جستجوی مقالات مرتبط با کلیدواژه "تنش شوری" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

Haloxylon salicornicum (Moq.) Bunge ex Boiss and Haloxylon aphyllum Iljin are two important halophytes in desert. Hammada salicornicum and Haloxylon aphyllum Iljin have grown extensively in playa and sand dunes and are essential for supplying of forage for livestock, especially camels. The present study investigated the effects of different soil conditions in two areas (soil saline-sodic of playa and sandy soil in erg), on antioxidant activity, pigments characteristics, total phenolics, glycine and glutamine. The results showed that the highest amounts of chlorophyll a and total chlorophyll were measured 4.35 and 5.72 mgg-1fw in H. aphyllum and playa habitats, respectively. The highest amounts of chlorophyll b with 2.85 mg/g fresh weight were measured in H. salicornicum in playa habitats. The amount of anthocyanin was double in the playa habitats and was more than these two plants. The highest amounts of phenol with 458.97 mg/g fresh weight was measured in playa habitats and in H. aphyllum with 469.53 mg/g fresh weight. The amounts of antioxidant activity in playa habitats and H. aphyllum were significantly more than the erg habitat H. Salicornicum. Glutamine was not significantly different between the two habitats. The highest amounts of glycine betaine were measured in sandy habitats in H. Salicornicum. H. Salicornicum and H. aphyllumknown as halophytes can be countered salinity by various mechanisms, such as improving their biochemical conditions, and thus improving the quality of forage and increasing the foliage preference value.

This study was conducted in two separated experiments in the National Salinity Research Center in 2016. In the first experiment, the effect of 12 priming treatments consisted of potassium nitrate, sodium chloride, calcium chloride, and GA3 with control were investigated on seed germination of Salicornia (Salicornia bigelovii var. LVYUAN no.1) in order to select the best priming for the second experiment. In the second experiment, the effects of different salinity levels (12.5, 25.0, 37.5 and 50.0 dS m-1) and GA3 concentrations including 500 and 1000 mg L-1 were also evaluated on seed germination of the Salicornia genotype. The salinity treatments were prepared by different percentage of Persian Gulf water. The results showed that all the priming treatments increased germination percentage compared to the control, and the highest effect belonged to the concentrations of 500 and 1000 mg l-1 of GA3,by 142.3% and 119.1%, respectively. It was revealed in the second experiment that salt stress significantly reduced percentage and rate of seed germination, so that salinity treatments as 12.5, 25.0, 37.5 and 50.0 dS m-1 could reduce germination percentage by 11.8%, 40.3%, 63.3% and germination rate by 81.4% and 21.3%, 40.0%, 62.3% and 70.1%, respectively. However, GA3 priming could improve the salt tolerance and compensate a part of this loss, especially at 500 mg L-1. Application of GA3 increased salt tolerance threshold of Salicornia at germination stage. In no prim and GA3-priming treatments at 500 and 1000 mg L-1, salinity tolerance thresholds were 4.15, 9.31 and 6.56 dS m-1 and the threshold of 50% reduction was 20.36, 35.97 and 31.39 dS m-1, respectively. In general, the results indicated that seed germination and rate of Salicornia were improved using GA3.

Salinity is one of the environmental parameters that its impact on plant species diversity requires further studies. In this research, change of plant diversity was studied along a salinity gradient that was resulted from proximity of water table to the land surface in Incheh Borun plain due to the altitudinal change in northern part of Aq-Qala city. A transect with the length of 1 km was laid out along one of the hills in the region. Sampling units (plots) with the size of 3×3 m were established at 100 meters intervals along the transect. A floristic list was compiled and plants canopy cover was estimated in each sampling unit in the direction of dominant altitudinal gradient. Shannon-Wiener and Simpson indexes were calculated by using of PAST software. β-diversity was calculated between the sampling units using the Whittaker index. The relationship of salinity changes between sampling units along the altitudinal gradient and Alfa diversity, Simpson and β-diversity was studied using the linear regression. Results showed that there are significant relationships between the altitude, soil salinity and plant diversity indices. Soil salinity increases by decrease of altitude and the biodiversity decreases by increasing of soil salinity. These changes occur due to increasing of salinity.

