Mohammadsadegh Sadeghi; Seyyed Jalal Tabatabaie; Hassan Bayat
Abstract
Introduction: Spinach is a leafy vegetable which is rich source of vitamins, antioxidant compounds (e.g. flavonoids, acid ascorbic) and essential elements (e.g. Fe, and Se). Spinach is capable of accumulating large amounts of nitrogen in the form of nitrate in shoot tissues which is undesirablein the ...
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Introduction: Spinach is a leafy vegetable which is rich source of vitamins, antioxidant compounds (e.g. flavonoids, acid ascorbic) and essential elements (e.g. Fe, and Se). Spinach is capable of accumulating large amounts of nitrogen in the form of nitrate in shoot tissues which is undesirablein the human diet. The concentration of nitrate in plants is affected by species, fertilizer use, and growing conditions. Green leafy vegetables such as spinach, generally contain higher levels of nitrate than other foods. Nitrate ofplant tissueslevels are clearly related to both form and concentration of N fertilizers applied. Nitrogen fertilizers have been known as the major factors that influence nitrate content in vegetables. Ideally, the N fertility level must be managed to produce optimum crop yield without leading to excessive accumulation of nitrate in the harvested tissues.Usinghigh amounts ofN fertilizer produced higher yield with higher nitrate inleaves but the highest amount of nitrate was accumulated in the petioles.There are several plant species that may accumulate nitrate, including the Brassica plants, green cereal grains (barley, wheat, rye and maize), sorghum and Sudan grasses, corn, beets, rape, docks, sweet clover and nightshades. The presence of nitrate in vegetables, as in water and generally in other foods, is a serious threat to man’s health. Nitrate is relatively non-toxic, but approximately 5% of all ingested nitrate is converted in saliva and the gastrointestinal tract to the more toxic nitrite. This study was aimed to investigate theeffects of nitrogen and nutrient removal on nitrate accumulation and growth characteristics of spinach (Spinacia oleraceae L.).
Materials and Methods: A pot hydroponic experiment was carried out to evaluate the effect of different levels of nitrogen and nutrient removal (one week before harvest) on nitrate accumulation and growth characters. A factorial experiment based on completely randomized design was conducted with twolevels of removal (removal of nutrient one week before harvest) or not to remove and fourlevels of nitrogen (25, 50, 100 and 200 mg/l) with sixreplications. During the growing season in the greenhouse, temperature was fixed between 24-27 °C and photoperiod of 16 hours of light and 8 hours of darkness. The measured traits were root fresh and dry weight, shoot fresh and dry weight, Fv/Fm ratio, and chlorophyll index, number of leaf per plant, leaf area, nitrate and total nitrogen.
Results and Discussion: The results of this experiment showed that increasingnitrogen concentration from 25 to 200 mg/l increased shoot dry weight, number of leaves and leaf area, by 22.00, 7.26, 4.79 and 14.00 fold, respectively. Nitrogen also increased Fv/Fm and chlorophyll index. Nutrient removal in a week before harvest had no significant effect on fresh and dry weight of shoots and roots, number of leaves,leaf area, chlorophyll index and Fv/Fm. Increasing concentrations of nitrogen increased nitrate and total nitrogen in petiole while removing the nutrient solution in a week before harvest significantly decreased amounts of the above-mentioned traits. Nutrient solution removal is an appropriate strategy to reduce nitrate accumulation in spinach that has no effect on yield loss.
Conclusions: The results showed that increasing the concentration of nitrogen increased plant growth indicators such as shoot fresh and dry weight, root fresh and dry weight, leaf area and number of leaf per plants, so that the greatest increase was obtained from concentration of 200 mg/lit. Increasing the concentration of nitrogen enhanced nitrate and total nitrogen of petiole so that the highest concentration of nitrate and total nitrogen was observed in200 mg/lit nitrogen. Nutrient solution removal in a week before the harvest had a significant effect in reducing all traits but it decreased nitrate accumulation and total nitrogen of petiole significantly. At the end of the experiment, it was found that increasing the concentration of nitrogen increased nitrate concentrations and total nitrogen in the petioles while nutrient removal in a week before harvest reducedthe amount of leaf nitrate. Thereforethe removal ofnutrient solution is one of the strategies to reduce nitrate accumulation that had no effect on yield loss of crop. Based on the results from this research, nitrogen at a concentration of 200 mg/lit, with the removal of nutrient solution a week before harvest is recommended for growing in hydroponic culture of spinach.
Mohammad Rahmnpourazar; Seyyed Jalal Tabatabaie; Sahebali Bolandnazar
Abstract
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 ...
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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.
Mehri Yusefi; Seyyed Jalal Tabatabaie; Jafar Hajilou; Naser Mahna
Abstract
Salinity affects the yield and quality of fruits crops as result of modifying water and nutrient uptake. In split root system, it should be possible to reduce the deleterious effect of salinity on the plant growth. Therefore, an experiment was conducted on strawberry with different concentration of NaCl ...
