جستجوی مقالات مرتبط با کلیدواژه "تنش های محیطی" در نشریات گروه "زراعت"

Tarragon is one of the most important medicinal plants with various medicinal properties and is widely used as a flavoring agent in the food industry. Drought stress affects a wide range of morphological, physiological, and biochemical characteristics of medicinal plants. However, the exogenous application of osmotic active substances such as polyamines is considered as a suitable alternative to deal with the adverse effects of various environmental stresses on plant yield. Nevertheless, little is known about their mechanism to reduce drought stress. The present study investigates the response of tarragon plants to different concentrations of putrescine under drought stress conditions.

This study was carried out in a factorial experiment based on a completely randomized design with 3 replications in a greenhouse as a pots experiment. After the growth of the plant in the soil of the pot, three stages of foliar spraying with experimental treatments were carried out in this research. Experimental treatments included drought stress (50, 70, and 90% of field capacity) and putrescine foliar spraying with zero (spraying with distilled water), 0.1 and 0.2 mM concentrations. The evaluated parameters include morphological and physiological traits (shoot dry weight, stem height, number of lateral stems, root length, stem diameter, leaf area, leaf relative water content) and phytochemical (chlorophyll a, chlorophyll b, total chlorophyll, electrolyte leakage, proline and malondialdehyde content, antioxidant enzyme activity and essential oil percentage). Data analysis was done using SAS software version 9.4

The results showed that putrescine foliar spraying increased the shoot dry weight, the stem height, and the number of lateral stems. The highest of these traits was obtained under 90% field capacity and no difference was observed between the levels of putrescine at this level of drought stress. Plants grown under 90% crop capacity had the highest stem diameter (35.59 mm) and leaf area (62.89 cm2). Under 50% field capacity, foliar spraying of 0.2 mM putrescine increased the content of chlorophyll a, b and total by 29.03, 11.76 and 22.91%, respectively, compared to the control. The results also showed thatfoliar spraying of putrescine increased the relative water content and decreased electrolyte leakage in stressed plants. The content of proline and the activity of antioxidant enzymes also improved under the influence of putrescine. 50% field capacity without putrescine foliar spraying produced the highest percentage of essential oil (2.58%) in tarragon plants.

In general, foliar spraying of putrescine (0.2 mM) through increasing photosynthetic pigments and antioxidant properties can be a useful and practical solution for improving biomass and dealing with drought stress in the tarragon plants.

Plants in the environment are affected by various stresses, depending on the duration, intensity and growth stage of the plant, these stresses can reduce the process of photosynthesis and affect their growth and performance. However, traditional methods, even technically advanced ones such as the measurements of photosynthetic rates through the gas exchange (CO2, H2O, and O2), are time-consuming and provide incomplete information on overall photosynthetic function. The development of knowledge in the field of chlorophyll fluorescence shows that this indicator has a high ability to study the photochemical efficiency of plant photosynthesis.

For measuring the chlorophyll fluorescence in plants, leaves were dark-adapted for 30 minutes using leaf clips provided by the producer of handy-PEA. Measurements were performed on the middle of plant leaves following the standard protocol with illumination with continuous red light (peak in 650 nm wavelength; the spectral line half-width of 22 nm) provided by an array of three light-emitting diodes. The light pulse intensity used was 3500 μmol(photon).m–2s–1 and the duration of the light pulse was 1 s. The measured data were used for the calculation of the photosynthetic parameters using Biolyzer v. 3.06 HP software (a software provided with handy-PEA). Some of the parameters we discussed in this article due to their significance are FO = minimum fluorescence, FM = maximum fluorescence, FO/FM = The maximum quantum yield of basal non-photochemical energy losses, FV/FM = the maximum quantum efficiency of PSII, VJ = the relative variable fluorescence in step J after 2 ms, VI = the relative variable fluorescence in step I after 30 ms, N = the number of QA redox turnovers until FM, SM = the pool size of the electron acceptors on the reducing side of PSII, PIABS = performance index.

The study of chlorophyll fluorescence can analyze with high detail the function and state of PSII reaction centres, and light-harvesting complexes. This index has a high correlation with other physiological parameters under different environmental stresses. In this article, an overview of the results of chlorophyll fluorescence analysis of crops underenvironmental stressesis given, and the key steps to stresses are presented. Under drought stress the ratio of active reaction centers in chlorophyll, primary photochemical reactions, and electron transfer are affected. By salinity stress in crops, the values of variable and, maximum fluorescence, the energy required to close the reaction centers, and the photosynthetic efficiency index decrease, while the time required to reach the maximum fluorescence increases. Under cold stress conditions, electron transfer flow per reactive centers, the quantum performance of photosystem II, and the efficiency of the water splitting complex in photosystem II decrease. Potassium affects light-dependent steps such as the size of receiving antennae and the electron connection of photosystem II reaction centers. The electron acceptor part of photosystem II is the main site of inhibition of photosynthetic electron transfer under the application of herbicides.

Conclusion and Implications:

This article has provided an overview of the information about the wide opportunities of using the chlorophyll fluorescence technique in plant science, agriculture and ecological research. The measured parameters of chlorophyll fluorescence are called the JIP-test and its analysis can be used to evaluate the effects of environmental stresses on plants. This technique requires more practical studies in biotic and even non-biotic stress conditions to provide reliable information to investigate the growth and development of plants, and this leads to an increase in our knowledge of the physiological basis of crop photosynthesis under stress conditions.

