جستجوی مقالات مرتبط با کلیدواژه « Nitrate » در نشریات گروه « باغبانی »

This research was conducted to investigate the influence of plant growth biostimulants on quantitative and qualitative characteristics of potato (Solanum tubersom cv. Sante) in randomized complete blocks design with eight treatments and three replications at Behbahan Agricultural Research Station in one year (2019-2020). Treatments included: control (no application of plant growth biostimulants), humic acid, free amino acid (L), amino acid-Zn, amino acid-K, amino acid-Ca, amino acid-K-Ca and combine application of humic acid, amino acid-Zn and amino acid-K-Ca. The results showed plant growth biostimulants (except free amino acid) significantly increased total and marketable tuber yield as compared with control. The treatment of combined significantly increased total and marketable yield in comparision to other treatments. Biostimulants significantly decreased unmarketable yield and its components (small tubers, cracked tubers and tubers with secondary growth) as compared with control. Application of biostimulants significantly increased the tuber protein percentage and concentrations of nitrogen, phosphorus (except amino acid-K, amino acid-Ca and amino acid-K-Ca) and potassium tubers (except amino acid-Ca). Amino acid-Ca and the treatment of combined significantly increased dry matter content. Application of growth biostimulants (except amino acid-K and amino acid-Ca) significantly decreased concentration of tuber nitrate. According to the results, application of combined plant growth biostimulants for cultivation of Sante cultivar is recommended.

This experiment was conducted to investigate the influence of integrated management of nitrogen fertilizers on growth, yield and quality characteristics of potato (Solanum tubersom cv Savalan) in Behbahan Agriculture Research Stations from 2014 to 2016. This research was carried out in randomized complete block design including four treatments: lack of nitrogen fertilizer (control), plots that received 50% nitrogen from chemical fertilizer (as urea) plus 50% nitrogen from vermicompost (50%U+50%V), plots that received 75% nitrogen from chemical fertilizer plus 25% nitrogen from vermicompost (75% U+25%V), and plots that obtained 100% nitrogen from chemical fertilizer (100% urea) and three replications. The Results of growth analysis showed that the haulm and tuber growth rate increased during the early stages, while reached a maximum value, following decline in the late season. In the most sampling periods, the highest tuber and crop growth rate were recorded in 75% urea +25% vermicompost. Therefore the highest yield was observed in this treatment. Application of vermicompost significantly increased tuber number, total and marketable yield, nitrogen use efficiency and agronomic nitrogen use efficiency in 75% urea +25% vermicompost and 50% urea +50% vermicompost as compared with 100% urea. The tuber nitrate content in   75% urea +25% vermicompost and 50% urea +50% vermicompost was significantly lower than 100% urea. According to results, the yield and qualitative characteristics of potato (Savalan cultivar) and farmers’ incomes can increase in Khuzestan province by supply of 75% required nitrogen fertilizer through urea and 25% nitrogen from vermicompost.

To investigating the effects of various concentrations of nitrogen (180, 230, 280 and 330 mg L-1) and potting media composition (peat moss:perlite or cocopeat:perlite as 2:1 V/V) on some growth traits of Euphorbia pulcherrima,  a factorial experiment was conducted based on a completely randomized design with 8 treatments and 3 replications. The results showed that the highest height, plant canopy diameter and protein content eamed by using of were observed in plants grown at the concentration of 230 mg L-1 N in cocopeat and perlite media. The concentration of 230 mg L-1 N increased the bract and leaf area in comparison with the other treatments. The concentration of 280 mg L-1 of nitrogen with cocopeat and perlite media caused the maximum amount of the Mg content in plant leaves tissue. Using of peat mass and perlite and 330 mg L-1 of nitrogen resulted in the highest bract anthocyanin and potassium content. Generally, the results of the study showed that the concentrations of 230 and 280 mg L-1 nitrogen and the combination of cocopeat and perlite as a media improved the growth indices and qualitative characteristics of Poinsettia.

Cherry tomatoes, all over the world, have become a popular product because of the favorable characteristics (a good source of vitamins A and C, soluble solids, flavor, low calorie and fruit formation at high temperature). Cultivar selection is one of the most important managerial decisions and, despite thousands of available varieties, it can be daunting task. Cultivars are different in attributes such as color, shape, size, taste, taste, growth, consumption, planting time, and resistance to pests and disease.

