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

 Climate change predictions indicate that drought and extreme heatwaves will become more frequent and extreme in many regions. Drought is the main abiotic stress that severely reduces plant yield across the globe. Thus, this may have negative consequences for the agricultural soils, as it limits the availability of water and nutrients to soil microorganisms and plants that develop on these soils. To cope with this situation, the use of organic amendments is the best option. Recent studies have shown that the application of organic fertilizers can affect soil moisture and thus, mitigate the negative effect of climate change on that parameter. Organic amendments increase soil organic matter content thus improving soil physical, chemical, and biological properties, and therefore, can confer drought resistance to soils. The application of organic residues has been presented as a great strategy against soil degradation in semiarid environments. However, the interactions between organic amendments and drought in hollyhock plants are not fully known. Here, we evaluate whether the organic amendment influences the physiological traits of hollyhocks and soil properties under drought conditions.

 The experiment was conducted in the research field at Ferdowsi University of Mashhad, Iran. The experiment consisted of three factors (cultivars, organic amendments, and drought) with organic amendments and drought having four and three levels, respectively. Drought treatments were controlled by a TDR at 80, 60, and 40% FC. The three sources of organic amendments were used cow manure, rice hull and wheat straw. Seeds were planted in cocopeat, perlite, and peat mixture trays in the greenhouse with an average temperature of 20 °C and under a photoperiod of 14 hours of light and 10 hours of darkness with a light intensity of 400 μmol-1 m2. In the 5-6 leaf stage, seedlings were transferred in pots (18 cm high and 8 cm in diameter) containing field soil. The plants were transferred to the field with four different substrates (field soil, field soil + manure, field soil + rice hull, and field soil + wheat straw) and were exposed to drought stress for one month during the flowering stage. This analysis examined both the physical and chemical properties of the soil, including changes in the macroelements nitrogen, phosphorus, and potassium.

 Soil nitrogen changes were significantly affected by the interactions of ecotype with drought, ecotype with the medium, and drought stress with medium. The highest nitrogen changes were recorded in Mashhad ecotype under 80% FC. Nitrogen content in amended soil had an increasing trend during the experiment, but the amount of nitrogen had a decreasing trend in soil. In all media under stress, the amount of soil phosphorus was increased and the highest amount of phosphorus was observed in soil + manure at all irrigation regimes. The highest amount of potassium in both ecotypes was observed in soil + manure. The amount of potassium in amended soils under stress significantly increased, but in all organic amendments with increasing drought stress from 80 to 40% FC, the potassium content decreased. In both ecotypes, soil salinity was increased in all culture media. Han et al. (2016) stated that the amount of nitrogen, phosphorus, and potassium in the amended soil was higher than the substrates containing chemical fertilizer. The medium EC was alkaline at the end of the experiment and the salinity of the culture medium increased compared to the control. This study revealed a negative correlation between electrolyte leakage and dry weight in hollyhock plants. Furthermore, all measured physiological and growth parameters were significantly affected by the treatments. Notably, the Mashhad ecotype grown in soil supplemented with animal manure at 80% field capacity (FC) exhibited the highest levels of physiological traits (SPAD and relative water content) and growth index (dry weight).The application of manure + soil by providing macro elements reduces the negative effects of drought stress.

 The type of crops grown in arid and semi-arid regions should be reconsidered. Also, some plants with high water requirements should be replaced with plants with low and unexpected water requirements. Because hollyhocks are low-expected plants that grow well in drought areas, so they can be considered as suitable species for cultivation in low-input systems and can tolerate drought situations by 40% FC in amended soil.

Environmental stress in plants, particularly due to heavy metal presence, poses a significant challenge to their growth. Manganese, an essential micronutrient, can become detrimental when accumulated in soil and plants. To assess the impact of silicon on linseed (Linum usitatissimum L.) under manganese stress, a factorial experiment was conducted. Linseed plants were grown in hydroponic culture with four different manganese levels (2, 250, 500 and 1000 μM) along with five silicon treatment levels (0, 0.5, 1, 1.5 and 2 mM). Results revealed that increasing manganese stress levels led to a rise in proline, soluble sugars content, and manganese in the root and shoot, accompanied by a decrease in other studied traits. Notably, the application of 2 mM silicon consistently yielded the highest values across all manganese levels for the examined traits. Silicon application enhanced proline and soluble sugars content in leaves, consequently increasing plant photosynthetic capacity and leading to greater root and shoot dry weights under various silicon levels. The use of silicon significantly ameliorated the harmful effects of manganese in linseed under manganese stress conditions. Therefore, 2 mM silicon is recommended as a beneficial solution in areas contaminated with manganese, which can lead to the reduction of this heavy metal in the root and shoot of plants.