Drought is known as the most important factor limiting corn production in the world. Depending on the growth stage and severity of drought stress, it can decrease corn yield by 76%. In addition, the increase in drought stress can decrease the efficiency of elements such as nitrogen in this crop. Therefore, many ways have been studied to decrease the effects of drought stress on crops. The results show that the use of cover crops can be an important approach for agriculture to protect crops against climate changes. These crops improve crop yields and soil nutrients by reducing runoff and soil erosion. The use of legumes as cover crops can decrease the need for chemical nitrogen fertilizer by biological N fixation in these crops.

In 2019, a pot experiment was conducted in the greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. The experimental treatments were faba bean cultivation (cultivated, non-cultivated), the different rates of nitrogen based on urea (0, 50, 100% of the recommended amount) and water deficit stress (40, 60, 80, 100% FC). In this experiment, 72 pots of 10 kg were used. First, the field capacity of the soil was determined, then the pots were filled with the air-dried soil. Ten grains of faba bean were planted in each pot, 5 of which were removed after germination. Shoots of faba bean were cut at the 50% flowering stage and mixed with the soil to the depth of 10 cm. Four corn grains were planted in each pot, two of which were removed after germination. In this experiment, the variety Shadan of faba bean and the corn hybrid 201 (single cross) were used. Different levels of nitrogen were applied at the V5 stage of corn, drought stress was applied ten days later and continued until the harvest stage of corn. Pots were weighed regularly for the application of drought stress. Corn was harvested at the pasty stage. Experimental characteristics included grain and shoot fresh and dry weights, grain and shoot protein content, nitrogen agronomic efficiency, nitrogen productivity, nitrogen recovery efficiency, and shoot and grain partial factor productivity. Statistical analysis of data was performed using SPSS software (version 26), and significant differences between treatment means were tested using Duncan's Multiple Range Test at P < 0.05.

Our results showed that all traits were influenced by interactions between faba bean cultivation × N fertilizer × water deficit stress. The highest grain yield was obtained of treatment the faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress, while no grains were observed in the treatment of non-cultivation of faba bean+100% of the recommended rate of nitrogen+application of severe water deficit stress, non-cultivation of faba bean+no nitrogen application+application of moderate water deficit stress and non-cultivation of faba bean+no nitrogen application+application of severe water deficit stress. The higher rate of nitrogen in the soil under severe water deficit stress can be considered as the limiting factor for crop growth, and therefore we observed lower yields in these treatments. Addition, our results showed that faba bean cultivation as cover crop increased some traits such as fresh and dry weight of shoot, agronomic efficiency and nitrogen recovery of nitrogen compared to non-cultivation of faba bean. The highest fresh dry shoot weight was obtained from the treatments of faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress and non-cultivation of faba bean cultivation+100% of the recommended nitrogen rate+no application of water deficit stress. Also, the highest shoot and grain agronomic efficiency was observed from the faba bean cultivation+100% of the recommended nitrogen rate+ no nitrogen application+application of moderate water deficit stress.

Overall, our results showed that the use of faba bean as cover crop can decrease the effects of water deficit stress and improve the growth status of corn, although the increase at higher water deficit stress level is lower than the other levels. Based on the results, it can be concluded that the use of faba bean as cover crop and and 50% of the recommended rate of nitrogen can be recommended under the same conditions (under water deficit stress).

Drought is assumed as one of the most severe abiotic stress factors limiting plant growth and crop production. Since in arid and semi-arid regions, some part of growth period of wheat is confronted with water limitation condition which can affect biochemical and physiological responses such as changes in photosynthetic efficiency of PSII, chlorophyll content, and stomatal conductance. Application of bio fertilizers and silicon is one of the most important strategies for alleviation of drought stress effects. Bio fertilizers (plant growth promoting rhizobacteria or PGPR and mycorrhiza) can improve plant performance under non-stress and stress conditions. Thererfore, it seems that application of nano silicon and bio-fertilizer can improve wheat yield under water limitation conditions.

In order to study the effects of biofertilizers and nanosilicon on phosphorus uptake, grain yield, and some physiological traits of wheat (Triticum aestivum L.) under withholding irrigation conditions, a factorial experiment was carried out at the research farm faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, with three replications during 2018-2019. The area is 38° 15′ N latitude, 48° 15′ E longitude, and 1350 m above mean sea level. Climatically, the area is situated in the semi-arid temperate zone with a cold winter and moderate summer. Factors were included irrigation in three levels (full irrigation as control; moderate water limitation or withholding irrigation at 50% of the heading stage; severe water limitation or withholding irrigation at 50% of the booting stage) based on codes 55 and 43 of the BBCH scale; foliar application of nano silicon (foliar application with water as control, 30 and 60 mg.L-1) and bio-fertilizer (no application as control, mycorrhiza application, both application of flavobacterium and pseudomonas, both application of flavobacterium and pseudomonas with mycorrhiza). Mycorrhiza fungi (mosseae) was purchased from the Zist Fanavar Turan Corporation and soils were treated based on method of Gianinazzi et al. (2001). Psedomunas and flovobacterium were isolated from the rhizospheres of wheat by Research Institute of Soil and Water, Tehran, Iran. For inoculation, seeds were coated with gum Arabic as an adhesive and rolled into the suspension of bacteria until uniformly coated. The strains and cell densities of microorganisms used as PGPR in this experiment were 1×108 colony forming units (CFU). In this study, electrical conductivity, stomatal conductance, leaf fluorescence parameters, phosphorus of root and grain, relative water content, electrolyte leakage, anthocyanins and grain yield of wheat were investigated. Analysis of variance and mean comparisons were performed using SAS ver 9.1 computer software packages. The main effects and interactions were tested using the least significant difference (LSD) test at the 0.05 probability level.

