition compared to the other two moisture environments, the relationships of the traits have undergone severe changes, which is a confirmation of the effect of initial stress and stress memory.

This research indicated a high genetic diversity among the smooth bromegrass genotypes in terms of stress memory responses, which can be used in the selection methods. For example, the means of dry matter yield and root dry weight decreased to a lesser extent when grown in the presence of twice drought stress, than once drought stress. This finding shows that the mechanisms of the stress memory related to morphological and root traits in this plant are activated by applying preliminary mild drought stress and help the plant to have a smaller decrease in growth. Based on the principal component analysis, superior genotypes were identified for future research. The results of this research can be used in breeding programs and future genetic research. It is also suggested that suitable genotypes be studied more in field conditions over several years.

Drought stress is the most important abiotic stress that affects the growth and development of plants. One of the strategies for soil moisture management and plant tolerance to drought stress is the use of organic materials compatible with the environment, including superabsorbent polymers. In order to investigate some morpho-physiological and biochemical characteristics of Acacia seedlings, this research was conducted with three types of superabsorbent polymers (A200, SNF and Barbary) at three concentrations (0, 1 and 2 g/kg) at three levels of drought stress (one week, two weeks and three weeks irrigation intervals). This experiment was factorial in randomized complete block design with three replications under field condition. The results showed that drought stress caused a significant decrease in fresh and dry weight of shoot, photosynthesis, transpiration, relative water content, chlorophyll and carotenoid content and significantly increased ion leakage, proline and total carbohydrates. The application of superabsorbent polymers increased the tolerance of Acacia to drought stress so that the use of 1 g/kg Barbary superabsorbent polymers in the first week had the highest shoot fresh weight (144 g) and the amount of chlorophyll (1.73 mg/g fw). in the first week, the use of 1 g/kg A200 superabsorbent polymer increased the rate of photosynthesis by 5.48% and the use of 2 g/kg A200 increased the rate of transpiration by 41.66% and the relative water content of leaves by 11.06% compared to control (0 gr/kg A200). Also, in the first week, the use of 2 g/kg SNF super absorbent increased the amount of carotenoids by 36.58% compared to 0 g/kg SNF. The use of 2 g/kg A200 in the third week reduced ion leakage by 22.50% compared to 0 g/kg A200 in the first week. The use of SNF superabsorbent at a concentration of 1 g/kg in the first week reduced the amount of proline by 22.08% compared to 0 gr/kg SNF. Therefore, the use of superabsorbent polymers especially Barbary increases the tolerance of Acasia to drought stress.

 UCB-1 hybrid rootstock is propagated from the seed of a controlled cross between a P. atlantica female and a P. integerrima male. Clonal propagation of this rootstock is also necessary since it produces identical genotypes. UCB1 has recently been introduced in Iran. However, little research has been done on this subject. Water stress is one of the most important environmental stresses and occurs for several reasons, including low rainfall, high and low temperatures, salinity, and high intensity of light, among others. Drought stress is a multidimensional stress and causes changes in the physiological, morphological, biochemical, and molecular traits in plants. Proline is also found widely in plants and accumulates in large quantities in response to environmental stresses such as drought. It is the essential amino acids that accumulate in different tissues of the plant, especially in the leaves through the effect of water stress, and that the accumulation of it has a function in the regulation of osmosis in the cell as the proline is increased in the cytoplasm to counterbalance effort osmosis cell sap. Proline is an indicator of water stress tolerance and its increase in the leaf proof that the plant suffered drought stress, also is the way the plant tolerance to drought stress.