Salinity stress is considered as one of the major factors that reduce plant growth in many regions in the world. Agropyron pectiniforme and Agropyron trichophorum species are perennial grasses species that product valuable forage and grazing material in pasture and rangelands of Iran. The aim of this study was determining effect of salinity stress with NaCl on seed germination traits of Ag. pectiniforme and Ag. trichophorum species. The experimental design was a two factorial (species treatments and salinity levels or salt stress 0, 50, 150, 250 mM NaCl) arranged in a completely randomized design with three replicates and 50 seeds per replicate. The data were statistically analysed by the MSTAT-C, computer program. The difference between the means was compared using Duncan test (P

Distribution and establishment of plants are affected by genetic characteristics and environmental conditions. Salsola imbricata distributed in arid and semiarid area of Iran. This study investigated some ecological characteristics of Salsola imbricata in Tabas area. Edaphic characteristics of the species habitat such as texture, Ec, gypsum, lime, Na+, organic matter were investigated. Climatic and biometric characteristics of the habitat, the effects of salinity stress on germination and Na and K content of the stem were measured. The results showed all of species need soils texture of loamy-sand with high amounts of gypsum and lime and pH of alkaline. Due to low humidity and organic matter of the soil, density and coverage of studied plant was low. Rainfall in all habitats was low, average temperature between summer and winter was high and annual aridity was between 10 to 12 months. The number of days in freezing-point in habitat was low. The highest and lowest germination percentage in control and in salinity of 22.8 g Nacl was equal to 65 and 22.5 percent respectively. Results also showed the amount of Na was more than K in aerial parts of the species.

This study aimed to evaluate the ameliorating effects of silicon nutrition on Festuca arundinacea under salinity stress. A completely randomized design was used to study the effects of different levels of salinity including 0 and 100 mM NaCl and silicon nutrition including 0, 0.75 and 1.5 mM sodium silicate on the species performances. The plants cultivated in greenhouse in sand culture with Hoagland nutrient solution. The results showed that the plants growth was reduced in salinity treatment. The plants performances were improved using silicon nutrition (especially 0.75 mM). Salt treatment increased the Na+ and decreased K+, Ca2+ and Fe content in aerial parts of the species, however, silicon treatment led to reducing the Na+ and increasing Fe content. The activities of soluble and cell wall peroxidase and polyphenol oxidase enzymes were declined in the species under salinity. The application of 0.75 mM Si approved to be an effective way to recover the activities of these enzymes. Salinity imposed significant reduction in contents of chlorophylls, total carotenoids and xanthophylls and soluble proteins, however, the hydrogen peroxide rate as well as lipid peroxidation contents were increased. On the contrary, chlorophylls, total carotenoids and xanthophylls and soluble proteins contents were increased and hydrogen peroxide and lipid peroxidation were decreased in salt-treated plants following Si treatment (0.75 mM Si). Salinity caused significant increase in electrolyte leakage from plant membranes; however, silicon nutrition (0.75 mM Si treatment) reduced these parameters. The result indicated that silicon nutrition (especially 0.75 mM treatment), mitigates harmful effects of salinity through declined Na+ content and increased antioxidant enzymes activities that reduced oxidative stress as evidenced by decreased lipid peroxidation and electrolyte leakage. Consequently, Si application led to better growth of salt –affected plants.

In rangeland watersheds, drought and salinity are the two preventive factors for production. So one of the obstacles to the development of plants that is salinity and drought during seed germination. in this study we evaluated the effects of salinity stress on Helichrysum globiferom and Helichrysum aucheri germination properties based on a In the form of a factorial experimental design with four replications and four salinity levels (0-50-100-150 mM sodium chloride) in seed Ecology laboratory of Sari Natural Resource Faculty. Seeds of two species were collected of Qushchy pastures in 70 kilometers of the old road of Urmia-Karabakh. Results showed that salinity stress had a significant reducer effect on percentage and speed of germination, growth of root and shoot length in two Species. Amount of reduction in the total in all traits species of Helichrysum globiferom species of Helichrysum aucheri. The amount of this reduction in all traits in Helichrysum globiferom was less than Helichrysum aucheri species. The ratio of Root to shoot length (allometric coefficient) also was the highest in Helichrysum globiferom. So we conclude that this species is more resistant than other species. So the highest decrease in both species was observed in germination percentage, germination speed, and root, shoot and plant length, in treatment 150 mM.

