Research paper
Mohammad Pessarakli
Abstract
Continuous desertification of arable lands mandates use of low quality/ saline water for irrigation, especially in regions experiencing water shortage. Using low quality/ saline water for irrigation imposes more stress on plants that are already under stress in these regions. Thus, a logical solution ...
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Continuous desertification of arable lands mandates use of low quality/ saline water for irrigation, especially in regions experiencing water shortage. Using low quality/ saline water for irrigation imposes more stress on plants that are already under stress in these regions. Thus, a logical solution will be to find a salt/ drought-tolerant plant species that will survive/sustain under such stressful conditions. As the native plants are already growing under such conditions and are adapted to these stresses, they are most suitable for use under these harsh arid environmental conditions. If stress-tolerant species/ genotypes of these native plants are identified, there will be substantial savings in inputs (i.e., water, fertilizers, and agrochemicals) in using them under these stressful conditions. My research studies at the University of Arizona on various native grasses indicate that saltgrass (Distichlis spicata) has a great potential to be used under harsh environmental desert conditions, to combat the desertification processes. The objectives of this review article are to introduce saltgrass, a halophytic plant species, which through my investigations on various salinity and drought-tolerant halophytic plant species has proven to be the most tolerant plant species for recommendation as the potential species for use in arid regions and in areas with saline soils and limited water supply or drought conditions, for sustainable agriculture and for combating desertification. In my various investigations, different saltgrass clones/accessions/genotypes were studied in a greenhouse, to evaluate their growth responses under salinity or drought stress conditions. The grasses were grown vegetatively either hydroponically in culture solution for salt tolerance or in galvanized cans that contained fritted clay for drought tolerance. For salt tolerance, the grasses were grown under four treatments (EC = 6 (control), 20, 34, and 48 dSm-1 salinity stress) with three replications in a randomized complete block (RCB) design experiment. During this period, the shoots were clipped bi-weekly for fresh and dry matter (DM) weight determination. At the last harvest, the roots were also harvested and the DM weights determined. For drought tolerance, the growth responses of the grasses were evaluated under a progressive drought condition for four months in a split plot design experiment with three replications. Shoots were harvested bi-weekly for DM determination. Although growth responses reduced at high salinity levels or as the drought period progressed, all the grasses showed a high degree of salinity/drought tolerance. However, there was a wide range of variations observed in salinity/ drought tolerance among the various clones/accessions/genotypes. The superior salinity/ drought-tolerant plants were identified, which could be recommended for sustainable production under arid regions and combating desertification.
Research paper
Maryam Bagheri; Mahmood Esna-Ashari; Ahmad Ershadi
Abstract
The objective of this study was to evaluate the storage life and quality of persimmon (Diospyros kaki Thunb.) fruit cv. ‘Karaj’ stored at 0°C for 4 months after postharvest calcium chloride treatment. Fruit weight loss, fruit firmness, total soluble solids, titratable acidity, total phenolic ...
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The objective of this study was to evaluate the storage life and quality of persimmon (Diospyros kaki Thunb.) fruit cv. ‘Karaj’ stored at 0°C for 4 months after postharvest calcium chloride treatment. Fruit weight loss, fruit firmness, total soluble solids, titratable acidity, total phenolic content, soluble tannin content, chilling injury, antioxidant activity, electrolyte leakage, and malondialdehyde content were measured in 0, 15, 30, 45, 60, 75, 90, 105, and 120 days after storage. Peroxidase and catalase enzyme activities were also determined at the end of the storage. Fruits were dipped in the solutions containing 0.5, 1, and 2% (w/v) CaCl2 as well as distilled water only as the control. Results showed that the fruit weight loss and chilling injury significantly decreased by CaCl2 treatments compared with the control. CaCl2 treatments also increased fruit firmness and catalase and antioxidant activities, whereas they reduced MDA content, EL, and peroxidase activity during 4 months of cold storage. The results indicated that CaCl2 application influenced TPC and soluble tannin compared with the control but had no significant effect on TA. The best result was obtained from the 2% CaCl2 treatment in almost all the studied parameters. In general, postharvest CaCl2 treatment of persimmon could decrease chilling symptoms during the cold storage.
