جستجوی مقالات مرتبط با کلیدواژه « محتوای نسبی آب برگ » در نشریات گروه « باغبانی »

 Medicinal plants have reservoirs rich in the active ingredients of many medicines. Medicinal plants have rich reservoirs of essential active ingredients of many drugs. Considering the importance of medicinal plants, especially in the pharmaceutical industry and their scarcity in nature, it is very important to study the various agricultural aspects of these plants, considering the increasing spread of saline soils, to find a solution. It seems necessary to prevent living and non-living environmental stresses or at least reduce them. One of these methods is the use of symbiotic relationships between mycorrhizal fungi and host plants, which reduces the stress caused by salinity. Due to the increasing expansion of saline soils, it seems necessary to find solutions that can prevent or at least reduce the living and non-living environmental stresses. There are different ways to overcome these tensions in different situations. Water salinization is one of the most important environmental limiting factors for crop production, especially in arid and semi-arid regions of the world, since Iran is located in the arid region of the world, given that salinity is one of the environmental factors. Are that have a strong effect on the growth and activity of lemongrass; There are also vast resources of saline and semi-saline groundwater, although not currently used and likely to be used in the future. Solutions to address abiotic stresses include the use of biofertilizers. One of these methods is to use the symbiosis of fungi with host plants, which leads to a reduction in salinity stress. The aim of this study was to investigate the effect of Arbuscular mycorrhizal fungi. On vegetative and biochemical traits of lemongrass under salinity stress. Salinity is one of the most important factors limiting the growth and production of crops. Fungi as a biological fertilizer can be useful in meeting the nutritional needs of plants and reducing the effects of environmental stresses on plants.
 
 The experiment was a factorial experiment in a completely randomized design with two factors of four salinity levels (0, 5, 10 and 15 ds.m-1 NaCl) and fungi (no inoculation and fungal inoculation). For inoculation of Arbuscular mycorrhizal fungi with mixed potting soil was applied to the lemongrass. Plant height, root length, fresh and dry weight of leaves, relative water content, catalase, peroxidase and polyphenol oxidase were measured.
 
 The results indicate that all studied traits were significantly affected by the interaction of mycorrhiza and salinity stress. The application of mycorrhizal fungi in the presence of salinity stress due to the absorption of nutrients and water led to improved growth of lemongrass. The results showed that under salinity stress of 150 mM plant height, root length, fresh and dry weight of leaves, relative water content, catalase, peroxidase and polyphenol oxidase enzymes in lemongrass inoculated with arbuscular fungus at 23.05, 32.69, 25.31, 48.14, 31.83, 30.33, 52.72 and 33.41% respectively, increased compared to the control (no inoculation). In general, based on the results of this study, it can be concluded that the use of mycorrhizal fungi can increase the salinity tolerance of lemongrass and cultivate it in saline soil.
 
In summary, the results of the present study showed that inoculation of the fungi can protect the lemongrass plant against salinity stress. In addition, the effect of mycorrhizal fungi on lemongrass under salinity stress has been investigated for the first time. According to the results obtained in this study, salinity reduced morphological parameters and lemongrass as a reaction to salinity to maintain its status to increase the amount of enzyme activity through the mechanism of osmotic regulation to stress conditions. Compromise and to some extent deal with salinity. In the study, it was observed that inoculation with Arbuscular had a positive effect on all measured traits. The application of mycorrhizal fungi in the presence of salinity stress due to the absorption of nutrients and water led to improved growth of lemongrass. By examining all the measured traits, it can be concluded that by using mycorrhizal fungi, the salinity resistance of lemongrass can be increased and cultivated in saline soil. Arbuscular species seems to be more suitable for improving the growth of lemongrass in all conditions.

Cumin (Cuminum cymium L.) is an annual plant with delicate stems and a height between 15 and 50 cm. For high yield and increased product quality, consuming the appropriate amount of dinitroaniline herbicides and using mulches to control weeds is important. Therefore, the use of trifluralin, pendimethalin herbicides, and wheat mulch was investigated in this experiment to investigate the population and growth of weeds, physiological and vegetative characteristics, yield, and percentage of cumin essential oil.

