محمود عطارزاده

One of the most important factors in reducing vigor of seed is the occurrence of water stress during seed development on mother plant. Also, the use of growth regulators in environmental stresses leads to the production of seeds with better germination ability. In order to study the effect of methyl jasmonate on germination indices and vigor of two bread wheat cultivars under different irrigation regimes, an experiment was conducted as a split factorial in a RCBD design in two growing seasons (2015 and 2017). In this experiment, different irrigation regimes including normal irrigation (control), irrigation cut off from bolting stage and irrigation cut off from the grain milking stage were investigated as the main factor, and two wheat cultivars Sirvan and Pishtaz and 0, 50, 100, and 150 μm of methyl as sub plots. The results showed that in both cultivars, germination indices decreased by stress, but application of 100 μM methyl jasmonate increased the germination percentage, germination rate, length and weight vigor, gluten and seed starch content in both years compared to the control. On average, at different levels of irrigation cut off and full irrigation, Sirvan cultivar showed higher germination percentage and rate than Pishtaz cultivar. Also, irrigation cut off from bolting stage had the greatest negative effect on the seed formed in the mother plant in different wheat cultivars. Overall, the results showed that among the treatments, the best methyl jasmonate application with a concentration of 100 mM was able to moderate the effects of drought stress and improve germination and qualitative traits of seed under stress and non-stress conditions and Sirvan had higher seed quality.

Contamination of soils with heavy metals is often resulted from human activities and phytoremediation is an effective and economic strategy to remove toxic metals from soils. Heavy metals are significant environmental pollutants, and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional and environmental reasons. The term ‘‘heavy metals’’ refers to any metallic element that has a relatively high density greater than 4 g/cm3, or 5 times or more, greater than water and is toxic or poisonous even at low concentration. However, chemical properties of the heavy metals are the most influencing factors compared to their density. Heavy metals include lead (Pb), cadmium (Cd), nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn), chromium (Cr), iron (Fe), arsenic (As), silver (Ag) and the platinum group elements. Plants experience oxidative stress upon exposure to heavy metals that leads to cellular damage. In addition, plants accumulate metal ions that disturb cellular ionic homeostasis. To minimize the detrimental effects of heavy metal exposure and their accumulation, plants have evolved detoxification mechanisms. Such mechanisms are mainly based on chelation and subcellular compartmentalization. Chelation of heavy metals is a ubiquitous detoxification strategy described in wide variety of plants. The aim of this study was to investigate the effect of different compounds to reduce the toxicity and accumulation of heavy metals in the planting bed is pinto beans. In order to evaluate the effects of different growing substrates on reducing toxicity and phytoremediation bean (cv. Sadri) under heavy metals, a greenhouse experiment was conducted as a factorial for four heavy metals (Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4) seperately, based on CRD design with three replications in Yasouj University, 2013. The first factor included of four levels of different growing substrates (control, compost, vermicompost and Populus sawdust) and the second factor included of two levels of heavy metals (heavy metals with 50 mg kg-1 soil concentration and control). Analysis of variance showed that the effect of organic compounds and cadmium nitrate in the soil and their interactions on amounts of cadmium accumulation in roots, shoot and grain was statistically significant. Compost and vermicompost significantly increased cadmium. Vermicompost can be used to remove metals from contaminated soils used because it is linked with metals and increases nutrient uptake by providing. A cadmium concentration in shoot tissue was more than adequate at all levels of the leveas (0.2-0.05 mg/kg dry weight). Lead levels in the tissues of roots, shoots and seeds in all treatments were the detection limit. It seems that due to the low accumulation of lead in beans can be attributed to the low mobility of lead in soil and plant. Means comparison showed the highest accumulation of nickel in the root of the control (normal soil) with an average of 14.45 mg/kg dry weight of roots and the lowest value of this attribute in use of poplar sawdust with an average of 11.42 mg/kg root dry weight that using compost and vermicompost was not significantly different. Analysis of variance showed that the effect of organic compounds in soil, copper sulfate and their interactions on the amount of copper metal roots was significant. When the low copper concentration in soil, compost and vermicompost with the stabilization of copper available and disabling decrease copper absorption and accumulation by the plants, but the high concentration of copper in the soil, add compost, vermicompost and poplar sawdust will not be enough to stabilize all accessible copper. In this study, the use of poplar sawdust to accumulate the highest amount of copper in copper sulphate roots in levels zero and 50 mg per kg dry weight soil. The results showed that the use of compost and vermicompost increased amounts of cadmium accumulation in shoot and root. On the other side, compost and Populus sawdust decreases the amount of nickel in the bean shoot and root. Also, the highest accumulation of copper in roots of beans was achived by application of the Populus sawdust and compost. Accumulation of heavy metals in roots far more than shoots and seeds. In general, the results of this study showed that due to low accumulation of heavy metals in the seed of bean and high absorption by the root and shoot, this plant is suitable for cultivation in contaminated areas and if possible leaving the roots and shoots is also appropriate for the purification.