The results showed that application of both flavobacterium and pseudomonas with mycorrhiza and foliar application of 60 mg.L-1 nano silicon under severe water limitation increased 84.32%, 49% and 49.52% of electrolyte leakage, electrical conductivity and minimum fluorescence (F0) respectively, and decreased root and grain phosphorus by 30.67 and 36.05% compared to full irrigation. The highest RWC (92.26%), stomatal conductance (58.86 mmol.m-2.s), anthocyanin (0.0274 µmol.g-1FW), Fm (860), and Fv/Fm (0.909) were obtained at foliar application of 60 mg.L-1 nano silicon, both applications of flavobacterium and pseudomonas with mycorrhiza under normal irrigation. Also, the highest grain yield was obtained with both flavobacterium and pseudomonas with mycorrhiza and foliar application of 30 mg.l-1 nano silicon under normal irrigation. According to the results of this study both the application of biofertilizers and nanosilicon can improve wheat grain yield under water limitation conditions by improving the physiological traits and also the uptake of phosphorus from the soil.

Generally, it seems that application of bio fertilizers and nano silicon can be recommended as the proper method for increasing the physiological trait grain yield of wheat under water limitation conditions.

Soil and water salinity are considered as the main factors limiting plant growth. The effect of salinity will affect root spread before it appears in the over ground parts. In saline conditions, the plant tries to increase the absorption potential of key elements, especially potassium, by increasing the number of roots as well as the root length. These changes are accompanied by shrinkage of the aerial parts. Therefore, the stronger the plants appear in this category, the more powerful they will be in relation to salinity.The increasing trend of soil salinity increases due to the imbalance of precipitation and annual evaporation on saline soil surfaces. Therefore, increasing the area under salinity-resistant plants or using conservation techniques will be very important.Stevia, despite its importance, is sensitive to soil and water salinity. Today, the role of biotic and abiotic stimulants in the adaptation of plants, especially medicinal plants to adverse environmental conditions is very important. In the present study, the effect of endophytic fungi and melatonin on stevia root changes in treatment with saline under hydroponic conditions will be investigated.

The present study was performed as a factorial study in a completely randomized design with six replications under greenhouse and hydroponic cultivation. This experiment was repeated twice to obtain more reliable results. Treatments used included endophytic fungi isolated from yew (in three levels of fungus-free control, strain TB20, strain TB2-3), melatonin spraying (in three levels of melatonin-free control, 0.5 μM pure melatonin and 0.5 μM Thymus vulgaris extract) And three salinity levels of NaCl (no salinity, medium salinity of 80 mM and high salinity of 150 mM irrigation water). In both experiments, the first foliar application was performed seven days and the first irrigation with salinity levels was performed 10 days after planting. Experimental plants were examined in terms of root traits. The over ground biomass yield was also examined.

In both experiments, similar results were obtained and showed the positive effects of melatonin and endophytic on the improvement of root growth characteristics under salinity stress. The best treatments used included thyme extract and TB20 endophytic fungus under salinity conditions. Most of the measured traits such as root volume, root length, fresh and dry weight of roots increased 2.5, 1.5-2 and 1.2-2, respectively, compared to the control using fungal and melatonin treatments. Although salinity increased the root traits to a moderate level, but with increasing salinity, the amount of these traits decreased sharply and significantly. A similar trend was observed in over ground biomass yield.

Since the use of melatonin and endophytes, especially TB20, has reduced the growth limitations of stevia in salinity conditions, it is suggested that in these salinity conditions, plant extracts containing melatonin be further studied.

Barley (Hordeum vulgare), a member of the Poaceae family, is an important cereal grown in temperate climates worldwide. It was one of the first cultivated grains, especially in Eurasia 10,000 years ago. Globally, 70% of barley production is used for animal feed. This plant is reasonably tolerant of abiotic stresses. Environmental or abiotic stresses such as heat and cold can significantly affect crop production. Plants respond to these abiotic stresses by altering the expression of many genes involved in different biological and physiological processes.

The microarray data of two experiments were analyzed to identify responsive genes related to cold and heat stresses in barley (Hordeum vulgare L.). This research was analyzed and investigated using the raw data in the ArrayExpress database, which is related to two separate experiments in heat and cold stress in 2 and 3 replications, respectively, in the barley plant. The desired analysis was performed using FlexArray software, and the differential genes present in the stresses were identified. The examined genes were normalized using the Robust Multiarray Average (RMA) method, and the genes with a P-value equal to and less than 5% were selected, and the fold change of genes above two was also selected. Gene ontology analysis was done using the AgriGo website, and their functional groups were categorized into three parts: biological processes, cellular components and molecular function. The sequence of 1500 nucleotides upstream of the effective genes in response to heat and cold stress was extracted from the Ensembl Plants site. Regulatory elements of effective functional genes in response to heat and cold stresses were identified and presented using the PlantCare site.

