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

Citrus fruits are one of the most commercial fruit products in the world, whose growth and production are affected by abiotic stresses. Drought stress is one of the most important abiotic stresses that affects all the vital processes of the plant. One of the ways to moderate the negative effects of drought stress is the use of polyamines. Polyamines are a group of biochemical compounds that are used as one of the most effective compounds to resist environmental stresses. Polyamines have a wide role in various plant growth processes, such that they play a significant role in modulating various types of biotic and abiotic stresses. Studies have shown that application of putrescine increases the fresh and dry weight of the shoot and root parts, leaf relative water content, photosynthetic pigments, leaf surface, and photosynthesis in plants under drought stress.

This study was conducted to investigate the effect of different levels of putrescine (0, 0.5, 1 and 2 mM) and different levels of irrigation (100, 75 and 50% of evotranspiration potential) on morpho-physical traits of lime seedlings as a factorial experiment based on randomized complete block design with 3 replications. Two-year-old lime seedlings were obtained from a commercial nursery located in Dezful city (approved by the Khuzestan Agricultural Jihad Organization). Then, they were located in 15-kilogram pots and kept for 2 months in the greenhouse to adapting to the environmental conditions. In order to apply the irrigation regime, 4 pots were considered as reference plants and the amount of irrigation water was determined by weighing these pots. First, the weight of reference pots was calculated in field capacity mode. Then, after 7 days, the pots were weighed again and the difference between the primary and secondary weights was considered as the amount of irrigation water of 100% plant evaporation and transpiration, and according to that, 75% irrigation and 50% evaporation and transpiration potential were applied. The first foliar spraying with putrescine was done at first of March in Field capacity (foliar spraying was done once every month for 4 months from March to June). At the end of the experiment, the fresh and dry weight of root and shoot, number of leaves, relative water content, leaf water potential, photosynthesis, transpiration, stomatal conductance, were measured. Statistical data analysis was done using MSTATC software and, Duncan's multi-range test was used to mean comparation at the 5% probability level.

Results showed that the rate of photosynthesis, stomatal conductance, relative water content of leaves, fresh and dry weight of aerial part and root decreased by reducing the amount of irrigation from 100 to 75 and 50%, of ETcrop. The reduction of growth parameters under drought stress can be due to the closing of the stomata and the reduction of carbon dioxide emission into the leaves, which can lead to lower levels of chlorophyll and photosynthesis, induction of oxidative stress, and finally less growth in plants. It has also been stated that the decrease in growth caused by drought stress in the initial stages of the stress can be due to the decrease in cell growth and development due to the decrease in turgor pressure and the decrease in the intensity of photosynthesis due to the closing of stomata. Also, the results showed that foliar spraying with 2 mM putrescine increased photosynthesis, stomatal conductance, relative water content of leaves, wet and dry weight of aerial parts and roots at all irrigation levels. The researchers believed that the increase in growth parameters, relative water content and photosynthetic pigments with putrescine foliar spraying can be related to the antioxidant properties of putrescine and its osmolality role in dry conditions. Other researches have shown that putrescine may modulate certain ion channels and increase the permeability of the membrane to calcium and cause a decrease in the entry of potassium into the membrane, which causes a decrease in the exit of water from the cell. Also, putrescine may increase leaf water potential and leaf content through osmotic regulation of the plant by increasing proline.

In general, the results showed that foliar spraying of putrescine, especially at 2 mM concentration has the greatest effect on increasing growth parameters, including fresh and dry weight of shoots and roots, leaf area, increasing the relative water content, leaf water potential and Gas exchanges and reducing the amount of ion leakage under drought stress conditions.