The role of allelopathy in weed management is useful and has attracted a lot of attention in the last two decades. The main goal of the allelopathic research is to find a reason for the interference of chemicals in natural circumstances and to introduce allelochemicals that affect the growth of other plant’s in farm or natural ecosystems. The other aim of this science is to identify and separate the plants allelochemicals. The prevention of weed growth by the crop allelopathy in the primary stages of establishment can reduce the need for commercial herbicides used at the beginning of the planting season. After that by increasing the competition, the crop can control the weed. The aim of this research is to identify the constituents of the leaf essence of Vitex pseudo-negundo and also to survey the allelopathic potential of different concentrations of the essence of Vitex pseudo-negundo in the prevention of the germination and the growth of Malva neglecta and Secale montanum weed bushes in the laboratory.
Material and The leaf samples of Vitex pseudo-negundo were collected from wild in Fasa, Fars province in 2016. To extract the essence, the leaves were collected and dried in the shade and then the essence was extracted. The extraction of the essence was done in the laboratory of the agricultural research and natural resources center of Shiraz. To analyze and survey the constituents of the essence, the gas chromatograph device with Flame Ionization detector and coupled chromatograph with mass spectrometer were used. In another part of this research, the potential of the allelopathy of the essence of the leaf of Vitex pseudo-negundo on the seed germination and the growth of Malva neglecta and Secale montanum were surveyed. This research was done in the form of factorial in the randomized complete block design with 4 repetitions in 2015. The first factorial included Malva neglecta and Secale montanum weeds and the second factorial included the essence of Vitex pseudo-negundo with the concentrations of 0, 250, 500, 1000, 200 ml. To analyze the data the statistical analysis software was used. To compare the means the Duncan test with 5 percent probability was used.
In this research, the analysis of the leaf essence of Vitex pseudo-negundo which was gained by distillation using gas chromatography and also gas chromatography attached to mass spectrometer made it possible to identify 53 compounds which constituted 98.91 percent of the essence. In this research, the essence of Vitex pseudo-negundo consisted of 37.743 percent Hydro carbonic monoterpenes, 28.865 percent Oxygen monoterpenes, 25.858 percent Sesquiterpene of Hydrocarbons, 6.32 percent Sesquiterpene Oxygen and 0.397 of other compounds. The most important constituents were α-Terpinyl acetate (22.007 percent) ¡ α-Pinene (16.378 percent))¡ E)-Caryophyllene (11.724 percent) and Limonene (8.68 percent). The highest percentage and rate of germination of Malva neglecta and Secale montanum were obtained in no essence condition of Vitex pseudo-negundo (control) with the increase of the essence concentration of Vitex pseudo-negundo, the percentage and rate of germination were decreased in Malva neglecta and Secale montanum so that lowest germination which was obtained in the treatment was 2000 ml. The length of the radical in Malva neglecta in the treatment was 1000 ml and the concentration of Vitex pseudo-negundo essence was 4.4 ml which showed a significant difference with 2000 ml treatment (2.2 ml). The length of the radical in Secale montanum in no essence condition of Vitex pseudo-negundo (control) showed a significant difference with 250 mg/l of the treatment Vitex pseudo-negundo. The shortest length of the radical of Secale montanum was 26.6 mm in average in the 2000 ml evidence of the essence of Vitex pseudo-negundo. The increase of the essence of Vitex pseudo-negundo caused the decrease of the wet weight average of Malva neglecta and Secale montanum. The other obtained results show that the wet weight of Malva neglecta with Secale montanum in different levels does not show any significant difference with Vitex pseudo-negundo when the concentrations are equal. The seed vigor index of Malva neglecta and Secale montanum were decreased with the increase of the essence concentration. The lowest seed vigor index was obtained in the essence concentration of 2000 mg/l. The highest seed vigor index in the no essence treatment of Vitex pseudo-negundo (control) in Malva neglecta and Secale montanum were 23.1 and 77.8 consecutively.
The results of this research showed that the essential oil of Vitex pseudo-negundo has a high allelopathic ability on Malva neglecta and Secale montanum weeds. The Malva neglecta weed had a higher sensitivity to the concentration of the essential oil. There has been a widespread effort to the degree of inhibition increased with an increase in the concentration of the essential oil so that in all the measured characteristics, the highest prevention was observed at 2000 ml. In the present situation that there has been a widespread effort to improve the performance of the crops, knowing the allelopathic effects of the plants can be a great help in the suitable management of sustainable agriculture and weed control methods.