This experiment was conducted as a randomized complete block design with three replications. In this study, the experimental treatments included 100% and 50% recommended amounts of trifluralin and pendimethalin herbicides alone and in combination with wheat stubble mulch, which was considered together with wheat stubble mulch alone and no weed control (control). Wheat stubble mulch, 5 cm long and equal to 5 tons per hectare, was applied. The herbicide was spread using a 20-liter book-back sprayer with a rain nozzle. Weed species were identified by Zarghan Agricultural Research Station, Fars Province weed experts. After that, quadrats with dimensions of 50 x 50 cm were used to determine weeds' density and dry weight. Three fully opened and fresh young leaves were selected to measure the relative water content of leaves and the chlorophyll content of each treatment. Sampling was done in the morning and before sunrise. Before the end of the growth period, the height and number of branches were measured. After harvesting, yield and yield components (including the number of umbels per plant, the number of seeds per umbel, and the weight of 1000 seeds) were determined. From the harvested seeds in each plot, 50 grams of samples were randomly taken and analyzed to determine the percentage of essential oil. To extract essential oil from the prepared samples, the steam distillation method was used by a Clevenger machine. The percentage of essential oil in each sample was determined. The mean comparison of the studied traits was compared using Duncan's multiple range test at 0.05.

The dominant weed species identified in the field included 6 genera and 6 species. The mean comparison results showed that using trifluralin herbicide with the recommended dose + mulch reduced weeds' density and dry weight by 88% and 87%, respectively, compared to no weed control (control). Mulch treatment alone reduced weed density and dry weight compared to control plants by 29.6% and 37.5%, respectively. 85% mulch + trifluralin herbicide at the recommended dose resulted in the highest relative leaf water content. Also, the highest chlorophyll b and total leaf chlorophyll content were obtained for both trifluralin and pendimethalin herbicides in combination with mulch, which showed a significant increase compared to mulch alone and no weed control. The lowest cumin plant height was observed in the weed-infested treatment (control). Among the management treatments, the number of lateral branches in the treatment of 100% of the recommended herbicide dose was more than in the treatment of 50%. Also, adding mulch to the treatments showed a significant increase in lateral branches. Cumin aerial parts dry weight increased by 4% with the 50% dose and 10% with the full dose. With trifluralin herbicides, cumin seed yield increased by 47% and pendimethalin by 45%. By applying mulch management treatments, cumin seed yield increased by 48%.

The application of wheat mulch, by increasing leaf water and chlorophyll's relative content, improves growth indicators. In addition to the application of 100% of the recommended dose of trifluralin and pendimethalin herbicides in combination with wheat mulch, which increased the dry weight of shoot and seed yield in cumin, the treatment of 50% of the recommended dose in combination with wheat mulch at a lower level improved these traits. Therefore, due to reduced herbicide consumption, 50% of the recommended dose of trifluralin herbicides in combination with wheat mulch is recommended to control weeds in cumin.

 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.

Geranium is one of the most important potted and bedding ornamental plants that selection and construction of a suitable growing medium is important for success in any stage of its production. In order to determine a suitable pot mixture for geranium, the effect of peat moss, cocopeat and licorice root residue in soil-based mixtures (50% by volume, including soil and perlite in a ratio of 5:2), an experiment with 6 treatments (50% by volume) including peat moss (P50), cocopeat (C50), licorice root residue (L50), peat + cocopeat (P25C25), peat + licorice residue (P25L25) and cocopeat + licorice residue (C25L25) was performed. The results showed that the highest values of plant height, shoot fresh weight, shoot dry weight, number of leaves, average leaf area, number of inflorescences, petiole length and apparent quality rating were belonged to P50 treatment. The highest values of root fresh and dry weight  and root volume were obtained in P25C25 mixture. The highest leaf area ratio (LAR) and relative leaf water content (RWC) were belonged to P50 treatment and the highest amount of chlorophyll was belonged to P25L25 mixture. In general, the best vegetative and flowering performance of plants were observed in P50 treatment (containing loamy soil (35%), perlite (15%) and peat moss (50%)) and then in P25C25 treatment. Therefore, with little access to peat moss, less than 50% of peat moss can be replaced with cocopeat, and more cocopeat has a negative effect on plant growth. Licorice residue had a negative effect on most of the measured indices.

