جستجوی مقالات مرتبط با کلیدواژه « طول ساقه چه » در نشریات گروه « زراعت »

 Lallemantia royleana is an annual herbaceous plant of Lamiaceae family in different parts of Europe, the Middle East, and especially Iran. Cyamopsis tetragonoloba L. is a plant of the legume family. A common feature between these two plants is hydrocolloid gums, which stabilize some food emulsions by absorbing water and increasing the viscosity or forming a gel in the aqueous phase. Due to its diverse and rich vegetation, Iran can produce countless types of plant gums, and many seeds such as Lallemantia royleana and Cyamopsis tetragonoloba contain valuable gums. Considering the important therapeutic and industrial applications of C. tetragonoloba and L. royleanaplants and the need for more information and reports on determining the best humic acid level and salt stress tolerance of these plants, the purpose of this research is to investigate the tolerance of two L.  royleana and C. tetragonoloba plants to salinity stress in the germination stage and the initial stages of the growth of two plants under the humic acid application.

The experiment was carried out as factorial in a completely randomized design with three replications at the seed laboratory of the Faculty of Agriculture of Zabol University in 1400. In this experiment, salinity stress was investigated using sodium chloride at control (no salinity), 70, 140, 210 mM levels and humic acid at (0, 40, 80, and 120 mg/L) levels. Humic acid solution at different salinity levels was added to each petri dish containing 25 seeds.

 The results showed that salinity stress decreased germination percentage, radicle length, plumule length, seedling length and seedling dry weight of C. tetragonoloba. In this plant, the germination percentage decreased by 35.34% compared to the control as the salinity stress level increased to 210 mM, and with the increase of the stress to more than 140 mM, a significant decrease in the germination percentage was observed. The maximum plumule length of L. royleanaplants was obtained in 70 mM salinity treatment and 40 mg/L fertilizer level. The maximum radicle length in the L.  royleanaplants plant was obtained in the treatment of 40 mg/L of humic acid at a 70 mM salinity stress level. Also, the results showed that the maximum radicle length (1.46 cm) in the C.  tetragonoloba plant was related to humic acid pretreatment at 70 and 140 mM salinity and fertilizer levels of 40 and 80 mg/L.

 In general, it can be stated that the germination indices significantly decreased under stress conditions, and this indicates that humic acid is a suitable pretreatment that can improve the growth indices of C. tetragonoloba and L.  royleanaplants under stressed and non-stressed conditions. With the application of humic acid at all salinity levels except 210 mM, the germination indices in the two mentioned plants were in a favorable condition.

1- The salinity stress tolerance threshold was studied in Cyamopsis tetragonoloba and Lallemantia plants.
2- Humic acid fertilizer in this study mitigated the destructive effects of salinity stress in Cyamopsis tetragonoloba and Lallemantia plants.

 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.

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.

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.

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.

Salinity stress is one of the most important factors in decreasing crop yield. Crossing between cultivars and wild relatives is one of the methods to creating salinity tolerant plants that has led to the creation of new Tritipyrum cereals. Investigation of the effect of salinity stress at the germination stage is a reliable test in assessing salinity tolerance of many species; it reduces percentage and rate germination as well as decreases of root and shoots growth. This research aims to investigate the effects of different levels of salinity stress on germination of promising non-Iranian Tritipyrum lines and two wheat cultivars, Alvand (salinity tolerant) and Ghods (salinity sensitive).

The experiment was conducted in factorial based on the completely randomized design at the Faculty of Agriculture, Yasouj University. The first factor consisted of 13 Tritipyrum lines and two wheat cultivars and the second factor consisted of different salinity levels (240, 160, 80, 0 mM NaCl). After surface disinfection and seed culture in a petri dish, germination-related traits were measured until the 14th day.