The use of plant hormones has been introduced as a simple and suitable strategy to reduce the adverse effect of heavy metals in plants. To investigate the effect of salicylic acid (SA) in reducing lead (Pb) stress in tomato (Lycopersicon esculentum L.), a factorial experiment was conducted based on completely randomized design with three replications in the greenhouse of Razi University. Factors included soil Pb contamination at three levels (0, 150 and 300 mg kg-1 soil as Pb(NO3)2) and SA at three levels (0, 250 and 500 μM). Results showed that the highest proline content (23.4 mmol g-1) and Pb concentration (4.26 mg kg-1) were obtained in 300 mg kg-1 of Pb and 0 μM SA, which shows an increase of 303 and 387%, respectively, compared to the control (without Pb and SA). Also, the highest amount of soluble sugars (0.48 mg kg-1), plant height (43.5 cm), root length (18.3 cm/plant), shoot dry weight (7.48 g/plant), and leaf area (263.1 cm2/plant) were found in the treatment of 500 μM SA and 0 mg kg-1 Pb. In general, the results showed that the application of SA, as a plant hormone, is a simple and convenient method to reduce the adverse effects of Pb stress in tomato.

The use of organic fertilizers is one of the appropriate ways to produce medicinal plants due to their proper impact on the various soil properties, maintaining environmental health and better plant growth. This study was conducted to investigate the impact of various vermicompost levels on the growth and the morphological and physiological properties of the medicinal-ornamental plant of the Mullein, under drought stress conditions. The research was carried out in the form of split plots in a complete blocks design with four replicates. Experimental treatments included the use of vermicompost organic fertilizer at three levels of zero, 4, and 8 kg/m2 (equivalent to zero, 4, and 8 tons per hectare) and drought stress at two levels of normal irrigation (no stress) and irrigation at 50% of soil field capacity (FC). The results showed that the use of vermicompost and drought stress improved the morphological and physiological traits of the medicinal plant of Mullein. The highest height of the stem, the stem flower, the number of leaves, the height of the flower, the dry weight of shoot, and the root length were obtained by the use of vermicompost at 4 and 8 kg/m2 levels. The use of vermicompost at the rate of 8 kg/m2 increased chlorophyll and anthocyanin, respectively, by 53.7 and 122% compared to control. It was observed that by applying vermicompost at the levels of 4 and 8 kg/m2, significant changes in the morphological and physiological traits of the Mullein plant occurred. On the other hand, the combination of vermicompost application and mild drought stress also caused positive changes in the plant traits. Therefore, mild drought stress, and also for improving the vegetative growth and reproductive efficiency of the medicinal-ornamental plant of the Mullein, the use of vermicompost at 4 kg/m2 (equivalent to 4 tons per hectare) are recommended.

Due to the prevalence of COVID-19 epidemic in society and its transformation into a major global problem, as well as according to the World Health Organization, it seems that mental disorders will be the most important side effect of this disease. Long-term mental disorders have serious and dangerous effects on all vital organs such as the heart and blood vessels. It seems that one of the strategies is to grow and maintain flowers and ornamental plants in apartment environments. The aim of this study was to investigate the role of houseplants in reducing depression during quarantine due to COVID-19 by a combined "descriptive-analytical" method in Ahvaz city. A questionnaire was designed to collect data, which included various sections including: among the personal and professional characteristics of the respondents as well as the variables measuring the respondents' attitude towards the position of houseplants in reducing depression during the quarantine caused by COVID-19. In this study, data comparisons were performed using T-test and F-test and ISDM method was used for leveling. The results of this study showed that the highest frequency of responses in the attitude of respondents towards the position of houseplants in reducing depression was at a relatively positive level with a frequency of 137 people (35.7%) regarding the position of houseplants in reducing depression caused by quarantine of COVID-19 disease in Ahvaz. The results of Duncan test showed that there is a significant difference between the attitudes of the respondents whose home area was less than 62.2 meters and the respondents whose home area was more, at the probability level of 5%. In the other words, respondents whose home area was more than 62.2 meters had a more positive attitude towards the role of houseplants in reducing depression caused by COVID-19 quarantine. Findings on how to select plants also showed that people who use scientific books and experts to select flowers and plants, have a more positive view of the position of houseplants in reducing depression caused by the quarantine of Covid-19 disease. In general, 80% of the respondents preferred ornamental and flowering plants for keeping at home, and fruit, vegetable and medicinal plants were placed in the next ranks with great differences, respectively. It was found that people who live with houseplants for a long time, have a higher level of happiness and tolerance threshold and less aggression, and ultimately suffer less from depression and other mental disorders.