 The results demonstrated that 338 and 291 genes were differentially expressed in response to cold and heat stresses, respectively. The gene ontology analysis revealed that differential expressed genes (DEG) were mainly involved in cellular compounds, biological processes, and different molecular functions. Transcription regulator activity has a critical role in the regulation of genes against stresses. Moreover, 1500 bp upstream of the DEGs were identified to find the most represented regulatory elements.

 Consequently, light and hormonal-related cis-regulatory elements, especially those related to methyl jasmonate, play an important role in controlling the gene expression against the studied abiotic stresses. This high-throughput comparative analysis provided insight into genes and cis-regulatory elements involved in response to heat and cold stresses in barley.

In order to investigate the effect of some biotic and abiotic elicitors on yield and yield components of stevia plant under different salinity stress, the present study has been perfoemed as a factorial experiment based on the randomized complete design with six replications. It has taken place in a greenhouse under hydroponic and conditions in two consequential experiments. Endophytic fungi isolated from yew (at three levels of control, TB20, TB2-3), foliar treatment with melatonin (at three levels of control, 0.5 μM melatonin tablets, and 0.5 μM Thymus vulgaris extract), and three salinity levels (without salinity, medium salinity 80mM, and high salinity 150mM) have incorporated the present experiments’ treatments. The experimental plants have been investigated based on morphological parameters. In both experiments, results show a positive effect of melatonin and endophytic fungi on characteristics of plant growth’s improvement (one to two times) under salinity stress. Nevertheless, the best growth conditions have been observed in low salinity levels, using thyme extract and TB20 endophytic fungus. Most traits of stevia plant in non-saline conditions along with thyme extract and endophytic fungus TB20 have been at their highest, showing an increase of approximately 1.5 folds, compared to the control. Due to the positive effects of melatonin and endophytes, especially TB20, it is recommended to use melatonin-containing plant extracts as a protective treatment in stevia cultivation in saline conditions.

Sesame (Sesamum indicum L.) is one of the oldest oil seed crops, growing widely in tropical and subtropical areas. Drought is a polygenic stress and is considered as one of the most important factors limiting crop yields around the world. Most of the Iranian soils have a high pH and calcareous nature, and micronutrients solubility in these soils is low. Micronutrient deficiency, especially iron, is widespread where soil is calcareous with high pH, low organic matter, continuous drought, high bicarbonate content in irrigation water, and imbalanced application of NPK fertilizers. Foliar nutrition is an option when nutrient deficiencies cannot be corrected by applications of nutrients to the soil. Microelements Foliar application is very helpful when the roots cannot provide necessary nutrients. Iron is an important element in crops, because it is essential for many enzymes including cytochromes, which is involved in the electron transport chain, chlorophyll synthesis, and maintains the structure of chloroplasts. Nowadays, nanoparticles of metals are widely used in many sections, such as medicine, agriculture, and industry. Iron oxide nanoparticles have a large surface area and high reactivity. Moreover, when compared to many other metallic nanoparticles, the iron oxide nanoparticles are constant, less expensive, and less toxic. Iron oxide nanoparticles have high magnetization amounts, a size smaller than 100 nm and a thin particle size distribution. These particles also have a special surface cover of magnetic particles, which has to be harmless and biocompatible.

To study the effect of drought stress and iron oxide nanoparticle foliar application on quantitative and qualitative traits of sesame (Sesamum indicum L.), an experiment was conducted as split-plot with three replications at the research farm of Agricultural Faculty, Lorestan University in 2016. The experimental factors were included drought stress in two levels of non-stress (Irrigation to reach soil water to FC 100%) and drought stress (Irrigation to reach soil water to FC 50%) as the main factor, and iron oxide nanoparticle foliar application in five levels of non-foliar application (Control), foliar application by water (1000 liters of water per hectare), iron oxide nanoparticle 0.05% (0.5 kg/1000 L of water per hectare), iron oxide nanoparticle 0.1% (1.0 kg/1000 L of water per hectare) and iron oxide nanoparticle 0.15% (1.5 kg/1000 L of water per hectare) as the sub factor. The measured traits included number of capsules per plant, 1000 grain weight, grain yield, biological yield, harvest index, grain oil content, grain oil yield, grain protein content and grain protein yield. Analysis of variance was performed using general linear model (GLM) procedure of statistical analysis system (SAS version: 9.3). The means were analyzed using the Tukey test at P=0.05.

Results showed that the drought stress decreased significantly traits of 1000 grain weight (18.51%), grain yield (26.52%), biological yield (9.42%), harvest index (3.94%), grain oil content (10.30%), grain oil yield (40.47%) and grain protein yield (24.90%) except for the number of capsules per plant and grain protein content. However, the iron oxide nanoparticle application improved significantly traits of 1000 grain weight (19.86%), grain yield (37.43%), biological yield (22.91%), harvest index (3.86%), grain oil content (6.49%), grain oil yield (45.70%) and grain protein yield (40.93%) under drought stress except for the number of capsules per plant, and grain protein content. Among different levels of foliar application, iron oxide nanoparticle 0.15% had the most effect on increasing the measured traits except for the harvest index.

In general, iron oxide nanoparticle foliar application can be used, especially at a concentration of 0.15%, to reduce the harmful effects of drought stress and improve the quantitative and qualitative traits of sesame in Khorramabad city.

