جستجوی مقالات مرتبط با کلیدواژه « pretreatment » در نشریات گروه « منابع طبیعی »

Suitable germination and crops establishment are one of the most significant and fundamental issues that overshadow the economic performance of the product. Improving the quality of seeds by relying on their pre-treatment is one of the issues that can be considered. Accordingly, the present study was performed to investigate the effect of pretreatment of sugar beet seeds using humic in factorial experiment in 2017. The first factor was humic acid including four levels of zero, 8.33, 12.50, and 25.00 mg per 100 g of seed, and the second factor, cultivar included two levels of Ekbatan and Paya. According to the results of the analysis of variance, the main effects of humic acid and cultivar had a significant effect on all evaluated characteristics except root dry weight at one and five percent probability levels. Humic acid-cultivar interaction was significant only for the three characteristics of mean germination time, root dry weight, and shoot dry weight. Based on the mean comparison results, the seed vigor (87.87%), germination rate (6.27 bud/day), seedling vigor length index (3.52) and seedling vigor weight index (1269.96) were assigned to seed pretreatment using 12.50 mg of humic acid per 100 grams of seeds. Seed pretreatment without significant difference in the amount of coating material increased the uniformity of seed germination. Among the two studied cultivars, the Ekbatan cultivar was superior to the Paya cultivar in terms of all studied characteristics. In general, the use of humic acid improved the germination characteristics and early growth of seedlings.

In order to investigate the effects of priming with salicylic acid and salinity stress on improvement of germination characteristics, activity of antioxidant enzymes and and membrane lipid peroxidation of wheat cultivar Mihan, an experiment was conducted as factorial in a completely randomized design with three replications in the physiology lab at the Islamic Azad University of Kaleiber Branch in 2018.The treatments consisted of different concentrations of acid salicylic in four levels (0, 0.5, 1 and 1.5 mM) and salt stress was inducted by NaCl solution (0, 50 100, 150 mM). The results analysis of variance showed that the effects of salinity and salicylic acid on germination indices and activity of antioxidant enzymes was significant.Results comparison of data showed that NaCl priming by salicylic acid increased the germination percentage, root growth, root, seedling dry weight and decreasing activity of antioxidant enzymes and seed protein content in the salty environment. Salicylic acid increased the level of cell division of seedlings and roots which caused an increase in plant growth. Enzymes activity assay showed that enzyme activity was increased under salt stress conditions and SA reduced activity of antioxidant enzyme by decreasing the salinity effects. In brief, the SA treatment reduced the damaging action of salinity on seedling growth and accelerated a restoration of growth processes. It seems that Salicylic acid as a plant growth regulator under salinity condition, activated plant tolerance mechanisms to salinity condition and decrease damaging effect of salinity on seed germination and seedling growth of wheat.

The cultivation of quinoa (Chenopodium quinoa Willd), an annual plant with high nutritional and economic significance, is expanding throughout the world. Quinoa is a traditional Andean seed crop highly tolerant to abiotic stresses. Since most seed crop cultivars are sensitive to drought stress, quinoa is regarded as a valuable candidate for the plant's exposure to harsh environmental conditions. Due to the importance of quinoa in arid regions, the effects of seed priming on yield and certain morphological and physiological traits were investigated in this study.

A factorial split-plot experiment based on a randomized complete block was designed with four replications was conducted in 2019 at Damghan Research Farm Station. The experimental treatments included drought stress based on the plant's water requirement at three levels (100% (control), 75%, and 50%) as the main factor, and sub-factors included three cultivars (Titicaca, Q26, and Q29) as well as priming at two levels (no priming and hydropriming) as a factorial experiment into sub-levels. To perform water requirement (WR) treatment, WR were calculated using the CROPWAT program and then applied to the 6-leaf stage plants.