Drought stress is one of the most important factors limiting plant growth and production and leads to a reduction of more than 50% in the average production of most crops worldwide. Drought stress due to increased soil osmotic potential, especially in greenhouses where fertilizer consumption is high, is one of the greenhouse crop problems.

In the present study, two concentrations of polyethylene glycol at three levels of 0 (D1), -1.48 (D2), 4-91 (D3 ds/m to create different levels of drought stress due to osmotic changes in culture medium and application of KCl two levels (0 (K1) and 6 (K2) mmol / l) was used to reduce the possible effects. The experiment was performed as a factorial experiment in a completely randomized design with three replications. To apply drought stress, pot water was measured using a tensiometer, and when the drought reached below the field capacity (FC), irrigation with different concentrations of PEG and once a week spraying with KCl at the desired concentrations was done. Cucumber seeds were planted directly in 5 kg plastic pots containing a mixture of potting soil, including soil + sand + animal manure in the ratio of 1 + 2 + 0.5. The number of seedlings in each pot was 2 to 3 kg, which was reduced to one seedling seventeen days after sowing the seeds in the stage of three to four leaves. KCl spraying and spraying began in the three to the four-leaf stage of the seedlings and lasted for about a month. The plants were kept in the greenhouse during the experiment with an average temperature of 25 ° C and relative humidity of 70%. At the end of the experiment, dry weight, fresh weight, chlorophyll, chlorophyll fluorescence, flavonoids, carotenoids, proline, phenol, total protein, abscisic acid, superoxide, and ascorbate peroxidase, antioxidants, and catalase were measured.

The results showed that the effect of foliar application of potassium in all traits except chlorophyll fluorescence and superoxide dismutase was significant (P <0.01). According to the obtained results, ccontrol treatment increased the amount of antioxidants and catalase, but the application of K2 on most of the measured parameters, including dry weight, fresh weight, chlorophyll, flavonoids, carotenoids, proline, phenol, total protein, abscisic acid, and superoxide disodium showed a positive effect. In D3 with the addition of K2 the highest amount of phenol and protein was observed. Also, the content of abscisic acid in all treatments increased with the addition of K2 and the highest amount was observed in D3 which can be concluded that the use of potassium at a concentration of 6 mM Acceptable cut. According to the results obtained in this study, it can be stated that the plant tries to maintain its osmotic pressure in the face of drought stress, and this is done by increasing osmolites such as proline and antioxidant enzymes that help maintain plant cell pressure and torsion. Potassium application can reduce the adverse effects of drought stress by improving the activity of antioxidant enzymes and preserving chlorophyll. Thus, the cell continues its vital activities and ultimately produces more acceptable performance under these conditions. In other words, increasing the antioxidant activity in drought conditions along with the application of potassium leads to a higher inhibitory capacity of reactive oxygen species and production stability in these conditions. Therefore, to compensate for at least some harmful effects of stress and help the plant to return to normal growth conditions after re-irrigation, foliar application of such elements can be effective in drought resistance of the plant and play a role. Based on the findings of this study, it seems that the application of potassium with a concentration of 6 mM is the most effective.