In this study, a pot experiment was conducted in the greenhouse conditions to investigate the drought tolerance of six Iranian grape cultivars. The experiment was factorial, based on a completely randomized design, with two factors including cultivars (‘Rotabi’, ‘Rashe’, ‘Chafte’, ‘Bidaneh Sefid’, ‘Khalili’, and ‘Laal’) and moisture treatments (40 % and 80 % of soil available water). Under drought stress, the lowest accumulation of soluble carbohydrates and proline (50.36 and 4.25 mg g-1 FW, respectively) and the highest stress susceptibility index (2.47, on average) and growth reduction were observed in ‘Bidaneh Sefid’ cultivar. ‘Chafte’ showed a considerable growth in optimal moisture condition; moreover, this cultivar had a relatively low stress susceptibility index (0.60, on average), designated as the most tolerant cultivar to drought stress. ‘Khalili’ had the highest root weight and root volume under optimal conditions. Although this cultivar had the highest stress susceptibility index in terms of root dry weight (1.24) and root volume (1.35) after ‘Bidaneh Sefid’, but under stress conditions it had a suitable root weight, root volume and number of roots. ‘Rotabi’ and ‘Laal’ had relatively less growth under optimal moisture conditions; however, they showed a subtle growth reduction under drought stress. These results indicate that in order to introduce drought tolerant plants, stress susceptibility index and vegetative growth rate under water shortage should be considered together.

Quinoa (Chenopodium quinoa Willd.) is a plant with high nutritional value and growth potential, thus has a proper production in adverse environmental conditions. However, the enhancement of plant growth in these conditions could be achieved by different approaches. The use of endophytic microorganisms such as Serendipita indica fungus may help plant growth, especially under salt-stressed conditions. In this research, an experiment was performed using a factorial completely randomized design with three replications in a sterile sandy loam soil under greenhouse conditions. Experimental factors included two levels of S. indica (inoculation and non-inoculation) and salinity levels of 1.47 (initial electrical conductivity of soil), 5, 10, 20 and 30 dS/m which prepared by sodium chloride solution. The results showed that the interaction effect of salinity and fungal inoculation was significant for all measured characteristics (P < 0.05) except for proline. The inoculation of S. indica was able to increase the fresh weight of quinoa shoot by 18.5, 15.0, 39.4 and 45.4% compared to the non-inoculated treatment at salinity levels of 1.47, 5, 10 and 20 dS/m, respectively. The inoculation caused an increase in shoot fresh weight by 18% at initial electrical conductivity (5 dS/m), while a marked increase (~41%) was observed in inoculated plants compared to the no fungus treatment at EC level of 20 dS/m. The fungus increased the root weight by 12.9, 20.1 and 31.5% at salinity levels of 1.47, 5 and 10 dS/m compared to the non-fungal treatment, respectively. Compared to the non-fungal plants, the electrolyte leakage was significantly reduced in the inoculated plants at 10 dS/m. Fungal inoculation had pronounced effect on relative water content (RWC) of leaf at 5 dS/m and increased RWC by 23%, compared to the non-fungus treatment. Moreover, the increasing of salinity stress up to 30 dS/m reduced the percentage of root colonization by 19.9% compared to the non-fungus control. Overall, the application of S. indica significantly increased the biomass production of quinoa under salinity stress conditions.

