جستجوی مقالات مرتبط با کلیدواژه « فیزیولوژیکی » در نشریات گروه « کشاورزی »

Verticillium wilt disease is one of the most important damaging and limiting factors for cotton production worldwide. This pathogen causes leaf chlorosis, necrosis or wilt, leaf or pollen drop, and even plant death. It also reduces the quantity and quality of the product. Because of the economic importance of the cotton disease Verticillium wilt, the best way to control this disease is to use tolerant varieties. Therefore, breeding resistant varieties in a wide range is considered one of the most effective control methods. This experiment was conducted to determine the effect of the disease on the morphological and physiological characteristics of cotton cultivars in order to identify tolerant genotypes

The experiment was carried out during two years 2020-2021 and in a factorial form in a completely randomized design with three replications in the greenhouse of Khorasan Razavi Agricultural Education and Natural Resources Research Center (Plant Protection Department). In the first year, ten Iranian cotton cultivars belonging to Gossypium hirsutum were cultivated. In the first year experiment, cotton agronomic traits such as plant height, number of leaves, number of branches, crown diameter, leaf area size, disease severity, chlorophyll index, relative leaf water content and electrical conductivity were measured. In the second year, two tolerant cultivars (Bakhtegan) and sinsitive (Varamin) resulting from the first-year experiment were cultivated in the greenhouse along with the resistant cultivar of Thermous 14. At this stage, the amount of proline, soluble carbohydrates and total phenol was evaluated at different times after inoculation with the pathogenic fungus. All traits measured over two years using SAS statistical software were analysis of variance and the means were compared using Duncan's test.

In the first year, it was found that among the ten genotypes grown, all agronomic traits (except plant height) were higher in the Bakhtegan cultivar and lower in the Varamin cultivar than in the other cultivars. Under infection conditions, disease severity was highest in Varamin and Cocker100 cultivars. The lowest severity of the disease was in the variety Bakhtegan. Physiological traits such as chlorophyll index and relative water content were higher in Bakhtegan and lower in Varamin. The opposite was true for membrane electrolyte losses. In the second year, it was found that in the three cultivated genotypes Thermous14 (resistant), Bakhtegan (tolerant), and Varamin (sensitive), the amount of biochemical traits proline, carbohydrate, and total phenol was significantly increased in the infected plants compared to the control plants (no inoculation with pathogenic fungi).

Therefore, plants with more leaves, higher chlorophyll index and relative water content, lower electrolyte leakage, more proline, carbohydrates and phenols are more resistant to infection.

Water and soil salinity is one of the important factors limiting the development of green space in arid regions of Iran .In this study, some morpho-physiological characteristics of Morus alba, Ailanthus altissima and Cupressus Sempervirens seedlings to water salinity stress in Sokan nursery of Semnan were investigated.Eight levels of water salinity treatment were considered as 0, 2, 4, 6, 8, 10, 12 and 14 ds/m and irrigation was performed twice a week in the amount of four liters from July to September.During the experiment, morphological characteristics such as height and collar diameter of seedling were measured every 15 days after the start of treatment.At the end of the experiment, leaf samples of seedlings were collected and transferred to laboratory and dry and fresh weight of roots, shoots, leaves, Rwc, amount of Na+ and K+ leaf with flammimetric method, Ca+2 and Mg+2 leaf was measured by the complexometry method, the leaf nitrogen level using titration and phosphorous leaf method by ammonium molybdate in the laboratory.The results showed that the traits of seedling height, collar diameter, number of leaves, fresh and dry roots and shoots and, Rwc, content of Na+, Ca+2, P, Mg+2, N and K+ of leaf in salinity and species treatments were significant at 1% percent level. However, the interaction effect of species and salinity were not significant for all the above traits at the level of 1% and for the trait diameter of the collar and the elements nitrogen and potassium of leaf were not significant. Results of comparison of means showed that with increasing salinity, the amount of leaf sodium increased, but others factor decreased. The critical point for the changes in the above traits was often at salinity 6 to 8 dS/m and above, which indicates that the studied tree species can tolerate salinity up to this level.In comparison, in terms of all seedling height, collar diameter, number of leaves, fresh and dry weight of roots and shoots and, Rwc, the amount of Na+, Ca+2, P, Mg+2, N and K+ in the leaves among the three species, respectively, Morus alba and Ailanthus altissima then Cupressus Sempervirens showed the highest salinity resistance.

