Yahya Selahvarzi; Maryam Kamali; Jafar Nabati; Hamid Ahmadpour Mir
Abstract
Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to ...
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Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to their cells, tissues, and organs. Research has shown that by altering membrane properties during cold stress, metabolic balance is disturbed and with the increase in toxic metabolites, secondary damage to the plant can occur. At low temperature, decreases the efficiency of energy transfer to the center of the photosystem II. In addition, low temperatures are the main cause of the formation of reactive oxygen radicals. Also, lowering the temperature in the presence of light, due to the imbalance between light absorption and photosynthesis, increases the risk of light oxidation. Low temperature also reduces the activity of Rubisco. The amount of free proline in many plants increases significantly in response to environmental stresses such as frost stress, and stabilizes the membrane during cold stress.On the other hand, the use of some organic materials such as organic mulches increase temperature of the soil, and thus helps plant from frostbite. Use of organic mulch is widespread in agriculture due to the positive effect in soil temperature, weed control and moisture retention. Also, these mulches are effective in height, growth and flowering, early maturity and total yield of the products. Mulches in the warm seasons reduces soil temperature. Use of mulch can also help plants to withstand frostbite. Organic mulch decomposition in appropriate temperature and humidity conditions, liberates the nutrients gradually and provides for root plant and microorganisms of the soil. Organic mulches can reduce the effect of salt toxicity on plant growth and actively increase soil desalination. The most important benefit of mulch is the increase in soil temperature in the seed area, which accelerates the growth and yield of the product. Use of straw as mulch resulted in accelerated germination in cucumber. Use of straw mulch leads to an increase in temperature at night, thus protecting plants from temperature stress that has a positive effect on the growth and development of wheat.
Material and methods: In order to investigate the effect of freezing stress and using different types of organic mulch for Aquilegia plant, this experiment was conducted as a factorial experiment based on completely randomized design with four replications at Faculty of Agriculture, Ferdowsi University of Mashhad. The experimental treatments included four types of mulch (control (without mulch), 50% soil + 50% manure, 50% soil + 50% leaf needle + 50% soil + 50% rice bran) and five levels of freezing temperature (0, -5, -10, -15 and 20). Characteristics such as percentage of electrolyte leakage, relative water content, chlorophyll index and total chlorophyll, leaves number, leaf area, plant dry weight and proline leaf content were considered.
Results and Discussion: The results showed with decrease of temperature from 0 to -20 °C, stem diameter, leaf area and leaf number in bran mulch treatment decreased by 42.6%, 73.4%, 21.2% respectively, also stem diameter, leaf area and leaf number in mulch of leaf needle were 35.2%, 9/64%, 47.6%, in manure mulch were 20.20%, 46.4%, 7.8% and in the control of mulch decreased, 32.8%, 79.7%, 30.7%, respectively. At -5 °C, the amount of proline was 26% in the leaf and at -20°C, the amount of proline increased 50% compared to the control. Also, the lowest proline (0.73 μmol / g fresh weight) was obtained from the plants that treated with bran mulch. With application of, electrolyte leakage reached 63.6%, 68%, 61% and 57% in control conditions bran, needle and manure, respectively. In short, the least electrolyte leakage was observed in manure. On the other hand, when temperature dropped from 0 to -20 °C, the percentage of electrolyte leakage increased in Aquilegia. Relative water content of the leaf were 24% at 0°C, 38% at -15 °C and 23% at -20 °C. In terms of non-use of mulch, the relative water content was 36% and reached a 42% and 40% with application of manure and needle using mulch. By measuring the total carbohydrate found in Aquilegia leaf, it was observed that the amount of this trait was increased under frost stress. In general, although frost stress reduced the morphological traits of Aquilegia, use of organic mulch resulted in the improvement of these traits. The best results were observed in manure mulch.
Jafar Nabati; Elahe Boroumand Rezazadeh; Mohammad Zare Mehrjerdi; Mohammad Kafi
Abstract
Introduction: Conventional seed programmes take more than 10 years and diseases during each round of field multiplication become increasingly common and especially those transmitted through seed tubers. In contrast, the production of large volume of propagation material in protected environments requires ...
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Introduction: Conventional seed programmes take more than 10 years and diseases during each round of field multiplication become increasingly common and especially those transmitted through seed tubers. In contrast, the production of large volume of propagation material in protected environments requires only a few additional years of traditional seed multiplication in the field to produce the desired seed with an improved health status. This is useful especially in countries where there are no vector-free production areas for producing high quality potato seed tubers. In the last few decades, alternative seed production programmers have been developed in which the first multiplication steps are speeded up using in vitro plantlets, microtubers or minitubers. In the area of controlled environment agriculture (CEA), one of the most commonly discussed topics is lighting. The lighting system is generally the most expensive component of a controlled environment agriculture facility in terms of upfront costs as well as ongoing expenses (electricity use as well as replacement lamps). Naturally, advances in lighting technology are of great interest to the controlled environment agriculture community for these very reasons. Light emitting diodes (LEDs) are the most recent lighting technology to enter the controlled environment agriculture arena and have great potential to improve performance and reduce the overall cost of controlled environment lighting. Growth and morphogenetic effects of light (quality, intensity, and duration) and phytohormones are well documented, but their modes of action and mutual interactions are far from clear. One of the important questions is whether at least some of the morphogenetic effects of light are mediated by changes in phytohormone levels. This experiment was conducted in order to study the effect of different light sources on morphology and growth of potato plantlets under in-vitro conditions and their effect on minituber production in greenhouse to decrease energy consumption and production costs.