Drought stress is the most important abiotic stress that affects the growth and development of plants. One of the strategies for soil moisture management and plant tolerance to drought stress is the use of organic materials compatible with the environment, including superabsorbent polymers. In order to investigate some morpho-physiological and biochemical characteristics of Acacia seedlings, this research was conducted with three types of superabsorbent polymers (A200, SNF and Barbary) at three concentrations (0, 1 and 2 g/kg) at three levels of drought stress (one week, two weeks and three weeks irrigation intervals). This experiment was factorial in randomized complete block design with three replications under field condition. The results showed that drought stress caused a significant decrease in fresh and dry weight of shoot, photosynthesis, transpiration, relative water content, chlorophyll and carotenoid content and significantly increased ion leakage, proline and total carbohydrates. The application of superabsorbent polymers increased the tolerance of Acacia to drought stress so that the use of 1 g/kg Barbary superabsorbent polymers in the first week had the highest shoot fresh weight (144 g) and the amount of chlorophyll (1.73 mg/g fw). in the first week, the use of 1 g/kg A200 superabsorbent polymer increased the rate of photosynthesis by 5.48% and the use of 2 g/kg A200 increased the rate of transpiration by 41.66% and the relative water content of leaves by 11.06% compared to control (0 gr/kg A200). Also, in the first week, the use of 2 g/kg SNF super absorbent increased the amount of carotenoids by 36.58% compared to 0 g/kg SNF. The use of 2 g/kg A200 in the third week reduced ion leakage by 22.50% compared to 0 g/kg A200 in the first week. The use of SNF superabsorbent at a concentration of 1 g/kg in the first week reduced the amount of proline by 22.08% compared to 0 gr/kg SNF. Therefore, the use of superabsorbent polymers especially Barbary increases the tolerance of Acasia to drought stress.

Phalaenopsis amabilis with facultative CAM photosynthetic mechanism is one of the most valuable ornamental plants in the world. This plant's most common method of propagation is through its in vitro culture. In tissue culture plants, photosynthesis is strongly affected by many factors. The role of photosynthesis of in vitro plantlets in their performance and acclimation is still unknown. In the present study, photosynthetic performance was investigated based on gas exchange and fluorometry in Phalaenopsis under in vitro conditions for two periods, including short-term (2 weeks) and long-term (8 weeks), and four times of recording during the day. The aim was to investigate the stomatal and photosynthetic behavior of Phalaenopsis plantlets under these conditions. According to the obtained results based on the gas exchanges and chlorophyll fluorometry, the rate of photosynthesis and the quantum yield of plantlets in vitro significantly affected the ability of plantlets to regenerate and create relative adaptation in plant cells under high humidity conditions. Photosynthetic and quantum performances in the long-term culture period were better than their performance in the short-term, while non-photochemical quenching (NPQ) and heat loss were decreased in the plantlets grown in the long-term culture period. The total chlorophyll and carotenoid content were also higher in the long-term than in the short-term. The performance of the stomata was disturbed due to high humidity for a long-term period. So, the effect of the stomata on photosynthesis in the plantlets was almost ineffective under in vitro conditions. Therefore, the finding showed flexibility, better photosynthetic and physiological performance for Phalaenopsis plantlets under in vitro conditions, and better adaptation to stress.

 Light is the main environmental factor for plant growth and development. Different attributes of light such as intensity, quality and duration affect plant growth and productivity. Light spectrum of growing environment is a determinant factor for plant growth and photosynthesis. The photosynthetic reactions are directly affected by various light parameters including its spectrum and intensity. Photosystem I and II (PSI and PSII) in the electron transport chain of photosynthetic apparatus are involved in converting solar energy to chemical compounds in plants. It has been found that the PSII is sensitive to light quality. Using The OJIP test, we can investigate the efficiency of various biological phases of the electron transport system. Light sources such as metal-halide, fluorescent, high-pressure sodium, neon lamps and light-emitting diode (LED) can be used for production of plants in closed environments instead of sunlight. Manipulation of the light spectrum of the lamps could trigger potential benefits by enhancing plant growth. Nowadays, by using the LED technology, it is possible to study the physiological effect of different light spectra for optimization of growth conditions and for increase the production of plants in controlled environments. This research was conducted to investigate photosynthetic apparatus, growth parameters, stomatal characteristics, transpiration rate and essential oil content of Salvia officinalis under different light spectra.
 