In order to study The Effects of drought Stress in response of wheat cultivars and wild genotype, a factorial experiment was carried out in completely randomized design in pot with three replications at 2017-2018 years. The wheat cultivars including (Bolani, behrang, shabrang, sistan) and wild (urartu, tauschii, speltoides) were as the first factor and irrigation treatment with three levels consisted of normal (80% of water holding capacity of soil), mild stress (60%) and severe stress (40%) was as the second factor. Physiological studies include: chlorophyll a and b, total chlorophyll, carotenoids, Water Use Efficiency, Leaf Relative water content and the was morphological: dry matter production (dry weight of plants), stem dry weight, stem fresh weight, Root dry weight, Root fresh weight, stem length and Rott length. Analysis of variance showed that simple effect of drought stress had a significant effect on the traits chlorophyll a and b, total, carotenoids, stem dry weight, plant dry weight of plant , leaf relative water contwnt, water use efficiency and also on stem length, stem fresh weight characteristics and Root dry weight. The result of the mean comparison showed that the tolerant cultivaers had the highest stem fresh weight, plant dry weight of plant, Leaf Relative water content and Water Use Efficiency. Comparison of cultivars and wild: cultiwars of Bolani and tauschii wild life showed more resistance.

In order to evaluate the tolerance of carob seedlings to drought and salinity stresses based on growth and ecophysiological indices, a factorial experiment was conducted based on a completely randomized design with three replications. Factors included drought at 3 levels (5, 10 and 15 days irrigation intervals) and 3 salinity levels (0, 80 and 160 mM NaCl). The results showed that drought and salinity stresses reduced the vegetative indices of carob seedlings so that the lowest vegetative indices were observed in 15 days irrigation interval and 160 mM NaCl. The shoot fresh and dry weight decreased with increasing salinity and drought intensity. The highest shoot fresh and dry weight were recorded in control plants and the lowest shoot fresh and dry weight were recorded in plants treated with 160 mM NaCl and 15 days irrigation interval. The results of this study also showed that relative water content of leave decreased in plants treated with 10 days irrigation interval with increasing salinity levels while there was no significant difference between salinity levels in 15 irrigation intervals. The results also showed that the concentration of Na in root and shoot was increased with increasing salinity and drought stresses so that the highest concentrations of Na in shoots and roots were observed in plants treated with 15 days irrigation interval and 160 mM NaCl. According to the results of this study, it can be concluded that carob seedlings can tolerate 10 days of irrigation and 80 mM salinity.

Yaghooti grape (Vitis vinifera L.) is an important variety in Iran and also it is the most important horticultural product of Sistan region. This variety is of interest for economical aspect. Because continuous drought in Sistan region has been a serious threat to the grape production, local farmers have to manage the problem by reducing the volume and irrigation intervals. The canopy plays a key role in radiation energy capture via photosynthesis apparatus, water use as regulated by transpiration, and microclimate of ripening grapes and also grape yield, quality, vigor, and the prevention of grape diseases. Since vines has high vegetative growth makes them compete with the reproductive growth, therefore vines be pruned every year.

In order to evaluate the effects of irrigation regime and green pruning on some physiological traits and fruit yield of Yaghooti grape, the present research was conducted in the research and extensional garden of Zahak city during 2017-2018. An experiment was carried out in the form of a split plot based on randomized complete block design with three replications. Three irrigation regimes of 100, 75 and 50 percent of the grape water requirement based on the potential evapotranspiration of grape and green pruning with three levels including the control plot or the local practice of not green pruning (P1), pruning the green branches starting from the sixth leaf above the last grape bunch (P2) and pruning the green branches starting from the sixth leaf above the last grape bunch along with green pruning of the green branches without fruit and pruning the unproductive brunches (P3) were allocated to main and sub-plots, respectively. ‘Yaghooti vines were 8 years old and trained as a traditional system. The vines were spaced 3 × 3 m. Water requirement of grape was determined according to the FAO method using data from a Class A evaporation pan. The analysis of variance for each variable was performed with the PROC GLM procedure in SAS 9.4. Multiple linear regression was used to determine the relationships of leaf relative water content, proline, soluble sugars, relative membrane permeability, chlorophyll index, and leaf area to fruit yield.

