فهرست مطالب

  • Volume:9 Issue:2, 2019
  • تاریخ انتشار: 1397/10/11
  • تعداد عناوین: 8
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  • Soheila Samadi, Ghader Habibi *, Atousa Vaziri Pages 2685-2694
    To further clarify the specific photochemical mechanisms of salicylic acid (SA)-mediated adaptation to salt stress, this experiment was conducted to examine the effect of SA (100 and 500 μM) on photosynthesis, antioxidative capacity and phenolic metabolism in strawberry plants under salt stress (50 mM). The results showed that high SA had a negative effect on strawberry plants as reduced leaf dry weight in plants that exposed to 500 μM SA under non-salt stress conditions. Salt stress negatively affected the leaf dry weight, whereas foliar spray of 100 μM SA alleviated the salt-induced inhibitory effects on the plant growth. Salt stress caused a significant decrease in photosystem performance index (PIabs); however, plants exposed to salt stress after SA pretreatment conserved their photosynthetic electron transport rate, compared with NaCl-alone treated plants, relating to the improvement of water-splitting complex on the donor side of PSII (Fv/Fo). The application of 100 μM SA in saline condition also increased the accumulation of soluble sugars like trehalose (Tre). Lipid peroxidation was observed in plants subjected to salinity stress, as evidenced by higher malondialdehyde (MDA) levels. In contrast, foliar spray of SA at a concentration of 100 μM promoted catalase (CAT) activity as well as phenolic content, thus reducing MDA and, consequently oxidative damage to membranes. Hence, foliar application of SA at 100 μM was effective in alleviation of salt stress in strawberry by improving PSII functioning, induction of compatible osmolytes and phenol metabolism, and mitigating membrane damage.
    Keywords: phenolic content, photosystem performance index, salicylic acid, salt stress, strawberry
  • Atena Alaghemand, Shahab Khaghani *, Mohammad Reza Bihamta, Masoud Gomarian, Mansour Ghorbanpour Pages 2695-2702
    In order to study the effect of drought stress at budding stage on five black cumin (Nigella sativa L.) ecotypes (Arak, Yasuj, Semirom, Azarbaijan, and Torbat Heydarieh), an experiment was conducted in based on a  factorial randomized complete block design (RCBD) with four replications in Islamic Azad University, Arak branch, Arak, Iran. Treatments included control (normal irrigation) and drought stress (stop irrigation at budding stage until the end of the growth period). Oil percentage, oleic acid, linoleic acid, and linolenic acid were affected by drought and the highest values of oil percentage (2.6%), oleic acid (0.27%), linoleic acid (13.02%) and linolenic acid (1.57%) were observed in Arak, Torbat Heydarieh, Yasuj, and Torbat Heydarieh ecotypes, respectively. Results of tolerance indices showed that Torbat Heydarieh had the highest value of GMP (233.8), STI (2.26), and SSI (84.64). The correlation analysis showed Yp with GMP (r=+0.89**), STI (r=+0.95**), and MP (r=+0.89**). Based on the present study, Torbat Heydarieh ecotype is recommended for planting in arid and semi-arid regions.
    Keywords: Oleic acid, Linoleic acid, linolenic acid, oil percent, black cumin
  • Azam Salimi, Zahra Oraghi Ardebili *, Maryam Salehibakhsh Pages 2703-2708
    The current study was carried out to investigate the efficiencies of foliar supplementations of Zinc and/or chitosan on the growth and physiology of tomato (Lycopersicon esculentum L.) and clarify the involved mechanisms. Seedlings were sprayed with three concentrations (0, 50, and 100 mgL-1) of chitosan and/or three levels of Zinc sulfate (0, 50 and 100 mgL-1). The application of Zn and/or chitosan led to increases in shoot fresh mass, about 31%, over control. In comparison with the control, enhancement (approximately 28.5%) in shoot dry mass resulted from the single application of chitosan or zinc while this percentage reached to about 45% for seedlings simultaneously treated with the chitosan and Zn supplements. About 29% improvements in the plant height resulted from the chitosan and/or zinc. Higher amounts of chlorophyll contents were recorded in the chitosan and/or zinc-treated plants, among which the highest levels were found in the combined treatments. Simultaneous applications of chitosan and zinc were the most effective treatments to induce PAL (phenylalanine ammonia lyase) activity (about 64%) when compared to the control. Chitosan and/or zinc treatments, especially the latter, significantly promoted the activity of (SOD) superoxide dismutase enzyme (about two folds), over the control. Also, increases in proline contents was provoked by applying the treatments. Foliar supplementations of these compounds as an eco-friendly solution may have considerable potential to act as exogenous elicitors and trigger various physiological traits, thereby improving plant growth and resistance under abiotic stress conditions.