 In this study, the effects of different light spectra were implemented and performed as a pot experiment using soilless media in the plant growth chamber based on a completely randomized design with 6 lighting spectra including White, Blue, Red and three combinations of R and B lights (R30:B70, R50:B50 and R70:B30) with three replications. The light intensity in all growth chambers was adjusted to photosynthetic photon flux density (PPFD) of 250 ±10 μmol m-2s-1 and light spectrum were monitored using a sekonic light meter (Sekonic C-7000, Japan). Growth condition was set at 14/10 h day/night cycles, 25/22oC day/night temperatures and 40% relative humidity. Three month following plant growth under different light spectra, the plants were evaluated for their growth parameters, stomatal characteristics (stomatal length, stomatal width, pore length or aperture) transpiration rate (E), relative water content (RWC), photosynthetic apparatus (evaluation of OJIP) and essential oil content. Data analysis of variance (ANOVA) was performed using IBM SAS software (Version 9.1) and the differences between means were assessed using Duncan’s multiple range tests at p≤ 0.05.
 
 The results showed that the stomata characteristics, photosynthetic performance, growth characteristics and essential oil content of Salvia officinalis were affected by different light spectra. Increasing the ratio of red light especially combined Red and Blue lights (R70:B30) led to the improvement of growth characteristics. Transient induction of chlorophyll fluorescence showed that the highest fluorescence intensities at all OJIP steps were detected in Red light. The lowest Fv/F0 and Fv/Fm were obtained in plants grown under Red light. Occurrence of leaf epinasty and decrease in Fv/Fm indicative of phenomenon of red light syndrome in the plants under Red treatment. Red light caused a reduction in performance index per absorbed light efficiency of (PIABS) and increase in quantum energy dissipation (ΦD0), light absorption (ABS/RC) and electron trapping (TR0/RC) per reaction center. The highest Fv/F0, Fv/Fm and PIABS were obtained under combination of Red and Rlue light. The highest ΦE0 was also detected in combination of Red and Blue light. The narrow and large stomatal apertures were detected under Red and Blue light, respectively. The highest transpiration rate was achieved in plants grown under Blue light LED. Increasing the ratio of Red light resulted in reduction in transpiration rate and improvement of leaf capacity to control water loss via reducing the opening of stomata. The highest amount of essential oil (1/75% v/w) was achieved in plants exposed to combination of Red:Blue light spectra (R70:B30).
 light spectrum during plant growth can change plant metabolism, LED can be used in favor of producing good-quality food in controlled environment agriculture due to their ease of application, waveband manipulation and limited heat production. Our result showed that photosynthetic apparatus, growth parameters, stomatal characteristics, transpiration rate, relative water content and essential oil content of plants were considerably influenced by light spectra. Using OJIP test confirmed that plants grown under monochromatic Red and Blue lights were less efficient to successfully transfer the excitons and most of the absorbed energy by the photosystems was dissipated as heat. In conclusion, combined Red and Blue lights (especially R70:B30) caused favorable growth, photosynthetic functionality and maximum essential oil content of Salvia officinalis. Therefore, combination of R and B lights (R70:B30) should be considered for production of Salvia officinalis under artificial light systems during commercial controlled environment production of plants.

One of the research requirements in agriculture is to find a new and practical method for sustainable production that brings the highest efficiency and the least harm to humans and the environment. In order to investigate the effect of different levels of carbon dioxide and ethanol foliar spraying on the physiological and biochemical characteristics of basil (Ocimum basilicm cv. Keshkeni luvelou), a factorial pot experiment based on a completely randomized design with three replications was conducted in the research greenhouse of the Department of Horticultural Sciences and Landscape of Ferdowsi University Mashhad in 2018. The factors included ethanol spraying at 4 levels (0, 10, 20, and 30% v/v) and carbon dioxide at 3 levels (380, 700, and 1050 µmol mol−1). The results showed that the highest relative water content (RWC) of leaf, photosynthesis rate, transpiration rate, stomatal conductance, and leaf protein were observed in the treatment of 20% v/v ethanol foliar application with the application of 700 µmol mol−1 of carbon dioxide, as they increased by 45%, 295%, 684%, 83%, and 328% compared to the control, respectively. Fresh and dry biomasses of shoot parts increased significantly with increasing carbon dioxide concentration and ethanol spraying. Thus, the highest fresh and dry biomasses of shoot parts were obtained in foliar spraying of 30% v/v of ethanol and 700 µmol mol−1 of carbon dioxide which increased by 176% and 76%, respectively, compared to the control. The highest activity of polyphenol oxidase and guaiacol peroxidase, stomatal resistance, and electrolyte leakage were related to spraying 30% v/v of ethanol with an application of 1050 µmol mol−1 of carbon dioxide which showed an increase of 2%, 4%, 65%, and 76%, respectively, compared to the control. Overall, the results showed that foliar spraying of 20 and 30% v/v of ethanol along with the application of 700 µmol mol−1 carbon dioxide had the greatest effect in increasing photosynthesis and finally the fresh and dry biomasses of basil.