IntroductionAbscisic acid (ABA) is a phytohormone which has a main role in plant life cycle and regulates many physiological processes including plant development and adoptability to environmental stresses. ABA controls water status of plants under stress and noticeably decreases undesirable heat stress damages. Since high temperature stress is a limiting factor for many crops growth and according to literature review there are evidences that ABA can induce thermo tolerance in plants, the present study was designed to evaluate the response of corn to heat stress when seeds are pretreated by ABA.
Materials and methodsThe experiment was factorial in a completely randomized block design with three replications and was done in agricultural college of Vali-e-Asr University of Rafsanjan in 2013. First factor was seed pretreatment by ABA solutions (zero, 50, 100 and 200 µM L-1) and second factor was different durations (zero, 8, 16 and 24 h) of heat stress in 40º C exerted on hybrid S.C.704 corn seedlings. In darkness seeds were soaked in ABA solutions for 24 h at the temperature of 25 ± 1º C. Following pretreatments seeds were sterilized by distilled water and finally were planted in pots in the depth of 1.5 cm. Seedlings were transported to growth chamber with the temperature of 40º C in four foliate stage to be treated by different heat durations. After thermo treatments seedling were transported to green house and plant responses were measured two weeks later.
Results and discussionResults indicated that the highest dry weight of shoots was obtained in ABA concentration of 50 µM L-1 but there were no significant differences at probability level of one percent among other concentrations. In addition corn seedlings were able to tolerate 8 h heat duration but negative effects of heat stress was significantly increased in 16 and 24 durations which led to the reduction of shoot dry matter production. Increase in heat duration and ABA concentration caused a significant raise in shoot to root weight ratio so that the highest ratio (31.66 percent) was observed in control treatment and the lowest (3.83 percent) in heat duration of 24 h accompanied with 200 µM L-1 ABA. Leaf relative water content in ABA concentrations of 50 and 100 µM L-1 showed a significant increase at probability level of five percent in respect to control and ABA concentration of 200 µM L-1 which can probably be due to stomata resistance in these treatments and may be used as suitable approach to increase plant thermo tolerance. Negative effect of ABA concentration of 200 µM L-1 on leaf relative water content indicated that ABA concentration must be chosen precisely. Increase in heat duration caused a significant raise in leaf temperature. In heat durations of 16 and 24 h the highest leaf chlorophyll index (27.2 and 24.5 respectively) was obtained in 50 µM L-1 ABA and the lowest ones (21.9 and 18.7 respectively) in 200 µM L-1. Increase in ABA concentration and heat stress led to a significant reduction of chlorophyll a content in corn leaf so that in heat duration of 24 h and ABA concentration of 200 µM L-1 a reduction of 36.9 percent was observed compared to control. In addition a reduction of 17 percent in carotenoids was associated with 24 h heat stress in respect to control. In all three durations of heat stress, rise in ABA concentration up to 100 µM L-1 made a decline in ion leakage while in the highest concentration (200 µM L-1) an increment in ion leakage was observed.
ConclusionsIn conclusion the results of the present study showed that high levels of heat stress in combination with undesirable concentrations of ABA can create negative effect on plant ability to preserve leaf relative water content and can lead to the destruction of chlorophyll and carotenoids structure and increase the ion leakage. On the other side ABA concentration of 50 and 100 µM L-1 decreased ion leakage while increased the leaf relative water content and chlorophyll index. By these simultaneous effects the corn shoot dry weight was improved under heat stress condition. It seems that external use of ABA can have positive and negative effects on plant growth depending on its concentration. Concentrations higher than threshold tolerance to ABA can cause disturbance in plant physiological processes and restrict plant growth and development.