    Keywords: Bio-fortification, Chitosan, elicitor, foliar, Lycpersicon
  • Behazd Kaviani *, Shahram Sedaghathoor, Mohammad Reza Safari Motlagh, Seddigeh Rouhi Pages 2709-2718
    Aglaonema widuri is an evergreen and indoor ornamental plant. This study aimed to investigate the effect of some plant growth regulators on micropropagation of A. widuri. A protocol was developed for high frequency in vitro multiplication of A. widuri on the same medium for both shoots and roots induction. This condition decreases time duration and cost of micropropagation. Apical buds as explants were obtained from greenhouse-grown A. widuri and were established on Murashige and Skoog (MS) medium. Three cytokinins [N6-benzyladenine (BA; 0.00, 3.00, 3.50, and 4.00 mgL-1), 1-phenyl-3-(1,2,3-thiaiazol-5-yl) urea (TDZ; 0.00, 0.50, and 1.00 mgL-1), and N6-(2-isopentenyl) adenine (2-iP; 0.00 and 7.00 mgL-1)] and one auxin [α-naphtaleneacetic acid (NAA; 0.00, 0.10, 0.20, 0.30, and 0.40 mgL-1)] were studied for their effect on miropropagation of A. widuri. BA and NAA treatments as 3.00 mgL-1 + 0.2 mgL-1 recorded the highest shoot proliferation rate (number: 6.00 shoots and length: 7.75 cm per explant). Treatment of 4.00 mgL-1 BA + 0.10 mgL-1 NAA + 0.50 mgL-1 TDZ produced maximum nodes (13.25 per explant). The largest number of leaf (4.25 per explant) was produced in the medium containing 3.50 mgL-1 BA + 0.20 mgL-1 NAA. Maximum root initiation and development (14.25 per explant) was obtained on medium containing 3.00 mgL-1 BA + 0.20 mgL-1 NAA. The combination of 3.50 mgL-1 BA + 0.20 mgL-1 NAA was found to be the most suitable growth regulators for obtaining the highest root length (8.25 cm per explant). The plantlets were transferred to pots and grown in the greenhouse with a success rate of 95%.
    Keywords: Araceae, in vitro micropropagation, ornamental plants, phytohormones, tissue culture
  • Khodabakhsh Safari, Mehrab Yadegari *, Behzad Hamedi Pages 2719-2726
    This research investigated the effects of climate and soil on the content and components of essential oils in Ferulago angulate (Schltdl.) Boiss, belonging to the Apiaceae family. Aerial parts of plants were collected from three elevations (2500, 3000, and 3500 m above sea level) and three regions (Kallar Mountain from Boroujen, Mili Mountain from Koohrang, and Saldaran Mountain in Farsan, Chaharmahal and Bakhtiari province) with three replications. Results suggested that soil and climatic conditions had significant effects on the quantitative and qualitative properties of essential oils. The highest (0.65%) and the lowest (0.15%) levels of essential oils were obtained from elevation of Mountain Kallar (3000 m) and Mili Mountain (3500 m), respectively. Forty-four compounds were detected most of them being alpha-pinene, alpha-thujene, alpha-phellandrene, cis-ocimene, beta-phellandrene, beta ocimene, and nonadecane. As for regional variations, most of alpha-pinene (20.88%), betaocimene (6.8%), cis-ocimene (23.6%) were recorded in the elevation of 3000 m from Saldaran Mountain and alpha-thujene (10.14%), alpha-phellandrene (3.49%), nonadecane (5.01%), and beta-phellandrene (7.57%) were obtained in the elevation of 3000 m from Kallar Mountain in clay loam soil texture. The lowest values were obtained from elevations of 3500 m in each region especially in sandy clay soil texture in Mili Mountain. It seems that the greater amount of nutrients was due to the presence of clay-loam texture, and the less environmental stresses and desirable soil enrichment in this elevation led to an increase in the essential oils content and components of this plant.