In this study, the possibility of growing greenhouse tomato cv. Dafnis with saving water consumption through grafting on different rootstocks was investigated by studying photosynthesis and plant growth. The experiment was carried out in the form of split plots based on completely randomized design in which the main-plot was irrigation levels (irrigation intervals of 3, 6 and 9 days) and the sub-plot consisted of 9 different grafting combinations. After grafting and establishment of tomato plants in greenhouse, the plants were exposed to the irrigation levels for 4 months and all were irrigated up to field capacity. Photosynthesis parameters were measured in four stages and shoot and root dry weights were determined at the end of the experiment. Based on the results, photosynthetic parameters were reduced by the intensity and duration of drought stress. The experimental results showed that the rate of photosynthesis was the same in all grafting combinations 36 days after the start of irrigation levels. However, after 72 days, the rate of photosynthesis in the “Emperador” rootstock was higher than in the control. The chlorophyll fluorescence indices were not sensitive to show the effects of drought stress and the role of rootstocks. Cherry tomato rootstock, in addition to having an extensive root system than the other rootstocks, resulted in more shoot growth at all levels of irrigation, although the least reduction in root weight was observed in the local eggplant rootstock of Yazd. In general, it can be concluded that the photosynthesis in this experiment was more affected by the interaction of environmental factors and grafting and the rootstocks used did not play a significant role in this regard. Furthermore, root and shoot growth traits were more affected by genetic potential of rootstock, and photosynthetic activities of the plant had a minor influence on them.

Cherry (Prunus avium L.) is one of the best fresh fruits, which has a special place and importance in the Iranian fruit industry. Considering the rich germplasm of the Cerasus subgenus in Iran, knowledge of the genetic potential of this subgenus is important for identifying gene reservoirs and developing effective strategies for germplasm conservation. In this study, the seedling of some genotypes in the Cerasus subgenus P. avium, P. microcarpa, and P. incana species was assayed in full and without irrigation conditions performing physiological analysis in response to stress. From a genomic point of view, the genetic diversity of these genotypes seedlings was assessed using simple-sequence repeat markers (SSR). Morphologically, P. microcarpa species showed lower leaf area, height, and diameter compared to P. incana and mainly P. avium. Photosynthesis in seedlings decreased during drought stress, but this decrease was more in Avi-Ala 11 (5,500 µmol CO2 m-2 s-1) compared to Inc-Kho (10,760 µmol CO2 m-2 s-1) and Mic-Kor 3 (10,340 µmol CO2 m-2 s-1). Our results show that both P. microcarpa and P. incana species can be considered drought-resistant rootstock in cherries and a possible genetic source for drought breeders. The results of this research can also help to determine the relationship between phenotypic and genotypic data for the identification of molecular markers associated with drought tolerance.

 Different aspects of light including intensity, quality (spectra), and duration (photoperiod) can influence plant growth and development. The growth and development of ornamental plants are also influenced by light intensity and quality. Energy saving in greenhouse production has received much attention lately. One reason for the interest in utilizing light quality to modulate plant growth and morphology is the recent development of light-emitting diodes (LEDs) as a lighting source in greenhouse production. Such small diodes can easily be placed close to the canopy and can be used to apply a narrow-band light spectrum to the plants. Specific requirements for light spectral distribution for specific processes like morphogenesis, photosynthesis, chlorophyll and anthocyanin synthesis have been determined in different species. The aim of the current study was to investigate the biophysical properties of chlorophyll fluorescence of Hypoestes phyllostachya plants in response to different light spectra