This study was carried out from the autumn of 2014 to spring of 2015, at the research greenhouses of the University of Shahid Chamran, Ahvaz, Iran. The study was performed in randomized complete block design with three replications. During the cultivation period and at the end of the experiment, the number of clusters in the plant, the number of fruits in the cluster, the number of fruits in the plant, the total function in the bush , the number of marketable and unmarketable fruits in plant, the harvest index, vitamin C and soluble solids were evaluated. In addition, nitrate content, nitrite, fruit lycopene and photosynthetic pigments (chlorophyll a, chlorophyll b, chlorophyll a to b ratio, total chlorophyll, carotenoid and chlorophyll to carotenoid ratio) and the SPAD index were measured.

According to the comparison of the means, there were the highest number of clusters in Baby Tom (16/44) and then in Belize (15/88), which were not statistically significant and the lowest number of clusters were observed in cultivar Sogno (12.77). The highest and lowest number of fruits in the cluster were found in the cultivars of Sogno and Belize (29.82 and 17.73), respectively. The highest number of fruits in the plant (295) were observed in Sogno and the Belize cultivar had the lowest number of fruits (193.56). The highest average of single fruit weight related to the Cherry Belle (11.13 g) and the lowest in Sogno (8 g) were observed. The lowest and the maximum percentage of the unmarketable fruits were obtained in Baby Tom (09/09 %) and Sogno (32 %), respectively. The maximum yield was observed in the Cherry Belle (2929 g) and then in Sogno (2482.4 g) and Baby Tom (2077.6 g) and the minimum yield (1637.7 g) in the Belize cultivar. The highest and lowest marketable yield were obtained in Belle (2928.6 g per plant) and Belize (1636.6 g per plant) cultivars, respectively. The maximum amount of soluble solids was observed in Baby Tom (4.86 °Brix), which had no statistically significant differences with the Belle and Sogno and the lowest soluble solids was found in Belize (3.15 °Brix). There were the highest and lowest vitamin C content in Cherry Belle (28.24 mg per 100 g FW) and Belize, respectively (23.1 mg in 100 g FW). According to the results, the maximum and lowest content of lycopene were observed in the Cherry Belle and Baby Tom, with an average of 32.411 and 19.402 mg/kg, respectively. The maximum content of nitrate in fruits was observed with 0.67 mg/gr DW in the fourth cluster and the lowest content of nitrate with 0.198 mg/gr DW in the tenth cluster. The highest indices of leaf SPAD were found in Belize (28.9) and lowest in Cherry Belle (16.32).

The selection of high - yield or high - quality cultivars in a greenhouse culture is critical to the economic efficiency of this product. The difference in yield is mainly related to the genetic variation among varieties. Study of yield and yield components of four samples of tomato in the environment and similar culture showed that the Belle Cherry was the best result for yield, harvest index, and vitamin C, so this cultivar is recommended to grow in Ahvaz greenhouses.

In this study, optimum level of nitrogen fertilizer and plant spacing on the row were investigated in spinach cv.”Harrier” based on the aims of four scenarios: economic, health of food, marketable and optimum production, using statistical response surface methodology. The independent variables including plant spacing on the row (7, 11 and 15 cm) and nitrogen fertilizer (0, 200 and 400 kg urea ha-1), were evaluated using central composite design at Research Field of University of Tehran. Leaf fresh weight, biomass, leaf area index, nitrogen use efficiency, nitrate concentration and total chlorophyll traits were considered as dependent variables. The fitting of data to second order polynomial equation and optimization of responses was performed using Mnitab16 software. Increasing of plant spacing on the row had alone a significant effect on total chlorophyll traits. High levels of nitrogen fertilizer had an increasing effect on dependent variables, except nitrogen use efficiency. The optimum combination of variables and desirability function for economic, environmental, marketable and optimal production limit scenarios were at plant spacing on the row of 7, 7.48, 7.24 and 7 cm, nitrogen fertilizer of 189.9, 60.6, 189.9 and 149.5 kg ha-1, and 0.97, 0.77, 0.9 and 0.82, respectively. Based on desirability function results, the model possesses a high power to simulate optimum level of independent variables at economic scenario than the others.

