جستجوی مقالات مرتبط با کلیدواژه "شیرین بیان" در نشریات گروه "زراعت"

Fallowing, which is one of the common practices in Iran's cropping systems, brings negative consequences such as soil erosion and reduction of its fertility, leaching of nutrients and, as a result, groundwater pollution. In addition, this practice increases weed infestation in an environment free of competition. Planting cover crops is one of the alternative methods to increase the quality and health of the soil and produce a healthy crop with minimal use of chemical inputs. Through competition and production and release of allelopathic substances in the soil environment, these crops are also considered as a suitable tool in suppressing weeds. The present study was conducted in order to investigate the effect of planting several species of cover crops as pure and mixed green manures on some soil characteristics and weed control.

This experiment was conducted in the form of a randomized complete block design with three replications in the Research Farm of Agriculture and Natural Resources Campus, Razi University, Kermanshah. Experimental treatments included cover crops of barley, common vetch and Persian clover in pure and mixed form at 10 levels: control (without cover crop), pure clover, pure barley, pure vetch, 50% barley + 50% clover, 50% barley +50 vetch, 50% vetch + 50% clover, 30% barley + 70% clover, 30% vetch + 70% barley, and 40% clover + 40% vetch + 20% barley. In order to cultivate cover crops, the land was first prepared by plowing and disk harrowing. Then, the seeds of cover crops were planted in plots of 7 × 6 m dimensions, using a furrower. The amount of seed used in the pure cultivation treatments of vetch, clover and barley was 60, 20 and 150 kg ha-1, respectively, and in the mixed treatments, different amounts of the seeds of each cover crop were planted based on the above-mentioned ratios. On the 30th of May (one month before planting potato) and at the stage when none of the cover crops had entered seed production stage, they were incorporated into the soil as green manures in two stages (one week apart) and at a depth of 10 to 15 cm.

The results showed that the cultivation of cover crops caused a decrease in pH and an increase in soil organic carbon compared to the control treatment, so that the lowest pH (7.32) and the highest soil organic carbon content (1.76%) were obtained from the pure barley treatment. Also, treatments of 40% clover + 40% vetch + 20% barley and 50% vetch + 50% clover caused a 38% and 36% increase in soil nitrogen, respectively, compared to the control treatment. The use of cover crops increased the content of phosphorus and potassium macronutrients in the soil both before and after potato harvest, compared to the control. The use of cover crops reduced the density of weeds in 20 and 40 days after potato cultivation, and the pure barley treatment reduced the density of weeds by 53 and 54%, respectively, compared to the control. The highest potato tuber yield was achieved under the treatments of 40% clover + 40% vetch + 20% barley and 50% vetch + 50% clover. The mentioned treatments increased the tuber yield by 71.09 and 59.79% compared to the control, respectively. The decrease in soil pH may be due to the accumulation of organic matter from crop residues and the acidification process during the mineralization of these residues, the increase in the amount of electrolytes, as well as the increase of microbial respiration and thereby the release of CO2 (5, 18). The increase in soil nitrogen availability following the application of green manures may have stemmed from the increase in root nodulation, release of a larger amount of nitrogen compounds by root nodules in the early stages of crop growth and their subsequent decomposition in later stages. Also, the increased nitrogen is at least partly due to the increase of organic matter through the return of biomass of cover crops in the cropping system (21). Covering the soil surface by cover crops and hence shading reduces weed seed germination and their subsequent growth due to competition of cover crops. In addition, during the decomposition of cover crop residues, allelopathic compounds are released in the soil environment, which affects the germination of weed seeds and establishment of their seedlings (15). Green manures obtained from cover crops increases moisture storage and improves soil fertility, enhancing the growth and yield of the main crop (16).

The results showed that the cultivation of cover crops instead of fallow increased the amount of organic carbon and macronutrients, despite decreasing the soil pH, leading to improvement in the access of the main crop to the soil nutrients. Weed control was another advantage of planting these crops. In the present study, the planting of leguminous cover crops with non-leguminous plants had the satisfactory results.