 Research experiments were conducted on Hypoestes phyllostachya in a completely randomized design with six treatments of different light quality and three replications. The seeds were planted in plugs and in a mixture of 70% peat moss and 30% perlite. Seedlings were grown in natural greenhouse (control) and LED (100% Blue, 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White and 30% Blue +50% Red + 20% White). Since the main goal of the study was to compare the effect of LED light quality with sunlight in conventional greenhouse conditions. The LED treatments were applied from fourth month old seedlings until five weeks in a growth chamber with the light/dark regime of 15/9 hours, 23±5°C temperature, and 65±5% relative humidity. While, their pots in the greenhouse with 55±5 mol.m-2.d-1 DLI, 21±5°C average daily temperature and 65±5% relative humidity (Data logger 8808 temp. + RH) were regarded as the control treatment. After five weeks, the fluorescence chlorophyll was measured.Selected leaves were dark-adapted prior to the measurements and OJIP protocol was applied using a fluorometer (FluorPen FP 100-MAX, photon system instruments, Drasov, Czech Republic). The fluorescence measurement was performed using a saturating. FluorPen software was used to extract data from the original measurement. Data extracted were used to analyze the following data according to the equations of the JIP test: fluorescence intensities at 50 μs (F 50 μs, considered as the F0), 2 ms (J-step denoted as FJ), 60 ms (I-step, FI), and maximum fluorescence intensity (FM, FP). The JIP-test was used to quantify the amount of energy that flow via the PSII. Performance index was measured on the absorption basis (PIABS, a multi-parametric expression). Probability that a trapped exaction promote an electron in electron transport chain (ETC) beyond the primary acceptor Quinone (QA−), maximum quantum efficiency of PSII (FV/FM), specific energy fluxes per reaction center (RC) for energy absorption (ABS/RC), trapped energy flux (TR0/RC), electron transport flux (ET0/RC) and dissipated energy flux (DI0/RC) were calculated according. Finally, the data were statistically analyzed with SAS (9.4) software package, and the means were compared by LSD test at p < 0.05 level.  

 Fast Chl fluorescence induction curves (OJIP) was the main parameters used for the screening of different light treatments. OJIP test is shown to be a proxy to detect PSII bioenergetics and indicates changes in the status and function of PSII reaction centers, antenna, as well as in donor and acceptor sides of PSII. The maximum quantum yield of PSII (FV/FM) and relative maximal variable fluorescence (Fm/F0), significantly increased in 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White. PIABS, one of the OIJP test parameters that provide valuable awareness about photosynthtic performance, considerably decreased under control and 30% Blue +50% Red + 20% White treatment. Unlike PIABS, ET0/RC did not show a significant difference under different treatments. The specific energy fluxes per RC for energy absorption (ABS/RC) significantly increased under control and 30% Blue +50% Red + 20% White treatment. TR0/RC increased in plants under control and 30% Blue +50% Red + 20% White treatment. Treated plants under 15% Blue +85% Red and 30% Blue +70% Red showed the lowest in dissipated energy flux (DI0/RC).  During an ideal condition without any additional stress, the total PSII pool can be completely inactivate and retrieve without a detectable photoinhibition.Conclusion When plants exposed to 100% Blue and 30% Blue +50% Red + 20% White treatments as well as in control plants, FM/F0, FV/FM and PIABS significantly decreased.  Also ABS/RC, TR0/RC and DI0/RC, significantly increased.

The aeroponic system is a promising technique for the future of agriculture, growing plants in an air or mist environment without the use of soil or an aggregate medium. In aeroponic, plants are suspended in a closed or semi-closed environment by spraying the plant's dangling roots and lower stem with an atomized or sprayed, nutrient-rich water solution (30). Increased aeration of nutrient solution delivers more oxygen to plant roots in aeroponic in compare to conventional hydroponic systems, stimulating growth and helping to prevent pathogen formation (1). Cultivation of medicinal plants under controlled conditions of aeroponic and hydroponic systems commercially provides a better result in terms of quality improvement, bioactivity and biomass production (5, 4).Mint (Mentha) is one of the most important genus of Lamiaceae family. Different species of the genus have high economic value, due to their active and aromatic substances and are used as raw materials in food, cosmetics, health, beverage and pharmaceutical industries. M. piperita, M. spicata and M. suaveolens are the most common and popular species of the genus for cultivation. M. aquatica is also a perennial plant of the genus that is cultivated in Europe, North and Northwest Africa and Southwest Asia (2). Aeroponic system is more cost effective than other systems. Because of the reduced volume of solution throughput, less water and fewer nutrients are needed in the system at any given time compared to other nutrient delivery systems. However, due to lack of research and sufficient technical information, the use of aeroponic system is not common among farmers and greenhouse owners. In addition, many tips are not yet scientifically known about the cultivation of different plant species in this system (4). Despite the benefits of aeroponics, no research has been previously conducted on the cultivation of different species of mint in this system. Therefore, the present study was conducted with the aim of investigation of growth, yield and morpho-physiological characteristics of five mint species in the aeroponic system.