A pot experiment was conducted, to investigate the effectiveness of foliar applied proline in mitigating the concurrent effects of drought stresses on UCB1 rootstock, at greenhouse of Faculty of Agriculture, University of Shahrekord. Experiment was carried out in a completely randomized design with split arrangement having three replications. Chl. and carotenoid contents were determined according to Lichtenthaler (1987). Leaf discs were obtained from expanded leaves of each pot in the morning. The leaf discs were weighed immediately to obtain the fresh weight (FW), and submerged in distilled water for 4 h at 4◦C in dark condition and then weighed to prepare turgor weight (TW). The leaves were dried in a forced-air oven at 70◦C for 24 h, and the dry weight (DW) was recorded. The RWC of samples was calculated using the following equation (Bastam et al., 2012): RWC = [(FW–DW)/(TW–DW)] × 100 Levels of glycine betaine were quantified as described previously by Arakawa et al. (1990). To determine the free-proline concentration, leaves were homogenized in 5 ml of ethanol at 95%. Proline concentration was calculated with a standard curve and expressed as µg g−1fresh mass (Paquin and Lechasseur, 1979).

The UCB1 proximate analysis in the present study depicted that imposition of drought stress increased the leaf and root proline content and electrolyte leakage. Exogenous application of proline as foliar spray significantly increased the moisture content of leaf and root, RWC, Chl a and total chlorophyll. Exogenous proline application upregulated leaf and root proline contents and decreased the lipid peroxidation (decrease electrolyte leakage), resulting into improvement in chlorophyll contents. 150 mg. l-1 proline application gave maximum alleviation against stress.Numerous reports depict that the exogenous application of proline as a foliar spray can play an important role in enhancing plant tolerance against drought stress, and our results are consistent with them. This ameliorating effect of exogenously applied proline can take the form of osmoprotection, cryoprotection, or protection against reactive oxygen species.For example, in various plant species growing under stress conditions, exogenously supplied proline provided osmoprotection and facilitated plant growth. Normally, proline accumulation in plants, is in response to drought or salinity stress occurs in the cytosol where it contributes substantially to the cytoplasmic osmotic adjustment. It actively takes part in plant osmotic adjustment under stressful environmental conditions. In addition to its role as an osmolyte for osmotic adjustment, it actively takes part to stabilize subcellular structures, biological membranes, proteins, and scavenge free radicals. It also plays a vital role in buffering cellular redox potential under stressful environmental conditions.

 In summary, our results showed that, drought induces a decrease in moisture content, RWC, T Chl and carotenoids and an increase in some osmoregulators (proline, glycine betaine, TSC). The most favorable treatment was 150 mg.l-1 proline foliar spray. 150 mg.l-1 proline application gave maximum alleviation against stress. Foliar application increased the moisture content of leaf and root, as well as increased the Chl a, total, RWC and proline content of leaf and root. It can be suggested that the foliar application of proline (150 mg L-1) used as a plants defense factor against drought stress conditions.

Occurance of recent droughts and expanding cultivation area of rain-fed fig orchards in Fars province requires the supplemental irrigation for increasing the economic productivity of fig crop cv. Sabz. Thus, the present study was conducted to improve water use efficiency of this crop. Three supplemental irrigation methods included surface, subsurface drip, and microjet were used. Control trees received no supplemental irrigation. Irrigation water volume for each tree was 1500 liters that was given to the trees in three times and equal amounts in March, May, and August. The results showed that supplemental irrigation significantly increased the yield of dried fig fruits compared to control. Microjet method increased leaf width, shoot growth length, node number, content of chlorophylls and carotenoids, and number of AA fruits (fruit diameter > 22 mm) and light yellow color fruits. Teherefore, microjet method is introduced as the superior irrigation method to improve vegetative and reproductive traits of fig cv. Sabz.

Drought stress is one of limitation factors in landscape expantion. In order to investigate response of four wild roses species (Rosa canina, R. beggeriana, R. orientalis & R. persica) to water deficit, a factorial experiment was carried out in a completely randomized block design with two factors Rosa species and water deficit at three levels (control (-0.03), -0.8 (moderate) & -1.5 (Severe) MPa). One year old plant obtained from mentioned rose sucker were subjected to water deficit treatment. Based on the results, leaf mass area (LMA) was different between species and water deficit had no effect on that. Water deficit caused decreased relative leaf water content (RWC), performance index (PI), chlorophyll content and increased electric leakage (EL) and malondialdehyde (MDA) in R. persica. In R. canina RWC, PI and free radical scavenging capacity (DPPH) decreased and EL and MDA increased. In R. beggeriana EL and DPPH increased and in other characteristics difference was invisible. In R. orientalis water deficit had no dramatic effect on traits. Based on the results R. orientalis and then R. beggeriana are more tolerable to drought stress.