The results demonstrated that drought stress (50% WR) reduced  relative leaf water content (13.1%), leaf membrane stability index (21.2%), chlorophyll content (38.7%), 1000-seed weight (18.2%), number of panicles per plant (27.5%), number of seeds per panicle (7.71%), and seed yield (40.4%). The use of hydropriming increased the membrane stability index, leaf chlorophyll content, 1000-seed weight, and the number of panicles per plant. Under 50% WR, the activity of antioxidant enzymes such as catalase and leaf ascorbate peroxidase increased by 139.58 and 42.55 percent, respectively, compared to the control. Additionally, drought stress increased quinoa seed protein content and decreased seed yield.. The percentage of seed yield reduction in drought stress was 50% and 75% of WR and was lower in Titicaca than the other two cultivars.  The comparison of the mean of irrigation interactions in the cultivars revealed that 100% WR produced the maximum quantities of Chl a, Chl b, and carotenoids in all three cultivars. Additionally, seed priming boosted the Chl a, and Chl b concentrations in Titicaca and Q26. Furthermore, the highest biological yield in the Damghan region was achieved in Q26 with 100% WR. Under normal irrigation conditions, Q26 cultivar had the highest seed yield, whereas under drought stress conditions, the seed yield of all cultivars decreased significantly. Nevertheless, this decline in the Titicaca cultivar was 12% less than in Q26 and Q29. The findings of the mean comparison revealed that priming improved seed yield in all three cultivars, with the Q29 cultivar producing the maximum seed yield at 1,452.03 kg/ha.

In general, Titicaca cultivar was more resistant to drought stress than other cultivars, hence its cultivation is encouraged in the Damghan region. Within the scope of this study, the use of hydropriming to improve quinoa's physiological features in conditions of drought stress is suggested. In conclusion, the results demonstrated that seed priming significantly increased seed yield, biological yield, leaf area index, and chlorophyll content in drought-stressed quinoa cultivars. These results indicated that seed priming can play a significant role in enhancing quinoa's drought resistance under low irrigation conditions. This study could contribute to the understanding of seed priming effects, which could be applied as an effective strategy to mitigate the negative effects of drought stress on quinoa cultivars.

Nickel is an essential microelement, but the increased concentration it in the medium disrupts the germination and growth of plants. In the present study, the effect of pretreatment and exogenous proline in the seedling growth of Cucumis melo under nickel stress was investigated. For this purpose, seeds were divided into two groups. In one group, seeds were sterilized for 24h, then they soaked in 0, 10 mM proline and finally cultured in different nickel concentrations. Another group seeds were soaked in deionized water for 24 hours and then cultured in petri dishes containing the same from one another concentrations of nickel and proline. All seeds were kept for 10 days, then measured germination, and growth parameters and membrane stability. The results showed that germination parameters were not affected by nickel. Radicle was more sensitive to Ni excess than hypocotyl. The amount of malondialdehyde increased with increasing nickel concentration. Add exogenous proline significantly reduces germination percentage and germination index but it increased mean germination time. Proline pretreatment in the presence of nickel treatments improved radical length, root to shoot ratio. But the addition of exogenous proline increased hypocotyl length while radical length and their ratio decreased in lower exposure levels. However, exogenous proline reduced lipid peroxidation and membrane permeability more than similar treatments under nickel treatments. Proline, as a pretreatment as a compatible solution and antioxidant, improves the early stages of growth and reduces the damage caused by nickel toxicity in the early stages of cucumber seedling growth.

Salinity is one of the main limiting factors for seed germination and seedling growth. The use of nutrients in priming treatment is known as an effective way to improve seed yield In this regard, a factorial experiment was conducted in the Khuzestan University of Agricultural Sciences and Natural Resources, based on randomize complete design with three replications. Priming treatment with nano and micro magnesium was performed at five concentrations zero, 50, 100, 200, 400 mg /litr, sepcratly. The durations of 12 and 24 hour were used for seed priming and salinity stress levels were zero, 50, 100, 150, 200, 250 mM made with sodium chloride. The results showed that increasing salinity stress declined hyssop seeds resistance and reduced the germination characteristics of this plant. Priming with 400 mg/litr magnesium microclate produced the highest germination percentage of 89.3%, average germination time of 5.9, seed vigor of 27.2 and root length of 24 mm. The highest germination rate (0.461 per day) and shoot length (18 mm) were observed in control and 400 mg/litr of nano-chelate, respectively. Results showed that nutrient seed priming with micochelate effectively alleviated salinity stress effects and improved seed germination properties compared to nanochelate magnesium. The optimum seed priming treatment obtained from 400 mg/litr micro chelate magnesium for 12 hours.