Knowlege of genotype × environment interactions helps breeders to select the best genotypes for different regions.The main objective of this research was to obtain high yielding durum wheat genotypes selected from several elite lines so that can be compatible to climatic conditions of the tropical and subtropical rainfed regions and superior to check varieties. In this research, 16 durum wheat genotypes selected from advanced yield trials along with two check cultivars, Dehdasht and Seimareh, were studied in a randomized complete block design with four replications for three cropping seosons (2013-2016) in four locations (Gachsaran, Gonbad, Khoramabad and Moghan). Combined analysis of variance indicated that main effects of genotype, year and location and interactions of year × location and genotype × year × location were significant at 1% probability level. AMMI analysis of variance also showed that the first four principal components were significant and explained about 81% of the total variance of genotype × environment interaction. The highest grain yield was observed in genotype 6 (3592 kg.ha-1) and the lowest in genotype 18 (3229 kg.ha-1). Environments 10, 8, 11 and 12 with long vectors had high resolution ability. The results of this study based on AMMI indices showed that genotypes 3, 5, 6, 13 and 15 with higher grain yield than the total mean in most environment were stable and superior genotypes in this experiments. Among them, genotype 13 with suitable general adaptability can be a promising genotype and a candidate to introduce a new cultivar for tropical and subtropical rainfed areas.

Wheat (Triticum aestivum L.) is considered as the major cereal crop in the world in respect of the cultivated area and total production. Drought is a polygenic stress and is considered as one of the most important factors limiting crop yields around the world. Most of the Iranian soils, have a high pH and calcareous nature, and micronutrients solubility in these soils is low. Micronutrients plays a critical role in increasing plant resistance to environmental stresses. Iron as a micronutrient, is critical for chlorophyll formation and photosynthesis and is important in the enzyme systems and respiration of plants. Zinc is a ubiquitous micronutrient. It is required as a structural and functional component of many enzymes and proteins, and increases the yield and yield components of wheat. Manganese as a micronutrient, is necessary in photosynthesis, nitrogen metabolism and to form other compounds required for plant metabolism.

To study the effect of micronutrients foliar application on some physiological and agronomic traits of bread wheat (Triticum aestivum L.) under complete irrigation and terminal drought stress condition, an experiment was conducted as split-plot based on randomized complete blocks design with four replications in Ramhormoz city located in south-western Iran. The experimental factors were included drought stress in two levels of complete irrigation (non-drought stress) and irrigation interruption from the beginning of flowering stage to the physiological ripening (terminal drought stress) as the main factor, and micronutrients foliar application in six levels of non-foliar application (control), foliar application by water, iron, zinc, manganese and iron + zinc + manganese (each 3 lit.h-1) as the sub factor. Solutions for foliar application were prepared by using Iron chelate (6%), Zinc chelate (7.5%) and Manganese chelate (7%). The measured traits included leaf chlorophyll index, leaf proline content, cell membrane stability index, grain yield, biological yield, harvest index and grain protein content. To determine the leaf chlorophyll index used of chlorophyll meter digital. To determine the leaf proline content, method of Bates et al. (1973) was used. To determine the cell membrane stability index used of method Lutts et al. (1996). The grain yield was determined at maturity stage and through the harvest of all spikes from the level of 1 m-2 per plot and after removing 0.5 m from the beginning and end respective planting rows (rows 5 and 6). To measure the biological yield at maturity stage, after removing 0.5 m from the beginning and end respective planting rows (rows 5 and 6) from the level of 1 m-2 per plot all the plants were harvested and weighted for each plot separately. The harvest index was determined by the equation GY/BY×100. The grain protein content was calculated as N% × 5.7 on a dry weight basis. N% in grain was determined by the Kjeldahl method according to A.A.C.C. (2000). Analysis of variance was performed using general linear model (GLM) procedure of statistical analysis system (SAS version: 9.3). The means were analyzed using the least significant difference (LSD) method at P=0.05 (LSD 0.05).

Results showed that the terminal drought stress decreased significantly traits of leaf chlorophyll index, cell membrane stability index, grain yield, biological yield and harvest index except for leaf proline content and grain protein. However, micronutrients foliar application of iron, zinc and manganese increased significantly the measured traits in both non-stress and terminal drought stress condition. Meanwhile, application of zinc spray showed the greatest effect in reducing the damage caused by terminal drought stress on measured traits.

In general, the use of micronutrients, especially zinc, as foliar application, can reduce the harmful effects caused by terminal drought stress and improve the physiological, agronomic traits and grain protein content of bread wheat in Ramhormoz region.

Lentil (Lens culinaris M. cv. GACHSARAN) has a high percentage of protein content, in comparison with animal protein so it is an important food source especially for people on low incomes and in developing countries. Lentil is a crop grown all over the world and is compatible with different climatic conditions; from temperate to thermal and humid to arid. Water stress is the most critical environmental factor that limits crop production. Yield reductions reported from different parts of the world caused by drought stress average at more than 50%. Responses of plants to moisture deficiency in soil are different and depend on the intensity and period of stress. These responses are of two types: 1- Moisture deficiency in low intensity leads to transpiration reduction, disruption of water translocation from roots to shoots, reduction of the photosynthetic products which ultimately lowers crop and morphological traits. 2- Moisture deficiency in high intensity that produces reactive oxygen species (ROS) in plants; it has a detrimental effect on D1 protein of PSII, electron transport and production of high-energy molecules such as ATP and NADPH. In recent decades, bio-fertilizer appli Study on the effects of organic fertilizer such as compost demonstrated that using this fertilizer can increase nitrogen in the soil by about 42%, phosphorus by about 29% and potassium by 57% cation has become a common method for improving land affected by drought. In comparison with other organic fertilizers, compost consists of high levels of nutrients such as nitrogen, phosphorus, potassium, calcium and magnesium, as well as micronutrients such as iron, zinc, copper and manganese. Compost is rich in humic compounds and researchers speculate that the hormone-like activities of humic substances play a role in amelioration of water deficit stress. Agricultural land in Iran is facing water shortage and lentil is an economically valuable crop that has a significant role in the human diet. The aim of this study was to investigate reducing the negative effects of water stress with compost fertilizer application.