Garlic (Allium sativum L) is the second most commonly used herb of alliums after onions. This plant has significant effects on lowering blood pressure, preventing atherosclerosis, reducing blood cholesterol and triglyceride and inhibiting platelet aggregation. In recent years, the increase in the yield of this product has been of interest to manufacturers of this product with respect to the preservation of qualitative characteristics, including the maximum content of nitrate. It has been shown that the absorption of nutrients in the soil affects the yield and yield components of the plant. In this regard, the timely and adequate supply of nutrients such as sulfur and nitrogen has a special role in promoting quantitative and qualitative characteristics of garlic. In order to study the effects of nitrogen and sulfur consumption on quantitative and qualitative traits of garlic, this study was conducted with 12 treatments and three replications in the form of a split plot design in two years in Agricultural Research Center of Agricultural and Natural Resources of Tehran Province which located in Varamin in Iran. Nitrogen factor was considered at four levels (0, 100, 200 and 300 kg ha-1) and sulfur at three levels (0, 500 and 1000 kg ha-1 with inoculation of Thiobacillus). Before planting, soil samples were taken from the experimental site and physical and chemical characteristics including texture, reaction, organic carbon, lime, nitrogen, phosphorus and potassium, and iron, manganese, copper, zinc and boron were measured. Dry matter yield, number of bulbs per garlic, single plant weight, garlic weight, plant height, leaf number per plant and leaf area were recorded at the end of experiment. Garlic nitrate content and nutrient concentration in garlic leaves were also measured. Data obtained were analyzed statistically using SAS software. The effects of nitrogen and sulfur on the yield of garlic cloves, number of bulbs in cloves, cloves weights, bulbs weights, plant height, leaf area and bulb nitrate were significant as all these traits were improved. Application of 1000 kg.ha-1 of sulfur increased the garlic cloves yield by 31% compared to the control. Nitrogen consumption up to 200 kg.ha-1 increased garlic cloves yield by 58% compared to the control. The highest economic yield of garlic cloves was obtained by 1000 kg.ha-1 sulfur and 200 kg.ha-1 nitrogen, which was 104% more than control treatment. Data also showed that the effects of sulfur and nitrogen and the interaction of sulfur and nitrogen on the leaf area of the garlic plant were significant. Consumption of 1000 kg.ha-1of sulfur increased the leaf area of the garlic plant by 42% compared to the control. Nitrogen consumption up to 200 kg.ha-1 increased the leaf area of garlic plant by 39.3% compared to the control. The highest leaf area of garlic plant was obtained from 1000 kg.ha-1sulfur and 200 kg.ha-1nitrogen, which was 104% higher than control. Increase of the growth and yield of garlic was attributed to the main role of nitrogen in increasing meristematic activity, cell division, prolongation of the cell. Sulfur is one of the essential nutrients of the plant, and without sulfur, the plant does not grow and function properly. Sulfur is the fourth essential element after nitrogen, potassium and phosphorus for garlic. This element is needed in production of amine acids, such as methionine and cysteine, which are essential for the production of vitamin A, and the activation of certain enzymes. The results of studies have shown that amino acids directly or indirectly affect the physiological activity of the plant, and positively affect the growth, increase in yield and increase plant tolerance to environmental stresses. The soil reaction was affected by sulfur consumption and decreased. There was a negative correlation between soil reaction as a dependent variable (Y) and consumed sulfur as an independent variable (X), which correlated with linear relation with correlation coefficient of 0.98. Data showed that use of 1000 kg.ha-1of sulfur reduced soil reaction from 7.49 to 7.26 and increased leaf iron concentration by 88% compared to control and increased leaf zinc concentration 110% compared to control treatment. The researchers believe that sulfur oxidation and sulfuric acid production in the soil reduce soil reactions and increase the absorption capacity of phosphorus and microelements. The effect of sulfur on the concentration of leaf phosphorus was significant. The phosphorus concentration was increased significantly with sulfur application into the soil, so that 1,000 kg.ha-1 of sulfur increased the concentration of leaf phosphorus by 63% compared with the control (0.33%). Research results have shown that phosphorus absorption capacity in soil is highly dependent on soil reaction and reducing soil reaction leads to increased phosphorus absorption capacity. Researchers have reported that sulfur consumption and the production of sulfuric acid, as a result of its oxidation, reduce soil reaction and increase phosphorus availability for plants. The effect of nitrogen, sulfur and the interaction of nitrogen and sulfur on the content of garlic nitrate was significant. Garlic nitrate content decreased with application of sulfur and increased with nitrogen addition. Application of sulfur at 1000 kg.ha-1 significantly reduced garlic nitrate content by 35% compared to control. The application of 100, 200 and 300 kg.ha-1 of nitrogen increased the content of garlic nitrate 97, 210 and 308%, respectively in comparison to control. At all levels of nitrogen addition, sulfur consumption reduced the content of garlic nitrate. Garlic nitrate content decreased with application of sulfur and increased with nitrogen addition.  Sulfur application at 1000 mg.kg-1 significantly reduced garlic nitrate content by 35% compared to control (mg.kg-1). Garlic nitrate was increased by the amount of nitrogen consumed. There was a positive correlation between garlic nitrate (Y) as a dependent variable (N) and independent nitrogen (X), which correlated with linear relation with the correlation coefficient of 0.99. Researchers have argued that excessive consumption of nitrogen fertilizers is the main factor causing the accumulation of nitrate in a number of vegetables and other plants such as garlic. Based on the results of the experiment, it was concluded that nitrogen and sulfur increase the yield of garlic. Meanwhile, sulfur reduces nitrate accumulation in garlic. Sulfur consumption reduces soil pH and increases the absorption availability of micronutrients and phosphorus in the soil and causes more absorption of these elements by the plant.