In order to investigate freezing tolerance in withania under controlled conditions, a completely randomized design was carried out with four replications and nine temperature treatments (0, -3, -6, -9, -12, -15, -18, -21 °C and control treatment 25°C). Studied traits included electrolyte leakage, cell membrane stability, proline content, chlorophyll fluorescence, chlorophyll degree, 50% lethal temperature based on survival (LT50su) and 50% lethal temperature based on electrolyte leakage (LT50el). Results showed that the effect of freezing stress on all traits was significant at a probability of one percent. Electrolyte leakage showed increased and cell membrane stability decreased. The leaf chlorophyll fluorescence decreased with increasing freezing stress, so that it reached its lowest point at temperatures below -9°C. Chlorophyll content index was also affected by the effect of freezing stress, which decreased at a steep slope of 0 to -6°C and lowered to -6 °C with lower slope. The highest content of proline was related to treatment at -6°C, which increased by 53% compared to control treatment. By decreasing the temperature, the survival rate decreased, so that the plants disappeared at temperatures below -9°C. Also, LT50el and LT50su occurred at temperatures of -10.153 and -8.958°C, respectively. Finally, the findings in this study showed that the medicinal plants withania can be tolerate at -6°C.

The present study was aimed to evaluate the effect of organic fertilizers of folic acid and amino acids (glycine and glutamic acid) on the plant resistance to stress and yield of cucumber under deficit irrigation conditions. The study was carried out as a factorial in randomized complete blocks with 3 replications. The first factor was fertilization at four levels as control, 200 mg/l folic acid, amino acid glycine and glutamic acid (6 liters per ha), and folic acid + amino acids (glycine and glutamic acid). The second factor was irrigation interval (3, 5 and 7 days). The results showed that an increase in irrigation interval caused a significant reduction in plant dry and fresh weights, internode length, root and shoot lengths, stomatal conductance and chlorophyll contents. Furthermore, combined use of folic acid and amino acid and 7 day irrigation interval increased root length, internode length, leaf area, chlorophyll a and relative leaf water content by 159, 46.9, 84.7, 138 and 36%, respectively, when compared with the control at the same irrigation interval. In addition, a 70% increase in plant fresh weight and 84% increase in fruit weight were observed in irrigation interval of five days and combined treatment of amino acid and folic acid. In general, it can be concluded that the combined application of amino acids and folic acid improved the morphophysiological characteristics of cucumber under deficit irrigation conditions, while it was not effective in improving yield and fruit production with the seven-day irrigation interval.

This research was performed to determine the effect of inoculation of two species of arbuscular mycorrhizal fungi (AMF) on soil available water (SAW) and glomalin concentration under drought and salinity stresses according to a factorial based on completely randomized design with three replications. Treatments included two plant species Atriplex canescens and Haloxylon ammodendron with inoculation of two fungal species Glomus geosporum and Glomus mosseae plus two levels of salinity stress at 7 and 14 dS m-1, and two levels of drought stress including maximum allowable depletion (MAD) of 50 and 80%. After one year of treatments, plant available water (PAW), least limiting water range (LLWR), integral water capacity (IWC), total and easily extractable glomalin concentration and soil organic carbon (SOC) content were measured. Results indicated a significant increase in SOC, glomalin concentration, PAW, LLWR, and IWC by increasing the salinity level in treatments inoculated with G. mosseae and G. geosporum. The highest percentages of increase in PAW (147%), LLWR (140%) and IWC (85%) as compared with control were observed under combined salinity and low drought treatment (14 dS cm-1 + MAD of 50%) in A. canescens inoculated by G. geosporum. The highest concentrations of total glomalin and easily extractable glomalin were observed in both plant species under salinity of 14 dS m-1 and severe drought treatment (MAD of 80%) with the inoculation by G. geosporum and G. mosseae. Overall the results of this research indicated a reduction in negative consequences of drought and salinity stresses in the soil under cultivation of A. canescens and H. ammodendron, with application of mycorrhizal fungi.