This study was conducted in greenhouses of faculty of Agriculture and Natural Resources of Lorestan University in 2020. The experiment was performed as a split plot design. Mentha species (including M. aquatica, M. pulegium, M. spicata, M. suaveolens and M. piperita) were considered as the main plot and harvest time (first and second harvests) was used as sub-plot. In each experimental block, one row (with ten plants) of five mint species was planted. In the early stages of growth, plants were fed with half Hoagland nutrient solution and then with complete Hoagland solution. Finally, morphological and physiological traits and some biochemical characteristics of plants were measured. After harvesting the first batch of plants and in order to better evaluation of species in the aeroponics system, all studied traits were measured about two months after the first harvest. Analysis of variance was performed based on the experimental design using SAS software. The comparison of means was also done with the least significant difference (LSD) test at the level of 5%.

The results showed that M. spicata and M. suaveolens had the highest leaf to stem ratio. The highest stem dry weight and plant height were related to M. pulegium. While, the highest leaf area, leaf fresh and dry weight, stem fresh and dry weight, stolon fresh and dry weight, shoot fresh and dry weight, total plant dry weight and relative water content were related to M. aquatic, followed by M. piperita. In addition, M. piperita had shown the highest fresh root weight. The highest amount of carotenoid and chlorophyll, photosynthesis rate and CO2 under the stomata was obtained in M. piperita. In this experiment, most of the yield-attributes traits including leaf area, leaf fresh and dry weight, root fresh weight, shoot fresh weight and total plant dry weight, as well as relative water content and photosynthesis rate were higher in the second harvest than the first one.

All studied species in this experiment were successfully growth in the aeroponic system. Due to high water use efficiency, no need for soil and high crop production, mint cultivation in the aeroponic system can be a healthy and profitable alternative to in soil cultivation approach. According to the results of the present study, M. aquatica has shown higher performance than other species in terms of the yield attributes traits (including leaf number, leaf area, fresh and dry weight of plant, fresh and dry weight of shoots and fresh and dry weight of leaves). Among the other species, the highest shoot dry weight and plant dry weight was obtained by M. piperita. Finally, the high potential of M. aquatica and M. piperita for cultivation in the aeroponic system can be concluded.

Olive consumption has been steadily increasing in recent years, due to the increase in consumption, attention to quality has become very important, so that researchers in various ways seek to maintain and improve the quality of the product of this plant. This experiment was designed and performed to investigate the effect of glycine betaine and salicylic acid on photosynthetic properties, macro elements, compounds in Leaf and fruit characteristics of three olive cultivars in a factorial experiment with three factors glycine betaine (water, 10 and 20 mM) and salicylic acid (water, 3 and 6 mM) and cultivars (Arbequina, Koroneiki and Conservolia). During this study were evaluated the flower characteristics, inflorescence, initial and final fruit formation percentage, fruit characteristics, Compounds in Leaf, photosynthesis, transpiration, chlorophyll and gas exchange. Proved the effect of glycine betaine, salicylic acid and cultivar on leaf elements and compounds was significant and the highest amount of total phenol observed in Koroneiki cultivar and 10 mM glycine betaine and 3 mM salicylic acid treatment. In the study of the effect of treatments on photosynthesis, transpiration, chlorophyll and gas exchange of leaves, it found that 20 mM glycine betaine treatment without salicylic acid and 10 mM glycine betaine combined with 6 mM salicylic acid had a positive effect on photosynthesis and water use efficiency. Finally, this study confirmed the increasing effects of glycine betaine and salicylic acid on indices such as leaf phenol, photosynthesis and water use efficiency under stress-free conditions.