 Plant growth and yield are affected often by stress conditions, especially drought, which is the most important factor in reducing crop production worldwide. Silybum marianum is an important pharmaceutical crop with great potential as a multipurpose plant for low-input cropping systems of the arid and semiarid regions.

 In this experiment, the effect of drought stress (full irrigation at field capacity; no stress, irrigation at 70% of field capacity; mild stress and irrigation at 40% of field capacity; severe stress) on physiologic traits, the amount of silybin a and b and 1000 seed weight in milk thistle was studied in the research field of Shahid Beheshti University in 2017-2018. The experimental site is located in Shahid Beheshti University, Tehran, Iran (51.23°N, 35.48°E, and 1769 m above mean sea level). It has a moderate and mountainous climate with a mean annual rainfall of 145.2 mm and a mean temperature of 22ºC. This experiment was performed in a completely randomized block design with 3 replications. Milk thistle seeds were prepared from Isfahan Pakanbazr Company. The soil composition consisted of 1/3 clay, 1/3 sand, and 1/3 leaf composts. The field area was 150.0 m2. Furrows were created to implement this study. The space of plants on rows was 0.5 m and between rows was 1 m. In general, 15 furrows were created and 15 plants were cultured on each furrow, so the total number of plants cultivated on the field was 225. Drought stress was applied at flowering stage. Soil moisture was measured by the weighing method. The soil samples were taken from various areas (randomly) of the field, three samples each day. After measuring the water content at F.C, based on that, the amount of 70%F.C and 40%F.C was also calculated. At the time of stress, F.C irrigation was performed every two days, 70% F.C irrigation every 4 days, and 40% F.C irrigation every 6 days. After 8 days, leaf sampling was performed to measure catalase, ascorbate peroxidase, proline and malondialdehyde content and seed sampling was performed to 1000 seed weight and extract analysis. For physiologic measurements, 3 plants were randomly assigned to each stack and their leaves were separated and transferred to the laboratory. Then, in the next step, their physiologic parameters (include Catalase and ascorbate peroxidase, proline and malondialdehyde content) were measured according to the relevant protocol. In order to measure silybin, 4 plants were randomly considered to each stack and their seeds were harvested and combined and dried in shade condition in the laboratory for one month. The dried seed samples were completely powdered using a mill, then 10 g of the powders weighed and the oil extract of them was isolated by Soxhlet using n-hexane solvent. The extraction temperature was 70 °C and the extraction time was 6 h. After the extraction was completed, the extract was poured into dark glass. Next, the oil-free powder was dried in an incubator at 37 ° C. Methanol extract of oil-free powder was extracted using methanol solvent. For this purpose, 2 g of samples powder was weighed and 200 ml of 80% methanol was added to each of them and the mixture stirred for two days by Shaker. The mixture was then passed from a filter paper and after that, 200 ml of 80% methanol was added to the sample precipitate (on filter paper) and placed again on the shaker. After 24 h, extraction was performed by the same method and were added to the previous extract. The extracts were then concentrated in the environment temperature for two weeks. Concentrated extracts (powder) as well as standard silymarin with certain concentrations were dissolved in methanol solvent and used for injection into HPLC (Model: Infinity1260, Manufacturer: Agilent) using syringe filters with a diameter of 0.2 μm. After receiving the HPLC results, the data and peaks were analyzed and the amounts of silybin a and b were determined and compared at different levels of water stress. Statistical analysis of data was performed using R 3.6.1 and RStudio 1.1.463 software. Mean data were compared using Duncan's test with agricolae package at a significance level of 0.05.