By reducing water consumption from 100 to 75% of grape water requirement, leaf relative water content, fruit juice acidity, chlorophyll index, leaf area and fruit yield decreased 10.1, 6.5, 8.6, 11 and 18.8%, respectively and also proline, soluble sugars and relative membrane permeability increased 67.3, 8.75 and 44.84%, respectively. The P3 treatment compared to control induced an increase in relative leaf water content, chlorophyll index, and fruit yield by 14.7, 12.2 and 25%, respectively as well as a reduction in proline, soluble sugars, relative membrane permeability, fruit juice acidity and leaf area index by 18.34%, 12.1%, 6.8%, 8.3% and 21.3%, respectively. Also the results indicated that providing the 100% of the water requirement combined with pruning the green branches starting from the sixth leaf above the last grape bunch in combination with green pruning of the green branches without fruit and pruning the unproductive brunches (P3) caused the highest grape fruit yield (7797 kg ha-1). Also the interaction effect of meeting 75% of the water requirement and the green pruning had the same result as that of meeting 100%of water requirement under no green pruning conditions. In other words, the green pruning could result in saving 25% of water used by the grape cv. Yaghooti without reducing fruit yield. The multiple linear regression analysis indicated that proline and leaf area were the most important traits impacting fruit yield in Yaghooti cultivar.

Reducing the water potential of vine causes different responses. The most important are a decrease in number cells of fruit, vegetative growth, leaf area, relative leaf water content, chlorophyll content, fruit yield, and increase in the compatible osmolytes. The growing shoots are a strong sink for the consumption of photosynthetic materials. The above mentioned effect causes an increase in the branch overgrowth and its overshadowing. All this factors compete with vine fruit production. So, green pruning and removal of apical dominance eliminates a strong place of nutrient absorption. In other words, green pruning results in a greater accumulation being used by flowers and fruits, causing sufficient light penetration into the crown and reducing evapotranspiration, leading to an increased water consumption and fruit yield.

To study the effect of different levels of drought stress on growth, yield and some physiological and phytochemical characteristics of oregano (Origanum vulgare L. ssp. gracile), a pot experiment, in a randomized complete design with four treatments and five replications, was conducted. Drought stress treatments were 100% (non-stress), 80%, 60% and 40% of field capacity. The results showed that drought stress had significant effect on growth parameters, dry herb yield, leaf relative water content (RWC), total phenol and flavonoid content, antioxidant activity, a, b and total chlorophyll content, essential oil content and yield. There was no significant difference between drought stress treatments for carotenoids. As the soil water content decreased, plant height, stem diameter, number and length of axillary shoots, dry herb yield, RWC, a, b and total chlorophyll content and essential oil yield decreased, but total phenol and flavonoid content, antioxidant activity and essential oil content increased. Despite the decrease in dry herb yield, the difference between 80%, 60% and 40% treatments was not significant. The highest essential oil content (1.54 ml/100 g DW) was observed in 60% of field capacity and the highest amounts of total phenol (5.21 mg gallic acid/g FW), total flavonoid (0.5 mg quercetin/g FW) and antioxidant activity (77.36%) were obtained in 40% of field capacity. The highest percentage of essential oil (54.1 mg / g dry matter) was observed in 60% of treatment capacity and the highest amount of total phenol (0.51 mg gallic acid per gram of fresh material), total flavonoid (0.5 mg Gram quercetin in grams of fresh milk) and antioxidant activity (37.36%) in 40% of treatment capacity.