In the current study, the salinity tolerance of Atriplex leucoclada, a native species to Iran with appropriate nutritional value for livestock, was investigated under greenhouse condition and natural habitats of Fars province. For this purpose, NaCl treatments at different concentrations of 0, 100, 200, 300, 400, and 500 mM were applied on pots in a growth chamber at 20°C and a photoperiod of 8/16 h (light: dark), and growth characteristics were measured. Soil and plant sampling was conducted in natural ecotypes of Atriplex leucoclada in Darab region. Plant samples were collected randomly from the roots and shoots in vegetative growth stage, and soil samples were taken from two soil depths of 0- 10 and 10-45 cm. The results of NaCl effects on growth characteristics of Atriplex leucoclada in vegetative growth stage showed that significant differences were found among the studiedconcentrations of NaCl as compared to the control group. Our results clearly showed that all studied growth characteristics including shoot fresh and dry weight, root fresh and dry weight,LWR, LAR, SLA, plant height and LA increased at concentrations of 0, 100, 200, and 300 mM in comparison with control. However, increasing salinity stress more than 300 mM caused to the reduction of growth characteristics significantly. As a result, salinity stress up to 300 mm NaCl not only limited the growth of Atriplex leucoclada but also increased the growth characteristics, indicating that this species is an obligatory halophyte in vegetative growth stage.

Salinity stress is one of the most important problems of arid and semi-arid regions in the world. Based on Food and Agriculture Organization report, more than 40% of Iran’s under Irrigation lands, are against secondary salinity. The effects of salinity stress on some of vegetative traits and water relations on two rangeland plants species of leguminosae family was the main objective of this experiment. The study conducted in completely random design with factorial experiment and four replications in greenhouse conditions. Experimental treatments were two Hedysarum criniferum and Hedysarum coronarium species and five levels of salty water solution containing pure sodium chloride with concentration of 0, 100, 200, 250 and 300 mM. Results of the experiment showed that salinity affected the vegetative traits and water relations on Hedysarum criniferum and Hedysarum coronarium. Increasing the salinity caused significant (P<0.05) increases in the water use efficiency of Hedysarum criniferum and Hedysarum coronarium.With increasing salinity rates, some vegetative traits decreases such as shoot dry weight and root dry weight were observed (P<0.05).

Aeluropus littoralis، a monocot halophyte، plays an effective role in the conservation of water and soil resources and the production of forage for livestock in saline lands. In the current study، physiological characteristics of Aeluropus littoralis was investigated in response to different salinity levels. After disinfection، the seeds of Aeluropus littoralis were cultured in acid-washed sand in a growth chamber under controlled condition، temperature of 25/16 °C and photoperiod of 14/10 h for day/night. After 45 days of start culture، salinity treatments (0،100،200،300،400mM NaCl) were applied. The experimental design was completely randomized design with five treatments and three replications. After 14 days of last salinity treatment، plant materials were harvested. Results showed that the highest amount of shoot dry weight and ash content was observed in 200 mM NaCl. According to the results، potassium content of the shoot unlike sodium decreased with increasing salinity، while secreted sodium and potassium from plant aerial parts increased. Root carbohydrate content and the ratio of chlorophyll a to b increased in response to salinity. The concentration of starch and total soluble sugars of shoot demonstrated no significant relationship with the ratio of chlorophyll a/b at the highest salinity level. Our results suggested that the management of detrimental ions along with the regulation of plant assimilations effectively involved in the performance of Aeluropus littoralis to avoid the inhibitory effect of saline condition.