To evaluate the response of Dracocephalum kotschyi Boiss. production to the livestock and chemical fertilizers, an experiment was conducted as a split plot with three replications in 2018 and 2019. The experimental treatments included the control (without fertilizer), chemical fertilizer, and different levels (100, 143, and 250 kg nitrogen ha-1) of poultry (PM100, PM143, and PM250), sheep (SM100, SM143, and SM250), and cattle (CM100, CM143, and CM250) manures. The traits including photosynthetic pigments, leaf area index, plant biomass, and percentage and essential oil yield were investigated. The effects of fertilizer, cutting, and the interaction of fertilizer and cutting were significant on all the triats. In the first cutting, the PM250 treatment produced more photosynthetic pigments than the chemical fertilizer. Also, the SM100 and CM100 treatments caused higher chlorophyll a and total chlorophyll compared to the chemical fertilizer. In the second cutting, the average photosynthetic pigments in the manure treatments were not superior to the chemical fertilizer. In the first cutting, the high level of livestock manures had a higher leaf area index compared to the chemical fertilizer, but in the second cutting, the medium and high levels of poultry manure and high level of sheep manure showed this superiority. In the first cutting, the all livestock manures treatments except CM100 produced the plant biomass similar to the chemical fertilizer, but in the second cutting, the PM143 treatment produced higher biomass compared to the chemical fertilizer. In the first cutting, the essential oil content of SM250 treatment was significantly superior to the chemical fertilizer. In the first cutting, the highest essential oil yield was obtained with the high level of livestock manures, but in the second cutting, there was no significant difference between the essential oil yield of different livestock manures levels and chemical fertilizer. In general, it could be concluded that the high level of poultry manure is a desirable alternative to the chemical fertilizer in D. kotschyi cultivation by creating the favorable conditions for the plant growth.

The physiological and biochemical traits of 12-year-old olive trees cvs. Zard and Direh were studied in response to thermal fluctuations during growing seasons in Tarom region (Zanjan province, NW of Iran) for two successive years 2017-2018. The experiment was carried out as split plots in time based on complete randomized block design (cultivar as main plot and time as sub-treatment). The sampling and data recording were performed during four different time including; May, July, August and September correspond to the 28, 45, 44 and 36 °C, respectively. The results showed that the photosynthesis rate of cv. Direh during stressful high temperature conditions at July, and in compare to May decreased two times more than cv. Zard. Cultivar Zard, in spite of its high photosynthesis rate, showed lower amount of cumulative shoot growth and dry weight, which was mainly due to the large amount of fruit yield efficiency in this cultivar. The proline accumulation in leaf tissue of ‘Direh’ failed to play a constructive role in developing higher heat stress tolerance in this cultivar. The soluble carbohydrates concentration in ‘Zard’ was higher than ‘Direh’ during all period of study. In general, cv. Zard had more tolerance to increased heat stress during growth season.

To study the effect of grafting on the tolerance of chilling and high temperature, the grafting of Super daminos was done on Cucurbita moschata (Isfahan), (Babol), (Ferro), (Sari) rootstocks and then compared with non-grafted and self-grafted ones as a factorial experiment based on completely randomized design with three treatments. Temperature treatments were optimum temperature (25 °C), low temperature (4 °C) and high temperature (40 °C), with four replicates. The results showed that root length, root volume, rootstock diameter, and fresh and dry weights of shoot were increased in all rootstocks, as compared with the non-grafted ones. The highest fresh and dry weights of the shoot were observed in Sari and Isfahan rootstocks, and the highest dry weight was observed in Ferro rootstock. The interactive effect showed that the highest fresh and dry weights were measured in Isfahan rootstock and at the optimum temperature; meanwhile, the lowest fresh and dry weights were observed in non-grafted one and at the high temperature. Moreover, the highest dry weight was determined at both low and high temperatures in the non-grafted sample. The highest photosynthesis rate was recorded in Babol rootstock and at the optimum temperature, while the lowest one was observed in Babol rootstock and at the high temperature. The interactive effect of rootstock and temperature showed that the highest stomatal resistance and transpiration rate were measured in the non-grafted sample and at the optimum temperature, while the lowest one was recorded in Isfahan rootstock and the optimum temperature; meanwhile, the lowest transpiration rate was observed in Sari rootstock and high temperature. Therefore, the use of Ferro and Babol rootstock for their resistances to high and low temperatures could be recommended. It seems, therefore, that these rootstocks by maintaining photosynthesis rate and chlorophyll and lowering transpiration rate, can decrease the deleterious effect of temperature on growth.