 The results showed that with increasing water stress intensity, the amount of silybin a and silybin b increased by 24% and 26%, respectively. The amount of these compounds in 40% were significantly higher than other treatments, so that its amount compared to F.C treatment (26.07 mg/g Grain DW in silybin a and 40.74 mg/g Grain DW in silybin b) and compared to the 70%F.C (25.32 mg/g Grain DW in silybin a and 34.64 mg/g Grain DW in silybin b) was higher. This indicates carbon assimilation from photosynthesis to produce secondary metabolites in this treatment. Also, the amount of silybin b compared to silybin a in all treatments was (0.8: 1.2), in which 1.2 is related to silybin b and 0.8 is related to silybin a. In severe stress treatment (40% of field capacity), the amount of silybin a and b (67.30 and 98.92 mg/g, respectively) increased significantly compared to other treatments. According to the mean comparison results, the highest activity of catalase (5.16 U/ml) and ascorbate peroxidase (2.26 U/ml) was observed in mild stress treatment. Proline content gradually increased with increasing stress intensity and reached its peak in severe stress (3.36 µM/gr). Lipid peroxidation also had their maximum in severe stress (8.35 nmol/grFW). The 1000 seeds weight was reduced by 6.8 g in severe stress treatment (40%F.C) compared to the control (F.C). 

 According to the results, the amount of milk thistle flavonoids can be increased for medicinal purposes including the treatment of liver disease and hepatitis by applying dehydration stress.

The present study was aimed to evaluate the effect of organic fertilizers of folic acid and amino acids (glycine and glutamic acid) on the plant resistance to stress and yield of cucumber under deficit irrigation conditions. The study was carried out as a factorial in randomized complete blocks with 3 replications. The first factor was fertilization at four levels as control, 200 mg/l folic acid, amino acid glycine and glutamic acid (6 liters per ha), and folic acid + amino acids (glycine and glutamic acid). The second factor was irrigation interval (3, 5 and 7 days). The results showed that an increase in irrigation interval caused a significant reduction in plant dry and fresh weights, internode length, root and shoot lengths, stomatal conductance and chlorophyll contents. Furthermore, combined use of folic acid and amino acid and 7 day irrigation interval increased root length, internode length, leaf area, chlorophyll a and relative leaf water content by 159, 46.9, 84.7, 138 and 36%, respectively, when compared with the control at the same irrigation interval. In addition, a 70% increase in plant fresh weight and 84% increase in fruit weight were observed in irrigation interval of five days and combined treatment of amino acid and folic acid. In general, it can be concluded that the combined application of amino acids and folic acid improved the morphophysiological characteristics of cucumber under deficit irrigation conditions, while it was not effective in improving yield and fruit production with the seven-day irrigation interval.

Drought is one of the major factors limiting horticultural products and this is more important in arid and semi-arid regions. Due to the importance of nanotechnology in improving the methods available in horticulture, this experiment was performed on Rosa × damascena Mill as factorial experiment based on the completely randomized design with three replications at Faculty of Agriculture, Ferdowsi University of Mashhad, in the growing season of 2018. The treatments consisted of 2 irrigation regimes (3 days and 6 days) and 5 levels of titanium (0 (control), 15 and 30 ppm titanium dioxide, 15 and 30 ppm nano-titanium dioxide). The results showed that with increasing the irrigation interval, decreased leaf area and flower diameter. Titanium was affected on flower diameter, peduncle diameter and length of peduncle at all levels. Number of flowers increased by 15 and 30 ppm titanium dioxide 40.8 and 54.9%, respectively, and with 15 and 30 ppm nano-titanium dioxide 84 and 69%. In treatment of 30 ppm nano-titanium dioxide and irrigation interval 3 days, the amount of proline was 0.20 and in the same treatment of titanium and irrigation interval 6 days, was equal to 0.50 µmol/g. In general, the use of titanium dioxide and nano titanium dioxide resulted in improved growth traits and flower diameter. Also, among the used levels, 15 ppm nano-titanium dioxide had a greater effect on flower diameter, flower number, relative water content, and spade.