In order to evaluate the effects of compost fertilizer on physiological and biochemical indices of lentil under water stress, a factorial experiment based on completely randomized design was conducted with three replications in 2016 at the Khatam-Alanbia University of Technology. Treatments consisted of five levels compost fertilizer and soil ratio (0:100, 5:95, 15:85, 25:75 and 35:65) and three levels of water stress non-stress (75% of field capacity), moderate stress (50% of field capacity) and severe stress (25% of field capacity). The internal leaf CO2 concentration (ppm), net-photosynthesis (μmol m-2 s-1) and water-use efficiency (kg mm-1 ha-1) were measured on the central sector of the youngest fully-expanded leaf and non-detached young. Measurements were performed between 9:00 and 11:00 am using a portable infrared gas analyzer (KR8700 system; Korea Tech Inc. Suwon., Korea). Evaluation of the Fv/Fm ratio was determined for lentil plants using a portable chlorophyll fluorometer (Pocket PEA, Hansatech, Instruments Ltd., King’s Lynn, Norfolk, England). Proline assay was determined according to the method cited in of Bates et al. (1973). Leaf soluble protein was measured by the Lowry method. Peroxidase enzyme (EC 1.11.1.7, POX) activity was measured by Holy protocol. To measure activity of catalase enzyme (EC 1.11.1.6, CAT), the Candlee & Scandalios (1984) method was used. The method cited in Beauchamp & Fridovich (1971) was applied for measuring superoxide dismutase activity (EC 1.15.1.1, SOD).
 

All of the physiological traits were mainly affected by severe water stress. Results showed that under non-stress, compost fertilizer application (25 and 35 Wt %) resulted in a significant increase in all studied traits. Under moderate and severe stress, application of compost (35 Wt%) significantly increased RWC (3.3%, 6.17%), Cell membrane stability (5.4%), leaf CO2 consenteration (9.3%), net-photosynthesis (58.77%, 65.3%), WUE (12.13%, 22.47%), proline (3%), total protein (18.8%, 7.9%), POX (3.7%, 18.9%), CAT (3.7%) and SOD (1.3%, 12.5%). Compost containing high levels of nutrients, plant hormones, and with good water storage capacity leads to improved uptake of nutrients that serves to reduce the detrimental effects of drought stress. Humic and fulvic acids and other organic acids found in compost, as well as the frequency of nutrients, especially nitrogen can stimulate physiological traits.
 

In summary, due to the structural properties and mineral nutrients in compost it has several advantages compared to cultivation in the soil alone. This study demonstrated that the addition of compost to soil (25 and 35 Wt%) increased RWC, Cell membrane stability, leaf CO2 consenteration, net-photosynthesis, WUE, proline, total protein, POX, CAT and SOD. The use of compost in the soil increased N content of soil leads to increased proline and protein biosynthesis in plants, and these compounds have the role of protecting osmosis (compatible osmolyte) in water deficit conditions. Using the ratio of 35:65 (compost:soil) presented the most effective levels of compost for reducing the negative impact of water deficit stress.

Strangle wort (Cynanchum acutum) is a perennial weed that could be propagated by seeds and vegetative organs. This brings about harvesting problems for some crops such as cotton, sugar beet, wheat and maize. In recent years, this weed has caused huge losses in sugar cane fields. The role of environmental conditions in weed management is highly important. Given this, the present study seeks to investigate the effects of environmental conditions (salinity and drought stress) on germination characteristics of strangle wort weed.

In order to investe the effect of different salinity and drought levels on strangle wort (Cynanchum acutum), two seperate experiments were conducted at Hakim Farabi Khuzestan Sugar Cane Research Institute in 2014-2015. The experimental design was completely randomized, with four replications. The treatments were different salinity levels at 8 levels (0, 2.5, 4.5, 6.5, 8.5, 12.5, 16.5 and 20.5ds/m) and the second experiment involved different drought stresses (osmotic potential) at 7 levels (0, -1, -3, -6, -9, -12 and -15 bar).

The results of salinity stress experiment showed that with increases in salinity levels from 0 to 20.5 ds/m, germination, radicle length, plumule length and seedling weight decreased by 61, 80, 91 and 99%, respectively. The results of drought stress experiment showed that with increases in salinity levels from 0 to -15 bar, all studied traits, i.e., germination, radicle length, plumule length and seedling weight all decreased by 100%. The analysis of variance results showed that in all the traits, there were significant differences between salinity and drought stress in 1% probability level. In this research, in the salinity experiment, in most of traits, especially radicle length quickly decreased after 8.5 ds/m salinity to higher levels and in drought stress experiment, after -3 bar to higher levels.