Heavy metals contamination of soil is a widespread global problem. One approach to reduce the accumulation of heavy metals in plants is using of different growing substrates. In order to investigate of different combinations substrate and heavy metals effect on physiological and biochemical traits in bean) cv. Sadri), an experiment was conducted. The first factor included four salt of heavy metals Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4) with 50 mg kg-1 soil concentration and a control surface without metal and the second factor included of four levels of different growing substrates (control (farm soil), compost, vermicompost and poplar sawdust). The results showed that the heavy metals reduced the rate of photosynthesis and increased ion leakage, proline, soluble sugar and MDA compared to control. Use of vermicompost by developing the physical and chemical of soil statuse caused to increase chlorophyll content, instantaneous water use efficiency, stomatal conductance, photosynthesis rate and soluble sugar and also reduced the electrolyte leakage of pinto bean leaves. As a result, it could play a positive role to reduce the effects of heavy metal stress on plant physiological and biochemical traits of pinto bean.

Recently barley cultivated area has been increased in Iran due to its adaptation to drought and salinity. To investigate some barley promising lines under saline conditions and introducing the superior lines, a field experiment was carried out in Zarrindasht region, Darab, Iran, during two consecutive years (2010-2011 and 2011-2012(. In this experiment, Nimrooz as the control variety along with 13 promising barley lines were compared in a randomized complete block design with three replications. The average soil and water salinity of the experimental site were about 6 and 9 dS.m-1, respectively. The results showed that the highest grain yield belonged to EBYT-79-10 line in both years (with two years mean of 5095 kg.ha-1) which was 21.3% more than the control variety Nimrooz (with average grain yield of 4173 kg ha-1). Also, L.527/Chn-01…, MBD-85-8, Karoon/Kavir//…, On-Farm No. 4 (Yazd), MBD-85-6,¡ Rihanee"s"//… and Productive/Rojo with grain yield of 4740, 4705, 4575, 4470, 4390, 4275 and 4205 kg.ha-1, respectively, were superior than control and the other lines produced lower yield than control. Grain yield of the studied lines and showed a significant negative correlation with sodium concentration of plant leaf and a significant positive correlation with potassium concentration and potassium to sodium ratio. In the present study, EBYT-79-10 with highest grain yield, proper early maturity, less water consumption and suitable salinity tolerance was identified as the best line for cultivating under saline conditions of Zarindasht regions, Darab, Iran.

To study the effect of water deficit and salinity stresses on morpho-physiological characteristics of wheat seedling cv. Flat, a pot experiment was conducted in completely randomized design with three replications in Faculty of Agriculture, University of Yasouj, Iran, in 2015. The studied treatments were seven treatments including three levels of each water deficit and salinity stresses with similar osmotic potential (-2.47, -4.94 and -7.42 bar) together with a control treatment (Hoagland solution). Salinity and drought stresses were applied using sodium chloride and polyethylene glycol 6000, respectively. The results showed that shoot dry weight significantly decreased under the effect of salinity and drought stresses compared to control treatment. Drought stress increased root dry weight of wheat, so that the highest root dry weight was observed in polyethylene glycol of -7.42 bar. The maximum and minimum sodium content of shoot and root obtained from -7.42 bar salinity and control, respectively which have not significant differences with drought stress levels. The salinity of -7.42 bar significantly reduced shoot and root potassium content. The highest shoot to root potassium ratio obtained form control and the lowest from -7.42 bar salinity stress. Protein content and catalase and peroxidase enzymes activity significantly increased by increasing the salinity and drought levels. In general, the results of this study showed that salinity compared to water stress have higher negative influence on wheat which reduces shoot and root dry weight.

