HORTICULTURAL PLANT NUTRITION
Year:2020 | Volume:3 | Issue:2|Papers Count:12

Introduction: Iron is considered as a micro-element with essential roles in plant metabolism and also, is a cofactor in function of antioxidant enzymes. The strawberry is one of the favorite fruits throughout the world and may be classified as a functional food as it is a rich source of phytochemicals and vitamins. Therefore, nutrition of foliar minerals is of particular importance for the rapid supply of plant nutrients. The aim of this study was to determination of optimum concentration and evaluation the pre-harvest application of iron on some antioxidant enzyme activities and qualitative characteristics of strawberry fruit during developmental stages. Material and methods: The experiment was factorial based on a randomized complete block design with three replications. This experiment was carried out at University of Zanjan in spring and summer of 2018. Firstly, in a pretest, the effect of different amounts of iron was investigated (0-200-400-600-800-1000-1200-1400-1600-1800 and 2000 μ mol/L) at 3, 6, 9 and 12 days after the foliar application in some of the characteristics. Then, the concentration of 1400 μ mol/L was considered as the optimum concentration. Finally, data analysis was done using SPSSver 22 and means were compared by Duncan’ s multiple range tests at 5% level of Probability. Results and discussion: Results showed that chlorophyll a, chlorophyll b, catalase, peroxides and ascorbate peroxidase were significantly increased by iron treatment in comparison to the controls. In addition, strawberry fruits treated with iron in comparison to the controls exhibited lower MDA and H2O2 content. But it had no significant effect on SOD enzyme, pH and soluble protein. In addition to the above results, application of 1400 μ mol/L iron accelerated fruit ripening for 3-4 days. The main reasons for the effect of treatment can be related to the increase iron content in plant, decrease in competition between vegetative and reproductive growth, as well as better chlorophylls efficiency. According to the results, application of iron during fruit growth stage increased the activity of most antioxidant enzymes and improved the quality of strawberry fruit. These results are in agreement with those obtained by Pestana et al. (2013) and Zaerei et al. (2016) of strawberry growth and crop yield improved by foliar application of iron chelate. The experiments clearly demonstrated the beneficial effects of foliar Fe-EDTA application on some antioxidant enzyme activities and qualitative characteristics of strawberry fruit during developmental stages. Conclusions: Overall, the findings of current study elucidated that for the production of strawberry cv. Camarosa greenhouses and its cultivation in hydroponic, according to the results of this study, a concentration of 1400 μ mol/L can be suggested by spraying method.

Introduction: Soil and water salinity in many parts of the world, especially in arid and semiarid areas, growth limiting factor. In recent years, much research into adapting the plants to environmental stresses such as salinity. The Pistachio plant salt-tolerant, but the yield on high salinities and decreases severely affected. The present study was to the effect of salinity on the Relative Growth Rate, Net Assimilation Rate, Leaf Weight Ratio three cultivars of pistachio(Akbari, Aghaei, and Kalle-Ghuchi). Understanding the mechanisms of tolerance of crop plants to high concentrations of NaCl in soils may ultimately help to improve yield on saline lands. Esmaeilpour et al. (2019) observed that drought and salinity stress significantly reduces photosynthesis and stomatal conduction in pistachio trees, which is the fastest stomatal response of the plant to soil moisture conditions. The physiological response of the plant to the availability of soil water such as stomatal conduction and vascular sap movement is always a better indicator of plant moisture conditions compared to soil moisture and suction (Parry, 2014). Material and methods: The experiment was arranged in a randomized complete block design consisting of a 3×4 factorial combination of three pistachio cultivars and four salinity levels (1, 5, 10, and 15 dS/m sodium chloride) with three replications. Four pots were selected and harvested from each experimental unit before and after 30 and 60 days of salinity application. Then RGR, NARw, LWR calculated (formula 1, 2, 3). Data were analyzed by SPSS software and mean comparison was performed using the Duncan test at a 5% level. Excel software was used to draw charts. Results and discussion: Aghaei have a high amount of Relative Growth Rate, Net Assimilation Rate, Leaf Weight Ratio, and Root length at the highest levels of salinity (15 dS/m) and Akbari due to having less amount of Relative Growth Rate, Net Assimilation Rate, Leaf Weight Ratio, and Root length sensitive to salinity. Root density was evaluated as an indicator of root morphology. The effect of salinity on root length and density is shown in Table (3). Increasing salinity treatment from 1 to 15 dS/m, root length, and density decreased significantly at a 5% probability level. Conclusions: According to the results, salinity has a significant and direct effect on the Relative Growth Rate, Net Assimilation Rate, and Root morphology of three pistachio cultivars and is not significant in terms of leaf weight among the studied cultivars.

