Pomology
Sayeede Khodaei; Ebrahim Ganji Moghadam; Mahbube Zamanipour
Abstract
IntroductionSince Iran is one of the arid and semi-arid regions of the world and due to the great importance of water in agriculture, it is very important to conduct research to improve drought stress in order to produce more quality products. In this regard, this study was conducted to investigate the ...
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IntroductionSince Iran is one of the arid and semi-arid regions of the world and due to the great importance of water in agriculture, it is very important to conduct research to improve drought stress in order to produce more quality products. In this regard, this study was conducted to investigate the effect of mycorrhiza species on some morphological and physiological characteristics of peach seedlings under drought stress. Arbuscular mycorrhizal fungi coexist with the roots of various plants and have a broad effect on their growth. These fungus are effective in the initial establishment of the plant under drought conditions. Arbuscular mycorrhizal fungi increases plant resistance to dehydration by increasing growth and uptake of nutrients, especially phosphorus. Matherials and MethodsIn order to investigate the effect of three species of Arbuscular mycorrhizal fungi on some vegetative characteristics and phosphorus absorption of peach seedlings under drought stress conditions, a factorial experiment was conducted based on a randomized complete block design with four replications. The experimental factors included: drought stress at four levels (100, 80, 60 and 40 percent of field capacity) and the second factor application of mycorrhizal fungus at four levels: application of three species of mycorrhiza fungi and three species of fungi, each in three concentration (75, 100, 125 g in a pot) with chemical fertilizer (100 g triple super phosphate for each pot) and fertilizer (without mycorrhiza) and control (without fertilizer and mycorrhiza). The measurements were comprised root traits, stem diameter, vegetative growth of branches, leaf area index, vegetation index, relative leaf water content, chlorophyll fluorescence, leaf electrolyte leakage, leaf phosphorus and colonization root percent. Results and DiscussionResult showed that application of mycorrhizal fungi seems to be effective in reducing the effects of dehydration stress. The use of these fungi had a positive effect on reducing leaf electrolyte leakage under severe dehydration. According to the results obtained in this experiment, the highest efficiency in drought stress conditions was observed in G. mosseae and G. intraradices. Under drought stress conditions, the lowest values of root volume, greenness index, chlorophyll fluorescence, leaf electrolyte leakage, root colonization and leaf phosphorus content were observed. With increasing of drought stress, all of the mentioned traits reduced and mycorrhiza fungi had a positive significant effect on all studied traits. In this study, it was found that with increasing stress intensity, the traits were negatively affected and led to irreparable damage to the product. Therefore, it is expected that by preventing or minimizing the effects of stress, an effective step was taken to increase performance. The significant decrease in root colonization with increasing stress is probably due to the decrease in the growth of hyphae. The most important step after spore germination is the growth of hyphae resulting from germination, which plays an essential role in root colonization. Apparently, hyphae growth is more affected by osmotic potential than spore growth. The results obtained from this research showed that the roots of peach seedlings have significant symbiosis potential with arbuscular mycorrhizal fungi (Peymaneh & Zarei, 2013). According to Miyashita et al. (2005) Leaf photosynthesis activity can be used as a useful tool for classification of drought tolerant plants. Sajjadinia et al. (2010) regarding the relative water content and photosynthesis of several pistachio cultivars reported high correlation and high diversity in different stages and cultivars and stated that the decrease in relative water content strongly reduces transpiration, stomatal conductance and photosynthesis, which our results are consistent. With the escalation of tension, the greenness index also decreased; So that in the conditions of severe stress (40% of crop capacity), the amount of greenness index reached the lowest value. In the conditions of severe stress due to interruption of continuous irrigation, the plants entered from the stage of mild stress to the stage of severe dry stress, which seems that under these conditions, the decrease in the concentration of chlorophyll, in addition to the decrease in the amount of synthesis, is caused by the decomposition of chlorophyll due to the increase in the amount chlorophyllase, peroxidase and phenolic compounds. According to Schutz and Fangmier (2001), the decrease in the amount of chlorophyll in stress conditions is related to the increase in the production of oxygen radicals in the cell. These free radicals cause peroxidation and as a result the decomposition of this pigment. The greenness index is considered one of the most important growth parameters, which is reduced by drought stress conditions, and the results indicate that the treatment of mycorrhizal fungi in all three types of inoculated mushrooms has improved the greenness index and the adverse effects It has removed the drought stress to a great extent (Figure 6), which can be attributed to the improvement of water and food absorption by mycorrhizal roots (Larsson et al., 2008). Conclusion In general, this study showed that the best treatment related to the mycorrizha fungi was mosseae, which had the most effect on reducing the negative effects of stress
Ali Naseri Moghadam; Hassan Bayat; Mohammad Hossein Aminifard; Farid Moradinezhad
Abstract
Introduction: Salinity and drought have adverse impacts on crop production throughout the world, especially in arid and semiarid areas. Salinity decreases crop growth and yield through modifications of ion balance, water status, stomatal behavior, photosynthetic efficiency, salinity-induced nutrient ...