High nitrate (NO3−) in vegetables, especially in leafy vegetables poses threaten to human health. Selenium (Se) is an important element for maintaining human health, and exogenous Se application during vegetable and crop production is an effective way to prevent Se deficiency in human bodies. Exogenous Se shows a positive function on plant growth and nutrition uptake under abiotic and biotic stresses. However, the influence of exogenous Se on NO3− accumulation in hydroponic leafy vegetables is still not clear.

The present study was conducted in a completely randomized design with four replications at Research Greenhouse of Lorestan University. In this study, hydroponic lettuce (Lactuca sativa L. var. Grin leek) and spinach (Spinacia oleracea L. var. Sirius) plants were subjected to six different concentrations (0, 0.1, 0.5, 5, 10 and 50 μmol L–1) of Se as Na2SeO3. Zero concentration was considered as control. The modified Hoagland nutrient solution were prepared and 8 liters was added to each pot. The nutrient solutions were replaced with fresh solution every five days throughout this experiment. After the emergence of new roots in the nutrient solution, treatment was applied and selenium was added to the pots at a specific concentration. After Se treatment for 40 days, three plants were randomly harvested from each treatment. The effects of Se on plant growth, NO3− content, activities of nitrogen metabolism enzymes, photosynthetic capacity and glutathione peroxidase enzyme activity of lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) were investigated. The second youngest, fully expanded leaf was used to monitor photosynthetic capacity using chlorophyll meter and portable photosynthetic apparatus, respectively. Nitrate concentration in dried samples was determined based on nitrate to nitrite reductions in the vicinity of zinc powder and hydrogen ion. Data preparation was done in the Excel program and data analysis was done using SPSS 16 software. The means comparison of the treatments was done by LSD test and finally, the figures were drawn using MS Excel.