In order to evaluate effect of salinity on the germination and vegetative growth of grassland different salad burent Poterium sanguisorba two different experiments were conducted under laboratory and glasshouse conditions in summer 2010. In the first experiment six ecotypes (Semirom, Fereidonshahr, Tehran, Karsang, Damavand and farokhshahr) and four levels of salinity (0, 4, 8 and 12 dS m-1 of sodium chlorid under laboratory condition and in the second experiment four ecotypes of Semirom, Fereidonshahr, Tehran and Karsang and four levels of salinity (0, 4, 8 and 12 dS m-1 of sodium chlorid under greenhouse condition were carried out in factorial experiment with three replications. Traits of germination percentage, germination speed, length of radicle and plumule and seedling wet weight in the first experiment, protein, proline content, percent of Cl and Na above ground plant in the second experiment were measured. The results under laboratory condition, showed that with increased in salinity stress, percent of germination and speed germination, length of radicle and plumule and seedling dry weight were significantly decreased. Based on the greenhouse result, protein content significantly decreased, percent of Cl, Na and proline concentration significantly increased. In the germination stage and seedling stage, Ecotype of Tehran showed the maximum resistance to salinity stress.

Salinity is one of the main osmotic stresses on growth and production of plants in arid limit. The use of salt endurance species in the restoration and development rangelands, particularly in arid is very important.Given the importance of annual medics in the restoration and development rangeland and the low awareness level of understanding of this species to salinity, This study aimed to evaluate the endurance to salinity during germination were annual medics. Salinity at the germination stage for the creation of Sodium chloride (Nacl) and salinity (0 (control), 0/25, 0/5, 0/75, 1 and 1/25 MPa) was used. Components, including germination percentage, speed and uniformity of germination and seedling growth components, including the shoot and root Length, dry weight root and shoot And their ratio under salt stress was being investigated. The results showed that with increasing concentration of salt in the germination percentage, speed and uniformity germination shoot and root Length and dry weight decreased in both species. The significant differences in the percentage of germination, root and shoot dry weight in salinity were observed among species. In this study, the increased levels of salinity, germination percentage decreased with the decrease in the value of M. scutellata the control treatment to 1/25 MPa Nacl treatment was reduced by 99 percent. M. polymorpha reduction of 96% in comparison to the control was observed in 1.25 MPa. The results showed that the species M. polymorpha and M.scuteellata is more resistant to salinity at the germination stage.

The effect of various concentrations of drought and salinity solutions on germination of two species known as Agropyron elongatum and Agropyron desertrum were investigated according to factorial design. This investigation contains three repetitions, nine drought levels (0,2,4,6,8,10,12,14,16), and seven salinity levels (0,2,4,8,16,33,64). 50 seeds of any species were cultivated in Petri dishes on filter papers inside the germinator during each repetition. Test results show that the maximum germination in drought potential of 2 MP in A.elongatum species has been about 62/70 percent and the maximum germination in salinity potential of 0, in A.desetrum species has been 100 percent. As a result, it can be said that, according to the overall results obtained from this study, the A.elongatum species are more resistant against salinity stress and drought stress,than other species.

To investigate the response of extremely hard seeds of Prosopis species from Fabaceae family in germination phase and growth seedling under saline stress, a factorial experiment (ABC) was conducted on the basis of Completely Randomized Design (CRD) with three replications at Seed technology laboratory of Collage of Agriculture, Shahed University. Salicylic acid Hormone at three levels (0, 0.3 and 0.6 mM) and salinity stress (NaCl) at four levels (0, 5, 10 and 15ds.m-1) were applied to study seed germination of Prosopis under scarification treatments. The results of the study showed that salinity had no significant effects (P≤0.05) on germination rate which indicates high salt tolerance of the species. No seed germination was recorded for Pods and seeds cultivated under no scratch treatment. Proline, protein and carbohydrates content were highest in the treatment of 0.3 mM salicylic acid, 10 ds.m-1 salinity and broken pods containing scratched seeds. Generally speaking, the results showed that Prosopis seedling needs to get rid of physical barriers and inhibitory components within pod and seed coat in order to obtain high seed germination. Moreover, salinity tolerance of this plant was 15 ds.m-1 considered as one of the most important legume species which stabilizes nitrogen in desert and semi- desert regions for combat desertification.