Medicinal plants are a rich and valuable source of secondary metabolites that are strongly influenced by the environmental factors, especially drought stress. In this regard, a greenhouse experiment was conducted on Thymus vulgaris L. as split plots in a randomized complete block design with three replications. The main plot included three levels of moisture supply (40, 65, and 90% of potting soil field capacity (FC)) and the sub-plot was the elicitors levels including (1) control: without elicitor, (2) 150 µM cyclodextrin (CYC), (3) 75 nM coronatine (COR) + 150 µM CYC, (4) 150 nM COR + 150 µM CYC, (5) 150 µM methyl jasmonate (MJ) + 150 µM CYC, and (6) 300 µM MJ + 150 µM CYC. Except for the essential oil percentage, the other traits including the leaves proline content, electrolyte leakage, relative water content, plant height, canopy diameter, dry and fresh weight of shoots, dry weight of leaves and stems, and weight of essential oil had a very significant correlation with each other. The highest amount of leaves proline was obtained form the interaction of elicitors (levels 4 and 6) and the 40% FC level of moisture supply (3.88 and 3.94 μmol g-1 fresh leaf weight, respectively). The highest amount of plant height (28.3 cm), canopy diameter (17 cm), and relative water content (79%) was observed at the 90% FC level of moisture supply. The highest percentage of essential oil was obtained in the treatment of non-application of elicitor (2.67%) and the highest essential oil weight per plant (0.046 g plant-1) was observed in the treatment of non-application of elicitor at the 65% FC level of moisture supply. The mild stress increased the essential oil yield and the elicitor treatments decreased it.

Salinity stress is a major factor limiting the plant growth and productivity. Strawberry is a perennial plant and one of the most important small fruits; it is considered as a plant sensitive to salinity. In order to investigate the effects of jasmonic acid and silica nanoparticles on the yield, growth and fruits characteristics of strawberry cv. Paros, an experiment was carried out with three levels of jasmonic acid (0, 0.25 and 0.5 mM) as the spray, three levels of silica nanoparticles (0, 1 and 2 mM), and two sodium chloride levels (0 and 50 mM). Therefore, a factorial experiment was designed based on a completely randomized design with three replications under hydroponic condition. In this study, the length of pedicel, root volume, the dry weights of shoot and root, the percent of the opened leaf stoma, some fruit traits (index color and firmness), leaf specific area, salinity tolerance index and yield were measured. The results showed that growth indices, yield and also, some fruit-related features of this cultivar were decreased by salinity. Application of jasmonic acid and silica nanoparticle improved the fruit quality, yield and morphological characteristics under both control and salinity conditions. Thus, the use of jasmonic acid and silica nanoparticles under salinity stress increased the root volume, crown dry weight, and yield by 49%, 146% and 57%, respectively. The best results were observed in the application of 50 mM jasmonic acid and 0.5 mM silica nanoparticles.

In dry and semi-arid areas, water and soil salinity can limit crop production. Evaluation of plants salt tolerance to grow in saline areas is, therefore, important. To investigate the effects of salinity on ten different pepper genotypes, a factorial experiment based on a completely randomized design was carried out with three replications at Lorestan University Greenhouse, in 2014. The first factor was salinity treatment using sodium chloride (NaCl) at four levels of zero, 25, 50 and 75 mmol per liter (mM); the second one consisted of 10 different genotypes of Chili pepper (including Bane, Mahal, Sabzevar, Urmia, Minab, Tabriz, Lordegan, Branch, Maragheh and Ghale-jigh). Statistical analysis indicated that the characteristics of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, fresh and dry weights of root and leaf dry weight were significantly reduced with increasing salinity level. Therefore, all studied traits in the 75 mM salinity level had experienced the most decrease, as compared to the control. The results also showed that only the amount of proline was increased with raising salinity, so the least amount of proline belonged to the control treatment, while the highest one was observed for 75 mM treatment.

Damask rose (Rosa damascene Mill) is one of the most important and economical rose species in Iran. After drought, salinity is the second most common environmental stress limiting agricultural production. In order to investigate the effect of salinity stress on Damask rose, an experiment was conducted based on a completely randomized design with three replications in the lysimeter condition at the Research Greenhouse of National Salinity Research Center during 2018-2019 growing season. The treatments were four levels of salinity stress (2.8, 5, 8 and 11 dS m‒1). The results indicated that the effect of different levels of salinity were significant for all traits except the number of branches per plant and the number of petals. The plants treated with the salinity levels of 2.8, 5 and 8 dS m‒1 had a significantly larger number of flowers per plant, flower weight, petal weight, yield flower and essential oil yield, compared to salinity level of 11 dS m‒1. Increasing the salinity level from 2.8 to 11 dS m‒1 caused the reduction in height (41.4%), 11 flowers per plant (47.8%), 0.77 g flower (39.9%), petal weight (18.3%), flower yield (62.4%), and essential oil yield (53.9%). Overall, the results showed that the salinity tolerance threshold of Damask rose of Mahalat was 8 dS m‒1.