Introduction: Purslane (Portulaca oleracea L. ) is an annual and C4 plant that belong to the family of Portulacaceae. Nitrogen is the key element in soil fertility and crop production. Attention to the soil quality and health has increased in recent years, especially for sustainable production of medicinal crops. So that, for production of healthy food, using natural and on-farm inputs has been considered (Den Hollander et al., 2007). Green manure application is one of the practical ways to achieve this goal. Therefor, this study was conducted to evaluate the biomass production and nitrogen efficiency indices of Portulaca oleracea under green manure and nitrogen application. Material and methods: In this experiment, the effect of four levels of green manure including: control (Without consuming green manure), Rocket Sativa (Eruca sativa L. ), Hairy vetch (Vicia villosa L. ), mix rocket sativa and hairy vetch (Eruca sativa + Vicia villosa) and three levels of nitrogen (0, 50 and 100 kg. ha-1 ) on purslane was studied as a split plot based on random complete blocks design with 3 replications. The studied traits included dry weight of stem, leaves and shoots, leaf to stem ratio, biomass nitrogen percentage and content, uptake efficiency, biomass physiological efficiency and biomass agronomic efficiency. After completing the vegetative growth period of clover and vetch and before entering the reproductive stage, these plants were returned to the soil. Nitrogen content of shoots was measured by Kjeldahl method (Ogg, 1960). The content of biomass nitrogen was obtained by multiplying the shoots nitrogen percentage and yield. Nitrogen content of the soil also was determined to calculate nitrogen use efficiency. Results and discussion: The results showed that the application of a mixture of Eruca sativa and Vicia villosa increased dry weight of the leaf by 11. 1% compared to the control (no fertilizer consumption). The highest dry weight of shoots was obtained from the treatment of Vicia villosa and the consumption of 100 kg N. ha-1, which had a 20. 9% increase compared to the control (non-consumption of fertilizer); while the lowest dry weight of the shoots was obtained from the treatment of Vicia villosa alone, which decreased by 19. 7% compared to the control (no fertilizer consumption). The highest percentage of biomass nitrogen was obtained jointly from control treatments and consumption of 100 kg N. ha-1 and Eruca sativa and Vicia villosa mixture, which had an increase of 36. 8% and 43. 1% compared to control (no fertilizer consumption), respectively. The lowest biomass nitrogen (0. 95%) was related to the control (non-use of fertilizer). The highest nitrogen agronomic efficiency of biomass was obtained jointly from control treatments, Vicia villosa and Eruca sativa and Vicia villosa mixture with 100 kg N. ha-1, which increased by 8. 2, 4. 9 and 7. 4 percent, respectively, compared to the control (no fertilizer use). The lowest nitrogen agronomic efficiency of biomass belonged to Vicia villosa treatment alone, which decreased by 29. 7% compared to control (no fertilizer use). Conclusions: The two-year results of this experiment showed that the use of green manure along with nitrogen fertilizer, only under using 100 kg N. ha-1, improved biomass yield and nitrogen consumption efficiency. On the other hands, the treatment of cluster flower mash along with 100 kg N. ha-1 increased shoot dry weight and crop nitrogen efficiency by 20. 9% and 4. 9%, respectively, compared to control. Therefore, to produce maximum biomass yield of portulaca in Birjand, the use of green manure fertilizer Vicia villosa along with 100 kg N. ha-1 is recommended.

Introduction: Fertilizer management is utmost important factor in success of pharmaceutical crops cultivation. Application of biological fertilizers is important in production of these plants. Therefore the use of this type of fertilizers in the production of medicinal plants is expanding and seems to be becoming a global approach. Material and methods: The effect of humic acid and nano-chalate zinc fertilizer on activity of catalase, peroxidase, superoxide dismutase enzymes and essential oil of savory plant was investigated using a factorial experiment based on completely randomized design two factors and with four replications in a greenhouse at Zabol University in 2014. The factors were humic acid with four levels (zero, 5. 0, 1 and 1. 5 mg/L) and nano-chalate zinc fertilizer with four levels (0, 50, 100 and 200 g/L). Results and discussion: The results of variance analysis showed that humic acid, nano zn chelated fertilizer and the interaction of factors had significant effects at 1 % probability level on leaf length, leaf area index, chlorophyll index, essential oil content and zinc conten, phosphorus, catalase enzyme, peroxidase enzyme and superoxidase dismutase enzyme but the interaction of nano zinc chelated and humic acid fertilizers was not significant on plant dry weight. The treatments showed significant effects on chlorophyll index, leaf length and area, enzyme activity of catalase, peroxidase, superoxide dismutase, zin contentc and percentage of essential oil. At all levels of humic acid, application of nano fertilizer increased the activity rate of catalase and peroxidase enzymes, zinc, phosphorus and essential oil percentage in the application of 1. 5 mg/L humic acid and 200 g/L nano fertilizer increased 58, 34, 75, 26 and 77%, respectively. Application of 1. 5 mg/L humic acid and 200 g/L of nano fertilizer had the greatest effect on leaf area index (4), plant dry weight (16. 15 g), leaf length (3/20 cm), zinc conten (0/950 mg/kg) catalas enzyme (1. 88 1  Mg Protein. Min-1 ) and peroxidase enzyme (0. 18 1  Mg Protein. Min-1 ). Conclusions: Based on the results, the combined application of nano-chelate fertilizer of zinc and humic acid (N4H4) showed a significant advantage over the separate application and nonuse treatments of nano-chelate zinc and humic acid (N1H1).