In order to study the effect of priming sunflower seeds by potassium nitrate on germination seeds was conducted experiments in salinity and drought conditions. Location of experiments was Physiology Laboratory, Faculty of Agriculture, Bu Ali Sina University, Hamedan. Salinity experiment was conducted as factorial based on randomized complete block design (RCBD) with two factor of seed priming and salinity and three replications. Priming levels included control and seed treatment by potassium nitrate and salinity levels included 0, -2, -4, -6, and -8 bar. Also, drought experiment was conducted as factorial based on randomized complete block design (RCBD) with two factor of seed priming and drought levels in three replications. Drought experiment treatment included control (non-priming) and priming by potassium nitrate and drought stress treatment were five levels (0, -2, -4, -6, and -8 bar). The results of two experiments showed that increasing in salinity and drought stress, decreased germination components including germination, germination rate and dry weight of seedlings. However, this reduction was lower for seeds that were treated by potassium nitrate. In terms of the studied traits, at all of the levels of salinity and drought treatment seeds were better than control seeds. In general, it can be concluded that the priming of sunflower seeds by potassium nitrate improved the germination components under salinity and drought stress and can increase sunflower plant resistant against these stresses in the germination stage.

Beautification of urban space and creating attractive face for cities by development of green space has caused to capita of urban green space be introduced as an important factor in urban development. Meanwhile, the important role of cover plants, especially turf grass, in creating green spaces has caused to add quickly the area of these beautiful plants in the cities. Nevertheless, existence of plants with high water requirements between the turf grasses, have created limitations in terms of water requirements supply. The grass planted in the country is mainly from imported seed types that are not so compatible with dry and semi-arid conditions in our country and from this point of view, sometimes they create limitations in terms of water supply. One of the native grasses in the country, is Tall Fescue (Festuca arundinaceous), which is a variety of cool-season, perennial and herbaceous grasses. One of the strategies to preserve grass under drought stress is improving soil structure with the aim of increasing the moisture. Organic compounds that improve soil physical and biological conditions (such as municipal waste compost and manure) can be effective. Using compost improves soil structure and strengthens soil mineral content and allows soil to retain moisture for longer. Because compost can hold water about two to six times its volume and prevent it from being wasted. Compost in heavy soils, improves soil porosity and makes the soil better ventilation elderly. In light soils, it acts like a sponge and by keeping water and food safe, it will greatly prevent them from being washed. Therefore, present research was done to evaluate the effect of mixing different amounts of Municipal Solid Waste (MSW) compost with soil on some physiological properties of Tall Fescue native grass under moisture stress conditions.

This research was conducted in the form of two experiments in research greenhouse of Ferdowsi University of Mashhad. The first experiment with aim of evaluating percentage and rate of grass emergence was conducted in a completely randomized design with four replications that the experimental treatments consisted of ten different levels of compost mixing with soil (10 up to 100 t.ha-1) and control treatment (agronomic soil without mixing compost). In the second experiment, three values of 70, 80 and 90 tons of compost per hectare plus control (no compost consumption) as the first factor and three levels of moisture stress of 25, 50 and 100 percent of field capacity as intense stress, mild stress and without stress, respectively as the second factor that were compared in factorial by a completely randomized design with four replications.

The results of the first experiment showed that the amounts of 70, 80 and 90 tons per hectare increased significantly the percentage and rate of grass emergence due to increased fertility and higher water holding capacity and in these treatments, the positive effect of rising water holding capacity has been dominated on negative effect of electrical conductivity of the soil and this topic has led to an improvement in the percentage of grass emergence in these treatments. Furthermore, in the amounts of 70, 80 and 90 tons of compost per hectare, the bulk density of soil significantly decreased and the C/N ratio dramatically increased. In the second experiment, with increasing drought stress in different amounts of compost, the total chlorophyll content decreased and relative water content of plant, proline and electrolyte leakage increased. In the compost treatment of 90 tons per hectare, due to its high ability to store water, the cell membrane integrity was more preserved and it was done less understanding of stress. The shoot dry weight decreased significantly as a result of increasing the severity of drought stress.