One of the ways to improve the food security of a growing population of the world is to increase the amount of production per unit area. Some of the nutrient elements such as silicon not only increase nutrient use efficiency but also increment product quality. In this research, the effects of various sources of silicon included Potassium silicate, Calcium silicate, Humistar Si in two levels 200 and 400 mg/kg and Nano-silicon in two levels 50 and 100 mg/kg and Control treatment on morphophysiological responses of the herb of the stevia plant were examined. After three months, the plants were harvested and fresh and dry weight of shoot and root, height and diameter of the shoot, root volume and leaf area as morphophysiological indices of the plant, and leaf chlorophyll, the concentration of silicon, phosphorus, potassium in the shoots, and Glycosides in the stevia leaf, including Stevioside, Rebaudioside A and B were measured. The results showed the effects of silicon sources on the fresh and dry weight of shoot and root, height of shoot, root volume, stem diameter, leaf area and leaf chlorophyll index were significant. The treatments of calcium silicate-200, Nanosilicon-100, and Humistar silicon-200 yielded the highest fresh weight of the shoot compared to the control samples and Nanosilicon-100 led to an increase of 55, 64, and 35% of mentioned elements compared to the control treatment. The treatment of Humistar silicon-400 showed the highest amounts of Stevioside (5.23%), Rebaudioside A (0.67%). Considering the effectiveness of the use of silicon element on morpho-physiological and nutritional responses, and improving the quality of Stevioside and Rebaudioside sugars, it is recommended that along with the optimal use of nutrients, more attention should be paid to the role of this valuable element.

Drought increases the salinity of agricultural lands. Recognizing some physiological mechanisms in strawberry plants is essential for facing the salinity.Methyl jasmonate is a plant growth regulator that affects many biochemical and physiological processes in a plant. Salicylic acid, as one of the hormones, plays an important role in increasing plant resistance to environmental stress. Growth regulators play a vital role during the growth stages of plants and their application can increase the quantitative and qualitative yields of plants. The present facotrial experiment followed arandomized complete block design with three replications andexplored the effect of different concentrations of methyl jasmonate (0, 1 and 2 micromolar) and Salicylic acid (0.2 and 4 mM) under conditions of salinity stress (0, 5 and 10 dS) on some morphological responses (plant height and leaf area), physiological traits (soluble solids, vitamin C and acidity), and function (fruit number, fruit weight and fruit yield) of strawberry plants. In the year 2018-2019, in Azad Shahr city of Golestan province, two strawberry cultivars (Silva and Camaroso (Fragaria × ananassa Duch, Selva and Camarosa)) were examined. The results of this study showed that salinity stress significantly reduced the morphological and physiological properties of two strawberry cultivars Silva and Camarrowso. Quantitative properties of plant height and leaf area, and the qualitative properties of soluble material, vitamin C, and acidity decreased with increasing salinity. Methyl jasmonate and salicylic acid significantly increased vegetative and reproductive growth. This result also correlates with the performance of two cultivars. In examining the effect of these two treatments under the same conditions of salinity, the salicylic acid in comparison with methyl jasmonate was shown to increase the quantitative and qualitative properties under salinity conditions.

Temperature reduction since late December until late February is a dominate climate phenomena in Khuzestan which caused plant damage and subsequently yield reduction. In order to study the effect of chilling stress at heading stage on yield, yield component and some physiological traits of wheat genotypes, this research was carried-out with five genotypes (Chamran, Vee/Nac, Star, Kharkheh cv. and line M-83-17) and four environmental temperatures(non-stress, and+3,0 and -3°C) under greenhouse condition, in factorial experiment using CRD with three replications in Khuzestan Natural Resources and Agricultural Research Center in 2013. Date of physiological maturity, plant height and spike length, yield components including spikelet/spike, grain no./spike, 1000 grain weight and grain weight in main spike and Fo, Fm, andFv/Fm indices were evaluated. Results showed that the effect of chilling stress was significant for days from germination to physiological maturity, grain no. per spike, grain weight in main spike and Fv/Fm traits. The highest grain weight in main spike under non-stress and -3°C chilling stress was belonged to line M-83-17 and Chamran cultivar, respectively and under zero and 3°C chilling stress were obtained from Chamran cv. and Vee/Nac, respectively. The highest difference before and after chilling in Fv/Fm index was belonged to zero chilling stress. Differences in traits which were studied in this research indicated genetic variation in genotype response to chilling stress