Introduction: The potato (Solanum tuberosum L. ) tuber is the third most important food crop in the world after rice and wheat for human consumption and makes an important contribution to the diet of people worldwide (Haverkort et al. 2009). Global cultivation area of about 19. 35 million hectares in 2014 and annual production of nearly 382 million tons and nearly 5 million tons has been reported in Iran (FAO, 2016). Selenium (Se), as an essential part of human nutrition, plays a significant role in a number of metabolic functions and also shelters plants from several abiotic and biotic stresses (Schiavon et al. 2017). Se can affect the quality of vegetables and fruit. Se spraying has been used to enhance the selenium content in broccoli (Sindelarova et al. 2015), radishes (Schiavon et al. 2016), basil (Mezeyova et al. 2016), tomatoes (Zhu et al. 2016), grapes (Zhu et al. 2017) and other crops (Puccinelli et al. 2017). Material and methods: Two field experiments were carried out in Jiroft (57 90 E L. 28 13 N Lat., 625 m above sea level), Kerman, Iran, during 2016-17 (October to Jan) and 2017 (Jan to Apr) with Sante cultivar. In Jiroft minimum and maximum temperatures over growing season were 8 and 40 ° C, respectively in first season and 8 and 43 º C, respectively in the second. Relative humidity was 55-60% in every two years. The soil had a sandy-loam texture, and the acidity (pH), electrical conductivity (EC), absorbable potassium, absorbable phosphorus, total nitrogen and selenium content of the soil extract were 7. 50, 2. 41 ds m-1, 159 mg/l, 8. 80 mg/l, 0. 03 % and 0. 17, respectively (table 1). This study was carried out as a split plot with three replicates. Experimental treatments included foliar application of nitrogen fertilization on 2 level normal (150kg/h) and high nitrogen (300kg/h) and selenium (Se) (0, 15, 30 and 60 mg/l) as sodium selenate (Na2SeO4) 35 days after plant emergence. During the experiment, morphological traits including plant height, plant fresh weight, tuber weight and tuber yield and chemical and biochemical traits including selenium and nitrogen levels, starch, ion leakage and malondialdehyde, chlorophyll content, Catalase enzymes, nitrate reductase and superoxide dismutase, and some amino acids were evaluated. Results and discussion: The lowest amount of nitrate accumulation and the highest selenium accumulation were obtained from 150 mg/l selenium treatment. The highest yield of the tuber was obtained from 150 mg/l Selenium treatment. Although Se is not yet confirmed as an essential micronutrient in higher plants (Turakainen et al. 2004; Rani et al. 2005), many researchers have already shown that selenium (Se) could increase the tolerance of plants exposed to stressful environments (Djanaguiraman et al. 2005; Djanaguiraman et al. 2010). In the present study, potato plants treated with Se resulted in an increase in shoot fresh weight and tuber yield. Se increases the allocation of phytosimulates to grow tubers, so tubers act as a rich source for carbohydrates and selenium accumulation. They also attributed the positive effect of selenium on potatoes to the antioxidant effects of selenium on the plant's aging delay. They reported that selenium fertilization could improve the nutritional value of potato by increasing the level of organic compounds containing selenium in the tubers. Conclusion: In general, it was found that increasing nitrogen improves quantitative traits and decreases the quality of potato tubers (increasing tuber nitrate and decreasing amino acids). While selenium increased quantitative traits, it also improved quality traits and increased selenium accumulation and reduced nitrate accumulation in potato tubers. The lowest nitrate accumulation and the highest selenium accumulation were obtained from selenium treatment of 150 mg / l.