The results showed that the lowest and highest biomass in both plants were observed in 50 and 5 μmol L–1 Se treatments, respectively. Different levels of selenium had no significant effect on root fresh weight in spinach. However, in the lettuce, at 50 μmol L–1, the root fresh weight significantly decreased compared to the 5 μmol L–1. Moreover, exogenous Se positively decreased NO3− content and this effect was concentration-dependent. The lowest NO3− content was obtained under 5 μmol L–1 Se treatment.NO3− content in lettuce was lower than that of spinach in all treatments. The application of Se enhanced photosynthetic capacity by increasing the stomatal conductance, photosynthesis rate and chlorophyll content of plants. No significant difference (p ≤0.05) was observed in spinach in chlorophyll, stomatal conductance and photosynthetic rate between 10 and 5 μmol L–1, however, in lettuce this difference was significant. Chlorophyll content in lettuce was higher than spinach in all treatments. The best concentration for photosynthetic capacity in both plants was five μmol L–1, which could explain similar changes in root and shoot dry weight in the different treatments. The results showed that low selenium concentrations (≤5 μmol L–1) stimulated NO3− assimilation by enhancing nitrate reductase (NR), nitrite reductase (NiR) and glutamine synthetase (GS) activities. The lowest nitrate reductase activity in lettuce and spinach was 50 μmol L–1 and control, respectively. In all treatments, nitrate reductase activity in lettuce was higher than in spinach. The reaction of nitrate reductase to selenium application was similar to nitrate reductase activity. Glutamine synthetase activity in both plants increased with increasing selenium concentration. However, as the concentration increased (≥ 5 μmol L–1), the activity of this enzyme began to decrease. In addition, the activity of this enzyme was higher than control in all treatments. Selenium also increased glutathione peroxidase concentration. A significant increase in glutathione peroxidase activity at five μmol L–1 was observed compared to the other treatments in lettuce. However, there was no significant difference in the activity of this enzyme in spinach at concentrations of 5 and 0.5 μmol L–1.

These results provided direct evidence that exogenous Se showed positive function on decreasing NO3− accumulation via enhancing activities of nitrogen metabolism enzyme in both plants. This study suggested that five μmol L–1 Se could be used to reduce NO3− content and increased hydroponic lettuce and spinach yield.

An experiment was conducted as split plot based on the randomized complete blocks design, in greenhouse complex of Shahid Chamran University of Ahvaz in 2017. The main plot consisted of light treatment at two levels [a) sunlight (control), b) sunlight + red and blue LEDs (50:50%) with light intensity of 70 μmol/m2s for 15 hours (from 5 PM to 8 AM as night light] and the subplot was six greenhouse lettuce cultivars (Black Seed Simpson, Green Ice, Vivian, Tom Thumb, Red Salad Bowl and Salad Bowl). Results of the experiment showed that some of the measured traits were influenced by cultivar and light increase and some of them were under the influence of interaction effects of cultivar and light and were significant at 1% level. Maximum fresh and dry weight of leaf, fresh and dry weight of stem, number of leaves and calcium content were observed in night light treatment. Maximum and minimum values of leaf nitrate content were observed in Tom Thumb cultivar and control treatment (1723 μg/g dry weight) and Green Ice cultivar and night light (1023 μg/g dry weight), respectively. Maximum and minimum values of calcium content were observed in Black Seed Simpson cultivar and night light (1477 μg/g dry weight) and Tom Thumb control treatment (271.1 μg/g dry weight), respectively. According to the results of this experiment, by increasing the night light, it is possible to enhance the quantitive growth of the leafy lettuce cultivars by 90%, and also increase the quality of their yield

This experiment was performed to evaluate the effect of different nitrogen forms (ammonium to nitrate ratio) on the growth and flowering characteristics of two gerbera cultivars (‘Stanza’ and ‘Double Dutch’). The aim was to recommend the appropriate amount of NH4+:NO3¯ ratio in the nutrient solution to optimize quantity and quality characteristics in gerbera. This experiment was conducted in a completely randomized factorial design with two factors including NH4+:NO3¯ ratios and cultivar type with three replications. The NH4+:NO3¯ ratios (0:100, 20:80, 40:60, and 60:40) were supplied as a first factor and second factor was gerbera cultivars (‘Stanza’ and ‘Double Dutch’). The results indicated that increasing ammonium concentration in the nutrient solution to more than 40% of total N, significantly reduced growth indices and gerbera flower numbers compared to NH4+:NO3¯ ratio of 20 to 80. Results showed that the highest flower number (314 flowers m-2 year-1), stalk dry weight (5.2 g), flower stalk diameter (0.92 cm), flower stalk weight (2.31 Kg) and vase life (14 days) were obtained in 80:20 of NH4+:NO3¯ ratio. Thereofre, nutrient solution with NH4+:NO3¯ ratio of 20:80 is an appropriate solution recommended for commercial production of gerbera cut flowers in order to achieve the optimum quantity and quality yield of Cut Gerbera.