Materials and Methods: A factorial experiment was conducted based on completely randomized design with six replications under in-vitro conditions and four replications in greenhouse. Factors were consisted of cultivars (cv. Agria and Savalan) and light sources (LEDs emitting red, blue, white, combination of red and blue and also tubular fluorescent lamps as control). The experiment was carried out at the tissue culture laboratory of Yeka Seed Technology of Iran. Disease-free potato in vitro plantlets of Agria and Savalan cultivars were derived from the potato germplasm bank of Agricultural Biotechnology Research Institute of Iran. The plantlets were propagated using single-node cutting. Eight explants were cultured in sterilized culture vessels containing 30 ml of MS and pH was set to 5.8 before adding agar and autoclaving. Culture vessel were closed with polycarbonate caps and sealed with household plastic foil and were placed in a growth chamber at 24 °C and 16 h photoperiod for 4 weeks.
Results and Discussion: Results indicated that red spectrum caused an increase in plantlet height and Agria had a higher plantlet height under in-vitro conditions. Root length was higher in red-blue combination and no difference was observed between cultivars under in-vitro condition. The highest and lowest leaf area was obtained in white and red spectrum, respectively. Also, Savalan showed a higher leaf area in comparison with Agria. The lowest node number in plantlets was observed in red spectrum and the highest in white. The highest and lowest internode length was related to red and blue spectrum, respectively. Fluorescent light was resulted in the lowest plantlet fresh weight and no significant difference was observed among other treatments according to this parameter. Stem diameter and number of branches was not affected by different lights. Results of greenhouse study indicated that light conditions before transplanting of plantlets did not affected minituber number, while minituber weight was significantly affected by this factor and the lowest mean of this parameter was obtained in red spectrum compared to the other treatments.
Conclusion: Generally, results showed that less leaf area plantlet in vitro was also less leaf area in greenhouse (red light emitting diode). Leaf area is an important criteria for photosynthetic and biomass production. Therefore, in this experiment fresh and dry matter production was affected by this characteristics and red light showed the lowest dry matter production. LEDs could be considered as suitable light sources producing plantlets comparable with those grown under fluorescent light under in-vitro conditions along with saving energy and ultimately lower production cost.
Reyhane Setayesh; Mohammad Kafi; Jafar Nabati
Abstract
Introduction: The population growth and water requirement for domestic consumption, industry, agriculture and urban development in Mashhad megacity, increase pressures on freshwater resources. Therefore, planning for water use optimization is necessary. The new allocation of water resources for landscape ...
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Introduction: The population growth and water requirement for domestic consumption, industry, agriculture and urban development in Mashhad megacity, increase pressures on freshwater resources. Therefore, planning for water use optimization is necessary. The new allocation of water resources for landscape greenish, especially in arid and semi-arid is difficult. Therefore, water allocation to landscape is valuable and should be used efficiently. According to water resource limitation, using drought-tolerant plant species and determine threshold of drought tolerance in landscape can improve water use management. Plants that naturally survive in your area are the ones best adapted to your soil, climate and rainfall. By selecting plants that either avoid or tolerate dry conditions, a beautiful, thriving landscape can be made possible. Drought-tolerant plants survive long periods of drought by storing water internally or by developing extensive root systems that sink deep into the soil. Many drought-tolerant plants have additional protection through a waxy coating that reduces evaporation or hairs on the leaf surface that reflect some of the light, insulating the plant. Most drought-tolerant plants use several of these features to survive on low amounts of precipitation. Japanese barberry is a compact woody deciduous shrub with arching branches. Leaf colours include green, bluish-green to dark red and purple. B. thunbergii's progress in the United States has, to date, been held in check to the south by, probably, its need for cold winter temperatures for stratification of the seeds, and to the west by, probably, drought conditions. Although very drought tolerant once established, a very dry terrain would tend to discourage its incursion. Rugged, adaptable, no serious problems or pests, easy to maintain, transplants readily, shade and drought tolerant, deer resistant is typical ad copy found at any site offering this shrub of colourful fall foliage. In this regard, drought stress tolerance thresholds of ornamental barberry plant in Mashhad landscape were evaluated.