Introduction: Currently, global drought stress has led to a decline in performance more than any other living or non-living factor. Weather forecasts are expected to intensify drought and increase droughts shortly (Heffernan, 2013). Drought is one of the most important non-biological stresses and a limiting factor in the successful production of plant products around the world and has adverse effects on plant growth and other metabolic processes (Yordanov and Tsoev, 2000) and time in The plant occurs to have a higher transpiration rate than the amount of water absorption (Wou and Zhou, 2009). Biological stimuli originate from natural and biological resources and in small amounts can improve plant growth and development. These compounds improve the efficiency of nutrients or structural and functional characteristics of the soil and thus increase plant growth. Biological stimuli are classified into eight groups: humic substances, organic matter complexes, useful chemical elements, inorganic salts such as phosphite, marine algae extracts, chitin and chitosan derivatives, antiperspirants and Amino acids or nitrogenous compounds (Calvo et al., 2014). There is considerable evidence that the use of many protein and non-protein amino acids such as glutamate, histidine, proline, and glycine betaine can protect plants from environmental stresses or activate metabolic signaling. Also, many non-protein amino acids are involved in plant defense activity (Liang et al., 2013). Material and methods: These experiments were performed in a three replicated-split plot factorial arranged in randomized complete block design with three drought stress levels ((I0) (no-stress) I1 (moderate stress) I2 (severe stress)) in the main plots and foliar application of different amino acids (Tyrosin, Argenin, Tryptophan, Glycine and without foliar application as control treatments) in subplots. This study was carried out during 2017-2018. During the sampling, three replications were taken from each treatment and three samples were taken from each iteration. This study stimulated plant height, number of fruit, total dry matter, SPAD, chlorophyll a (CHLa), chlorophyll b (CHLb), total chlorophyll (CHLt), and carotenoids. To determine the content of chlorophyll and carotenoids before the end of the growing season, sampling of plant leaves was performed. Analysis of variance and mean comparisons of data (at a 5% probability level based on LSD test) were performed using SAS software (Ver. 9. 4). MS Excel was also used to plot the diagrams. Results and discussion: The results indicated that drought stress had significantly affect (p ≤ 0. 01) on all traits except SPAD, and also foliar application of amino acids was significant in all traits. Interaction effects CHLb, CHLt, and carotenoids was significant. The highest amount of plant height, number of fruits, fruit dry weight, total dry matter, and SPAD obtained from control (no drought stress) and the highest amount of CHLa, CHLb, and CHLt, shown in moderate stress and finally, Severe drought had the Lowest amount of all treatments. Besides, the most number of fruit, fruit dry matter, and CHLa, CHLb, CHLt was in the foliar application of Arginine, and plant height and carotenoids and total dry matter and SPAD were in glycerin and Tyrosin respectively. Fruit dry matter is the main index of assessment and increased by argenin application by 39. 8 percent than control. Furthermore, nonfoliar application (control) had the lowest amount in all traits. Conclusions: in general, Biostimulants application improved the vegetative and morphophysiological characteristics and caused a reduction in chemical fertilizer consumption and sustainable agriculture progress.

Introduction: Onion (Allium cepa L. ) is a vegetable of family Alliaceae. Onion in addition to being used as food is one of the most widely consumed vegetables. Nitrogen is an important component of protein and its availability is important for optimal product performance. Excessive use of nitrogen at the end of the season increases leaf growth and delays onion maturation, thus reducing yield. The use of nitrogen affects the growth and yield of onions as well as the precursors of onion flavor. Excessive use of chemical fertilizers, including nitrogen, has negative effects on the environment and human health (Noura and Nesreen., 2019). Although selenium is not an essential element for plant growth, its beneficial effects on plant tolerance to environmental stresses have often been reported. Selenium is also a vital nutrient for humans and animals. Plants play an important role in the transmission of selenium from the soil to humans and animals. The antioxidant and anticancer properties of some selenium compounds justify the cultivation of selenium-enriched vegetables (Groth et al., 2020). Nitrogen and selenium fertilizers interact in many cases. For example, the uptake and assimilation of nitrogen and selenium is very similar, and there are many common products of nitrogen and selenium metabolism in plants (Klikocka et al., 2017). Therefore, the aim of this study was to investigate the effect of selenium on improving some physiological characteristics and precursors of onion flavor and also the methods of using urea fertilizer in order to reduce urea fertilizer consumption and improve quantitative and qualitative yield of onion in field conditions. Material and methods: In the present study, the effect of different levels of selenium and nitrogen split on activity antioxidant enzymes and flavor precursors of Isfahan yellow iandraces onion was studied. In this experiment, the factors involved the management of nitrogen use in 6 levels including control, total fertilization at the time of transplantation and one-third fertilization recommended at the time of transplantation+ one-third fertilization at the time of bulb initiation+ onethird fertilization at the time of bulb growth, and the second factor is the selenium in 3 levels: 0, 10 and 50 mg L-1 sodium selenate. Plant harvesting when the leaves of more than 50% of the plants have turned yellow and is done in late October. Some physiological characteristics were measured, including antioxidant enzymes (catalase and peroxidase), amino acids (serine and