Heavy metals of biosphere rise since the beginning industrial revolution and the toxicity of heavy metals cause to impair in the process of germination and growth of plants. In order to evaluate the effects of heavy metals on the germination of pinto bean (cv. Sadri) an experiment was conducted at Seed Technology Laboratory of Yasouj University in 2013. The experiment was conducted as CRD in five replications include different concentration of Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4 (25, 50, 75 and 100 mg/l) and a control treatment. Germination characteristics include the rate and percentage of germination, seedling weight and length and seed vigor index were studied .Results showed that the highest rate and percentage of germination was belonged to control, and least in the 100 mg/l of Pb(NO3)2. With the increase in concentrations of Pb, percentage and rate of germination and root and shoot dry weight showed a downward trend. 100 mg/l concentration of Cadmium nitrate decreased the rate germination of pinto bean seeds in compare with control. Increasing the concentration of cadmium impairs the growth of seedling root; shoot and vigor index of bean. Toxic concentration of copper compared to nickel had more negative effect on germination, root and shoot length, root and shoot dry weight and seedling vigor. In general, the results of this study showed that cadmium and Pb may give to plants allows germination, but increased in their concentration impaired the some seed germination indices of pinto been seed.

Heavy metals are the most important pollutants in the environment. One approach to reduce the accumulation of heavy metals in plants is usage of different growing substrates. In order to investigate of heavy metals effect on growth and yield components of pinto bean (cv. Sadri), a greenhouse experiment was conducted as a factorial based on completely randomized design with three replications in Yasouj university, in 2013. The first factor included of five levels of heavy metals (control without heavy metals, Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4) and the second factor included of four levels of different growing substrates (compost, vermicompost, Populus sawdust and non-application of organic compounds). The results showed that the addition of vermicompost respectively increased plant height and root length in conditions of without heavy metals 53, 88%, nickel nitrate 61, 35%, lead nitrate 63, 17% and copper sulfate 25, 85% compared to non-application of organic compounds. Vermicompost application also increased 87% the number of pods per plant and seed per pod in cadmium nitrate stress. On the other side, use of vermicompost, compost and Populus sawdust could not limit the adverse effects of heavy metals on seed weight per plant. Vermicompost increased hundred grain weights (11%) and protein content of bean (9%) compared to non-organic material conditions. In general, the results of this study showed that application of vermicompost on soil contaminated with heavy metals, to some extent, can improve undesirable effects of heavy metals stress.

This research was conducted to find an appropriate method to increase rooting percentage in difficult to root olive cultivars. This experiment, with 15 treatments and 2 cultivars (Fishomi and Shiraz) was arranged as a split-plot based on completely randomized design and four replications. The main factor was cultivar and the sub-main factor was hormonal treatments. Treatments consisted of indole-3-butyric acid) IBA ((concentrations of 2000, 4000 and 6000 mg/L) and naphthalene acetic acid )NAA( with concentration of 2000 mg/L alone or with 2% ascorbic acid and 3.5% H2O2. Meanwhile, distilled water was taken as control treatment. After 110 days, number of rooted cutting, number of cuttings with buds, number of roots per cutting and root length in each cutting. Results showed that rooting percentage in Shiraz cultivar was more than Fishomi cultivar. Hormonal treatments had significant difference in all the measured traits (P≤0.01). Combination of 4000 mg/L IBA for 5 seconds plus 3.5% H2O2 for 30 seconds was the most effective treatment in rooting of the olive cuttings. Also, the next effective treatment on rooting of the cuttings was 4000 mg/L IBA for 5 seconds plus 2% ascorbic acid for 15 minutes. Therefore, with regards to the results of this research, it could be stated that using cofactors plus rooting hormones, has had positive effects on improving the rooting in difficult to root olive cultivars.