Materials and Methods: In order to determine the qualitative and quantitative drought stress tolerance thresholds of ornamental barberry (Berberis thunbergii) plant an experiment was conducted basis on randomized complete block design with three replications in Plant Production Complex of Mashhad Municipality. Treatments included; 100, 80, 60, 40, and 20% of culculated water requirements based on evaporation pan data. Two years old plants with similar size were transplanted from pots to field in 16 March 2012. Treatments were applied after establishment in 28 April and sampling was arranged in 6 August, 23 August, 6 September, and 7 October. During the growing season, the evaporation level was daily measured from pan Class A. In each sampling two plants sampled randomly from each plot for measuring the plant height, highest branches, number of branches, fresh and dry weight, dry mater percentage, irrigation water use index and freshness index.
Results and Discussion: Results showed that with increasing severity of drought stress plant height of barberry reduced significantly, but there were no significant difference between 100 and 80% of water requirement treatments. The highest branches reduced by diminishing water application volume but there were no significant difference among 100, 80 and 60% of water requirement application. The maximum of branch number was observed at 60 percent water requirement, however, there were no significant difference between 100 and 60% of water requirement treatments. The number of branches in 60% was 26% lower than 80% of water requirement. Therefore, application of 60% water requirement with 23 branches per plant produced highest branch number. The highest and lowest plant fresh weight was measured in 100% and 20% water requirement application, respectively. Application of 60% of water requirement produced statistically on the same biomass production of 100% of water requirement application. The lowest freshness index was observed in 20 and 40% of water requirement, but there were no significant difference among 60, 80 and 100% of water requirement applications.
Conclusion: Generally, results showed that ornamental barberry plant is a drought resistant plant and it can be alive by only 20% of its water requirement application, but for having freshness ornamental barberry in urban landscape, at least 60% of its water requirement should be applied. Based on the present results, water application of ornamental barberry could be reduced to 60% of calculated water requirement. It could be saved water application of barberry up to 4400 m-3.ha-1 in a growing season in Mashhad condition.
Saeid Khaninejad; Hamidreza Khazaie; Jafar Nabati; Mohammad Kafi
Abstract
Potato is one of the most productive crops in agriculture and is a valuable food source in developing countries. Mycorrhizal fungi involve a symbiosis with most of crop roots and leads to improve the crops growth and yield. In order to investigate the effect of mycorrhiza fungi species on yield of potato ...
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Potato is one of the most productive crops in agriculture and is a valuable food source in developing countries. Mycorrhizal fungi involve a symbiosis with most of crop roots and leads to improve the crops growth and yield. In order to investigate the effect of mycorrhiza fungi species on yield of potato cultivars a factorial experiment was arranged in a randomized complete block design with eight treatments (seven mycorrhiza fungi species and control treatment) on two potato cultivars, Agria and Fontane, in three repetitions. Results show that there is no significant difference in tuber yield and shoot P content in Agria and Fontane, but leaf area and shoot dry weight and total tubers weight in Fontane were higher than Agria. Control treatment and A. longula had the least and G. mosseae، G.intraradices and G. versiform had the highest tuber weights. Among fungi G. mosseae produced the highest tuber yield in both cutivars. Inoculation of root medium with G. versiform produced the highest average tubers weight compared to other treatments. Phosphorus content of treated plants with mycorrhiza was higher than control.
Morteza Goldani; Yahya Selahvarzi; Jafar Nabati; Morteza Alirezaie Noghondar
Abstract
Salinity is one of the environmental stresses that have limited influence on the crop growth. Oxidative process is a secondary stress due to salinity. Oregano is enumerated as one of the most important of medicinal plant that its production and development is possible in Iran. In order to study the effect ...
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Salinity is one of the environmental stresses that have limited influence on the crop growth. Oxidative process is a secondary stress due to salinity. Oregano is enumerated as one of the most important of medicinal plant that its production and development is possible in Iran. In order to study the effect of exogenous application of hydrogen peroxide on salt tolerance in oregano (Origanum majorana L.) an experiment was conducted in greenhouse conditions. This study was designed as factorial based on completely randomized design with 3 replications. Different concentration of hydrogen peroxide (0, 2.5 and 5 mM) and four levels of NaCl (0, 50, 10 and 150 mM) were treated in this study. Results showed that foliar application of hydrogen peroxide can improve shoot and root dry weight and alleviate adverse effects of salinity. In the other hand, high concentration of hydrogen peroxide (5mM) increased total chlorophyll and caroteoid content about 46.6 and 100.6 percent comparing to control plant, respectively. Salt stress had no significant effect on cellular hydrogen peroxide, but it increased free proline and reduced K:Na ratio. While hydrogen peroxide content, free proline and K:Na ratio were increased 104.6, 320.7 and 77.8 percent by high level of hydrogen peroxide, respectively. The final result showed that foliar application of hydrogen peroxide decreased salt stress.