The results showed that by increasing salinity level, germination rate and percentage, root length, shoot length, dry and fresh root weight, and shoot dry weight decreased. The highest percentage (79.79%) and rate (75.74 seed per day) of germination in stress and non-stress conditions were related to the Az/b line. The germination percentage of the Alvand tolerant cultivar (55.59%) was higher than 5 Tritipyrum lines but less than the other 7 lines, its germination rate (53.69 seed per day) was higher than 10 Tritipyrum lines. The percentage and germination rate of sensitive cultivar Ghods (40.98 and 36.87 seed per day, respectively) were lower than all Tritipyrum lines. Under salinity stress, the La/b line had the highest root length (7.77 cm) which was even longer than the root length of the Alvand tolerant cultivar (4.9 cm). The highest root dry weight (0.027 g) under stress conditions was related to the Ka/b line and the lowest root dry weight (0.013 cm) was related to the Ghods cultivar. Among germination traits, the highest and the lowest heritability were related to shoot length under stress and non-stress conditions and root fresh weight (under non-stress conditions) and root length (under stress conditions), respectively. Genetic variance of shoot length and germination percentage in non-stress conditions was higher than stress conditions and selection under non-stress conditions had a higher yield than stress conditions. Clustering of genotypes by cluster analysis divided the genotypes into four groups under normal and salinity conditions. Under salinity stress, the salt-tolerant cultivar was placed alone in the fourth cluster. The salinity-sensitive cultivar was also in the third cluster with the St/b line. The rest of the Tritipyrum lines were clustered in the first and second clusters, with (Ka/b)(Cr/b)F6 hybrid line in the first cluster. Salt stress condition seems to have separated Qods from all Tritipyrum lines (except St/b), but under normal conditions, it did not indicate clustering accuracy of the studied genotypes.

The results of this study demonstrated salinity tolerance in the most simple and hybrid lines of this plant at the germination stage, among them (St/b)(Cr/b)F3, (Ka/b)(Cr/b)F6, and (Ka/b)(Cr/b)F3 and La(4B/4D)×(b) and the simple lines La/b, Az/b and St/b were better than others. Therefore, these selected lines can be considered in further complementary studies.

Fitness costs of herbicide resistance may be more evident and increase under stress environmental conditions. To test this hypothesis, a herbicide-resistant (R) and a herbicide-susceptible (S) phenotype with controlled and homogenized genetic background were isolated within a non–target-site resistant (NTSR) black-grass population. Accumulated maximum germination (Gmax) and time to reach the Gmax (G50) of biotypes were examined under non- and abiotic-stress conditions (salinity at 16 dSm-1, drought at -0.8 Mpa). In addition, seedling pre-emergence growth of the biotypes were evaluated at non-stress condition. There was no difference in Gmax between the R and S biotypes, whereas the Gmax of R phenotype was 28% and 49% lower than that of the S phenotype under salinity- and drought-stress conditions, respectively. The R phenotype germinated around seven to 16 hours later than the S phenotype under all non- and abiotic-stress conditions, i.e. the R phenotype had higher G50 than the other phenotype. The experiments of seedling pre-emergence growth showed that the R and S biotypes had similar root and shoot length under non-stress condition. The results clearly showed that the germinability fitness costs of NTSR black-grass increase when the plants are grown under salinity- and drought- stress conditions.

Allelopathy refers to the interaction of plants with their released chemicals on each other. Allelopathic compounds play an important role in biodiversity and the ability to produce ecosystems.In order to investigate the effects of allelopathy on Rosa damascena Mill on germination of wheat (Triticum aestivum L.) seeds. The experiment was done as factorial based on completely randomized design with three replications. The distilled water treatments used as control and different concentrations (0, 1, 2, 3, 4 and 5%) of aqueous extract of dried Rosa flowers used as treatments. Rosa flowers were from Boukan and Khansar, the designwere completely randomized in three replications. The results of this experiment showed that the juice extract with the mentioned concentrations did not reduce germination as compared to the control.The aqueous extract of Boukan showed a significant decrease in plumulelength, radiclelength, plumuledry weight, radicledry weight, and soluble protein content in wheat. Also, the extract of Khansar showed the highest inhibitory effect on plumule fresh weight, radicle fresh weight and soluble sugar content on the wheat plant.The analysis of variance showed that the difference between the extracts, treatments and extract × treatment was significant (P <0.05). There was a significant correlation (P <0.05) between fresh weight, dry weightand length, as well as protein and sugar content in both plants.

