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Volume 3, Issue 2 (2-2017)
The purpose of this study was to evaluate the effect of Nano TiO2 and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in a laboratory at Shahrekord University during 2014. The study was a factorial, adopting a completely randomized design with four replications. Treatments consisted of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l-1) which were applied to seeds of hulled barley cultivars such as Bahman, Makoii and Nosrat. The traits measured were the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed that carbon nanotubes treatments with 60 mg.l-1 had a significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight, as compared with other treatments. In this experiment, the highest percentages of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat Cultivar were obtained under 60 mg.l-1 carbon nanotube treatment, which was 70, 122.2 and 64.9%, respectively, as compared with control treatment. In addition, 60 mg.l-1 carbon nanotube treatment increased the seedling vigor of Makoii cultivar by 39.8%, as compared with the control treatment. The findings were that in terms of seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radical, the Nosrat Cultivar showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory conditions.
Volume 6, Issue 2 (3-2020)
Extended Abstract
Introduction: Salinity is one of the most serious abiotic stresses, causing instability in germination and seed emergence due to low osmotic potential and ionic toxicity. Development of simple and low-cost biologic methods is essential for short-term management of salt stress. The use of plant growth-promoting rhizobacteria increases the rate and uniformity of germination. This research aimed to investigate the effect of bacterial growth-promoting bacteria on the germination and seedling growth indices of alfalfa c.v. Hamedani in different salinity levels.
Materials and Methods: A CRD factorial experiment with four replications was conducted in Seed Science and Technology Laboratory of Shahrekord University in 2016. The first factor consisted of 6 salinity levels 0, 2.5, 5, 7.5, 10 and 12.5 dS/m created with sodium chloride, and the second was four levels of bacterial pre-treatment: no inoculation with bacteria and biopriming, inoculation of alfalfa seeds with Acinetrobacter calcoaceticus PTCC 1318, Bacillus megaterium PTCC 1250 and Enterobacter aerogenes PTCC 1221. The seeds were treated with bacteria and placed at a 20 °C growth chamber. They were then irrigated with desired solutions depending on the salinity treatment. Germinated seeds were counted daily and the parameters of germination percentage and rate, seedling length, seedling dry weight, vigour index I, II and allometric coefficient were calculated after 10 days.
Results: Salinity levels higher than 10 dS/m reduced germination indices and seedling growth of alfalfa. The highest reductions were obtained for 12.5 ds/m salinity level versus control for germination percentage (10.81%), germination rate (49.48%), plumule and radicle length (13.30% and 28.88% respectively) and vigor index I and II, which were 30.27% and 6.28%, respectively. The seed treated with A. calcoaceticus was able to tolerate salinity stresses more than others. For example, the reduction for the seed treated with A. calcoaceticus was only 4%, compared with non-stressed control. In salinity conditions 2.5 and 5 dS/m, the highest rate of germination was obtained, using A. calcoaceticus bacteria. In addition, the seeds treated with E. aerogenes showed higher stability at different levels of salinity for seedling length traits. The highest vigour index related to the use of A. calcoaceticus in salinity was 7.5 ds/m.
Conclusions: A. calcoaceticus had a significant role in reducing the negative effects of salinity on germination percentage and rate, vigour index I and II and allometric coefficient while E. aerogenes bacteria were more effective in reducing negative effects of salinity on seedling length and dry weight.
Highlights:
- Acinetrobacter calcoaceticus bacterium increased the percentage and rate of germination of alfalfa seeds under salt stress.
- Enterobacter aerogenes bacteria efficiently adjusted the negative effects of salinity on alfalfa seedlings length and dry weight.
Volume 7, Issue 2 (3-2021)
Introduction: One of the biological methods of weed control is the use of allelopathic substances or herbal secretions that have the potential to inhibit growth weeds. Wheat allelopathic studies include the study of wheat allelopathy against other crops, weeds, pests and diseases, isolation and identification of allelopathic compounds, the effects of wheat toxicity on self-storage and management of wheat residues. Wild mustard (Sinapis arvensis) is a problematic weed in the country, especially in Golestan province. The present study was conducted to investigate the allelopathic potential of four wheat cultivars to use those cultivars in integrated weed management system to reduction growth mustard weed.
Materials and methods: A factorial experiment was conducted in completely randomized design with three replications at Physiology Laboratory of Golestan Agricultural Research Center. Treatments included concentrations of 0, 2.5, 5, and 7.5% aqueous extract of aerial and underground organs of four wheat cultivars (Morvarid, Moghan, Tajan, and Arta) with 6000 polyethylene glycol treatment in four concentration (zero, 2.5, 5, and 7.5 percent). Three-parameter logistic model was used to evaluate the allelopathic potential of wheat genotypes for reducing the percentage of wild mustard germination and liquid chromatography (HPLC) was used to determine the phenolic acids composition in wheat cultivar extract.