In order to evaluate the tolerance of carob seedlings to drought and salinity stresses based on growth and ecophysiological indices, a factorial experiment was conducted based on a completely randomized design with three replications. Factors included drought at 3 levels (5, 10 and 15 days irrigation intervals) and 3 salinity levels (0, 80 and 160 mM NaCl). The results showed that drought and salinity stresses reduced the vegetative indices of carob seedlings so that the lowest vegetative indices were observed in 15 days irrigation interval and 160 mM NaCl. The shoot fresh and dry weight decreased with increasing salinity and drought intensity. The highest shoot fresh and dry weight were recorded in control plants and the lowest shoot fresh and dry weight were recorded in plants treated with 160 mM NaCl and 15 days irrigation interval. The results of this study also showed that relative water content of leave decreased in plants treated with 10 days irrigation interval with increasing salinity levels while there was no significant difference between salinity levels in 15 irrigation intervals. The results also showed that the concentration of Na in root and shoot was increased with increasing salinity and drought stresses so that the highest concentrations of Na in shoots and roots were observed in plants treated with 15 days irrigation interval and 160 mM NaCl. According to the results of this study, it can be concluded that carob seedlings can tolerate 10 days of irrigation and 80 mM salinity.

To investigate the effect of mycorrhiza inoculation on increasing the resistance of medicinal plant dill (Anethum graveolens L.) to salinity stress, a factorial experiment was conducted in a randomized complete block design with three replications at the research greenhouse of Imam Khomeini International University, Qazvin province, Iran. The first factor was ecotype at two levels (Isfahan and Varamin), the second factor was salinity at three levels (0, 5 and 10 dS/m), and the third factor was mycorrhiza at three levels (0, 75 and 150 g fungi). The results showed that mycorrhizal inoculation improved all the quantitative traits studied so that under salinity conditions, the plants inoculated with mycorrhiza showed better growth than non-inoculated plants. The highest dry weight, plant height, number of seeds plant-1, and 1000-seed weight were obtained in ecotype Isfahan, salinity level 5 dS/m and 150 g of mycorrhiza. Eleven compounds were identified in dill essential oil. The highest percentage of limonene (7.5%) was obtained from ecotype Varamin plants treated with 5 dS/m salinity and 150 g mycorrhiza. The highest percentage of carvone (86.3%) was obtained in ecotype Isfahan treated with 150 g mycorrhiza and non-salinity.

Due to its low level of calorie and being as an excellent source of C and A vitamins as well as containing lycopene as a powerful antioxidant, Tomato (solanum lycopersicum, 2n=2 x=24), is extensively consumed in the world. According to the statistics presented in 2013, following China, United States, Turkey and Egypt, Iran ranked sixth in tomato production (6174182 kg per year) world tomato production. Similar to other tropical crops, tomato is sensitive to chilling stress. The chilling stress is considered as one of the environmental factors influencing growth and development of many plants including tomato. Applying different environmental conditions and cultivation techniques within transplant production can mitigate the chilling stress of seedlings. The seedling hardening is one of the simple technique being employed to physiological characters of plant, so as to induce subsequent stress resistance. This phenomenon is so-called cross tolerance and it means that exposing plants to stressful conditions can induce plant tolerance to upcoming stresses. Therefore, the objective of our study was to investigate the effect of drought hardening and chilling stress on tomato plant growth and productivity in field condition.

This experiment was conducted in greenhouse and research laboratories of agricultural college of Bu Ali Sina University. First of all, the seeds of tomato cv. C.H Falat, were sown in pots filled with perlite and vermiculite (ratio 2:1) and then maintained under natural light and at 25±2°C / 18±2°C (day/night). At four-leaf full development stage, seedlings were subjected to seven-day drought stress simulated with polyethylene glycol 6000 (PEG) at three levels: control (0% PEG), moderate drought stress (10 % PEG equaling to 0.18 Mpa osmotic potential) and severe drought stress (20% PEG equaling to 0.57 Mpa osmotic potential). After employing different levels of drought stress and consequently placing them in recovery for 48 h, they were exposed to chilling stress and non-chilling stress condition. For imposing chilling stress, the seedlings were transferred into growth chamber under 3°C for 6 days and 6 h per day. After receiving chilling stress treatments, the produced seedlings, were planted in the field.