Research paper
Mahmood Izadi; Elham Aslmoshtaghi
Abstract
The date palm bunch fading disorder/disease is one of the greatest challenges faced by date palm growers. In the present study, the effect of appropriate orchard management on some qualitative and quantitative features of date palm bunch was studied. For this purpose, two orchards of cv ‘Kabkab’ ...
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The date palm bunch fading disorder/disease is one of the greatest challenges faced by date palm growers. In the present study, the effect of appropriate orchard management on some qualitative and quantitative features of date palm bunch was studied. For this purpose, two orchards of cv ‘Kabkab’ with a history of previous incidence were selected in two districts of Bushehr province; Tangestan and Dashtestan. The orchards were divided into two parts; one as control and another as treated plants. On the treated part, some management practices such as plowing, leaf pruning, proper nutrition, regular irrigation, pollination, regulation of leaf-bunch ratio, thinning in pollination stage, control of weeds, pests and diseases were conducted scientifically while the control part was maintained with conventional local practices. During the treatment phase, all bunches in the Khalal stage were covered with a white cloth bag. The results from both treatment plots showed that proper orchard management can improve fruit yield (Dashtestan 52.2 kg tree-1, Tangestan 88.1 kg tree-1) and reduce the severity of symptoms and therefore reduce date palm bunch fading disorder.
Research paper
Mohsen Ashrfai; Mohammad Farsi; Amin Mirshamsi; Mozhgan Parvandi
Abstract
Many recent studies have shown that glycosylation patterns of Agaricus bisporus are similar to those of mammalians, so that this organism is a good candidate for the expression of glycosylated pharmaceutical protein. To achieve constant interested gene expression in all cells of the organism, proper ...
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Many recent studies have shown that glycosylation patterns of Agaricus bisporus are similar to those of mammalians, so that this organism is a good candidate for the expression of glycosylated pharmaceutical protein. To achieve constant interested gene expression in all cells of the organism, proper promoter isolation is necessary. To isolate this promoter, PCR with specific primers was performed on extracted DNA of the white button mushroom strains Holland737 and IM008. The PCR amplified 290 bp fragments of gpdII promoters. IM008 gpdII promoter was used to construct pCAMBIAH8 plasmid. Comparison of isolated promoters among sequence records at NCBI demonstrated high similarity between IM008 gpdII promoter and previously reported gpdII promoter. Sequence analysis of isolated promoters revealed several point mutations on this promoter. TACAAA promoter sequence in −65 site acts as TATA box. Among the three CAAT candidate sequences, one is functional, which is located at position −108. Transformation of the white button mushroom with constructed pCAMBIAH8 plasmid was successfully performed.
Research paper
Mansoureh Danesh; Mahmoud Lotfi; Shiva Azizinia
Abstract
Iran is a part of the secondary centre of origin of melons, and therefore, there is a wealth of genetic variation of these species in this country. The Amplified Fragment Length Polymorphism (AFLP) marker was applied to investigate the genetic variations among five major Iranian melon cultigens (Cucumis ...
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Iran is a part of the secondary centre of origin of melons, and therefore, there is a wealth of genetic variation of these species in this country. The Amplified Fragment Length Polymorphism (AFLP) marker was applied to investigate the genetic variations among five major Iranian melon cultigens (Cucumis melo) and ‘Ananasi’ as a general well-known cultivar. Ten primer pairs were used on 90 individuals producing 318 polymorphic fragments, with an average of 31.8 fragments per primer combination. The polymorphism rates ranged from 80 to 100%. The genetic similarities among accessions were calculated according to Dice’s Similarity Index and used to construct a dendrogram based on the Unweighted Pair Group Method with Arithmetic Average (UPGMA). The genetic distance estimates based on AFLPs ranged from 0.29 to 0.63, with a mean of 47±0.3. Iranian melon genotypes and the ‘Ananasi’ cultivar were considered as two separate groups on the cluster analysis. The principal coordinate analysis showed a separate allocation of the melon cultivar groups. The results demonstrated a wide diversity of Iranian melon cultigens. The high number of alleles and the high expected genetic diversity detected with the AFLP marker indicated that the Iranian melon cultigens had distinctive characteristics and were an important genetic diversity pool, which made them a valuable source of breeding materials.