methionine, cysteine and glutathione, flavor precursors and nutrients (total sulfur and total nitrogen). Analysis of amino acids and precursors of onion flavor was performed by HPLC. Results and discussion: At all three levels of nitrogen, the activity of the enzyme catalase increased with increasing selenium concentration. Selenium is an important element in increasing antioxidant activity in plants, microorganisms, animals and humans. In addition, selenium reduces the amount of lipid peroxidation and hydrogen peroxide by increasing the activity of antioxidant enzymes, thus delaying aging. As a result, selenium spraying increases the activity of antioxidant enzymes and reduces the content of free radicals in the cells that are produced during the physiological processes of the plant, thus reducing the damage caused by oxidative stress to plant cells. At all three levels of nitrogen, with increasing selenium concentration, the total nitrogen content of onion bulb increased (Table 4). Regulation of nitrogen metabolism is associated with increased nitrate reductase activity. The enzyme nitrate reductase is responsible for converting nitrate to nitrite, which is an essential enzyme for nitrogen metabolism. Selenium also has a positive effect on the activity of the enzyme nitrate reductase. At all three levels of nitrogen, the amount of amino acids in onion bulb decreased with increasing selenium concentration (Table 6). Plant nutrition and fertilization can have a significant effect on the amino acid content of plant tissues. In plants, selenium metabolism is closely related to the metabolism of nitrogenous substances, especially amino acids, and selenium leads to improved nitrogen assimilation process, which leads to a decrease in nitrate levels and an increase in amino acid levels. As the concentration of selenium increased in all three levels of nitrogen, the precursors of onion flavor decreased (Table 8). Selenium has led to changes in the precursors of onion flavor, which is due to the increased absorption of selenium and its participation in the structure of sulfur amino acids. The effect of selenium on the biosynthesis pathway of precursors of onion flavor is similar to when onions grow in conditions with low sulfur levels. Nitrogen can affect the amount of flavor precursors by affecting sulfate uptake. Conclusions: As the concentration of selenium increased, the total sulfur content decreased, which resulted in a decrease in the amount of amino acids and flavor precursors. The results showed that the combined use of selenium and nitrogen had a positive effect on the amount of antioxidant enzymes, amino acids and onion flavor precursors. In addition, split time of nitrogen fertilizer affected the physiological characteristics studied. Therefore, the use of three-stage nitrogen fertilizer (Consumption of one-third of recommended fertilizer at the time of transplantation+one-third fertilizer at the time of bulb initiation+one-third fertilizer at the time of bulb growth) with 50 mg L-1 of sodium selenate is recommended.

Introduction: Strawberries with scientific name (Fragaria × ananassa Duch) are frome Rosaceae family. Today, due to high demand for higher quality and out-of-season strawberries, breeders have turned to greenhouse production and soilless cultivation. Hydroponics is the knowledge of planting plants without the use of soil, in which micro and macro element is added to the water (Tullaie, 2002). Excessive consumption of chemical fertilizers and high prices of fertilizers are some of the reasons for the increase in production costs. Due to the shortage of phosphorus ore mines in Iran and the need to import to provide the required phosphorus fertilizer and sanitary conditions, leaf nutrition is one of the ways to reduce consumption in chemical fertilizers. Phosphorus is one of the most macro element nutrients and is highly mobile in plant organs, especially in flowers and seeds. After nitrogen the phosphorus is the second limiting factor performance (Shen et al., 2011). Phosphorus in biochemical processes, compositions energy and energy transfer mechanisms involved (Tabatabaei, 1392). Phosphorus in strawberries is affects the size, shape of the fruit, ability to retain and form the color of the fruit. It also contributes to increased root formation and better plant growth and development. Phosphorus acts as a substrate and regulator of anti-oxidative stress. Rising prices for chemical fertilizers, the need for economical production and pollution of groundwater due to unconventional use of chemical fertilizers are some of the problems that can be solved with proper planning. Therefore, the purpose of this project is to investigate the effect of consumption method including phosphorus solution and phosphorus spraying from the source (Monopotassium phosphate) on the quality of Strawberry Paros cultivar and determine the appropriate concentration of solution on vegetative and yield properties. Material and methods: This experiment was performed in November 2017 in the hydroponic research greenhouse of Shahed University. The treatments included three different concentrations of phosphorus foliar application (F) (0, 5, 10 mg/l) and three different concentrations of phosphorus solution (N) (5, 10, 20 mg/l) from the source of Monopotassium phosphate. For the culture, a rectangular cube 45 cm long and 35 cm wide was filled with pumice. In each bag, 3 strawberry seedlings were planted with the appropriate distance. Greenhouse temperature and humidity were regularly adjusted by the central system for proper growth. Different concentrations of phosphorus solution were placed in barrels were in the main source, which were given to the plant in certain amounts during the growing period through irrigation. The other nutrients were the same in all treatments. Phosphorus concentrations sprayed after opening 80% of the flowers at one time. To measure total yield, after ripening strawberry fruits belonging to the plants of each experimental unit were harvested and weighed. Leaf area was measured with leaf area meter. To measure the fresh and dry weight of the leaves, a plant bush was selected where the plant had full growth. The weight of the leaves of each treatment was weighed by digital scale with an accuracy of 0. 