Salinity is one of the most important abiotic stresses that negatively affects the seed germination and growth of seedlings in plants. NaCl priming is of techniques to improve the seed performance and could increase germination percentage, growth of the seedlings and the mean time of seed germination under salinity conditions. This study was conducted to improve the seed performance of Festuca ovina under salinity stress conditions. A factorial experiment was applied based upon a completely randomized design with three replications (50 seeds per Petri dish). The effects of priming with three optimized dose (15, 30 and 45 dS/m) of NaCl solution for 24 h at 22±2 oC under dark conditions were assessed for improving seed traits of sheep fescue. NaCl primed Seeds were also examined at different salinity levels) 0, 5, 10, 15 and 20 dS/m). Germination percentage and mean germination time were significantly affected by interaction of salinity and priming. Root length, shoot length and vigor index was not affected significantly by priming treatments in all salinity levels. Germination percentage of primed seeds especially in high salinity levels (15 and 20 dS/m) was greater than to non-primed seeds. The results showed that NaCl priming (especially at 45 dS/m for 24 h) in high salinity levels could increase the seed yield of Festuca ovina in terms of seed germination.

Salsola arbuscula is a shrub with relatively wide distribution in arid rangelands and desert regions that has created extensive rangelands types in winter rangelands. Salsola arbuscula is considered as a forage and concrvative plant in arid regions and its development in these habitats especially with Artemisia siberi creates pastures with high power in winter rangelands. In the present study for investigating the effect of salinity and drought stress on seed germination of Salsola arbuscula two separate experiments in a completly randomized design with four replications were conducted in seed research laboratory faculty of agriculture university of Birjand. Salinity and drought have 12 treatments totally (six levels of salinity and six levels of drought) that consisted of zero (control)، -0. 5، -1، -1. 5، -2 and -2. 5 Mpa osmotic potentials. Salinity and drought treatments were prepared using Nacl and PEG6000 respectively in 25 degree celsius. The results indicated that salinity and drought stress decreased germination percentage، rate، shoot and root length and seedling dry weight very significantly but the most significant decrease was related to shoot length. Furthermore based on the obtained resultes it was indicated that Salsola arbuscula is more sensitive to salinity stress than drought stress at the stage of germination.

Agropyron deserterum and Ag. elongatum species have a high value for both fresh and dry forage and because of high production and top acceptance by livestock they have specific value in the beginning of the growth season for livestock grazing. This research was conducted to study the effects of salinity stress on the mentioned species in germination and vegetative growth stages. A completely randomized design including five levels of 0, 100, 200, 300 and 400 mM NaCl and CaCl2 with 4 replications was used. Seeds were sown in laboratory and germination percentage, germination velocity, vigor index, plumule and radicle length and seedling dry weight were calculated. In greenhouse condition, shoot and root length, seedling dry weight, dry weight to fresh weight ratio, leaf area and specific leaf area were measured. According to the results, in both studied species germination percentage, plumule and radicle length, seedling dry weight, leaf area and specific leaf area were reduced with increase of salinity. The results showed significant differences between two species for germination percentage and germination velocity (P≤0.01). In both germination and vegetative growth stages, Ag.elongatum was more salt tolerant than Ag.desertorum. The results indicated that Ag.elongatum was more salt tolerant species than Ag.desertorum and it can be recommended for cultivation in moderate saline rangelands.

In rangelands، drought and salinity are the two preventive factors for foliage production، due to their effect on seed germination and seedling emergence. In this study we evaluated the effects of salinity and drought stress on Trifolium alexandrium L. germination properties based on a completely randomized design (CRD) with four replications in water- soil and plant laboratory of Sari Natural Resource Faculty. Salinity treatments included 0، 100، 200، 300، and 400 Mm NaCl and the treatments of drought were 0، -0. 3، -o. 6، -0. 9، and -1. 2 Mpa. Salinity and drought treatments were provided from NaCl and Polyethilenglychol (PEG) 6000، respectively. Results showed that salinity and drought stress had a significant reducer effect (p<0. 05) on percentage and speed of germination، vigority index، stem and root length. Germination stopped at 300 Mm NaCl while in drought stress significant difference was observed in all understudy characteristics. Results of this study indicated that Trifolium alexanderium is a sensitive species to salinity and drought stress.