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Salinity affects the yield and quality of fruits crops as result of modifying water and nutrient uptake. In split root system, it should be possible to reduce the deleterious effect of salinity on the plant growth. Therefore, an experiment was conducted on strawberry with different concentration of NaCl (0, 30, 60 and 90 mM) in a completely randomized blocks design in studding hydroponic greenhouse. The roots were divided into two portions and either even or uneven salinity was applied to the root portions. The treatments consist of 0:0, 0:30, 0:60, 0:90, 30:30, 60:60 and 90:90 with three replications. In general, the increased salinity reduced photosynthesis rate but in uneven salinity the photosynthesis rate was increased. Proline concentration was reduced in 0:0 treatments but increased in 0:30 and 30:30 treatments. Ca, N, P and K concentrations were reduced by increasing salinity, but were increase in uneven salinity. The highest concentrations of Cl and Na were observed in 60:60 and 90:90 salinity treatments. Na and Cl concentrations were reduced in uneven salinity in the root zone so that in 0:30 treatments, the concentration of Na were 20% lower than that in 30:30 treatments. Based on the results of this study the application of uneven salinity in a concentration of 30 mM could be recommended for growing strawberry in salinity stress conditions.
Hojatollah Rostami; Seyyed Jalal Tabatabaie; Fariborz Zare Nahandi; Jafar Hajilou
Abstract
Boron toxicity is one of the most important disorders for plant cultivation in the arid and semi-arid regions. Boron accumulation usually occurs in deeper soil layers due to leaching and therefore improvement of such a soil in this situation is difficult. An experiment was conducted to find out the effect ...
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Boron toxicity is one of the most important disorders for plant cultivation in the arid and semi-arid regions. Boron accumulation usually occurs in deeper soil layers due to leaching and therefore improvement of such a soil in this situation is difficult. An experiment was conducted to find out the effect of boron on the vegetative and physiological aspects of olive trees. Six concentrations of boron (0.2, 10, 20, 30, 40 and 50 mg/l) and two cultivars (Amygdalia and Konsevolia) were used in this experiment. The experiment was arranged in a completely randomized design with four replications. The results showed that with increasing levels of boron dry weight of leaves, stems and roots compared with controls in both cultivars declined. Amygdalia cultivar in the high concentration of boron was unable to grow and decrease in the production of new leaves was significant but Konsevolia cultivar high concentrations of boron also could grow, although the growth of this cultivar was as well significantly reduced. Efficiency of photosynthesis (Fv/Fm) in both cultivars decreased with increasing boron levels. However, Amygdalolia showed a more reduction than Konservolia. Boron toxicity symptoms appeared 45 days after the start of the experiment in concentrations (30, 40 and 50 mg/l) in Amygdalolia cultivar. However, 75 days after the Amygdaloia cultivar symptoms were observed at concentrations 40 and 50 mg/l. The results showed that olive can have a good resistance to boron toxicity, although much of this resistance is largely dependent on the cultivar.
Mehdi Oraei; Seyyed Jalal Tabatabaie; Esmaeil Fallahi; Ali Imani; Leila S. Fatemy
Abstract
Boron (B) toxicity is an important disorder that can limit plant growth in arid and semi-arid environments. It has been proven that use of tolerant rootstocks impede B uptake or transport to the aerial portions of plants. This may alleviate B toxicity in the scion, consequently improves the tolerance ...
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Boron (B) toxicity is an important disorder that can limit plant growth in arid and semi-arid environments. It has been proven that use of tolerant rootstocks impede B uptake or transport to the aerial portions of plants. This may alleviate B toxicity in the scion, consequently improves the tolerance to excess B in the root zone. An experiment was conducted to find the effects of B toxicity on vegetative growth, physiological characteristics and B distribution of almond tree (Prunus dulcis Mill.) cv. “Ferragnes” grown in the controlled environment. Three levels of B (0.25, 10, 20 mg/L) from H3BO3 and two almond rootstocks (GF677, Tuono) were factorially combined in a completely randomized design with four replications. The results showed that B toxicity had significant effects on vegetative growth, physiological characteristics and B distribution in almond tree. With increasing B levels in nutrient solution, vegetative characteristics including leaf production percentage and main shoot elongation was decreased significantly. However, Fr/Tuono was affected less than Fr/GF677. Also, physiological characteristics such as electrolyte leakage percentage, proline content and leaf necrosis percentage were increased significantly in two scion-rootstock combinations. On the basis of these results, GF677 because of an inability to restrict uptake and/ or transport of excess B from root system to aerial parts of scion, have a higher sensitivity to B toxicity. Instead, Tuono via mechanism of preferential distribution of B in roots inhibited the accumulation of high concentration of B either in young leaves or meristematic tissues partially and protected these susceptible organs against injury caused by B toxicity. In conclusion, it seem that under excess B conditions Tuono rootstock have higher tolerance than GF677.
Somaye Kokabi; Seyyed Jalal Tabatabaie
Abstract
Abstract
Supplement of optimum concentration nutrients such as K and Ca in soil less culture seems to have a remarkable effect on the yield and quality of fruity crops. An experiment was conducted to find out the effect of different K:Ca ratios on the growth, yield and quality in Galia (Cucumis melo ...