001 g. For dry weight, the leaves were placed in an oven at 75 C for 48 hours and weighed after complete drying. The volume of the root was taken based on the displaced of water transferred in the graduated cylinder divided by the density of the water. To measure titratable acidity, 0. 1% sodium hydroxide was used to change the color of the juice in the presence of a few drops of phenolphthalein reagent. Fruit diluted with distilled water with 1% starch reagent was measured by 10 milliliters of potassium iodide 5% and titration by copper sulfate 1% to the stage of color to brown change to measure vitamin C. The pH differential method was used to measure the total amount of anthocyanin (Wang and Gao, 2013). This experiment was performed as a factorial in a completely randomized design in three replications. Data analysis was performed by SAS software and mean comparison using Duncan's multidimensional test. Results and discussion: According to the results, the interaction of foliar spraying and Solution of phosphorus had a significant effect on leaf weight, leaf area, root volume, yield, titration acidity, vitamin C and anthocyanin. According to the results obtained from the comparison charts, the mean maximum leaf weight and leaf area were observed in F10N20 (mg/L) treatment. Maier et al. (2002) showed that using simple superphosphate fertilizer at 100 kg / ha created the highest growth of the aerial part in potatoes. The highest root volume was measured at F10N10 (mg/L) and F5N10 (mg/L). The highest yield was measured at F10N10 (mg/L). Increasing the concentration of potassium monophosphate foliar application from zero to one milligram per liter increased the number of fruits and total yield in strawberries (Molaei et al., 2018). Most vitamin C and anthocyanins obtained in F10N20 (mg/L) and F5N10 (mg/L) was measured. Phosphorus acts as a substrate and regulator of antioxidative stress agents (Jain et al., 2007). Conclusions: Today, due to population growth, the demand for fresh strawberry consumption has increased. According to the results of this experiment, strawberry yield at F10N10 (mg/L) was higher than other phosphorus solutions was used.

Introduction: Kinnow mandarin is a high yield cultivar that has special importance due to its interesting flavor and high tolerance againts high temperature conditons (Nawaz et al., 2008). Unfortunately, it has alternate bearing habit that affecteing its economic efficiency (Safaei-Nejad et al., 2015). Foliar application of fruit thining compounds and nutrientes in on-year could be efective to adjust alternate bearing in fruits (Rabe, 1994; Safaei-Nejad et al., 2015; Sebastian et al., 2019). This research was carried out in order to the evaluation of the possibility of alternative bearing adjustment of Kinnow mandarin using foliar application of thinning compounds and nutrients in Dezful region of Iran. Material and methods: To cope with alternative bearing problem of Kinnow mandarin trees in Dezful region of Iran, two separate experiments were conducted during 2018. In the first experiment, in order to increase the yield of Kinnow mandarin trees in off-crop year, the trees were treated with foliar application of urea (0, 0. 3 %, and 0. 5%) and magnesium sulfate (0, 0. 1%, and 0. 3%) fertilizers and the mixture of them in the early of January, February and March in on-crop year. In the second experiment, trees were treated by spray application of Naphthalene acetic (NAA) (zero, 200, 300, and 400 mg/l) and Carbaryl (zero, 700, 1200, and 1700 mg/l) at 40 days after full bloom stage during on-year. At the end, yield, fruit characteristics including fruit weight, fruit length and diameter and their ratio, total soluble solids, vitamin C, total acidity and TSS/TA ratio were measured. Analysis of variance was performed by ANOVA procedures (SAS 9. 1 for Windows) and significant differences were calculated according to Duncan‟ s multiple range tests (P < 0. 05). Results and discussion: according to the results, yield and fruit weight were significantly affected by the interaction of type of fertilizer × time of foliar application, while fruit length and diameter were not significantly affected by them. Also, fruit length and diameter were affected significantly by fertilizer type. Foliar application of urea (0. 3%) + Magnesium sulphate (0. 1%) in the early of February at on-crop year significantly increased the yield of Kinnow mandarin trees in off-year. It highlights the role of time of foliar application and ratio of nutrients on adjustment of alternative bearing of Kinnow mandarin in a special region. Results shows, total acidity of fruits was significantly affected by time of foliar application while other chemical properties of fruits were not significantly affected by time of foliar application, type of fertilizers and their interaction. The results indicated, the effects of foliar application of NAA and Carbaryl at 40 days after full bloom stage in on-year on yield and fruit length were significant while fruit weight and diameter and the ratio of fruit length to diameter were no significantly affected by these compounds. The highest and lowest yield of kinnow mandarin trees was related to the treatments of control and foliar application of NAA (400 mg/l), respectively. Regarding to the yield of Kinow mandarin trees, there were no statically significant difference between foliar application of Carbaryl and control treatment. Conclusions: Overall, the highest yield of trees in off-crop year was related to the treatment of foliar application of urea (0. 3%) + Magnesium sulphate (0. 1%) in the early of February (on-crop year) that had significant difference with control trees and it was able to adjust alternative bearing to a satisfactory level. Based on the results, Carbaryl compound is not able to adjust alternative bearing of Kinnow mandarin trees at 40 days after full bloom stage in Dezful region. Among different concentration of NAA, NAA spraying with concentration of 200 mg/l adjust alternative bearing more appropriately and had significant difference with control trees, but the concentration of 300 and 400 mg/l NAA reduced the level of yield with a great intensity, which is not recommended.