Based on the findings of this study, application of 90 tons of compost per hectare significantly improved some of physiological traits for Tall Fescue grass in drought stress conditions. Also, it seems that Tall Fescue grass cleverly has tried to deal with drought stress with target of increase the amount of moisture available for itself. Therefore, using 90 tons of compost per hectare for Tall Fescue grass in low water conditions and occurrence of moisture stresses is recommended.

To determaine th effect of root inoculation of Rasha grape cultivar with three species of arbuscular mycorrhizal fungus(G.versiforme, G. etunicatum, G. intraradices) on shoot growth, macro nutrient elements, chlorophyll content, leaf temperature, RWC, soluble sugars and drought symptoms rate under deficiet irrigation condition (75%, 50% and 35% water requirment) a factorial experiment based on RBCD was conducted in Kahriz Horticultural Research Station, Urmia, Iran. Results showed that increasing deficiet irrigation level, reduced shoot growthand fungus inoculation did not have a posetive effect on this trait in comparision with control. Leaf temperature and dry symptoms on leaves was lowest in vines that inoculated with G. versiforme under 35% deficiet irrigation condition. Leaves of vines with this fungus showed the high RWCin all stress tretments, too. By increasing deficiet irrigation level, soluble sugars were decreased in 55% water requirement and then increased in 35% water requirement. Among macro nutrient elements, the highest amount of P (0.14%) was measured in leaves of vines inoculated by G. versiforme.

Drought and salinity are the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool season grass species are not well adapted to extended periods of drought and salinity stress. The decline in turf quality caused by drought and salinity stresses is a major concern in turfgrass cultivation and management. Therefore, developing management practices for improving drought and salinity resistance of turfgrasses has become imperative in arid and semiarid regions. Grass genotypes differ in their responses to drought and salinity stresses, which involve changes in morphological and physiological aspects. Understanding of relative involvement of each morphological and physiological characteristic in drought and salinity tolerance is important in selecting grass genotypes to facilitate breeding of drought and salinity-tolerant genotypes. The purposes of this research were to make selections of genotypes tolerant to drought and salinity stress for turfgrass management program.

To study some morphological and physiological responses of six Iranian crested wheatgrasses (Agropyron cristatum L.) under drought and salinity, an experiment was conducted in the greenhouse of College of Abureyhan, University of Tehran, Iran. Six Iranian Agropyron cristatum genotypes were collected from six locations in Iran. Agropyron cristatum genotypes were planted in polyvinyl chloride tubes and kept in the greenhouse. Pots were filled with sandy loam soil which had been sterilized in an oven at 160ºC for 6 h. Irrigation was applied as needed to prevent any visible stress during grass establishment. Grasses were watered three times weekly to maintain plants under well-watered conditions and soil moisture at field capacity. The experiment consisted of three treatments: 1) well-watered plants were irrigated three times per week with distilled water (control), 2) Drought stress was imposed by withholding irrigation for 45 days (drought stress), and 3) plants were irrigated daily with 100 mL of 9 dS.m–1 NaCl solution (salinity stress). To avoid primary salinity shock, the soil in each pot was drenched with 100 mL NaCl solution at incremental electrical conductivity (EC) by 3 dS.m–1 per day until the final EC reached 9 dS.m–1. Data were subjected to analysis based on a split-plot design with water treatments as main-plots and genotypes as sub-plots. Irrigation treatment as the main factor in three levels (control, drought, and salinity) and crested wheatgrass at six levels were considered as sub-plots. Studied characteristics such as height, turf quality, chlorophyll content, soluble carbohydrates, relative water content, electrolyte leakage, root penetration, and effective root depth were recorded. Statistical significance was tested using the analysis of variance procedure in SAS 9.1 (SAS Institute Inc., Cary, NC). Differences between the means were determined using the Fisher’s protected LSD test at the 5% probability level.