In order to evaluate the effect of drought stress on corn germination indices produced under drought stress on a parent plant, experiment was conducted in a completely randomized design with three replications in a Bahar university in 2017. The factors applied to the mother plant were: full irrigation as control (R1), full flowering stage (R2), pod closure (R3), pod filling (R4), seed start (R5), and complete seeding (R6). The results showed that the highest germination percentage, root length, stem length and dry weight of soybean seedlings were obtained in irrigation treatments throughout the plant life (control). No significant difference was observed between the treatments in the traits and the mean germination time. The lowest dry weight was obtained in drought stress at full flowering stage. Drought stress had an impact on the traits studied and it is recommended that soybeans, especially at full flowering stage, do not undergo drought stress.

The aim of this study was to evaluate the seed germination characteristics of A. desertorum and A. Pectiniforme primed with ascorbic acid under drought stress on laboratory conditions in germinator. Environmental stress, particularly drought stress, are the factors inhibiting growth and development of plants. Lack of water in germination stage depends on the severity and duration of stress leads to lack of germination. The present study was conducted to two important species of A. desertorum and A. Pectiniforme rangelands, which are the most valuable forage species for rangeland regeneration. Drought stress induced by polyethylene glycol at four levels (Zero, -4, -8 and -16 bar) and priming with ascorbic acid at four levels (Zero, 0.3, 0.5 and 0.8 mM) for 24 hours in four replicates and 50 seeds per replicate. The results showed that the most studied traits (germination percentage and speed, radicle length, plumule length and vigor index) in both species, except the mean germination time, significantly decreased with increasing ascorbic acid concentration and drought stress. Tolerance threshold in species A. Pectiniforme at 0 mM (control) priming in zero and 4 bar drought stress had the highest percentage of germination, vigor index and germination value, that there was no significant difference between the two levels of drought stress. In general, it can be concluded that tolerance threshold of A. Pectiniforme to drought was -4 bar and had more tolerant to drought stress than A. desertroum

IntroductionRange plants have important and crucial roles in medicinal industry andtogether with scarcity and low quality of the water and soil resources, prevent a quick recovery of the soil plant covering. Because of these restrictions, it is important to consider the use of salt and drought tolerant species for plantation and to preserve plant cover. In this sense, the use of native species such as black cumin (Bunium persicum Boiss) may be of interest due to their medicinal characteristics and potential ability to adapt to adverse conditions (dry and saline conditions). Black cumin (B. persicum) as a medicinal plant plays a vital role in Iranian medicine so there is a need to know about the factors affecting their growth and propagation.
Materials and MethodsTo investigate the effects of drought and salt stresses on germination and growth in black cumin two separate experiments were conducted. Drought stress was applied through incubation in four different concentrations of PEG 6000 that provide solutions with water potentials ranging from -0.2 to -0.8 MPa (including control and four levels of dryness). Salinity treatments (including control and four levels of salinity) were prepared by adding molar concentrations of NaCl to provide a range of salinity from 50 to 300 mM. Germination percentage and speed was calculated by computation of germinated seeds every day. Growth parameters (rootlet, shoot and seedling length total), allometric index and seed vigority were obtained accordingly.
Results and DiscussionSeeds under both drought and salt stress showed significant reduction in germination percentage, germination rate, radicle length, plumule length, and alometric and seed vigor indices. This trend was much pronounced under high levels of NaCl and low levels of water potentials, so that germination at Ψs = -0.6 MP was completely stopped.
ConclusionsAssessment of drought and salt stresses on germination and growth in black cumin is very important in the management of its planting. With increasing salinity and drought levels, the germination reduced significantly. Although due to higher germination of seeds in different levels of salinity rather than drought, this species seems to be more sensitive to drought stress.

There have been a little studies on removing the seed pods in annual medics, despite its importance. To investigate the role of pod removal on seed germination, seedling growth and antioxidant enzyme activities in annual medic (Medicago scutellata L.) Under salt stress, a factorial experiment was conducted based on a completely randomized design with four replications in 2014. Salinity at 5 levels: 0.62 (tap water as control), 3, 6, 9 and 12 dS m-1 was applied using sodium chloride. The results showed that salt stress caused changes in the characteristics of germination, seedling growth and antioxidant enzyme activities. With increasing in salinity levels, rate and percentage of germination as well as root length, shoot length and seedling weight was significantly decreased. However, increasing salinity levels increased the activity of antioxidant enzymes. Germination and growth in seed without pod was greater than those in seeds with pod; however, there were no significant differences between antioxidant enzyme activity; except about ascorbic peroxide that was significantly higher in seed without a pod. In general, salinity reduced germination and growth and increased antioxidant enzyme activity of annual medics. The results showed that planting seeds without pod had advantages for better germination and growth, especially under saline conditions.