Nowadays in order to produce healthy foods، application of compost and other organic fertilizers has received more attention as a suitable alternative for utilization of chemical fertilizers. It’s due to the fact that excess use of chemical fertilizers can cause threats to human health and lead to salinity or pollution of agriculture soils. Due to low organic-matter content in most soils in arid and semi-arid regions of Iran، application of organic-wastes’ like compost can increase water-holding capacity of the soil. In order to evaluate the effect of licorice compost application on decreasing of water stress in greenhouse cucumber (cv. Negin)، an investigation was conducted in a research greenhouse of Fasa in 2012. The experiment was factorial in a randomized completely block design with four replications. Treatments were composted root residue of licorice in four levels (0، 10، 20 and 40 percent of pot soil) and three irrigation regimes (50، 75 and 100% of field capacity moisture). Results showed that increasing in the amount of waste Licorice significantly increased shoot dry and fresh weight of cucumber. By reduction in moisture content of the soil and the amount of licorice residue، number of flower and fruit، plant height and internode length were reduced significantly. But 100% of field capacity moisture and 40 percent of licorice residue increased fruit weight and yield per plant significantly. The result of this study showed that water stress in cucumber can be controlled using licorice residue.

Given the importance of soybean oil as a valuable oilseed crop compatible with Iranian climate، this study was conducted to evaluate the effects of biological and organic fertilizers on soybean yield and yield components. A factorial experiment based on randomized complete block design was conducted with three replications in the spring of 2011 in Yasouj، Iran. Experimental factors included five levels of organic fertilizer (10 and 15 t/ha manure، 5 and 10 t/ha vermicompost and control without organic fertilizer) and two levels of bio-fertilizer (lack of bacteria and the use of the Bradyrhizobium japanicum bacterium plus phosphate Barvar 2). The results showed that the highest grain and oil yield were obtained using 15 t/ha manure (449 and 102 g/m2، respectively) and 5 t/ha vermicompost without bio-fertilizers (400 and 98. 6 g/m2، respectively) and the lowest were obtained in the control treatment without organic fertilizer. Application of 10 t/ha vermicompost decreased oil content significantly compared to treatment without organic fertilizer. The use of organic fertilizers increased pods per plant، biological yield، grain yield، oil yield، protein percentage and protein yield. Results showed that application of 15 t/ha manure and five t/ha vermicompost can caused higher soybean grain yield in Yasouj.

In order to evaluate the effect of priming on some germination and seedling growth characteristics of safflower (Carthamus tinctorius L.) under drought stress an experiment was conducted base on completely randomized design with four replications at the Seed Technology Laboratory of Yasouj University، in 2011. Treatments were included of five priming levels (control or no prime، hydro priming، potassium nitrate 3% (KNO3)، PEG and Urea -4 bar) as the first factor and three levels of drought stress (0، -4 and -8 bar) as the second factor. The results showed that the interactions of drought stress and seed priming on germination percentage and the germination rate was not significant. But the main impact of priming and drought stress on them were so significant at 1% probability. The highest germination percentage and germination rate (75. 66% and 3. 62 seed. day-1، respectively) were shown in urea priming and the lowest (52% and 2. 31 seed. day-1 respectively) in the control treatment (no prime). Drought stress was caused to significant decrease in germination traits. In general، the results obtained in this study showed that treatment with urea and potassium nitrate compared with PEG improved germination and seedling growth of safflower.

In order to study the effect of Ca, K, and Mn foliar application on physiological traits of safflower Padideh cultivar under salt stress, a factorial experiment was conducted based on randomized complete block design with three replications in Vali-asr university of Rafsanjan greenhouse. Factors included salinity with four levels of 0, 500, 1000, and 1500 mg NaCl kg-1, and foliar application with four level representing distilled water, Ca(NO3)2, KH2PO4 (10 mM) and MnSO4 (1 mM), sprayed two weeks after emergence, Every fortnight. The results showed that foliar application of KH2PO4 and MnSO4 inhibited ions leaching in 1000 mg NaCl. Ca(NO3)2 foliar application increased soluble sugar content (no salinity control) while Ca(NO3)2, KH2PO4, and MnSO foliar application somewhat increased Ca and K content in 1000 and 1500 mg NaCl treatments. Salinity and foliar application treatments didn’t affect Mg content. Increasing salinity increased Na content and Proline content significantly increased in 1500 mg NaCl under C (NO3)2 and KH2PO4 foliar application.