The results of this study showed that drought and salinity stress decreased the quality of crested wheatgrass masses, and reduced the level of quality varied among the masses. Throughout the experiment, ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions maintained higher Turf quality compared with other genotypes. Total chlorophyll content of ‘Sabzevar’ and ‘Damavand’ were higher than other genotypes under drought and salinity conditions. The maintenance of higher chlorophyll content has been associated with better drought and salinity tolerance in plant. The soluble sugar content of ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions were higher than other genotypes during the experiment. Soluble sugar content is an important compatible osmolyte in plants. Increased accumulation of soluble sugar content in stressed plants may be an adaptation process and resistance strategy to abiotic stresses in plants. Throughout the experiment, ‘AEKQI’, ‘Sabzevar’ and ‘Damavand’ genotypes under drought conditions and ‘Sabzevar’ genotypes under salinity conditions maintained higher relative water content in compared with other genotypes. Higher RWC indicates the ability of the leaf to maintain its higher water content under stress conditions with the simultaneous capability of the root system to take up adequate water. Based on morphological and physiological analysis for drought and salinity tolerance in investigated genotypes, the tolerance ranking would appear to be ‘Sabzevar’ > ‘Damavand’ > ‘Arak’ > ‘Urmia’ = Takestan > ‘Hashtgerd’ under drought stress and ‘Sabzevar’> ‘Arak’ > ‘Damavand’ > ‘Takestan’ = ‘Hashtgerd’> ‘Urmia’ under salinity stress. The results of this study showed that ‘Sabzevar’ and ‘Damavand’ genotypes had good tolerance to drought stress, and ‘Sabzevar’ and ‘Arak’ genotypes had good tolerance to salt stress than other Iranian crested wheatgrass genotypes.

Today, due to limited of water resources, more attention is paid to the use of water storage methods. Thus, a factorial experiment was conducted in a completely randomized design with five replications in a controlled greenhouse in Ferdowsi University of Mashhad in 20017. The studied factors included three irrigation treatments (Full irrigation, deficit irrigation, partial root zone drying) and two levels of phosphate fertilizer (required amount based on soil analysis (25ppm) and adding 25% more than recommended (31ppm)). In partial root treatments, a part of the pots was under drought stress two weeks after planting, and the second part of the zone drying pots was irrigated until the beginning of flowering and 50% of flowering was applied to dry conditions. Results showed that drought stress in both flowering and 21 days after flowering caused a decrease in the physiological traits including chlorophyll content index, photosynthesis rate, stomatal conductance and transpiration rate. As the duration of drought increased, the density of stomata in the lower leaf area increased. In spite of decreasing photosynthesis and dry matter content in drought stressed plants, biomass content in partial root zone drying was higher than deficit irrigated treatment. Increased phosphorus had no significant effect on stomatal density, but at 21 days after flowering the substomatal CO2, photosynthesis rate, transpiration rate, reduced stomatal conductance, and biomass directly were related to increasing phosphorus.

Ajowan (Trachyspermum copticum L.), belonging to the Apiaceae family, is remarked as an important pharmaceutical and economical product. In order to determine the most important traits affecting grain yield, a split plot experiment was conducted in two conditions of irrigation (normal and drought stress) as the main factor and 36 ecotypes of ajowan, belonging to nine different provinces of Iran, as a sub plot based on a randomized complete block design with two replications in 2015 and 2016 crop year in Kerman. The results of linear multiple regression analysis with stepwise method showed that in drought stress condition, number of umbrellas per plant, number of seeds per umbrella and essential oil yield, and in normal irrigation conditions, biological yield, 1000-seed weight and seed number per umbrella had the highest effect on grain yield, explaining 87% and 99% of the changes, respectively. Based on the results of path analysis, traits including number of umbels per plant under stress conditions and biological yield under normal conditions had the most direct effect on the grain yield and were recognized as the most important components of the grain yield. Therefore, these traits can be considered as main appropriate criteria for facilitating the indirect selection process and evaluating the seed yield potential in ajowan breeding programs.