Glycyrrhiza glabra L., commonly known as licorice is a perennial medicinal plant, which possesses multiple health benefits. Licorice root extract can be used for traditional medicine and food and pharmaceutical industries since it contains bioactive compounds and main ingredients, glycyrrhizin, liquiritin, and glabridin. The utilization of plant growth-promoting rhizobacteria as biofertilizers is increasingly being suggested as a way to reduce the application rate of chemical fertilizers in agricultural systems. Therefore, the aim of this study was to assess the impact of Azotobacter as one of the plant growth-promoting bacteria alone and in combination with a reduced application rate of chemical fertilizer on photosynthesis, gas exchange, and biomass production of licorice plants propagated through seeds and rhizomes. A field experiment was conducted by inoculating the seeds and rhizomes of licorice plants with Azotobacter chroococcum (Ac; strain 1087) alone or in combination with reduced level of chemical fertilizer. The five treatments for the experiment were (i) control (no inoculation and fertilization) (ii) Ac inoculation; (iii) 100% recommended N (100% N) (iv) 50% recommended N (50% N); and (v) Ac inoculation + 50% N which were evaluated in both propagation methods (seeds and rhizomes). Net photosynthesis rate, leaf transpiration rate, intracellular CO2, photosynthetic water use efficiency, chlorophyll content (SPAD value), plant height, leaf area, and shoot, root, and rhizome dry weight, and total biomass production (root + rhizome) were measured. The observed results revealed that the licorice plants produced from the rhizomes showed an increase in plant height by 75%, a four-fold increase in the leaf area, a nine-fold increase in the shoot dry weight, a 6.6-fold increase in each rhizome weight, and increase of 23-fold, 7.3-fold, and 11.1-fold in production of the rhizome, root, and total biomass respectively, compared with the plants produced from seeds. The findings also showed that Ac inoculation further influenced root and rhizome biomass production more than vegetative growth-related parameters and shoot biomass production. Integrated inoculation of Ac with 50% N applied, interestingly, improved the plant shoot dry weight by 134 and 147% and total biomass production by 149 and 94% through improving the leaf area by 180 and 114%, SPAD value by 13 and 9%, net photosynthesis rate by 119 and 15%, and water use efficiency by 43 and 42% in plants resulted from rhizomes and seeds, respectively. Moreover, results demonstrated that simultaneous inoculation of Ac and the application of 50% N showed similar results compared with the application of 100% N. These findings suggest that inoculation of A. chroococcum integrated with a reduced dose of urea can reduce the amount of nitrogen fertilization up to 50% without significantly reducing the yield of licorice produced through seeds and rhizomes. The results of this study also showed that the licorice produced from the rhizomes showed a multifold increase in various growth and yield traits compared to the licorice obtained from the seed during the first growing year. This can be considered in the production of licorice plants in different conditions, based on different production aspects.

The function of a growth substrate is to provide an ideal medium for plantlet emergence which allows for the optimal development of plants during the time they stay in the container. A high-water storage capacity is necessary due to the limited volume available in growth substrate. There is a large variety of materials available for substrate elaboration, and their selection depends on the plant species to be propagated, season, propagation system, price, substrate availability and proper features. Compost seems to be an excellent alternative to peat. Also, the fresh material presents a high carbon: nitrogen ratio (C: N) and it may contain substances that are toxic to the plants, such as phenols, resins and tannins. Choosing the suitable planting bed for ornamental plants is one of the problems for most greenhouse managers. In this regard, in order to investigate the possibility of using liquorice residue compost as a by-product of the medicinal plant industry, in growth medium, the effect of peat moss, coir and liquorice root residue compost on the growth of African violet tested in an experiment.  
 
The experiment was done with 7 treatments and 5 replications in a completely randomized design. Experimental treatments included: 60% (volumetric) peat moss, 60% coir, 60% liquorice root residue compost, 30% peat moss + 30% coir, 30% peat moss + 30% liquorice root residue compost, 30% coir + 30% liquorice root residue compost. Each treatment was mixed with 40% perlite. According to the results of a pre-test on the low water retention capacity of liquorice compost, a treatment was also performed using liquorice compost with superabsorbent polymer (Aquasorb made by SNF) at a rate of 5g/kg mixed medium.
 
Experiment results in African violet showed that in shoot fresh weight, leaf number, root fresh weight, leaf area and relative leaf water content of 30% peat + 30% coir treatment and shoot dry weight, flower number and chlorophyll a were the best in 30% peat moss + 30% liquorice root residue compost treatment. The highest amount of chlorophyll b and total chlorophyll were observed in 60% liquorice root residue compost + superabsorbent polymer, the highest carotenoid content in 60% peat treatment, and the highest root dry weight and proline content in 60% liquorice root residue compost treatment. In general, according to the obtained results, by using licorice root residue compost with peat, it is possible to achieve favorable growth results, and it is recommended to use it up to 50% of the required organic matter in the bed of African violets. Based on the results of this study, licorice root resigue compost with peat moss can achieve favorable growth results and it can be used up to 50% of the required organic matter in African violet bed. The effects of licorice compost on morphological and physiological parameters of plants may be due to its effects on increased water content and soil aeration. Because there is a strong relationship between RWC and plant biomass. That also suggests that plants having greater biomass can maintain higher water content in their leaves.
 