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Introduction: Salinity and drought have adverse impacts on crop production throughout the world, especially in arid and semiarid areas. Salinity decreases crop growth and yield through modifications of ion balance, water status, stomatal behavior, photosynthetic efficiency, salinity-induced nutrient deficiency and changes to the soil structure. Drought is another one of the main factors limiting the growth and development through the anatomical, morphological, and physiological and biochemical changes that the severity of drought damage varies depending on the duration of the stress and plant growth stage. Water stress reduces relative water content, photosynthesis pigments, stomatal conductance, biomass, growth and ultimately plant performance. Narcissus (Narcissus tazetta L. cv. ‘Shahla’) belongs to the Amaryllidaceae family is grown as a cut flower, landscape and medicinal plant that grows throughout the world except tropical regions. It is necessary to know the tolerance of N. tazzeta to drought and salinity stress in order to produce optimal product. According to previous studies, no complete research has been done on the effects of drought and salinity stress on N. tazzeta. Therefore, the present study was carried out with the aim of investigating the combined effects of drought and salinity stress on growth, flowering and biochemical characteristics of N. tazzeta.
Materials and Methods: This research was carried out in Faculty of Agriculture, University of Birjand, in 2017. A pot experiment was conducted in completely randomized deign with factorial arrangement and three replications. The treatments included sodium chloride (NaCl) in four levels 0 (control), 20, 40 and 60 mM and drought stress in four levels 30, 50, 70 and 90% of field capacity. The plants were harvested four months after the start of salt and drought treatments. The investigation traits were included vegetative, reproductive and biochemical characterizes. Measured traits were included root length, volume of root, root fresh weight, bulb length, bulb fresh weight, shoot fresh weight, total dry weight, flower diameter, flower crown diameter, stem diameter, days from planting to flowering, days from flowering to senescence, antioxidant activity, total phenolic content and total soluble sugar of leaf and root. The data were analyzed by SAS version 9.4 and the means separated by Duncan's multiple range test at p < 0.05. Excel was used to draw graphs.
Results and Discussion: The results of simple effects showed that drought and salinity stresses decreased the values of flowering stem diameter, flower diameter, root length, root volume, root fresh weight, bulb fresh weight, bulb length, shoot fresh weight, total dry weight and days from flowering to senescence. In contrast, the values of the number of days from sowing to flowering, total soluble sugars of leaf and root, antioxidant activity and total phenolic content increased under the influence of these two stresses. The results of interaction effects showed that the destructive effects of salinity and drought stress were intensified in co-application conditions, so that the lowest values of growth and reproductive traits were observed in the most severe stress (30% field capacity × 60 mM salinity). Usually, root and shoot length in sodium chloride solution is reduced due to the toxicity of ions and their negative effects on cell membranes. Drought stress and salinity reduce cell division and also reduce the size of cells and consequently the length of the plant decreases. Delay in flowering is due to multiple stresses (osmotic imbalance, nutrient insufficiency and cellular toxicity) that is caused by salinity and drought stresses. These stresses produce ROS compounds that damage the proteins, lipids, carbohydrates, and nucleic acids. Plants for scavenging and detoxifying these compounds from the cell surface use enzymatic (catalase, superoxide dismutase, etc.) and non-enzymatic (phenolic compounds and carotenoids) defense systems that increase the antioxidant activity of the plant.
Conclusion: The results of this study showed that drought and salinity stresses had negative effects on growth and flowering traits, which was exacerbated by the combined application of these two stresses. On the other hand, the highest levels of antioxidant activity, total phenolic content and total soluble sugars were obtained under severe stress conditions (drought or salinity). Salinity and drought stress reduced the flowering rate, quality of flowers and the flower life on the plant, but all the levels of stress reached to flowering stage. Also, the growth of narcissus plant was not affected by the highest levels of drought (30% crop capacity) and salinity (60 mM) stress. In general, the results showed that both drought and salinity stress reduced the growth and yield of narcissus flower, but the destructive effects of salinity stress on the growth, ornamental and physiological traits of narcissus flower were more than drought stress.