In order to evaluate the effects of NaCl on some morpho- physiological traits in almond and alteration of photosynthetic parameters, an experiment was performed based on completely randomized design with five treatments included 0, 25, 50, 75 and 100 mM of sodium chloride in three replications. The results indicated that the contents of sodium and chloride were increased in almond seedlings but quantities of relative water content, chlorophyll index and dry weight of leaves were decreased in parallel with augmentation of salt levels significantly (p ≤ 0.05). In these conditions, alterations of leaf temperature were not significant but the seedlings percentage indicating marginal leaf scorch symptoms was increased up to 89% with relatively regular template. Applied salt in the lowest level enhanced the mean of internal CO2 and metabolic-stomatal limitation up to 35 μmol.mol-1 and 39.5% as well as decreased the mean of CO2 assimilation and stomatal conductance up to 6 mol.m-2.s-1 and 0.15 mol.m-2, respectively (p ≤ 0.05). In this probe, high efficiency of some measured traits such as relative water content, chlorophyll index and marginal leaf scorch symptoms was revealed in quick screen of the salt tolerant genotypes.

In this complete random block study we aimed to assess the morphologic reactions of Petunia under water deficiency. We used four irrigation treatments (irrigation amount of 25%، 50%، 75%، and 100% of the field''s irrigation capacity. The study consisted of 8 repetitions during 6 months in the greenhouse. Data were analyzed using SPSS software، version 12. 0 and the mean data were compared with each other using the least standard deviation (LSD) at a 5% level. The results showed that the root''s length، weight، and dry weight، the wet to dry weight ration of the branch، number of branches، number of flowers، relative water content of the leaf، and chlorophyll content reduced. However، the flower period، profil content، and the potassium and sodium percentage increased. The Petunia can sustain low irrigation and can be used as a resistant plant to poor water conditions in green spaces.

Drought has a major influence on morphological and physiological characteristics of plant species. Drought stress has a direct relationship with germination characteristics including germination percentage, seedling length (mm/plant), root to shoot ratio, seedling weight (g), ratio of dry weight to fresh weight of seedlings (g.dfw-1) and seed vigor index (V). In this research, effects of drought stress on these characteristics were examined on four genotypes of Bromus inermis (Alborz 303, Mazandaran 3151, Firozkuh 3966 and Esfahan 200060) under laboratory and greenhouse conditions. In greenhouse experiment, three physiological traits including chlorophyll, carbohydrates and proline contents were measured. Drought treatments included four levels of osmotic potential (0, -0.3, -0.6 and -0.9 MPa) in germinator and four levels of osmotic potential (FC, 25% FC, 50% FC and 75% FC) in greenhouse, made by Poly-Ethylene-Glycol (PEG 6000) solution in laboratory and weighting method in greenhouses, respectively. Results showed that Esfahan (200060) genotype was better than two other genotypes in terms of germination percentage under the two conditions. Increasing drought stress increased proline and carbohydrate and decreased the chlorophyll content.

In order to study the effect and efficiency of municipal solid waste compost and vermicompost on morpho-physiological properties and yield of canola under drought stress conditions, an experiment was conducted as factorial arrangement based on randomized complete block design with four replications. Treatments consisted of three levels of irrigation, including: normal irrigation (0.75 FC), mild stress (0.55 FC) and severe stress (0.35 FC), and biofertilizer combination in five levels including: non-application of biofertilizer (control), application of municipal solid waste compost at two and four percent levels and application of vermicompost at two and four percent. Results showed that the effect of irrigation and biofertilizer levels in all traits was significant. The interaction of irrigation and biofertilizer had significantly affected on all traits except leaf area ratio and plant nitrogen percent. The results of mean comparison indicated that the mild and severe stress significantly reduced growth, nitrogen percentage, SPAD index, leaf relative water content and grain yield of canola compared to normal irrigation. Application of four percent vermicompost was resulted increase growth, biomass and yield of canola under normal irrigation, mild and severe drought stress compared to other biofertilizer treatments, and in generally, the efficiency of vermicompost in increase canola yield was more than waste compost.

To evaluate terminal drought tolerance in barley genotypes and to study the relationship between morpho-physiological traits and grain yield in terminal drought stress conditions, 214 barley genotypes as well as two checks were examined at three locations; Varamin, Birjand and Esfahan Research Field Stations in 2002 -2003 growing season. Morpho-physiological traits including: days to anthesis, days to maturity, plant height, peduncle length, spike length, number of fertile tillers, grain.spike-1 and 1000-grain weight were measure and recorded in three locations. Results indicated significant differences between Six row and two row genotypes for grain yield components (number of fertile tillers, grain.spike-1 and 1000 grain weight), days to heading and spike length. Correlation, stepwise regression and path analyses studies indicated that days to anthesis, peduncle length and 1000 grain weight not only had the highest correlation with grain yield, but also had the highest direct effects on grain yield in both six row and two row barley genotypes. However, these correlations and effects were more pronounced in two row barley genotypes.