Presence of nutrient elements increased the overall fertility, and functionality of the tested media, leading to maintain better plant growth. RWC is a measure of plant water status, which reflects metabolic activity in plant tissues and is one of the most important indicators to identify differences in substrate conditions.

Licorice (Glycyrrhiza glabra L.) is a perennial medicinal plant which its root and rhizome extract broadly use for food and pharmaceutical industries. Considering the necessity of its domestication as an alternative approach for its wild collection, this experiment was counducted to investigate the effect of electrical conductivity (EC) of nutrient solution on growth and yield of three licorice ecotypes under hydroponic culture.

the experiment was conducted as factorial based on randomized complete block design with three replications in Research Greenhouse of Department of Horticultural Science and Landscape Engineering, University of Tehran in 2018. Treatments were included four levels of electrical conductivity (EC) of nutrient solution (1.5, 2, 2.5 and 3 dS.m-1) and three licorice ecotypes (Baft and Lalehzar from Kerman province and Eqlid from Fars province). In this study, some morphophysiological traits such as plant height and diameter, main stem diameter, number of lateral branches per plant, internode length, leaf area, root length and diameter, root and shoot fresh and dry weight and some biochemical traits such as Chlorophyll index, total phenol content and total antioxidant activity were measured.

the results showed that there was a significant difference between ecotypes on all studied traits except total phenol and total antioxidant activity. Also, different levels of electrical conductivity significantly affected the studied traits, except for root dry weight and total phenol. The interaction effect of both treatments was significant in terms of the morphophysiological and biochemical traits. In each of the three ecotypes studied, with increasing the electrical conductivity of the nutrient solution, plant height and diameter, internode length, leaf area and root diameter showed a decreasing trend. The highest dry weight of shoots was observed in Baft ecotype from Kerman with electrical conductivity levels of 1.5 and 2 dS.m-1 (4.51 and 4.91 g.plant-1, respectively) and Eghlid ecotype from Fars with electrical conductivity of 2.5 dS.m-1 (4.91 g.plant-1). Also, Baft ecotype from Kerman showed the highest dry weight of root (16.02 g.plant-1) in electrical conductivity of 3 dS.m-1. In terms of biochemical traits, the highest amount of chlorophyll index was observed in Lalehzar ecotype from Kerman and electrical conductivity level of 2.5 dS.m-1. The highest amount of total phenol and percentage of antioxidant activity was related to Lalehzar ecotype at the electrical conductivity level of 3 dS.m-1.

according to the results, Baft ecotype from Kerman province and then Eqlid from Fars province in range of electrical conductivity level of 1.5-2 dS.m-1 performed better while in terms of quality criteria, Lalehzar ecotype from Kerman showed the highest amount in electrical conductivity of 3 dS.m-1 compared to other treatments.

The root of liquorice contains a large amount of glycyrrhizic acid which are known to have various food, industrial, cosmetic and pharmaceutical applications. Regarding to spreading of salinity in arid and semi-arid regions, to assay the tolerance levels of salinity in germination and vegetative stages and the effect of salt stress on the concentration of glycyrrhizic acid in liquorice plant, an experiment performed based on a randomized complete design with at least three replications. Salt stress applied at four levels including 0, 100, 200 and 300 mM NaCl. Our results at the germination stage showed that NaCl at 100 mM level caused a significant decrease in germination rate and percentage and the length of primary root and hypocotyl were diminished. While 200 and 300 mM levels of NaCl inhibited the germination. The results at vegetative stage showed that high salinity levels decrease the root/shoot dry weight ratio, plant yield, protein content and the K/Na, Ca/Na, Mg/Na ratios of shoot and root while the concentration of 300 mM NaCl caused a significant increase in root dry weight and shoot malondialdehyde and total phenol content in comparison with control. Also, the high concentrations of salinity increased the concentration of glycyrrhizic acid in roots. According to measured results at germination and vegetative stages of liquorice plant, it can be concluded that salt tolerance is a developmental stage specific phenomenon. Also, that cultivation of liquorice in saline soils potentially could increase glycyrrhizic acid accumulation in liquorice roots.

The licorice is a perennial herb of the Fabaceae family, which is native to the Mediterranean, south of Russia and Asia, but is now cultivated throughout Europe, the Middle East and Asia. This plant grows in different regions of Iran. Although, from north to south of Iran, licorice carcasses come to the car, but since this plant is extracted from the ground, it gradually decreases in nature, so that in southern provinces of the country, especially the provinces of Fars and Kerman, this plant danger of extinction, so special attention is increasingly given to maintaining the heritable reserves of this plant more and more. quantitative and qualitative study of this plant in the natural habitats of different regions of the country has a significant role in identifying the best ecotypes for cultivation and domestication of this medicinal plant.