On the whole, it seems that sufficient information about this weed is vital for the adoption of the best control method, and gaining insights into how strangle wort responds to environmental stress, especially salinity stress, could help us to come up with new control approaches for this invasive weed. This can present a proper ecological approach that could be adopted in sustainable agriculture programs, which is environmentally sound as it decreases the use of chemical inputs. In addition, in order to lower the tolerance of this weed to salinity and especially drought stress, it is suggested that it be used for weed management programs. According to the results of this study, soil salinity higher than 8.5 ds/m and drought tension above than -3 bar can cause sizeable reduction in most traits (growth parameters) especially in root length. In most of the traits scrutinized, the tolerance of the weed to salinity and drought stress was 12.5 ds/m and -6 bar, respectively.

Evaluation of germination characteristics of strangles wort under salinity and drought stress conditions. Determination of tolerance threshold of strangles wort germination seed to salinity and drought stress.

Foliar application of phytohormones and nutrients can affect the saffron vegetative growth and its tolerance to environmental stress. In order to evaluate the role of salicylic acid and potassium nitrate foliar application on saffron growth, a two years' study (2014-16) was carried out based on a randomized complete block design with four replications at Sarayan faculty of agriculture, university of Birjand. In this study, different levels of salicylic acid (0.5, 1 and 2 mM) and potassium nitrate (250, 500 and 1000 mg L-1) plus control (distilled water) was sprayed twice during plant growth. Based on the results, the highest chlorophyll a (6.93 mg/g FW) and chlorophyll a/b obtained at plants treated with 1000 mg L-1 of potassium nitrate, which had no significant difference with level of 2 mM Salicylic acid. The highest chlorophyll b content was obtained at 0.5 mM salicylic acid (1.084 mg/g FW) that showed no significant different with 1 mM treatment. All levels of salicylic acid and potassium nitrate reduced the electrolyte leakage percentage. Moreover, the highest amounts of daughter corms fresh weight (3.9 g), number of leaves (8 leaf per plant), and leaf length (33.81 cm) were gained at concentration of 2 mM salicylic acid. Overall, it can be concluded that foliar application of salicylic acid and potassium nitrate is an appropriate strategy in saffron cultivation which can reduce the effects of thermal stress (reduce in electrolyte leakage) and increase replacement corm growth and leaf extension

Evaluation of varieties and soybean lines under drought stress helps to breeders for detecting of stable and high-yielding genotypes. In this regard an experiment was conducted in randomized complete block design with three replications under normal and drought stress conditions across two locations (four environments). The results of combined analysis of grain yield/plant revealed effects of stress, location and genotype, interaction of stress × location, genotype × stress, genotype × location and genotype × stress × location were significant. In the present study was used GGE biplot method for assessment of 121 varieties and advanced lines of soybean across four environments. The results of biplot method showed that first and second components explained 66 and 22 percent (in total 88 percent) of total variation respectively. That is showing relatively good reliability in explanation of G variation. The results of graphical method showed Gonbad environments (normal and stress) and Rasht environments (normal and stress) were different each other in ranking and determine of adaption. In investigation of polygon biplot was observed in Rasht location under drought stress condition (RD), Gonbad location under normal condition (GN) and Gonbad location under drought condition (GD) genotypes 37 and 34 had the highest yield. In addition these three environments can be considered as one Mega-Environment. Several genotypes were located in sectors that no environments were placed. These genotypes had low yield in most environments. In stability ranking graph, genotypes 8, 9, 49, 63, 42, 86, 39 and 46 had moderate yield and high adaption and those had suitable combination of stability (adaptation) and yield.

The aim of this study was to find out the effects of salinity stress along with Salicylic and Ascorbic acid priming on seed germination of Trifolium repens and Trifolium pratense (native) and Trifolium pratense cv. Marino. A factorial experiment based on completely randomized design was conducted using salt stress at 4 levels (0، 100، 150 and 200 mM) and 5 levels of alleviators (0، 100 and 200 ppm of each) with 3 replicates. Results showed that salt stress، interaction between salinity and alleviator and 3 way interactions had significant effects on measured traits (P≤0. 01). Highest and lowest values measured for different traits in this experiment were in control and higher salinity treatments، respectively. Germination percentage in the highest levels of salinity (200 mM) in T. repens، T. pratense (native) and T. pratense cv. Marino were 90، 77 and 78% respectively، compared to the control and applying Ascorbic acid (200 ppm) at the same level of salinity improved germination percentage by 88، 71 and 70%، respectively. Similar results were obtained for germination rate. In general، although salinity stress markedly reduced both germination percentage and rate، but using alleviators such as، salicylic and ascorbic acid recovers undesirable effects of salt stress and increases germination percentage and germination rate significantly.

Increasing the concentration of different heavy metals, such as lead, copper, nickel and other heavy metals in air, soil and water can pose negative effects on the entire ecosystem and cause harmful health consequences for all forms of life. The major sources of pollution in many parts of world are overburdens of mine, industrial effluents, fertilizers and pesticides. In order to study the effects of different heavy metals on some of the physiological attributes of saffron such as photosynthetic pigments, Prolin and carbohydrates of leaf and the amount of crocin in the saffron stigmas, an experiment was conducted based on completely randomized design (CRD) with four replications and seven treatments. The experimental treatments were control and six different heavy metals (i.e. nickel nitrate, silver nitrate, zinc nitrate, copper carbonate, lead nitrate and manganese sulfate). Before sowing the corms, all of the heavy metals were added to the soil based on the concentration of 500 mg.kg-1 soil. The effects of experimental treatments on chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll a/b were significant, but there was no significant effect on leaf carotenoids. Proline and soluble carbohydrates were significantly affected by the treatments. However, the effects of these treatments on reducing carbohydrates were not significant. Heavy metals also had significant effects on crocin content of the saffron stigmas. By using all of the heavy metals except for nickel nitrate, the amount of crocin increased.