In this study, the effect of 5 nutrient solutions containing different ratios of ammonium nitrogen to total nitrogen on quantity and quality properties of two apple varieties (Golabe-Kohanz and Granny Smith), were studied. One of the nutrient solution (number 1) had no ammonium nitrogen but the ammonium to total nitrogen ratios of other nutrient solutions were, 0.04, 0.07, 0.10, 0.14 meq/liters, respectively. Fresh weight, length, diameter and length to diameter ratio of fruits (shape of fruits), fruit firmness, pH, total soluble solids (TSS), titrable acidity (TA) and TSS / TA ratios were evaluated. When ammonium nitrogen increased in nutrient solutions there was no significant difference in fruits fresh weight and shape of fruits. While firmness, pH, total soluble solids significantly decreased when the ammonium to total nitrogen ratios increased in nutrient solutions.

The effect of different nutritional solutions on growth and flowering of potted anthurium (Anthurium andreanum cv. LentiniRed) was comparised in soilless culture in a completely randomized design with four nutrient solutions (treatments) and four replications (each replication five pots), in a research green house in University of Guilan from November '2014 to July '2015. The first (nitrate/total nitrogen, 3.5/3.5) and second (nitrate/total nitrogen, 3/3) nutritional solutions were without ammunium and the third (nitrate/total nitrogen, 4/4.5 and ammonium/total nitrogen, 0.5/4.5) and forth (nitrate/total nitrogen, 3.5/4 and ammonium/total nitrogen, 0.5/4) ones included it. The first and third nutritional solutions included 2.9 and the second and forth ones included 2.4 meqK/l solution. The results showed significant differences among different treatments regarding the number of leaf, flower, flowering time, and the amount of spathʾs anthocyanins, leaf chlorophylls a, b and carotenoids, the concentrations of nitrogen, potassium, magnesium, calcium and iron in leaf. There were no significant difference for plant height, length and width of spath, length, width and area of the leaves and leaf phosphorus concentration. The most number of the leaves and flowers was found in the third nutrient solution. Flowering in third and forth treatments were faster than others. The most concentration of spathʾs anthocyanin was seen in plants related to the second treatment and the most chlorophyll a and carotenoid concentrations were observed in the first and third treatments. Ammonium as a nitrogen source led to a significant decrease in the cationsʼs concentration and an increase in iron concentration in leaf.

Spinach is one of the most important leafy vegetables, rich in calcium, phosphorus, potassium, vitamin C and B-carotene, and it is likely to be Iran's origin. More than 30 percent of the area under cultivation of in Iran leafy vegetables, allocated to spinach plant. Spinach is a cool season crop and its cultivation is done inthe fall and in early spring. Various regions of Iran, has the vast genetic diversity in relation to the mass of spinach. In a study to evaluate the yield and agronomic traits spinach 121 mass Iran, the masses were divided into six clusters that each cluster has specific morphological and agronomic traits. Leafy vegetables, especially spinach are the main sources of nitrate absorption and about 70 percent of total dietary nitrate intake per person per day is provided by leafy vegetables.
Material and To study the preliminary agronomic and morphological traits and nitrate amounts of 100 Iranian spinach mass are available in GenBank, an investigation was carried out in Agriculture and Education Center Research in Esfahan for two years (2013-2014) by using of five mass dominant cultivars, and two control landrace (Varamin 88 and Varamin prickly seed). The aim of the first year of the study was the primary isolation of superior landraces based on agronomic traits of spinach. At the end of the first year of growth, seed traits, including the type (smooth-prick), the width of the blade, leaf color, wrinkling of leaf area, leaf thickness, the petiole (standing, half-standing and sleeping), petiole length, shape of leaf, the shape of the leaf tip, bolting during plant growth and the number of male and female were determined. A total of 25 landraces selected in the first year of study were compared in the second year using a randomized complete block design with three replications. Studied traits were: yield, dry matter yield, number of leaves, leaf length, leaf width, and petiole length and nitrate levels. Statistical analyses of the data, correlated traits were performed using SAS software and comparisons of means calculated by using LSD at 5%.
Result and The results showed that 21.5% of the populations used in this study had the petiole with a standing (vertical) position and 25.2% of them had a long petiole. Length of the petiole and hoisted were considered desirable trait for mechanized harvesting. However, varieties have high nitrate concentrations, or in cases where the management of nitrogen fertilizers does not do well, longer tail leaves are an undesirable trait because the accumulation of nitrate in the tail leaves is more than leaf spinach. 35.5% of spinach leaves landrace used in this study were green color. Leaf color in leafy vegetables is very important. Leaf length, have a range of 11 cm in the Kashan, up to 18 cm in mass TN-69-101 (collected from Lorestan). In this study the agronomic characteristics of the mass of the spinach, length of leaf blade mass in Kashan, Shahreza and Najaf Abad, were 15.50, 11.50, and 9.50 cm, respectively, and all three populations were significantly different in this respect. A significant positive correlation was observed between leaf length and leaf width (0.7 **). The highest of fresh yield was 32.59 t ha-1 and produced by Varamin 88 that with six masses (TN-69-73, Varamin- prickly, TN-69- 74, TN-69-153, TN-69-140, TN-69-58) did not differ statistically. Three populations of TN 69-153, TN-69-140 and Varamin- prickly (advanced masses prickly Varamin) both in terms of fresh and dry matter yield were superior. The (TN-69-78) mass with 17 leaves, the highest, and (TN-69-22) mass with 11/33 leaves, the lowest number of leaves produced among the different masses. Leaf blade width in the mass TN 69-31, was equal to 12/38 cm and with the eleven other populations had a significantly blade width more than other the masses. In terms of nitrate in shoots, TN-69-153 population with 1708 mg of nitrate per kg of dry matter had the highest amount of nitrate.
The results of this study showed that considering the diversity traits among different populations of spinach in various parts of the Iran can be provide suitable potential for agronomic and breeding purposes. The masses after selection and purification can be available to farmers and producers.