Introduction: Roselle from the Malvaceae family, which specialized in warm climates (Copley, 1975), is considered a medicinal plant (Aziz et al., 2007). The growing trend towards the consumption of medicinal plants without proper planting methods, proper management and planning will have alarming consequences such as environmental degradation. The evaluation of plant nutrition systems is one of the most important crop planning needs in order to achieve high yield and optimum quality. Soil fertility and plant nutrition can improve input efficiency while preserving the environment, water quality, and reducing erosion. The results of numerous studies indicate the significant effect of combined fertilizers along with organic and biofertilizers on plant height, leaf protein percentage, anthocyanin content and dry weight of roselle (Mohammadpour Vashvaei et al., 2017; Ahmad et al., 2011). Due to the importance and role of medicinal plants in various industries and the need for their production in agricultural systems and the need to manage plant nutrition to increase production and environmental protection, it is necessary to conduct this type of research. Material and methods: Experiment was conducted in a completely randomized block design with four replications in Ghale Ganj city in 2017-18. Treatments comprised NPK fertilizer, humic acid, Nano Biozar, 50% NPK + 50% humic acid, 50% NPK + 50% Nano Biozar, 50% humic acid + 50% Nano Biozar and control. The measured traits include characteristics plant height, stem diameter, dry weight of sepals, number of boll per plant, weight of boll, weight of fresh shoot, percentage of leaf protein, chlorophyll, relative leaf water content and anthocyanin. Finally, data was analyzed using SAS9. 1 and means were compared by Duncan’ s multiple range test at 5% level of probability. Results and discussion: Results of analysis of variance showed that plant height, stem diameter, dry weight of sepals, number of boll per plant, weight of boll, weight of fresh shoot, leaf protein percentage, leaf chlorophyll, relative water content were affected by different feeding schedules. The highest amount of mentioned traits belonged to the application of 50% NPK and 50% humic acid and the lowest values belonged to the control treatment. So that dry weight of sepals increased about 47% in 50% humic acid + 50% NPK fertilizer compared to control. The lowest amount of dry weight of sepals was obtained from the control treatment and the highest amount from the use of 50% NPK + 50% humic acid and the use of humic acid and Nano-biozar had 27. 0% and 21. 2% higher dry weight of sepals compared to the control, respectively. The results showed that the highest amount of anthocyanin were obtained from the use of 50% NPK + 50% humic acid, although the difference with NPK treatment was not statistically significant. Conclusions: Results showed that the combined application of humic acid + chemical fertilizer improved the physiological and morphological traits and increased roselle growth by accelerating root nutrient uptake and this resulted in rapid establishment of plants.

Introduction: Nowadays chemical pollutants endanger human health and the environment. Heavy metals are among these pollutants that have been named because of their high atomic weight and atomic density greater than four grams per cubic centimeter. Heavy metals are not decomposed by living organisms, and most of them forms are stable compounds in nature. There is no comprehensive information on the concentration of pollutants such as nitrate and heavy metals and the risk assessment of the consumption of vegetable, especially leafy vegetables in farms in the southeast of Tehran province. Material and methods: To investigate the concentration of nitrate and heavy metals including lead, cadmium and nickel in leafy vegetables and risk assessment of the use of this product, this study was conducted during one year in 2014 on agricultural lands of Varamin region (Varamin, Pishva, Pakdasht), which is the hub of vegetable production. Results and discussion: The maximum concentration of lead measured in leafy vegetables was 3. 8 mg/kg in mint and minimum was 1 mg/kg in coriander with mean of 2. 0 mg/kg. The average lead concentration was 900% higher than the maximum permissible limit for leafy vegetables, which was 0. 2 mg/kg (National Iranian Standards Organization, 2013). The maximum total Pb measured in the soil was 21 mg/kg and at least 3. 1 mg/kg with a mean of 10. 7 mg/kg. The maximum level of cadmium measured in leafy vegetables was 0. 16 mg/kg in lettuce and its minimum was 0. 03 mg/kg in coriander with mean of 0. 07 mg/kg. The mean concentration of cadmium was nott higher than the maximum permissible limit for leafy vegetables (0. 1 mg/kg) according to the national standard. In 43% of the studied farms, the cadmium content exceeded the national standard limit. Conclusions: The results showed that the risk index for all pollutants was less than one. The results showed that leafy vegetables consumers with 40 grams of leafy vegetables daily do not face significant non-cancer risks. Among leafy vegetables, lettuce had the highest nitrate risk index with 0. 37 and the highest cadmium risk index with 0. 08. Also, the highest lead risk index with 0. 5 index was related to mint. Parsley also had the highest risk index of nickel with a risk index of 0. 18.