Results: Extract of shoot of all wheat cultivars reduced root length of wild mustard in comparison of control. Wheat cultivars reduced shoot length of wild mustard by 28% to 51% compared to control. The highest reduction in mustard shoot length was obtained from the Morvarid extract. Increase in shoot extract concentration of Arta to 7.5%, reduced root and shoot dry weight as 47 and 29% in compare of control treatment and Moghan cultivar in the same concentration (7.5%) caused reduction in root and shoot dry weight with 68 and 41% respectively. The highest reduction in germination indices of wild mustard was obtained from high concentrations of Morvarid and Moghan wheat extract. It was also found that with increasing concentration of polyethylene glycol (PEG) growth indices and germination components of wild mustard seed decreased, but this decrease was not significant. This confirms that the osmotic potential of the extract concentration is not involved in the exacerbation of the allelochemical effect and the likelihood of osmotic effect seems poor. In total, Morvarid cultivar with 25.34 mg phenolic acid content had the highest phenolic acid concentration, which was approximately three times more than that of Tajan, 1.5 times Moghan and three times of Arta cultivar. Morvarid cultivar had higher concentration of vanillic acid and ferulic acid than the other three cultivars. Overall, the least allelopathic effect was observed in Tajan cultivar and the most allelopathic effect was in Morvarid cultivar.
Conclusion: Among the cultivars studied, the highest inhibition was related to Morvarid cultivar. The results also showed that the highest amount of inhibition was related to shoot extract so that the root extract inhibition was less than the shoot on studied traits. In general, the results of the present study showed that some wheat cultivars have greater inhibitory potential against wild mustard weed, which can be used in breeding programs to produce cultivar with high allelopathic potential. Awareness of this issue is more important, especially in sustainable weed-management. Therefore, it is suitable to perform comprehensive studies on their allelopathic potential so that they can be used in agriculture, including combating with weeds, pests and plant diseases, breeding crop and horticulture, design herbicides and pesticides that is provide environmentally friendly, safe, and biodegradable.
Highlights:
- The allelopathic potential of wheat cultivars was investigated on germination of wild mustard seeds.
- High performance liquid chromatography was used to detect inhibitors and other allopathic substances of wheat cultivars.
- Biological inhibition was investigation in wild mustard weed.
Volume 10, Issue 2 (3-2024)
Introduction: In agricultural systems, several environmental stresses can remarkably alter the growth, physiological, and biochemical responses of plants under stress. One of these factors is the biochemical reactions between plants along with the production of secondary compounds. Allelochemicals mainly have defence and cell wall ligninization roles in plants and do not directly play a role in the growth processes of plants. Thus, an experiment was carried out to evaluate the effect of allelopathic stress of Hypericum perforatum on the germination, physiological, biochemical, and antioxidant activity characteristics of green pea, the benchmark plant sensitive to allelochemicals.
Materials and methods: The treatments included different concentrations of H. perforatum at 11 levels (i.e., 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% of the aqueous extract). This research was carried out as a completely randomized design with three replications at the weed science laboratory of Gonbad Kavous University in 2023.
Results: The results of this study showed that one of the factors influencing the physiological, and biochemical characteristics of green pea is the concentration of the H. perforatum extract. In most cases, the percentage and rate of green pea germination, radicle and plumule length, and dry weight of radicle and plumule decreased with increased concentration of aqueous extract compared to the control, so that the greatest reduction in these characteristics was observed in 100% of H. perforatum extract. In contrast, the content of compatible osmolytes such as proline and soluble sugars, phenolic and flavonoid compounds, and antioxidant activity of green pea roots and plumules increased significantly in all studied treatments, with the highest increase in these characteristics observed at the concentration of 100% of H. perforatum aqueous extract. In general, the decrease in the dry weight of green pea seedlings due to the increase in the concentration of the aqueous extract of H. perforatum, despite the relative increase in the content of physiological and biochemical traits, indicates the high intensity of allelopathic stress of H. perforatum extract and their insufficiency, which leads to cytotoxicity against oxidative stress.
Conclusion: Considering the heterotoxicity effect of H. perforatum on green pea sensitive to allelochemicals and its distribution in gardens, barren lands, and wheat and corn fields, the possible effect of their residues in the next planting and even in case of presence in mixed cultivation should be considered.
Highlights:
- Aqueous extract obtained from the H. perforatum drastically reduces the germination and seedling growth of green peas.
- The difference in the effect of the aqueous extract of H. perforatum on green pea, the benchmark plant sensitive to allelochemicals, depends on their concentration threshold.
- The high intensity of allelopathic stress of H. perforatum extract and insufficient non-enzymatic antioxidants lead to oxidative stress.
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