In the present study, drought pretreatment reduced the effects of cold stress on fruit yield and quality. Results revealed that, the growth and yield of tomato plants were significantly increased by drought stress pretreatment in field condition. Herein, Seedlings without receiving drought pretreatment slowly grew and gained lower yield than those receiving drought. Some traits such as higher fruit size and shelf life and low number of decayed end blossom fruits were gained by drought application. The highest growth and yield rates were obtained through 10% PEG. These results indicate that drought stress at seedling stage increases the yield of tomato without harmful effects on fruit quality. The results showed that in 0% PEG treatment (control), chilling stress increased the number of days for flowering and fruiting, which indicates the growth retardation in this plant under cold stress condition. Drought pre-treatment using PEG increased the thickness of the pericarp and its post-harvest life, which may indicate the maintenance of the effects of initial stress in all stages of vegetative and reproductive growth. It has been reported that cold stress directly affects the growth potential of plants that interfere with the proper production of plants by disrupting metabolic reactions and indirectly by preventing the absorption of water by plants and oxidative stress (Hussain et al., 2018). In the present study, pre-treatment of drought reduced the destructive effects of chilling stress on fruit size. These results show that pre-treatment of drought (especially 10% PEG) had a significant effect on increasing fruit size and preventing its fruit yield reduction due to cold treatment. Similarly, Paradosi et al. (1987) reported that water stress in tomato plants increased its tolerance to cold and maintained the growth of tomato plants and its yield in cold greenhouse conditions. So far, there have been no reports of interactions between environmental stresses on fruit size, but the effects of drought stress on tomato fruit have been studied.

In general, the results of this experiment showed that the effects of drought pre-treatment on seedling remain in the next stages of tomato growth and can have beneficial effects on growth and yield of tomato in field conditions.

The present research was conducted in order to evaluate the effects of different amounts of cadmium (Cd) and lead (Pb) on the morpho- physiological and biochemical aspects of sweet basil. Pre-treatments of the soil with different concentrations of Cd and Pb was applied two months before starting the experiment in the greenhouse, and then seeds were sown in pots containing contaminated soil, under greenhouse conditions. The results showed that application of cadmium and lead have led to significant changes in morphological traits and reduction in physiological and quality traits including number of lateral shoots, flowering intensities and stem diameter. By increasing concentrations of Cd from 0 to 20 mg. kg-1 soils, the amount of basil cadmium from 0.71 to 3.6 mg. g-1DW and with increasing concentrations of Pb from 0 to 400mg. kg-1 soil, the amount of basil Pb from 0.93 to 4.95 mg. g-1DWwas increased. Different levels of both heavy metals have resulted in significant reduction of SPAD value (22.95 to 13.98) as well as in the amount of chlorophyll a (0.755 to 0.333 mg. g-1 FW) chlorophyll b (0.330 to 0.125 mg. g-1 FW) and carotenoids (0.228 to 0.095 mg.g-1 FW) and photosystem II in chloroplasts (0.834 to 0.422) decreased compared to control plants. According to the increase of Cd and Pb in the plants is harmful and associated with the serious human health, therefore preventing culturing vegetable crops in the heavy metal contaminated soils should be considered.

About 75 percent of Iran`s land is arid and semi-arid. Hence, the use of high-efficiency irrigation methods in agriculture will be important. In order to study the effects of both regulated deficit irrigation (RDI) and super absorbent (SA) on the storage quality of Japanese plum fruits (Prunus salicina cv. Santarosa), an experiment was conducted under factorial design with three replicates. Plum trees from the pit-hardening period (seven weeks after full bloom) were exposed to RDI treatments; 100%, 75% and 50% of seasonal crop evapotranspiration (ETc) and four super absorbent treatments including 0, 100, 200 and 300 g (per tree). Harvested fruits at the ripening stage were stored at 4ᵒC in 80% relative humidity for one month, then, some quality characteristics of fruits were evaluated. The firmness of fruits tissues and total flavonoids in RDI treated plants was higher than the control fruits. However, RDI levels and different concentrations of super absorbents did not show significant effects on the TA, SSC and SSC/TA when compared to controls. The interaction of treatments increased fruit juice, total phenol and antioxidant capacity significantly. Fruit juice decreased by RDI and increased due to SA, and while total phenol and antioxidant capacity of fruit under RDI was considerable, SA application could reduce both traits significantly.