In order to study the effect of different amounts of nitrogen fertilizer and foliar application of boron on some physiological traits in karela plants (Momordica charantia L.), a factorial experiment in a randomized complete block design with three replications was conducted at the Sharood University of Technology in 2013. The treatments consisted of three levels of nitrogen fertilizer: 75, 150 and 225 kg N.ha-1 (urea source) as the first factor and four foliar applications of boron including: 0, 1, 2 and 3 g per liter of boric acid as the second factor. The traits measured in this study included the length and diameter of fruit, fruit yield, chlorophyll "a","b", and carotenoids, the conent of sugar nitrate and nitrate reductase enzyme activity. The results showed that, nitrogen fertilizer except diameter of fruit had significant on all of attribute traits. Foliar application of boron in this study had significant effect on fruit yield, the content of chlorophyll "b" (P

Selenium is a non metallic chemical element that affects plant growth and development and but it can due to the presence of antioxidant defense system as a matter of basic human and animal health has been identified. An experiment was conducted to study the effect of Se on physiological characteristics and yield of Brussels sprouts (Brassica oleracea var. Gemmifera) with six levels of Se (0، 2، 4، 8، 16 and 32 mg/l) from sodium selenate. The experiment was arranged in a completely randomized design with four replications under greenhouse conditions. The results showed that yield in terms of fresh weight of sprout was significantly (P≤0. 01) affected by Se concentration so that increasing Se concentration from 0 to 8 mg/l increased the yield and chlorophyll index، electrolyte leakage (EL) in leaves decreased then with increasing Se concentration decreased the yield and EL in young leaves increased. The highest yield was observed at 8 mg/l Se concentration that was 40% higher compared to the control treatment. With increase concentration of Se in the nutrient solution increased Se concentration and as follow old leaves>young leaves> sprouts. The results showed that Se can be added at the 8 mg/l to the nutrient solution for growing Brussels sprout.

Nitrate is an essential component for plants and vegetables are of the most important source of nitrate for human being. It is estimated that vegetables provide 92 % of nitrate for human nutrition. The positive and negative effects of elevated root zone CO2 on growth and yield of some plants have been reported. This study has been conducted in order to examine the effect of root zone CO2 on growth and nitrate accumulation in lettuce. The experiment was conducted as a completely randomized design with four levels of CO2 (0، 200، 400 and 600 ml per minute) and with five replication on two cultivars of lettuce (Sativa and Capitata). The study performed in floating system and aeration was supplied by air pump. The results showed that injection of CO2 had significant effect on the fresh and dry weight of leaves، stems and roots of plants. By increasing the concentration of CO2 fresh and dry weight of leaves، stems and roots increased in both cultivars. Photosynthesis efficiency increased in both cultivars in the treatment of 400 ml/min root zone CO2. The influence root zone CO2 significantly decreased nitrate content in leaves of lettuce. Nitrate concentration in the leaves of lettuce was decreased by injection of root zone CO2 in L. sativa. var. Capitata in the treatment of 400 ml/min and in L. sativa. var Sativa in the treatment 600 ml/min. respectively by 27% and 47. 6%. With increasing input root zone CO2 increased activity of nitrate reductase enzyme in both cultivars that showed highest content in treatment 400 ml/min.