In order to study the responses of redstem filaree (Erodium cicutarium L.) seed germination to temperature levels, an experiment was carried out in a completely randomized design with four replications and twelve levels of temperature (0, 3, 5, 7, 10, 12, 15, 20, 25, 30, 35, 40 0C). Results showed that the effect of treatments on germination properties of redstem was significant, so the highest percentage of germination was achieved at 150C and reduced with increasing temperature and was totally inhibited at 40ºC. Based on linear regression between germination rate and temperature, the cardinal temperatures: minimum (Tmin), optimum (To) and maximum (Tmax) were determined: 0, 15.20 and 37.18 ºC, respectively. Significant difference was not observed in plumule length at a range of 5-30°C that showed that it is less sensitive to temperature in comparison with root length. Highest wet dry weight was achieved at 20 °C that was not different by 10, 12 and 20°C. Above results suggest that redstem failure could grow in a wide range of growing conditions, but prefers temperate zones. The results of this study are important to understand thermal requirements and improvement of management strategies of redstem filaree.

In order to study the effect of seed priming by indole-3-butyric acid (IBA) on germination characteristics of pinto bean under salinity stress, a factorial laboratory experiment, based on completely randomized design with three replications, was carried out at the Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran, in 2011-2012. Three levels of pretreatment (0, 10 and 20 mg/L IBA) and five levels of salinity stress due to NaCl (0, 1, 2, 3 and 4 dS/m) were considered. Results represented the significant effect of IBA on shoot length, root dry matter as well as allometric coefficient. Salinity had significant effect on shoot and root length, shoot dry weight, vigor index and allometric coefficient. While, interaction effect of IBA and salinity was significant only for allometric coefficient. In this experiment, the rate and percentage of germination were not affected by any of the treatments. Comparison of means showed that increasing IBA concentration resulted in an increase in shoot length (1.9 to 2.1 cm), shoot dry weight (0.03 to 0.05 gm) and allometric coefficient (0.71 to 1.06 cm), while increased salinity resulted in a decrease in root length (2.6 to 2 cm), vigor index (202.8 to 147.7) as well as allometric coefficient (1.1 to 0.78 cm). Increasing salinity increased shoot length first, and then reduced it. Overall, it appears that application of IBA for pretreatment of pinto been seeds could enhance seedling establishment under saline conditions through the improvement of root length.

Seed germination is a crucial stage in the plant life cycle and salt tolerance during germination stage is vital for the establishment of plants in saline soils. In order to evaluation of sesame (Sesamum indicum) landraces germination to salinity stress at different temperature, an experiment was conducted at Ferdowsi University of Mashhad, Collage of Agriculture during 2009. Experimental type was complete randomized design in factorial arrangement with 4 replications. Factors included salinity at 7 levels (0, -2, -3, -4, -6, -8, -10 and -12 bar), temperature at 3 levels (15°c, 20°c, 25°c) and 3 sesame landraces (Sabzevar, Kalat and Oltan). Results showed that germination parameters (germination percentage, germination rate, root length, shoot length, dry weight of roots and dry weight of shoots) in all landraces were significantly (p≤0.01) affected by salinity and temperature. Increasing salinity reduced all above parameters in sesame cultivars, so that highest tolerated dose of salt was obtained in 25°c and increasing of temperature reduced effects of salinity. The highest germination percent was observed in salinity between 0 to -4 bar at 25°c. Sabzevar and Oltan landraces exhibited the highest and the lowest indicators at different temperatures respectively. According to these results, it seems that in saline condition and temperature variation, Sabzevar is the appropriate sesame landraces for optimal seedling establishment.