Water deficit stress is a major environmental limiting factor for plant growth and crop productivity. In present investigation, to study the effects of jasmonic acid on reducing the damage caused by drought on growth parameters, some physiological and antioxidant responses on Salvia officinalis L., a factorial experiment in a completely randomized design with three replications was conducted at the University of Zabol. The experimental treatments included drought stress (irrigated in field capacity, depletion of soil water content up to 50% and 75% of FC condition) and foliar jasmonic acid spray (0, 75 and 150 mg.l-1). The results showed that spraying with a concentration of 150 (mg. l-1) jasmonic acid under drought stress increased the height (% 10.02), fresh and dry weight (27.88% and 12.81%), relative water content (21.04%) and chlorophyll a and b content (12.15% and 10.34%). The highest phenolic content (34.13 mg-1fw), proline concentration (5.52 mg-1fw), essential oil yield (2.1 mg-1fw) and the activities of peroxidase (3.15 mg-1fw) and guaiacol peroxidase (0.76 mg-1fw) were obtained in plants sprayed with 150mg.l-1 jasmonic acidand in depletion of soil water content up to 75% of FC. On the other hand, the highest ascorbate peroxidase (0.76 mg-1fw), superoxide dismutase (5.64 mg-1fw) and catalase (5.12 mg-1fw), were obtained in plants sprayed with 150 mg -1 jasmonic acid under drought stress (depletion of soil water content up to 75 and 50% FC). Based on our results, it seemed that Jasmonic acid, with increasing antioxidant defense and accumulation of osmotic regulators (such as proline), reduced the oxidative stress in plants under drought stress. Moreover, maintaining the relative water content and photosynthetic pigment improved growth conditions of sage plants in drought conditions.

An experimental was conducted in order to investigate the effect of different levels of salicylic acid (0, 0.5, 1 and 2 mM) and three levels of irrigation [100, 66 and 33 percent evapotranspiration] on some morphological and physiological characteristics of olive cv. ‘Konsevalia as factorial based on a randomized complete block design with three replications in greenhouse of Agricultural Faculty of Shahid Chamran University of Ahvaz in 2015-2016. Results of ANOVA table showed that interaction of salicylic acid and irrigation had significan effect on fresh and dry root weight, stem and leaf, leaf area and plant height at P

In order to study the yield and some physiological characteristics of borage (Borago officinalis L.) under different plant densities and sowing dates in Ahwaz city, an experiment was carried out in a split plot arrangement based on randomized complete block design with three replications in Khuzestan Ramin Agriculture and Natural Resources University, Iran during 2016-2017. The treatments included sowing date as main plot in five levels (15 October, 5 November, 25 November, 15 December and 5 January) and plant densities as sub-factor in four levels (6, 10, 14 and 18 plant per m2) were considered. The results showed that delayed sowing (5 January) caused anincreased temperature at flowering stage and significantly reduced the grain yield and biological yield (182.22 and 1443.4 kg ha-1, respectively). The sowing dates of 5 November at a density of 10 plants/m2 caused the highest grain yield and oil yield with average values of 1243.82 and 437.47 kg ha-1, respectively. The sowing date of 15 October at a density of 14 plants/m2 caused the highest chlorophyll a and total chlorophyll content with average values of 1.13 and 3.39 mg/g fw, respectively. A delay in sowing date from 15 October to 5 January led to a decreased relative leaf water content, cell membrane stability and chlorophyll content. High plant density per m-2 increased the plant height and biological yield and reduced the oil percentage. Sowing date had significant effects on all traits expect oil percentage.

Citrus tolerate low temperature and weak drainage. Growing citrus in warm regions, expose them to drought. This research was conducted to investigate drought effect on relative water content, ion leackage, malondialdehyde, soluble sugars, potassium and calcium nutrients in nucellar seedlings of citrus natural genotypeswith two susceptible and tolerant rootstocks in factorial test based on randomized completely design with three replications in glasshouse conditions. Factors included commercial Citrus genotypes and two level of irrigation (optimum irrigation and withholding irrigation). The results showed that Poncirus because of lower ion leakage (31.85 %), lower malondealdehyde accumulation (134.4 nm/gdw) and higher calcium content (57 mg/gdw) compared with other genotypes was more tolerant to drought. Rough lemon because of higher malondealdehyde accumulation (356.9 nm/gdw), high ion leakage (69.43 %) and lower calcium content (32.63 mg/gdw) compared with other genotypes, was susceptible to drought. Genotype of Shelmahalleh because of high ion leakage (77.17 %) and slight total soluble carbohydrate accumulation was susceptible to drought after Rough lemon. Therefore, we could consider ion leakage as a proper physiological marker for drought tolerance with regard to means comparison and its good correlation to survival time.