Maryam Haghighi; Bahareh Naghavi
Abstract
Introduction: Salinity has deleterious effect through ion toxicity and changes nutrient balance on plant growth parameter. For decreasing the hazardous effect of salinity stress, some effort has done to reduce uptake and accumulation of Na. Adding of Ca decreased these deleterious effect of salinity. ...
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Introduction: Salinity has deleterious effect through ion toxicity and changes nutrient balance on plant growth parameter. For decreasing the hazardous effect of salinity stress, some effort has done to reduce uptake and accumulation of Na. Adding of Ca decreased these deleterious effect of salinity. Calcium ions have significant effects on the physiological processes of plants and improve the morphological and biochemical factors of plants under salinity stress. The effect of calcium on reducing the harmful impacts of salinity from sodium depends on the plant type, calcium concentration and sodium source. Recently, the addition of nanoparticles to plants as fertilizers has attracted the attention of researchers because of its unpredictable effects, such as faster and easier penetration into the membrane of the cell. A few studies have examined the effect of different nanoparticles on the growth and physiology of plants. So, a research was conducted to investigate the effects of salinity and supplemental calcium in the form of spraying into two metal and nano-metal forms on vegetative growth of tomato plants under crop cultivation conditions.
Materials and Methods: To study the effect of CaCl2 and Nano-Ca on tomato (Lycopersicon escuhentum var. Falcato), a factorial experiment based on completely randomized design (CRD) with 4 replicates was designed with NaCl (0, 25 and 50 mM) and Ca and N-Ca (0, 150 and 200 mg/l) in Isfahan University of Technology greenhouse. Indicators include chlorophyll index, relative water content, ion leakage, leaf water potential, root and shoot dry weights, root and shoot length and root volume were measured. Finally, the analysis of the results was done by statistical statistic software and comparing the meanings by LSD test at 5% level.
Result and Discussion: Results showed that Ca and Nano-Ca was effective on decreasing hazardous effect of salinity on fresh and dry weight of shoot and root volume and Ca was more effective than Nano-Ca. In high salinity level (50mM NaCl), application of 150 mg/l Ca increased fresh and dry weight of root, fresh weigh of shoot and root volume by 60, 63, 50 and 70 % compare to control ,respectively. As well as, the highest root length and shoot was observed in this treatment. Application of 200 mg/l calcium and 150 mg/l of nano-calcium significantly improved chlorophyll content in 50 mM sodium chloride treatment. The plant's compatibility mechanism is very complex in the salinity conditions, from reasons for the growth of the plant under saline conditions are the accumulation of toxic ions, chlorine and sodium in plant tissues, which reduces enzyme activity and changes the pattern of carbohydrate distribution. Loss of the fresh and dry weight shoots and root of tomato has been reported in salinity conditions, which can be attributed to reduce plant growth due to the decrease in leaf area growth and thus the reduction of photosynthesis and the production of proteins. There is little research on the use of nanoparticles in plant growth and the use of nano-calcium has been used to reduce salinity stress for the first time, but the beneficial effects of some nano-materials on plants have been proven. With the use of titanium and nano-titanium in spinach, nano-titanium increases the fresh and dry weight of the plant relative to the use of titanium. In this study, the effects of calcium salinity stress were observed, but nano-calcium had less effects than calcium, and probably due to the fact that the concentrations of nano-calcium were used, using less concentrations in future research to achieve possible concentrations are suggested.
Conclusions: The use of nano-calcium to reduce salt stress was used for the first time in this experiment. The results of this experiment showed that the application of 150 mg calcium per liter on many tomato traits such as root and shoot fresh weight, root length shoots and root volume were effective under salinity stress, especially intense salinity (50 mM sodium chloride). The comparison of the effects of calcium and nano-calcium showed that the particle size reduction hadn’t shown a significant effect on calcium salt modification and may be due to the concentrations of nano-calcium. Therefore, nanotechnology needs more research in the application of nano-calcium and other nano-materials. Ca also alleviated the hazardous effects of salinity but comparing Ca and nano-Ca showed that nano-Ca has not significant alleviating effect on salinity stress.