In this research the effects of cold were evaluated on coleoptile growth of 18 rice genotypes in two separate experiments. The first experiment was carried out as factorial based on randomized complete block design with three replications. In this experiment، two factors were including genotypes at 18 levels and temperature at 5 levels (9، 13، 17، 21 and 25 C°). The seeds of genotypes don’t germinate at 9 C°. The length of coleoptile was measured in plantlets at the end of using of each temperature factor. Analysis of variance revealed that the effect of temperature، genotype and interaction effects of two factors were significant on length of coleoptile at 1% probability levels. The low temperature treatments decreased the growth of coleoptile in all of the studied cultivars. Taichung and Sadri showed a significantly bigger coleoptile length at the three low temperature treatments including 13، 17، 21 and 25 C°. The percentage of coleoptile reduction was calculated form comparison of the length of coleoptile at 13 and 25 C°. The coleoptile reduction rate was lower than 10 percentages in Hashemi، Gerde and Neamat، indicating these varieties as tolerant varieties to cold stress. Second experiment was carried out on randomized complete block design with three replications. In this experiment، the seeds were placed in 25 C° for 72 h and then the temperature was adjusted to 10 C° for 96 hr. Temperature was further increased to 25 C° and treated plantlets to this temperature for 72 h. The length of coleoptile was measured in two stage contain after 10 C° for 96 hr (length 1) and 25 C° for 72 hr (length 1). The difference between these two lengths were calculated and called coleoptile regrowth. Analysis of variance indicated that the effect of genotype were significant on coleoptile regrowth. Gerde was as a tolerant variety due to percentage of reduction in coleoptile length and coleoptile regrowth.

Allelopathic compounds display an important role in biodiversity، stability and ability of ecosystems production. This phenomenon that has not been considered in range improvement is of important concerns in restoration of rangelands. Artemisia aucheri due to having chemical properties may contain allelochemical components. In this study، allelopathic effect of mentioned species was tested on Festuca arundinacea and Dactylis glomerata of seed germination. To do so، aerial part powder of Artemisia aucheri (stem، leaf and seed) collected from habitats in flowering stage (end of November). Also a control treatment (distilled water) was used. A completely randomised design was carried out using six treatments and four replications in laboratory. Results showed a significant effect of aqueous extract of Artemisia aucheri on seed germination indices. The percentage of germination، seed germination rate and plumule and radicle length، and seed vigor of Festuca arundinacea، and Dactylis glomerata significantly reduced under aqueous extract of Artemisia aucheri.

In order to evaluate the effect of seed treatment with glycinebetaine, a factorial experiment with 5 glycinebetaine levels (0, 2, 4, 8 and 16 mM) and 6 drought stress levels (0, -0.1, -0.2, -0.4, -0.8 and -1 MPa) was conducted based on completely randomized design with 3 replications. Corn seeds were immersed in water for 24 hours at corresponding glycinebetaine concentrations. These seeds were placed in petri dish and were exposed to different drought stress levels using PEG 6000. Results showed that drought stress caused a significant reduction in all measured parameters at different glycinebetaine concentrations. However, glycinebetaine concentrations of 2 and 4 mM effectively decreased the drought stress impact on seeds. Seed treatment with glycinebetaine, however, could not alleviate the effect of drought stress on germination rate. The three-parameter logistic model fitted to germination percentage effectively successfully justified the advantageous effect of seed treatment with glycinebetaine under drought stress. According to the model estimation, the drought level which causes 50% reduction in germinability was happened at higher drought stress levels when seeds were treated with glycinebetaine. Seed treating with glycinebetaine could alleviate the effect of drought stress on germination percentage, radicle and coleoptile length and fresh weight. Nevertheless, increasing the glycinebetaine concentration above 8 mM negatively affected germination and related parameters.

In order to study the influence of seed treatment with glycinebetaine (GB) on alleviating the negative effect of salinity stress at germination and early seedling growth stage of corn, a factorial experiment was conducted based on CRD with three replications. Seeds were soaked for 24 hours at different GB levels including 0, 2, 4, 8 and 16 mM and then were placed in petri dish. To apply salinity stress, NaCl solutions at different levels (0, 5, 10, 15 and 20 dS.m-1) were added to the Petri dishes. Results indicated that all measured parameters showed a significant negative response to salinity. Seed treatment with GB, however, caused a significant increase in germination percentage and length and fresh weight of radicle and coleoptile. This experiment showed that seed treatment with GB had a positive effect on reducing the effect of salinity stress and using GB proved its positive effect up to the salinity level of 10 dS. m-1. Comparison of the means showed that GB concentration of 4 mM provided the best situation in alleviating the salinity stress at germination stage and was in the highest statistical level. It is notable that GB concentration of 16 mM caused a negative impact on germination characteristics.