In order to evaluatethe effect of salicylic acid on some morpho physiological charactristics of Calendula officinalis.L. under water deficit stress, an experiment was set out in split plot design based on RCBD with three replications under Zanjan climate conditions. Treatments consisted of 3 different irrigation regimes(100, 66, 33% ETC) as main plot and SA at 4 levels (0, 0.5, 1, 1.5 mM) as sub plots. Results indicated that, water deficit stress significantly increased proline content and peroxidase enzyme activity and reduced height, fresh and dry weights of shoot, flower number, flower vase life and leaf relative water content (RWC). Foliar application of SA at the 1 mM significantly increased fresh and dry weight of shoot, flower number, flower vase life, relative water content (RWC), peroxidase enzyme activity and proline content under water deficit stress. According to the results of this research, foliar application of salicylic acid could improve plant response in most traits at 1% level to drought stress.

In order to evaluate the tolerance of Banabaghi and Badami-Riz-e-Zarand pistachio rootstocks to salinity, an experiment was conducted as factorial based on completely randomized design with three replications. Each replication consisted of two samples and each sample containing a pot with three seedlings. Treatments were three levels of salinity (0, 70 and 140 mM) of sodium chloride, calcium chloride and magnesium chloride with ratio (3:2:1) and three rootstocks (Badami-Riz-e-Zarand, Banabaghi with pistachio growth type and Banabaghi with mutica growth type). The results showed that salt stress decreased the growth characteristics and eco-physiological parameters so that the most leaf dry weight was observed in Banabaghi with pistachio growth type and the lowest was in the Badami-Riz-e-Zarand rootstock. Also, at the highest level of salinity, Banabaghi rootstock with pistachio growth type had the highest relative water content of leaf and the Banabaghi rootstock with mutica growth type had the lowest content. The highest proline content of leaves obtained in the Banabaghi rootstock with pistachio growth type and the lowest content was observed in the Badami-riz Zarand rootstock. Also, the results showed that the lowest shoot Na concentration was observed in Banabaghi with pistachio growth type. Based on the present study, Banabaghi rootstock with pistachio growth type had higher tolerance to salinity stress than Banabaghi with mutica growth type.

Most plants have developed morphological and physiological mechanisms which allow them to cope with drought stress. Almost all the studies conducted on grapevines (Vitisvinifera L.) responses to drought conditions have focused on physiological responses such as stomatal reactions, photosynthesis and osmotic adjustment, and biochemical responses like carbohydrates and proline. According to these studies, physiological and biochemical responses of grapevines to water stress are quite variable. This variability could be related to cultivar, time of the year, previous water stress level, intensity of stress, and environmental conditions. Osmotic adjustment in terms of compatible solutes accumulation has been considered as an important physiological adaptation for plant to resist drought, which facilitates the extraction of water from dry soils and maintenance of cell turgor, gas exchange and growth in very dry environments. Acting as compatible solutes as well as antioxidants, a significant rise in proline amount was observed in grapevine leaves under water stress conditions, suggesting that this amino acid has a protective role against the formation of excessive reactive oxygen species (ROS). Plants, in order to overcome oxidative stress, have developed enzymatic and non-enzymatic antioxidant defense mechanisms against scavenge ROS.
This research was conducted to assess the effect of different levels of irrigation on some characteristics of three cultivars of grapevine (Yaghooti, Bidanesefid and Askari), as a factorial based on a randomized complete block design in two years with four replications. The experiment started in June 21, 2014 and 2015. Water treatments were applied in four levels including: control plant (100% FC), moderate stress (60% FC), severe stress (30% FC) and rewatering treatment after severe stress treatment. Increase height, leaf number, stem diameter, leaf fresh and dry weight, stem dry weight, chlorophyll index,RWC, electrolyte leakage, soluble sugar, antioxidant activity, phenolic compound and proline were measured at the end of the experiment. JMP8 software was used to test the significant differences among the treatments and the interactions. When there were significant differences, means were separated by Tukey HSD test at the probability level p