In order to study the diversity of morphological and functional traits of different populations in Zanjan climate, after collecting populations in autumn, they were cultivated in a randomized complete block design with 5 replications. Morphological and functional traits of different populations were evaluated late in the growing season. Plant height, plant width, leaf length, leaf width, leaf number, leaf length, leaflet width, lateral branch, main stem diameter, fresh shoot weight, root fresh weight, shoot dry weight and root dry weight, ratio Root to shoot, shoots yield, root yield, total phenol, total flavonoid and Glycyrrhizic acid were investigated. Data were analyzed using SAS and SPSS software. For cluster analysis, the cluster analysis was performed by input method and factor analysis was done using the Variomax rotation method.

The results of analysis of variance showed that there was a significant difference among 22 licorice populations for all studied traits at 1% level. The highest plant height in population AH (9 cm) was the highest plant width in population E (86.6 cm), the highest fresh weight in the population D (400.4 gr / plant), the highest root fresh weight in population E (356.2 gr / Plant) had the highest shoots yield in the population D (643.75 gr / m2) and the highest root yield in population E (692.25 gr / m2) and the highest percentage of Glycyrrhizic acid in population D (8.3%). The root yield was significantly correlated with plant height, plant height, main stem diameter, leaflet length, lateral branch number, fresh weight of shoot, root fresh weight, dry shoot weight, root dry weight, shoot yield, total phenol, total flavonoid and glycyrrhizic acid. There was a positive and significant correlation between dry weight ratio of root and shoot in 5%, but no significant correlation was observed between leaf length, leaf width, leaf number and leaf width. Based on the results of cluster analysis, 22 populations were divided into four main groups. Factor analysis showed that the first four factors were able to justify 84.184 percent of the total variance.

The overall results of this study showed that there is a great diversity among the studied populations on the basis of morphological and functional traits. According to the results of D, E, MS, SH, SP, and TF populations, they have desirable traits and proper yields and were identified as the most desirable populations in this research, which indicates high genetic potential among different populations and which can be considered as superior populations in breeding projects in order to create high quality and desirable food industries and the medicine was used.

In order to evaluate the effect of different mechanical treatments (application of sulphuric acid, boiling water and flooding) on seed dormancy breaking of Licorice, an experiment was carried out in randomized complete block design in 2012. Moreover, a factorial scheme in RCBD was performed to assess the application of giberalic acid and potassium nitrate treatment as well as stratification and rotational temperature/light treatment. Treatments included different levels of giberalic acid (0, 100, 250 and 500 mg) at two time levels of 2 and 24 hour (along with scarification pre-treatment), concentrations of potassium nitrate (0, 50, 100 and 150 mM) in 10 and 30 minutes (along with scarification pre-treatment), stratification temperatures treatment of -5, 0 and 5 °C for one, two and three weeks of treatment, treatment of rotational temperature (5-15 and 10-20 °C), in full light, dark and rotational light periods (8 h light and 16 h dark) and mechanical treatments of dormancy breaking. Treatment duration of two minutes in boiling water and two days water-logging treatment were the most effective treatments on germination percentage of Licorice (81.33% and 53.33% increase in germination percentage compared to control, respectively). Application of giberalic acid and potassium nitrate treatments and stratification had no effect on Licorice dormancy. According to the Licorice seed dormancy breaking in mechanical treatments and the effect of rotational temperature and light, it can be concluded that the dormancy of Licorice seeds is intermittent.

Licorice, Glycyrrhiza glabra (Fabaceae), is one of the herbal medicines. Glycyrrhizin is the importance content through compounds exiting in licorice, which is 50 times sweeter than sucrose. Glycyrrhizin used as the primary matter in pharmacy and used to remedy of many diseases, and also, used in tobacco, confectionary and beverage industries. Since Glycyrrhizin in the phases of growth received at maximum and then decreased; and also to consider of root diameter and harvest time effect on active substance content, This study done for determine the best harvest time and suitable root diameter to obtain the greatest Glycyrrhizin in this plant. For this study, root of Glycyrrhiza glabra were collected in four times (Nov, Dec, Jan and Feb) and in three root diameter (<1 Cm, 1-2 Cm and >2 Cm) from gorgan (Araghi mahalle agricultural station). Variant of measurement in this study were including fresh weight, dry weight (for determination of percentage of humidity) and glycyrrhizin content. Extraction of glycyrrhizin was done with methanol and its measurement done with used hight performance liquid chromatography (HPLC). The result showed that the least root diameter were containing the least humidity percentage (32.46%) and the greatest of glycyrrhizin (1.187%), the root were harvested in Jan., in comparison with other harvest time, were containing the least humidity percentage (22.26%) and the greatest amount of glycyrrhizin (1.112%).