Indigo (Indigofera tinctoria) is one of the legume family which its flowers because of producing a blue color and having wound healing properties is widely used in traditional medicine and cosmetics industries. Due to reduction of water resources and agricultural lands salinization، evaluation of tolerance of this plant to drought and salinity stress conditions at germination stage was investigated. In order to investigate the effects of drought stress caused by PEG 6000 (0، -2، -4، -6 and -8 bar) and salinity stress induced by NaCl (0، 100، 200، 300، 400 and 500 mM)، two separate experiments were carried out. According to the results، different levels of drought and salinity had significant effects on all germination indices، so that germination percentage in control treatments was highest in both experiments (90. 1 and 90 percent respectively) and was lowest at -8 bar and 500 mM treatments (17. 7 and 72. 5 percent، respectively). According to the results، it seems that this plant has a good tolerance to drought and salinity stresses at germination stage.

Aftab cultivar originated from national cereal breeding programs .The new cultivar was evaluated in International high rainfall wheat yield trial nursery at Gachsaran and Gonbad Agricultural Research Stations (2008-2009). Due to optimum grain yield and other agronomic traits, the new cultivar was tested in advanced yield trials in Gachsaran, Ilam, Khoram Abad and Gonbad research stations (2009-2010). Aftab cultivar with high grain yield, high kernel weight and earliness compare to Koohdasht cultivar as check was classified as desirable genotype .Aftab cultivar showed high grain yield (3183kg.ha-1) in advanced experiment trials during five years, it was 13.3% more than check cultivars (Koohdasht and Karim) with 2810 kg.ha-1.The new cultivar showed the best rank, compering to all cultivar and advanced lines, such as Koohdasht which cultivated in large scale by farmers in warm dryland regions, based on stability parameters: low standard deviation and small within location coefficient of variation. Aftab cultivar showed remarkable resistance against important current wheat diseases such as yellow rust, brown rust, and fusarim head blight in warm dryland stations under natural infection and artificial inoculation conditions, in addition it has optimum bread flour quality. On-farm experimental results, the new cultivar showed high grain yield.

The new line (KAUZ/PASTOR//BAV92/RAYON CMSS00M02400S-030M-030WGY-030M-9M-0Y) (Gaboos cultivar) was evaluated at Gachsaran and Gonbad Agricultural Research Stations in the first time in 2006-2007. Due to optimum earliness, plant height, kernel weight and successful performance of grain yield in observation nursery, preliminary and advanced yield trials (2007-2009), this genotype along to 16 promised lines and check (Koohdasht cv.) studied during three years (2009-2012) in uniform regional wheat yield trials in Gachsaran, Khoram Abad, Gonbad and Ilam stations. Three years average of grain yield across all stations for new cultivar was 3514 kg/ha which showed significant difference at 5% probability level in compare to check (3333 kg/ha), and also, considered line had 17 and 11 percent grain yield increasing with significant preference at 5% and 1% probability level in Gachsaran and Gonbad stations respectively. In view of stability parameters, Gaboos cultivar had the best rank with low standard deviation and small within location coefficient of variation among all advanced lines. Koohdasht cultivar (check) had seventh rank with partially high standard deviation of rank, but, the least within location coefficient of variation. Mean while, it has good preference for qualitative characteristics particularly: protein percent, wet gluten, gluten index, water absorption, seed hardiness, zeleny number, sodium dodecyl solphat and bread volume in compare to check. New cultivar has not showed remarkable susceptibility to important current diseases such as yellow rust, brown rust, common bunt and Fusarim head blight in warm dry land stations under natural infection and artificial inoculation conditions.

Salvia genus has 58 annual and perennial herbaceous species in Iran that 17 species are endemic and Salvia sahendica Boiss & Buhse is one of them. In order to investigate the effects of drought stress caused by PEG 6000 and salinity stress induced by NaCl on germination factors of Salvia sahendica، two experiments were carried out based on a completely randomized design with 3 replications. In the first experiment، the effects of drought levels (0 as control، -2، -4، -6، -8 and -10 bar) and in the second one، the effects of salinity levels (0 as control، 50، 100، 150، 200 and 250 mMol) on percentage and rate of germination، vigor index، radicle and plumule length were studied. According to the results، different levels of drought and salt stress had significant effects on all measured characteristics. In drought stress test، the highest and lowest percentage of germination was observed in -2 and -10 bar (respectively، 60. 11 and 41. 55 %) and highest vigor index was measured in -4 bar (62. 07). Study of salinity stress test showed that the highest and lowest percentage of germination was in 50 and 250 mM treatments (55. 61 and 12. 43 %، respectively) and highest vigor index was observed in control (54. 07). Radicle length was affected less than plumule length in these stress conditions. It seems that S. sahendica is well tolerance to drought and salt stress in germination stage.