جستجوی مقالات مرتبط با کلیدواژه « تنش محیطی » در نشریات گروه « آب و خاک »

The use of modifiers can reduce the effects of environmental stress in plants. The aim of this study was to investigate the effect of salicylic acid and zeolite in reducing alkalinity stress in black seed (Nigella sativa L.). A factorial experiment was conducted based on a completely randomized design with three replications in 2022 in the greenhouse of Razi university, Kermanshah. The factors included alkalinity stress (at three levels of 0, 50 and 100 mM as NaHCO3), salicylic acid (at three levels of 0, 0.5 and 1 mM), and zeolite (at three levels of 0, 0.25 and 0.5 % by weight). The results showed that the effects of salicylic acid and zeolite on most of the plant growth characteristics under alkalinity stress were significant (P ≤ 0.01). The highest amount of proline (12.65 μmol/g) and soluble sugars (0.2 mg/g) were obtained under severe alkalinity stress without the use of salicylic acid and zeolite. Also, the highest shoot height (24.6 cm), root length (19.5 cm), shoot dry mass (0.78 g) and leaf area (22.47 cm2) were obtained without alkalinity and with application of 1 mM salicylic acid and 0.5 % zeolite. In general, the use of salicylic acid, as a plant hormone, and zeolite, as a soil amendment, is a suitable and cheap strategy to reduce the effects of alkalinity stress in black seed.

Plant growth promoting rhizobacteria with ACC deaminase activity can be applied for stimulating plant growth under tension situations. In the present study, bacterial isolates were isolated from wheat rhizosphere in three provinces of Zanjan, Kurdistan and Hamedan and then screened for ACC deaminase production and salinity tolerance. Six isolates out of 167 isolates were able to degrade ACC to alpha-keto-butyrate and ammonia and the K78 isolate was selected as superior isolate. A completely randomized design with factorial arrangement was carried out on wheat plant in a greenhouse experiment. Experimental factors include: five salinity levels (1.3, 8, 12, 14, and 16 dS.m-1), three bacterial inoculation levels (no inoculation (B0), inoculation with salinity-resistant isolate and ACC deaminase production capacity (B1), inoculation with salinity-resistant isolate without ACC deaminase production capacity (B2). The results showed that salinity had a significant and negative effects on growth and nutrient uptake and decreased shoot length. The K78 isolate increased shoot length (21.5 %) and potassium uptake (15 %) significantly compare to B0 treatment but had no significant effect on sodium uptake. Overall, it can be concluded that inoculation of K78 isolate can reduce the negative effects of salinity on growth indices and the nutritional conditions of wheat.

Evening Primrose is one of the medicinal plants that have a high potential for Gamma linolenic acid production, which is essential as an intermediary in human body metabolism and Prostaglandins synthesis. In order to determine the effect of Salinity Stress and irrigation levels on morphologic and physiological characteristics of Evening Primrose, a pot experiment was conducted as a factorial based on completely randomized design with four replications in spring of 2018 at the Meteorological Station of Faculty of Agriculture, Ferdowsi University of Mashhad. The experimental factors consisted of irrigation treatments in 4 levels (100, 85, 70 and 55% Field Capacity) and salinity treatments at 3 levels (1.23, 4 and 8 ds/m). According on the results of this study, Evening Primrose plant could tolerate salinity and deficit irrigation stress before flowering at all levels. However, at flowering stage, it could not withstand the salinity levels at 4 and 8 ds/m and disappeared. Plant height, stem diameter and number of lateral branches in the interaction of stresses were less than Control treatment, while leaf length and width increased compared to control treatment. Simple irrigation effect was significant on electrolyte leakage in 0.01 level, chlorophyll b and Carotenoid in 0.05 level. deficit irrigation increased all physiological parameters compared to control treatment.

Climate warming causes prevention of the latest spring frosts and reduces the spring freeze risk during flowering. The purpose of this study was to explore the effect of climate change on the chilling requirement and the flowering date of completion of the phonological stages of different plants in Sari. A 45-year weather data (1970-1970) of Kiasar Synoptic Station were used with data access from National Centers for Environmental Prediction. The predetermined output of the large-scale climatic model (CanESM2) was used after the downscaling observation for RCP2.6 scenarios. Using the ChillR and Climdex model, the flowering date of DOY (day of year) and the Growing Season Length (GSL) were estimated. Mann-Whitney non-parametric test and Kendall's trend were used to compare the first half of the near future (2016-2055) and the second half of the distant future (2056-2100) with the present. The results showed although the growing season length increases, but a significant difference between the air temperature in the chilling and forcing phases is caused a significant change in the appearance of phenology stages of the deciduous fruit trees in the studied area. Over the past decades (1980-2000), about two weeks was added to the length of the growing season. However, the flowering date will take place three decades earlier than the past climate. These significant changes in cultivated climate parameters lead to irreparable phonological disorders in the coming periods.

Crop growth simulation models have been developed for predicting the effects of water and salinity on grain and biomass yields and water productivity of different crops. These models are calibrated and validated for different regions using the data generated from field. This study was carried in Mashhad for two years (2010 and 2011) in order to evaluate the AquaCrop model under simultaneous salinity and water stress. Calibration was done using the data of 2009-2010 and validation with the data of 2010-2011.Results indicated that AquaCrop successfully simulated yield, biomass, water productivity, harvest index, soil moisture and salinity profiles for spring wheat under salinity and water-limiting treatments with high accuracy, although simulation of harvest index and soil salinity profiles were less accurate. Average value of normalized root mean square error (NRMSE), maximum error (ME), index of agreement (d), coefficient of the residual mass (CRM) and coefficient of determination (R2) in both the calibration and verification were 13.3 %, 36.1 %, 0.95, -0.072, and 0.87, respectively, for grain yield, while these measures were 12.59%, 34.46%, 0.92, 0.057, and 0.77, respectively, for biomass. Also, value of NRMSE, ME, d and CRM were 11.84 %, 25.72 %, 0.93, and 0.032, respectively, for soil moisture, while these measures were 26.25%, 58.5%, 0.91 and -0.12, respectively, for soil salinity. Sensitivity analysis revealed that crop transpiration coefficient (KC-Tr), normalized crop water productivity (WP*), reference harvest index (HIO), volumetric water content at field capacity, soil water content at saturation[S1], and air temperature were the most sensitive parameters. Although the accuracy of the model simulation decreased with increasing salinity and water stress, AquaCrop can be a valuable model for simulating spring wheat yield and soil water content and salinity in Mashhad region, because the model requires few input data which can be readily available or easily collected. [S1]This is probably”initial conditions” and not saturation.