The present study was conducted to evaluate the effects of salicylic acid and High temperature on physiological characteristics of maize (cv. SC704). In order to, a factorial experiment based on randomized complete blocks design with three replications was carried out in Research Greenhouse of Vali-e-Asr University of Rafsanjan. The factors were included pre-treatment of concentrations of salicylic acid (0, 50, 100 and 200 μM) and duration of 40°C (0, 8, 16 and 24 hours). Results showed that SPAD index increased significantly in levels of 50 and 100μM salicylic acid but it was low in control and 200μM salicylic acid. In level of 50μM salicylic acid, increase in duration of heat stress was resulted in increasing content of a and ab chlorophyll. However, it was occurred conversely in level of 200 μM salicylic acid, i.e., content of a and ab was decreased. Levels of salicylic acid and duration of heat stress did not effect on Fv/Fm and content of soluble sugar. Use of 200 μM salicylic acid decreased significantly relative water content, while increase in duration of heat stress caused to increase relative water content. In addition, increase in duration of heat stress resulted in increasing leaf temperature and proline content.

In order to study the effect of Ca، K، and Mn foliar spray on vegetative traits of safflower (Padideh cultivar) under salt stress، a factorial experiment was conducted based on randomized complete blocks design with three replications in Vali-asr university greenhouse. Factors included salinity with four levels representing 0، 500، 1000، and 1500 mg NaCl kg -1، and foliar spray with four level representing 10 mM spray of distilled water، CaNo3، K2HPO4 and MnSo4، 1 mM spray، respectively، sprayed two weeks after emergence، one application per 2 weeks. Results showed that increasing salinity level، reduced plant dry weight، leaf area، height، while salinity and foliar spray treatments has no effect on number of leaves. Highest leaf area was obtained after K2HPO4 and CaNo3 foliar spray، and lowest leaf area was obtained from MnSo4، K2HPO4 and CaNo3 foliar spray prevented somewhat early plant growth rate reduction treated with 500 and 1000 mg NaCl. Applying 1500 mg NaCl reduced SPAD value، and leaf chlorophyll fluorescence. MnSo4، K2HPO4 and CaNo3 foliar spray nutrients، also reduced SPAD value.

In order to evaluate the effect of cotton (Gossypium hirsutum) and common lambsquarters (Chenopodium album) densities on yield and yield components of cotton, a field experiment was conducted in the Agricultural Research station in Birjand University, Iran. A factorial experiment was carried out in a complete block design with three replications. Treatments included weed density (0, 6, 9, 12 plants.m-2) and crop density (6, 9, 12 plants.m-2). Three pure stand of common lambsquarter densities (6, 9, 12 plants.m-2) was added to each block. Results indicated that there was a significant decrease in yield and yield components of cotton under weed densities. Six plants.m-2 of weed caused 15% decrease in seed cotton and increase of weed density up to 9 and 12 plants/m2 caused further decrease in seed cotton. These weed densities (6, 9 and 12 plants.m-2) caused 16, 30 and 45% decrease in cotton seeds respectively. Lint yield was decreased 13, 24 and 42% as weed density increased from 6 plants.m-2 to 9 and 12 respectively. In this experiment, increasing cotton density was able to soften the negative impact of increasing weed density. Increasing crop density can be utilized effectively to minimize cotton yield reduction due to weed interference.

In order to investigate the tolerance of wild barley (Hordeum spontaneum), wild oat (Avena ludoviciana) and different wheat (Triticum aestivum) cultivars to metribuzin (Sencore®), a completely randomized design experiment was conducted in Ferdowsi university of Mashhad. The treatment were replicated three times and included wheat cultivars (Atila, Chamran, Niknejad, Dorum, Gaskojen), weed species (wild barley, and wild oat), and herbicide doses (0, 100, 200, 400, 800, and 1600 g/ha of commercial formulation). The results demonstrated that wild oat was the most susceptible species to metribuzin, and wild barley (ED50=722) was significantly more tolerance than wild oat (ED50=257). Among wheat cultivars, Niknejad (ED50=1022) and Gaskojen (ED50=958) had more tolerance and Atila (ED50=307) and Dorum (ED50=498) were less tolerance than other cultivars and wild barley, but were significantly more tolerant than wild oat.