Introduction: Salinity stress is one of the main factors that limited crop production. The expansion of saline areas has significantly increased. Based on severity and duration of the salinity stress, the plants show different reactions. First of all, salinity reduces the growth of plants due to the existing osmotic materials around the roots. Furthermore, salinity exerts hypertonic stress on the plants. Under salt stress, ions, mostly Na+ and Cl-, accumulate in the tissues of plants and cause significant physiological and biochemical disorders, reactive oxygen species (ROS) production, and inhibition of K+ uptake. Therefore, these occurrences lead to a reduction in plant growth and development. Therefore, using different methods for reducing the harmful effects of salinity is very important. Superabsorbent polymers application has extended to aid the growth of plants in saline soils. These substances have been applied as a soil amendment to improve plant growth under salt stress. Superabsorbent polymers are hydrocarbon compounds that they do not have any pollution effects on soil, water and plant tissues. They are more important in the regions where water availability is deficient and could be a good strategy for holding water in arid and semi-arid regions. Basil (Ocimum basilicum) is a medicinal plant from Lamiaceae family that used in food and cosmetic industries. Material and methods: In order to study the comparison between three types of superabsorbent on growth characteristics and basil elements content under salinity stress in two harvesting times, a pot experiment was conducted at the research greenhouse of Ferdowsi University of Mashhad as factorial based on completely randomized design with four levels of NaCl (0, 40, 80 and 120 mM NaCl in irrigation water (respectively: 0, 3. 5, 7, and 10. 5 dS/m) and four levels of superabsorbent polymers (control, Ackoasorb, Stockosorb and Terracottem) in three replications in 2019. The studied traits were included growth characteristic (plant height, number of brunches, stem diameter, internode distance, length and width of leaf, inflorescence height, fresh and dry weight of leaf, stem, and inflorescence) and element content (N, P, K, Na, K/Na, Ca and Mg). Statistical analysis was performed using Minitab 17 software. The mean comparison was done by Bonferroni test at the 5% probability level. The figure drew by Microsoft Excel software. Results and discussion: The results of the mean comparison in both harvesting times showed that, with increasing salinity, the growth characteristics of the plant decreased and the application of superabsorbents, especially in the second harvesting time, improved these traits. In the first harvesting time, the amount of potassium, phosphorus and nitrogen were increased by using Terracottem superabsorbent polymer 28. 43, 68. 96, and 71. 55, respectively. Moreover, potassium to sodium ratio was increased by applying Ackoasorb superabsorbent polymer 18. 85%, in 120 mM salinity compared to the control. Also, the results showed that at the highest salinity level, application of all three types of superabsorbent polymers were able to significantly decrease sodium compared to the control. On the second harvesting time, the results showed that at the highest salinity level (80 mM), potassium and phosphorus levels increased by 34. 66% and 44. 44%, respectively, and the sodium content was 19. 95% higher than the control. It seems that superabsorbents with water storage and reduction of salt concentration around the root can reduce the negative effects of NaCl stress. Among the superabsorbents used in this study, the Terracottem was more effective. Conclusions: Based on the results of this experiment, the growth characteristics and elements of O. basilicum cv. Keshkeni luvelu were influenced by NaCl. At the higher NaCl levels, the negative effects of NaCl on plants and osmotic abilities were observed. The application of superabsorbent polymers had different effects on the studied traits. In most cases, Terracottem was the most effective superabsorbent to mitigate the negative effects of salinity. Superabsorbent polymers application can protect the plants from harmful effects of salinity by increasing K+ amount as well as decreasing Na+. However, there is little knowledge about the mechanism of superabsorbent polymers application under salinity stress in the previous study. The findings of this study indicated that superabsorbent polymers application, especially the Terracottem can alleviate the negative effects of salinity on sweet basil by increasing water holding capacity and decreasing Na+ concentration.