Research paper
Mehdi Abdolmaleki; Morteza Khosh-Khui; Saeid Eshghi; Asghar Ramezanian
Abstract
Rosa hybrida L. is an important commercial cut flower. Salicylic acid (SA) and calcium chloride (CaCl2) act as endogenous signal molecules responsible for growth parameters in plants. The aim of this study was to evaluate the effects of preharvest SA and CaCl2 treatments in extending the vase life of ...
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Rosa hybrida L. is an important commercial cut flower. Salicylic acid (SA) and calcium chloride (CaCl2) act as endogenous signal molecules responsible for growth parameters in plants. The aim of this study was to evaluate the effects of preharvest SA and CaCl2 treatments in extending the vase life of cut rose flowers. Therefore, a factorial experiment based on completely randomized design with SA (0, 150, 300, and 450 mg L-1) and CaCl2 (0, 0.75, 1.5, and 2.25%) with 4 replicates and 2 samples (individual flowers) in each replicate, was conducted. Changes in growth, macronutrient concentration, chlorophyll content, leaf relative water content (LRWC), flower quality, vase life, and membrane stability index were investigated in R. hybrida cv. “Dolce Vita.” Exogenously applied SA and CaCl2 increased plant growth (such as shoots and flower buds). Foliar application of SA and CaCl2 also increased macronutrient concentration (N, K, Ca, and Mg), chlorophyll content, LRWC, flower quality, and vase life; however membrane stability index was decreased with increasing levels of SA and CaCl2. These results suggest that SA and CaCl2 could be used as potential growth promoters to improve postharvest life of roses. According to the results of this experiment, SA and CaCl2 as natural, cheap, safe, and biodegradable compounds are suitable alternatives for conventional chemical treatments in order to prolong vase life of cut rose flowers. Commercialization of these compounds for optimum formulations needs further experiments.
Research paper
Siamak Kalantari; Mohsen Hatami; Mojtaba Delshad
Abstract
Sensitivity of tomato fruits to chilling injury limits its storage and marketability. This study investigated the effect of hot water treatment (HWT) on reducing the consequences of chilling injury (CI) with respect to quality attributes of tomatoes during storage. Tomatoes were harvested at three ripening ...
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Sensitivity of tomato fruits to chilling injury limits its storage and marketability. This study investigated the effect of hot water treatment (HWT) on reducing the consequences of chilling injury (CI) with respect to quality attributes of tomatoes during storage. Tomatoes were harvested at three ripening stages: mature green, pink, and red; dipped in hot water at 45°C for 15 min; and stored at three storage temperature conditions: 5°C, 13°C, and a simulated condition (SC: 3 days at 25°C and then at 5°C) representing the time between harvest and consumption by consumer. Quality analysis was carried out at the beginning of the experiment and every 10 days of storage 3 days of shelf life evaluation. Fruit color, lycopene content, weight loss, and CI were evaluated during the experiment. HWT reduced CI in mature green tomatoes but had little effect in pink and red fruits. It also caused delay in surface color development and reduced weight loss. During storage, heated mature green fruits often had significantly more lycopene content but low a* compared with unheated ones, whereas in heated red fruits, both a* and lycopene content were lower than unheated ones. This study showed that HWT could be used to reduce CI in mature green tomatoes, but not in pink and red fruits.
Research paper
Hamideh Mohammadi; Zahra Pakkish; Vahidreza Saffari
Abstract
Peach (Prunus persica L. Batsch.) is produced in most areas of Iran, where flowering is hindered by temperature. Using plant growth regulators to delay bloom is a suggestive measure to avoid frost damage. The objective of this study was to determine the effects of methyl jasmonate (MJ) and salicylic ...