    Keywords: Elevation, environmental properties, essential oil, clay loam
  • Narges Oraghi Ardebili *, Alireza Iranbakhsh, Zahra Oraghi Ardebili Pages 2727-2738
    This study was carried out in order to minimize risks associated with salinity. Soybean seedlings were treated with salicylic acid (SA) of 0 and 0.5 mM, selenium (Se) at 0, 25, and 50 mgl-1, and/or NaCl, 0 and 100 mM. The supplements promoted shoot fresh mass and markedly relieved toxicity signs of salinity. Se and/or SA increased calcium and potassium contents in different organs and mitigated the inhibiting effects of salinity on the nutritional status. Simultaneous applications of these elicitors were the most effective strategy to induce antioxidant enzymes (peroxidase, polyphenol oxidase, and catalase). Also, these compounds increased proline, phenolics, and soluble carbohydrates in leaves and roots. Activities of phenylalanine ammonia lyase in roots and leaves were induced in the Se and/or SA-supplemented plants. In addition, the elicitors triggered accumulations of non-protein thiols. Therefore, the simultaneous application of Se and SA may be considered as a promising way to relieve the toxicity signs of salinity.
    Keywords: elicitor, Heavy Metal, Nutrition, salt stress
  • Maryam Nazir, Shahab Sadat *, Mehdi Soltani Howyzeh Pages 2739-2747
    Direct and indirect somatic embryogenesis in Agave Americana through basal parts of micropropagated shoots were considered in this study. For micropropagation, 2 factors (BA and NAA) were utilized in different concentrations. A factorial experiment based on a completely randomized design (CRD) was accomplished with four replicates in a modified Murashige and Skoog medium (MSB). BA in 3 mg/L along with NAA in 0.1 mg/L was the best treatment for multiplication. Callus and embryo induction were evaluated using different auxins in a CRD experiment with three replicates in MS medium supplemented with L2 vitamins. Picloram 2.5 and 2 mg/L and also Dicamba 1 mg/L induced 66.7%, 60%, and 53.3% of explants to somatic embryo, respectively. Also, 2,4-D 2 mg/L had the highest impact on callus induction (95.6%). Embryogenesis was studied using Dicamba and Picloram in the same culture medium in a factorial experiment based on CRD with three replicates. The results of orthogonal polynomial analaysisindicated that high concentrations of Dicamba from 0 to 1.5 mg/L had a significant effect on somatic embryo induction. However, higher concentrations had the opposite effect on somatic embryo numbers. Germination of somatic embryos was performed in MSB medium without growth regulators.
    Keywords: Agave, Micropropagation, Somatic embryogenesis, Callus, Hormones
  • Borzo Kazerani, Saied Navabpour *, Hossein Sabouri, Seyedeh Sanaz Ramezanpour, Khalil Zaynali Nezhad, Ali Eskandari Pages 2749-2758
    To study proline content and enzyme defense system in response to drought stress in rice, a randomized complete block design with three replications was conducted in two separate environments (drought stress and non-stress). The rice cultivars used included two commercial cultivars, i.e., Ahlemi Tarom (low-yield and drought tolerant) and Sepidrood (high-yield and sensitive to drought) and three promising lines of fourth generation mutants (high-yield and drought tolerant), namely, No. 4, 94 and 95 tested on a research farm at Gonbad Kavous University in the 2018 crop year. Plant roots were separately sampled in each block at the reproductive stage. The proline content and activity of the enzymes involved in the defense system, including superoxide dismutase, catalase, ascorbate peroxidase and glutathione peroxidase were measured by extracting the enzymes from each root sample. Results indicated that the drought-tolerant mutant lines had lower proline contents. The mutant lines and Ahlemi Tarom and Sepidrood cultivars had the highest to lowest levels of defense enzymes in the oxidative pathway, respectively. Correlation was found between the decrease in proline contents and increase in levels of defense enzymes of the oxidative stress pathway. The mutants possessed reliable genetic storages for tolerance to drought stress and had a significant superiority over the commercial cultivars at P≤0.05.
    Keywords: ascorbate peroxidase, catalase, glutathione peroxidase, proline, rice, superoxide dismutase