Spinach (Spinacea oleracea L.) is one of the most important vegetables of Chenopodiaceae. Excessive nitrogen fertilizers application increases plant nitrateaccumulation. A complete randomized block design greenhouse experiment was carried out to study the effects of nitrogen levels on growth, nitrate accumulation and nitrate reductase in ‘New persian’ variety of spinach in Gorgan University of Agricultural Sciences and Natural Resources. Treatments included 0, 100, 200, 300, 400 and 500 kg ha-1 urea. Measured traits included leaf number, leaf area, leaf dry weight, protein, nitrate content, chlorophyll a, b and nitrate reductase gene expression. Results showed that leaf number, leaf area, leaf dry weight and leaf protein content increased as urea level increased up to 300 kg ha-1 but there was no significant increase when urea increased to 400 and 500 kg ha-1. Chlorophyll content (a, b) and nitrate formation increased when more urea were used. Nitrate level was greater in petiol than leaf blade. Urea fertilizer up to 200 kg ha-1 increased nitrate reductase transcript significantly but at higher levels, the gene expression showed lower activity and caused higher accumulation of nitrate in the leaves.

Production of onion all thruough the year particularly in semi tropical regions has been considered as an alternative to fulfil the local markets needs. In order to determine the best amount and method of urea fertilizer application so that to have higher yeild and lower amount of nitrate content the effects of seven levels of urea fertilizer including 0، 90، 180، 270، 360، 450 and 540 kg of nitrogen per ha and three different partitioning method of fertilizer application including application at 2، 3 and 4 times of each of the above mentioned amounts of fertilizers during the growing period were examined in a factorial experiment based on randomized complete block design with three replications in Jiroft. Results showed that increasing the amount of nitrogen fertilizer increased leaf length and crown diameter but decreased dry matter. The amount of fertilizer also showed significant effect on diameter and length. The highest bulb dry meter and length and yield were obtianed by application of 270 kg/ha of nitrogen while using higher amounts caused them to decrease. Nitrate content of the bulbs was strongly affected by the amount of nitrogen fertilizer applied so that the highest value (126. 8 mg/kg/ fresh weight) was obtianed under highest level of nitrogen fertilizer. Nitrate content and bulb dry matter were also affected by the number of times of fertilizer application. Results of this study suggesting that to obtain high yield and low nitrate content، more than 180 kg of nitrogen per ha should not be applied.

In this study the effect of nitrogen form and different oxygen levels on growth and development and macronutrients concentrations in lettuce plants was investigated. This investigation showed that sole ammonium application caused fresh and dry weight reduction of shoot and root in lettuce plant. But different oxygen levels had no effect on them. Nitrogen concentration of shoot was higher in ammonium treatments compared to nitrate treatment and with increasing of oxygen levels in the presence of ammonium، nitrogen content also increased، although it was not the same in nitrate treatment. Phosphorous concentrations in shoot and root were not affected by any of treatments and their interaction. Ammonium also caused reduction of potassium concentration in shoots، but different oxygen levels and its interaction with nitrogen form had no significant effect on it. Magnesium content of shoot also decreased in the presence of ammonium، although it was not the same in root. With increase of dissolved oxygen level، magnesium content of shoot decreased in ammonium treatment، but in nitrate treatment the concentration of this element was not affected by oxygen levels. It is concluded that probably reduction of potassium and magnesium in ammonium-fed plants has a role in plant growth reduction، and it was also observed that in spite of increase in the concentration of shoot nitrogen and root magnesium with increase of dissolved oxygen level in ammonium treated plants، lettuce growth was not affected by oxygen levels.