Organic substrate can increase crop productivity. This experiment aimed to improve the yield and growth parameters of sweet pepper (Capsicum annuum L. cv. ‘Gold flame’) by using three levels of modified Johnson’s nutrient solution (JNS), including full JNS as the control (NSc), 75% JNS (NS1) and 50% JNS (NS2) as well as three types of substrates that were based on three levels of vermicompost: vermicompost:perlite:cocopeat (1:1:1 v/v; V1) as the control, vermicompost:perlite:cocopeat (1:1:2 v/v; V2) and vermicompost:perlite:cocopeat (2:1:1 v/v; V3). Fruit fresh weight (86.18%) and dry weight (43.03%), root dry weight (68.63%) and root volume (43.67%), fruit diameter (12.39%) and yield (59.30%) increased significantly in V3 treatment. The application of vermicompost increased photosynthesis rate, respiration, nitrogen, phosphorus, and potassium concentrations more than Johnson’s nutrient solution. Fruit fresh and dry weights, root fresh and dry weights, root volume, fruit diameter and yield decreased in NS2 and NS1 and application of V3 improves the fresh weight of fruit in NS1. The highest fruit yield was observed in NSc treatment in combination with V3. Photosynthetic rate, and P and K concentrations increased with vermicompost application in all nutrient solution. The N and P concentrations decreased in NS1 and NS2 while respiration was stimulated by V2 and V3 in combination with NS1. The P decreased in NS1 and NS2 but was stimulated by both V2 and V3 treatments. The N level was reduced in NS1 and NS2 but V3 enhanced the level of N when combined with NS1. Overall, plant growth, yield, photosynthesis and nutrient N, P, K concentrations can be increased in sweet pepper by the addition of vermicompost and nutrient solution.

Due to decreasing in precipitation and under-ground water resources and increasing the chance of drought stress, it is necessary to select drought resistant or tolerant cultivars and genotypes. Hazelnut is one of the most important nut trees. In order to study responses of six hazelnut cultivars (‘Fertile’, ‘Ronde’, ‘Longue’, ‘Segorbe’, ‘Gerd’ and ‘Merville’) to drought stress, a RCBD based factorial experiment was carried out on three-year-old outdoor potted saplings. Irrigation treatments included control (regular watering), and drought stress (withdraw watering). Rewatering after drought stress period was performed and recovery of plants after one day and after one week were studied. Results of variance analysis showed significant differences between irrigation treatments as well as the cultivars. Photosynthetic pigments and the quantum efficiency decreased under drought stress, whereas, MDA and proline contents increased. The highest quantum efficiency of photosystem II was observed in control treatment (0.731) and the lowest was in stress treatment before rewatering, but one week after rewatering it returned to the control level. Gerd cultivar with highest amount of photosynthetic pigments had also the highest amounts of antioxidant compounds (phenolic compounds and flavonoids). Proline content had negative correlations with most of the studied characters except MDA. Under drought stress, ‘Longue’ and ‘Ronde’ expressed the lowest and the highest leaf injury (necrosis %), respectively. ‘Longue’, ‘Fertile’ and ‘Gerd’ cultivars were more tolerant to drought than other cultivars.

In order to reduce vegetative growth and increase the quality of strawberry fruits a research was carried out using paclobutrazole and calcium prohexadione on cultivar Paros. In this study calcium prohexadione at three concentrations (0, 100 and 150 mg L-1) and paclobutrazole at four concentrations (0, 60, 90 and 120 mg L-1) in two stages (four and seven weeks after planting) were sprayed. The results showed that the effects of paclobutrazole, calcium-prohexadione, and their interaction significantly increased the photosynthesis rate, chlorophyll content, leaf carotenoids, yield, and fruit anthocyanins. The effect of paclobutrazole at 5% probability level and calcium prohexadione at 1% probability level increased significant in the photosynthetic efficiency. Calcium prohexadione and its interaction with paclobutrazole at 1% probability level increased significant in the firmness of the fruit tissue and significantly decreased in the titratable acidity. Soluble solids were not affected by these retardants. Using from calcium prohexadione alone at 5% probability level increased significantly in the vitamin C. Generally, the physiological characteristics of the plant were increased by the use of both growth retardants, while the qualitative factors were more affected by calcium prohexadione.