Abiotic stresses, in particular drought, not only compromise crop quality and limit yield, but also restrict the geographical range over which crop production is viable. Plant species have evolved a number of physiological and molecular means to cope with adverse environmental conditions. Grapevine is a perennial crop grown in various areas around the world. It is highly responsive to local environmental conditions and viticultural practices. Abiotic stresses cause extensive losses to agricultural productivity. Grapevine is no exception to the rule and faces several abiotic stresses throughout its lifespan. Drought, salinity, or heavy metals are serious problems in many parts of the world. The potential of AMF to enhance plant tolerance to abiotic stress conditions has long been known, and their use in sustainable agricultural systems will be of tremendous importance for soil quality and crop productivity under severe edapho-climatic conditions. Arbuscular mycorrhizal fungi (AMF), a kind of beneficial soil microorganism, can create a symbiotic association with plant roots forming arbuscular mycorrhizas (AMs), which play a role in the regulation of plant growth. This research was carried out in order to determine the effect of deficit irrigation on morphological characteristics of grapevine ʽAsgariʼ cultivar in greenhouse conditions in 2016. The layout was as a factorial experiment in a completely randomized design with three replication and two factors, including Arbuscular mycorrhizal and irrigation regimes. Irrigation treatments were irrigation with 100% moisture content of field capacity (control), 70% moisture content between field capacity and permanent wilting point (MAD 30) and 40% moisture content between field capacity and permanent wilting point (MAD 60) and mycorrhizal treatments was including non-use of mycorrhizal and use of Glomus mosseae, G. intraradices, G. etunicatum and G. verciform. Some morphological traits including height, root length, root volume and root density, fresh and dry weight of leaf, stem and root, leaf area, number of leaf damage, leaf area, leaf diameter and symbiosis percent of grape roots with fungi were measured. The results showed that mycorrhizal and 100% irrigation treatments increased the fresh and dry weight of leaf, stem and root, leaf area and the percentage of mycorrhizal symbiosis. Due to irrigation, the indices measured in the experiment such as height, fresh and dry weight of root, leaf and stem decreased, so that the decrease in without mycorrhizal plants was more than the with mycorrhizal plants. Generally, the use of mycorrhiza in this research has reduced the damaging effects of water stress on the morphological characteristics of grapevine, which in between the G. verciform and G. etunicatum were better than the G. mosseae and G. intraradices. Grapevine phosphorus deficiency is usually rarely observed, not only mainly because of limited phosphorus requirement, but also because of sufficient phosphorus richness in the majority of vineyard soils and remobilization from bark, wood, and roots during periods of high P demand. Nevertheless, P deficiency have been described in vineyards in Australia, France, Germany and USA. Phosphorus deficiency symptoms correspond to stunt shoot growth, decrease in dry matter, and berry clusters. Mycorrhizal treatments helped in alleviation of drought stresses. Enhanced uptake and storage of P, beyond what is required for immediate vegetative growth may be of particular importance for heavily pruned crops like grapes, since most of the new shoot growth is removed every year. These results were achieved in the greenhouse under almost controlled conditions and can be difficult to suggest for applying in the field conditions. Such experiments may be organized in the field conditions. Present-day vineyard practices place several constraints on the use of functions provided by mycorrhiza. The risk of large, costly, or irreversible changes is to be reduced or averted. Future (modern) agriculture should be based on the implementation of ecological management practices that deliberately maintain resilience of ecosystem services. This means integrating the development of vineyard management strategies that optimize the impact of beneficial microbes like mycorrhizal fungi on production. Furthermore, AMF vary in their ability to provide ecological services so that suitable tools have to be defined to fully assess their contribution. Molecular tools have considerably improved the possibility to identify and monitor mycorrhizal fungi in ecosystems, but a quick and reliable test for assessing their functionality is still lacking. For producers’ expectations to be met, a novel industry encompassing soil/mycorrhiza analyses and advice to producers/managers is needed. Additional barriers to rationally exploiting beneficial soil microbes like mycorrhizal fungi as ecosystem services range from economical, technical, and cultural aspects to legislative questions. In spite of this, considerable progress has been made in the last decade for crop plants in general, but also for grapevine, towards the use of AMF.