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Peach (Prunus persica L. Batsch.) is produced in most areas of Iran, where flowering is hindered by temperature. Using plant growth regulators to delay bloom is a suggestive measure to avoid frost damage. The objective of this study was to determine the effects of methyl jasmonate (MJ) and salicylic acid (SA) on peach bloom delay and yield. This study evaluated the applications of MJ 0 (control, water only), 100 and 200 mg L-1 and SA at 150 and 300 mg L-1 at swollen bud and green tip stages. In ‘Elberta’ peach, MJ at 200 mg L-1, its combinations with SA at 150 mg L-1 and MJ 200 mg L-1 and SA300 mg L-1 together at the two stages (green tip, swollen bud stages) delayed blooming for 6 and 8 days, respectively. The maturity and ripening of treated peach fruits were delayed for 8-12 days in green tip and swollen bud stage. Flowering percentage amount (57.83-61.80%), fruit set amount (22.59-23.53%) and yield (1.69-1.72 kg cm-2 branch) were increased by MJ 200 mg L-1 and SA300 mg L-1 treatments compared to the control treatment (flowering percentage amount (39.31%), fruit set amount (6.25%) and yield (0.82 kg cm-2 branch). The interactions of MJ and SA had more impacts on flowering (89.53%), fruit set (33.22%), fruit weight average (124.93 g), and yield (2.09 kg cm-2 branch)compared to their individual application. The present study was the first evidence for the SA and MJ effect on bloom delay, flowering and fruiting of peach.
Research paper
Mohammad Javad Nazarideljou; Masoud Azizi
Abstract
Scape bending disorder is the most important factor affecting postharvest loss of gerbera cut flowers. One of the ultimate reasons for gerbera stem bending is lignin, with deformation structural functions and defensive mechanisms. This postharvest experiment was conducted to evaluate the role of phenylalanine ...
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Scape bending disorder is the most important factor affecting postharvest loss of gerbera cut flowers. One of the ultimate reasons for gerbera stem bending is lignin, with deformation structural functions and defensive mechanisms. This postharvest experiment was conducted to evaluate the role of phenylalanine ammonia lyase (PAL) and peroxidase (POD) enzymes activity in stem bending of two gerbera cultivars; (‘Beaudine’ (sensitive)) and (‘Aqua’(resistant)). This experiment was based on a completely randomized design with three replications over eight days. Results showed the significant effects of cultivar on stem bending percentage, total phenol content, PAL and POD enzyme activities and lignin content (P<0.05). The ‘Aqua’ cultivar had the highest phenol and lignin content and the lowest stem bending percentage. The maximum and the minimum PAL and POD enzyme activities were observed in resistant and sensitive cultivars, respectively. Based on the results, induction of PAL and POD enzymes activity, and consequently lignin formation could have direct effects on stem strength and as a result reduce gerbera stem bending disorder.
Research paper
Ali Pourkhaloee; Morteza Khosh-Khui
Abstract
Two separate factorial experiments were conducted to study the effects of explant sources, plant growth regulators, sucrose concentrations, and light conditions on in vitro cormlet formation of freesia (Freesia ×hybrida Bailey 'Argenta'). Interestingly, it was observed that the pupae had lower ...
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Two separate factorial experiments were conducted to study the effects of explant sources, plant growth regulators, sucrose concentrations, and light conditions on in vitro cormlet formation of freesia (Freesia ×hybrida Bailey 'Argenta'). Interestingly, it was observed that the pupae had lower contamination levels compared to mother corms. Using 40% sodium hypochlorite solution for 40 min, contamination levels of pupae and mother corms reduced to 19.80 and 46.40%, respectively. Moreover, pupae showed the highest regeneration frequency. In the first experiment, 6.67 cormlets were directly produced per pupa (cold storage-produced corm) on Murashige and Skoog (MS) medium supplemented with 6 mg L-1 1-naphthaleneacetic acid (NAA), 1 mg L-1 6-benzylaminopurine (BA), and 60 g L-1 sucrose, when cultures were stored in the dark. In the second experiment, on average, 5.67 shoots were proliferated per pupa explant in the presence of 4 mg L-1 BA and 2 mg L-1 Kinetin (Kin). Subculturing these shoots on MS medium containing 3 mg L-1 BA and 0.5 mg L-1 NAA led to production of 3.67 cormlets per shoot. Finally, in vitro derived cormlets showed the highest percentage of rooting (77.80%), root number (8.33), and root length (2.13 cm) on MS medium containing 1 mg L-1 indole-3-butyric acid (IBA).