To study the effects of salt stress on some physiological parameters of grapevine and the effect of foliar application of potassium silicate and zinc sulphate in alleviating saline effects, a pot experiment was conducted under greenhouse condition. Rooted sapling of two grapevine cultivars, ‘Rasha’ (salt-tolerant cultivar) and ‘Bidaneh ghermez’ (salt-semi sensitive cultivar) were subjected to different NaCl concentrations (0, 50 and 100 mM) and foliar application of potassium silicate (0, 150 and 300 mg/l) and zinc sulphate (0, 2 and 4 g/l) in hydroponic conditions. The experiment was conducted using a factorial design (cultivar, salinity levels and foliar application as factors) based on randomized complete block design with three replications. The results showed that relative water content, photosynthesis, stomatal conductance, transpiration and chlorophyll content decreased with increasing salinity level. The reduction of physiological parameters in ‘Rasha’ was less than ‘Bidaneh ghermez’. Foliar application of different concentrations of potassium silicate and zinc sulphate increased relative water content, photosynthesis, stomatal conductance, transpiration and chlorophyll content in both cultivars. The most effective treatment was potassium silicate 300 mg/l zinc sulphate 2 g/l, so that at the highest salinity level (100 mM) relative water content, stomatal conductance and photosynthesis in this treatment was 13.75%, 91.14% and 47.56% more than no foliar application treatment, respectively. According to the results of this study foliar application of potassium silicate and zinc sulphate can be used to alleviate salinity effects in grapevine.

This experiment was conducted to study the effect of plastic mulch on the growth and some physiological characteristics of two strawberry cultivars (Paros and Queen elisa) under drought stress. A factorial experiment was performed based on randomized complete block design with four treatments, including mulch, without mulch, normal irrigation (control) and deficit irrigation (-10 bar) with three replications. Some vegetative and physiological parameters in first year and yield of second year were measured. Results showed that leaf relative water content and stomatal conductance reduced by drought stress in both cultivars. Using of mulch increased leaf relative water content, cell membrane stability index and stomatal conductance in both cultivars compared with drought stress conditions. Drought stress reduced cell membrane stability index in Queen Eliza. However, Parus had higher cell membrane stability index than Queen elisa under drought conditions. Proline and total soluble carbohydrates significantly increased in both cultivars under drought stress compared to control. The amount of total soluble carbohydrates increased in Parus under drought conditions even with using mulch. Root to shoot dry weight ratio was increased under drought stress. Reduction of total dry matter was obtained by decline in leaf and petiole dry matter. However, application of mulch had significant effect on increasing of root dry weight, volume and length under drought stress. Yield of next year increased by mulch application under drought stress compared to non-mulch application. Results showed that using plastic mulch improved growth characteristics of strawberry under drought stress and helped to lower reduction of next year yield.

Drought has adverse effects on plant growth and production. Plants respond to drought stress through biochemical and physiological processes. In the present study, physiological responses of two cumin (Cuminum cyminum L.) ecotypes including Ravar and Gonbad, which belong to dry and sub-humid regions of Iran, respectively, were evaluated in a split-plot factorial experiment with three replications in controlled greenhouse conditions. Physiological traits such as relative water content, relative leaf water loss and electrolyte leakage were measured. Analysis of variance showed that there are considerable genetic variations for drought tolerance between the ecotypes. Drought stress decreased relative water content and relative leaf water loss rate, while electrolyte leakage was significantly increased in both ecotypes. Most of the significant changes were recorded in Gonbad ecotype. The Ravar ecotype demonstrated higher tolerance to drought stress, as compared to Gonbad ecotype, which can be due to compatibility of this genotype to water-deficit conditions. Therefore, this ecotype was recommended as a tolerant ecotype to drought stress. In conclusion, the investigated traits in this experiment were found to be valuable criteria in selection of drought-tolerant ecotypes at seedling stage under greenhouse conditions.