Mahrokh Rostami; Ali Akbar Shokouhian
Abstract
Introduction: Strawberry fruit is soft and has a variety of vitamins, especially vitamin C and minerals. Parus is one of the most important short-day cultivars and suitable for the fresh produce market. Nitrogen is involved in vegetative and reproductive growth of most horticultural crops and excessive ...
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Introduction: Strawberry fruit is soft and has a variety of vitamins, especially vitamin C and minerals. Parus is one of the most important short-day cultivars and suitable for the fresh produce market. Nitrogen is involved in vegetative and reproductive growth of most horticultural crops and excessive use of itdecrease yield and quality of products and increasing pollution of the environment. Humic substances are contained nutrients that improve the soil nutrients and increases the availability of food and therefore plant growth and yield. Studies haveshown that to adding a certain amount ofhumic acid fertilizer with nitrogen can improve the growth of roots, stems and leaves and enhances the yield and quality of products and increases the efficiency of nitrogen fertilizer consumption. On this basis, this research was performed aimed at achieving the best combination of treatments of humic acid and its application method and nitrogen in improving strawberry vegetative and reproductive growth cv. Paros.
Materials and Methods: This study was conducted in the campus of Agriculture and Natural Resources University of Mohaghegh Ardabili at during 2015-2016. In early september, land preparation was carried out, and then were calculated base fertilizers 150 and 50 kg.ha-1 of potassium and phosphorus, respectively plus forty tons per hectare of manure. Stacks was prepared to dimensions of 1.5 × 1 m and the distance of rows was 40 cm. Strawberry seedlings were planted with distance of 25 cm on the row (10plants m-2)in late November.
The experiment was carried out as a split split plot based on complete randomized block design with the application of foliar and soil treatments of Humic acid levels (control, 2, 4 and 6 kg.ha-1) and nitrogen fertilizer (50, 100 and 150 kg.ha-1) with three replications. Nitrogen levels were placed in the main plots and the type of humic acid application in sub plots and humic acid concentrations in the sub- sub plots. Half of N(urea fertilizer) was used at the time of planting and 25 %on the early may and 25 %on the early June. To apply foliar and soil treatments, humic acid was used (Humaster tob with 85% of humic and fulvic acid, Yazd Golsangkavir Company) with the start of the growing season at the intervals of every 10 days once (four times total). In the soil method, humic acid is measured based on the desired treatments and then dissolved with deionized water and added to irrigation water. In the foliar method, after irrigation thehumic acid powder was solutioned with a certain amount of deionized water and it was sprayed on the plants in equal measure. In addition, only irrigation water and deodorizing water were applied to the control of soil and foliar treatments, respectively. Traits were as: leaf number and area, number of runners, fresh and dry weight of shoot and root, root volume, number of flowers and fruits, fruit weight average and yield per plant. Data analysis were performed by using SAS 9.1 and comparison of data by the LSD test at the 5% probability level.
Results and Discussion: All results due to different concentrations of nitrogen, humic acid and methods of its application and their interaction on most traits were significant at 5% probability level. The highest values in the leaf number (17.91) and area (1304.34 cm2) obtained in 6 kg.ha-1 drench application of humic acid. Also,the most number of flowers (13.27) was observed in 100 kgN.ha-1combined with foliar application of humic acid and the highest number of runners (22.34) was obtainedin 150 kgN.ha-1with drench application of humic acid. The most flowers (17.55), fruits (14.5) number and yield (104.43 g.plant-1) observed in 100 kgN.ha-1with 4 kg.ha-1humicacid. The results trilateral interactions of nitrogen,humic acid and application methods showed that the highest values of fresh weight (48.32 g.plant-1) and volume (44.13 cm3.plant-1) of root, dry weight of shoot (21.08 g.plant-1) and root (16.28 g.plant-1) obtained infoliar application of 4 kg.ha-1humic acid.The most of shoot fresh weight (77.7 g.plant-1) also observed in drench application of 4 kg.ha-1humic acid and highestfruit weight average (11.68 g) obtained in foliar application of 2 kg.ha-1humic acid with 100 kgN.ha-1.
Conclusion: Results showed that the majority of evaluated traits, the highest values have been achieved of 100 kgN.ha-1with foliar application of 4 kg.ha-1humic acid. On this basis, combined application of chemical and biological fertilizers can be the best strategy to achieve sustainable agriculture and reducing the pollution of soil and water resources along with increasing the product.