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Abstract
Supplement of optimum concentration nutrients such as K and Ca in soil less culture seems to have a remarkable effect on the yield and quality of fruity crops. An experiment was conducted to find out the effect of different K:Ca ratios on the growth, yield and quality in Galia (Cucumis melo var. reticulatus L. Naud. cv. Galia) grown in hydroponics. The experiment was arranged in the completely randomized design with three replicates. The seeds of melon were sown in the media containing perlite and vermiculate (3:1 V:V)with different K:Ca ratios (1.5, 2, 2.5, 3, 3.5, 4). The fruits were harvested in the physiological ripened stage and their quality and quantity attributes were measured. The fresh weight of fruits were determined and brushed in a hot water rinse at 59 oC for 15 s and then they were stored at 5-6 oC for 14 days and an additional 5 days at 20 oC then quality characteristic were measured. The results showed that the yield of melon was significantly affected by various K:Ca ratios, so that the highest and lowest yield was observed in K:Ca ratio 3 and 4, respectively. The firmness was significantly affected by various K:Ca ratios, so that with increasing K:Ca ratios the firmness of fruit was decreased. Calcium concentration in fruits and leaves were significantly reduced with increasing K:Ca ratios. It can be concluded that K:Ca 3 improved the yield and quality of galia, therefore adjustment of K:Ca=3 in the nutrient solution seems to be crucial to obtain the highest yield and quality
Keywords: Potassium, Galia melon, Yield, Calcium, Quality
Mohanna Mollavali; Sahebali Bolandnazar; Seyyed Jalal Tabatabaie
Abstract
Abstract
Nitrogen is a key nutrient in plant growth and it is necessary for amino acid synthesis. Sulfur has very important role in the biosynthesis of the Alliums flavor and pungency precursors and Potassium improve crop yield and quality. In order to study the effect of ammonium nitrate and potassium ...
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Abstract
Nitrogen is a key nutrient in plant growth and it is necessary for amino acid synthesis. Sulfur has very important role in the biosynthesis of the Alliums flavor and pungency precursors and Potassium improve crop yield and quality. In order to study the effect of ammonium nitrate and potassium sulfate on concentration some of the mineral elements in onion (Allium cepa L. Azar Shahr cv.) a pot experiment was carried out with two factors, comprised nitrogen and sulfur, in a randomized complete block design with four replications. Nitrogen and sulfate were supplied as NH4NO3 (50, 100, 67.5 and 90kg ha-1) and K2SO4 (0, 78.3 and 156.6 kg ha-1) respectively. Three 8 weeks old onion seedlings were transplanted to pots with 7 kg soil as a experimental unit so, 144 plant were performed in 48 pots. At bulbing stage, one plant were sampled per pot and N, P, K and S concentration in leaves were determined and after bulb harvesting, also N and S in bulbs were measured. The result indicated that, by increasing K2SO4 to 156.6 kg/ha P, K and S concentration in leaves and bulb increased, however the highest N concentration in leaves and bulb were observed by application 78.3 kg/ha K2SO4. Increasing trends in leaves and bulb N and leaves K were observed by 67.5 kg/ha NH4NO3. In conclusion, by considering of nutrient absorption and dry matter production 156.6 kg/ha K2SO4 and 67.5 kg/ha NH4NO3 for better onion bulb production is recommended.
Keywords: Onion, Ammonium nitrate, Potassium sulfate, Nitrogen, Potassium, Sulfur
Leila Seyed lor; Seyyed Jalal Tabatabaie; Esmaeil Fallahi
Abstract
Abstract
Silicon (Si) is considered one of the beneficial elements for plant, however recent studies show that Si plays an important role in plant resistance to environmental stresses , like salinity. An experiment was conducted to study the effect of Si and NaCl salinity on the growth, yield and ...
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Abstract
Silicon (Si) is considered one of the beneficial elements for plant, however recent studies show that Si plays an important role in plant resistance to environmental stresses , like salinity. An experiment was conducted to study the effect of Si and NaCl salinity on the growth, yield and fruit quality of strawberry (Fragaria × ananassa Duch) cv “selva” was grown hydroponically in the controlled environment glasshouse. Three levels of NaCl (0, 20 , 40 mM ) and three levels of Si ( 0, 1 , 2 mM ) was factorially combined in a completely randomized design with four replicates .The yield characteristics and fruit quality were measured during the experimental period. At the end of the experiment, plants were cut and vegetative characteristics such as number, fresh and dry weights and leaf area were measured. In addition, leaf relative water content and chlorophyll index were measured. The results showed that salinity reduced the vegetative characteristics, increasing the Si in the saline conditions, increased the number, fresh and dry weights and leaf area of the strawberry plants. The yield characteristics was reduced in the saline conditions, however applying Si reduced the adverse effects of salinity on the yield components. Both salinity and Si had no effect on the chlorophyll index. Leaf relative water content was reduced in salt stress, but silicon treatment largely improved relative water content of leaf. Both salinity and Si treatments increased acidity of fruit, but other quality characteristics were not affected by the treatments. The results reported here indicated that application of Si is recommend under salinity stress in strawberry.
Key words: Strawberry, Silicon, Salinity, Yield, Quality
