جستجوی مقالات مرتبط با کلیدواژه « pgpr » در نشریات گروه « زیست شناسی »

Improper use of soil resources leads to reduced fertility and soil degradation, and ultimately reduced crop production. Chemical fertilizers are a very strong competitor to biofertilizers because they are cheaper, easier to access, and faster return on investment. Accordingly, the aim of this study was conducted to evaluate the rhizosphere bacteria that stimulate plant growth and provide biosecurity with the approach of modifying the root structure of plants. The study showed that the rhizosphere supports the development and activity of a large and diverse community of microbial organisms, including organisms in plant growth, which can be used in the biological control of plant diseases. Bacillus sp. and Pseudomonas sp. It also causes an increase in all biological diseases. These microorganisms are investigated in the present study. Findings showed that reducing production costs on a large scale is a difficult task but can be achieved with careful research. In addition, the analysis of the benefits, risks, and limitations of the use of Rhizobacteria requires a more comprehensive and detailed investigation. Because the choice of appropriate method of plant disease control is based on balance.

Salinity is one of the most important abiotic stresses that reduce the growth and development of wheat. Reducing the effects of salinity with the help of plant growth-promoting rhizosphere bacteria has been considered by researchers as an environmentally friendly solution. In the present study, some physiological responses of wheat cultivar of Narin to salinity-resistant growth-promoting bacteria isolated from the rhizosphere of salt-tolerant plants) Atriplex lentiformis, Tamarix ramosissim, Seidlitzia rosmarinus, Halostachys belangeriana) were investigated. Wheat seeds after inoculation with the identified bacteria (Bacillus safensis, B. pumilus and Zhihengliuella halotolerans) were planted in pots and irrigated with saline water of 0.2 (control) 4, 8 and 16 dS / m. The results showed all isolated bacteria had the ability to produce auxin, siderophore, hydrogen cyanide, 1-aminocyclopropane-1-carboxylic acid deaminase (ACC deaminase) and phosphate solubility.With increasing salinity, chlorophyll content decreased in all treatments compared to the control. The use of bacteria increased 21 to 92, 6 to 175 and 21 to 52% of chlorophyll a, b and total chlorophyll content among salinity treatments, respectively. Increased salinity increased content of proline (136-136%), total phenol (11-92.5%), free radical scavenging capacity (12.5-89%) and total soluble sugars (7.5-1.5%) in salinity treatments inoculated with bacteria compared to control. The growth-promoting bacteria in this study with improved wheat resistance to salinity stress. Improving the physiological conditions of plant under the positive effect of bacteria eventually increased the plant biomass, in which the role of B. safensis was more than the other two bacteria. The results of this study showed that the plant growth-promoting bacteria of halophytic rangeland plants can play a role in improving the growth indices of wheat plants in saline conditions.

Recognition of environmental factors has an important role in the success of medicinal plants cultivation. Growth-promoting bacteria, through their effects on biosynthesis cycles, cause changes in plant products. In ord levels of control (field capacity), 20% FC, 40% FC, 60% FC and 80% FC. Characteristics such as plant height, , number of leaves, leaf area fresh and dry weight of the shoot, as well as essential oil percentage and and analyzed by GC/MS yield were measured. The results showed with increasing the drought stress the growth and yield in basis decreased. But inoculation of plants with PGPR increased the growth under drought stress conditions and improved the plant performance in such conditions. The highest fresh and dry weight of shoot was in inoculated plants and irrigation control (FC) treatment and the least amount of these traits were obtained in non-inoculated plants and 20% FC treatment, these traits were reduced by 50% and 70%, respectively, compared to plants inoculated with bacteria and FC irrigation. Also, the highest percentage of basil essential oil was obtained in bacteria inoculated plants and 40% FC treatment. The highest yield of essential oil was observed in the control treatment and the effect of the bacteria was not observed. The use of growth-promoting rhizobacteria (PGPR) can improve the production of medicinal plants in environmental stresses such as drought stress and greatly repair the effects of this stress.

Environmental stresses are one of the most important factors in reducing the function of medicinal plants. The use of plant growth regulators such as PGPR can be a way to reduce the effects of salinity stress. Environmental factors, cause changes in the growth of medicinal plants and, on the other hand, alter the amount and quality of their active substances, such as alkaloids, glycosides, steroids, volatile oils (essential oils). The experiment was conducted factorial based on a randomized complete block design with 12 treatments in four replications at greenhouse of University of Kashan. The first factor was salinity stress at 3 levels including 25, 50 and 100 (MM) Mili molar and salinity treatments were performed after complete sowing of cultivated plants. The second factor was bacterial growth stimulus in four levels including control (0), 10-10, 10-8 and 10-6 molar and the addition to the potted soil as a solution before applying salinity stress. It was found that the use of plant growth regulator PGPR is essential for maintaining the economic performance of plants under stress. The results showed that increased levels of salinity had a significant effect on reducing the growth parameters including dry weight, root length, plant height and essential oil yield. According to the results, the percentage of essential oil with increased levels of salinity significantly at 1% level, so that the percentage of essential oil from 0.45 in 25 (MM) treatment was increased to 0.96 in 100(MM) and the use of 10-8 M PGPR.

In order to study the effect of seeds priming with growth stimulating bacteria (biopriming) and hydroperiming on germination parameters, an experiment was carried out on a factorial experiment based on randomized complete design with three replications. Experimental treatments consisted of hydropriming at different times (72, 48, 24, 12 h) and biopriming with Pseudomonas fluorescens and P. putida growth stimulating bacteria at different times (72, 48, 24, 12 h) compared to control (without inoculation). The results showed that seed hydropriming at different times had a significant effect at 1% probability level on germination indices, seed vigor, mean radicle and plumule length, percentage and germination rate. Germination and vigor index showed significant difference upon biopriming treatment. The highest germination index was obtained in inoculation with P. putida in 48 h and the lowest seed vigor index was obtained in seed inoculation with P. fluorescens within 72 h. The maximum mean radicle and plumule length were observed upon P. putida (3.30 and 3.67 mm) and P. fluorescens (3.13 and 3.17 mm) inoculation treatments, respectively. Also, biopriming with P. putida had a positive and significant effect on water uptake and alpha-amylase enzyme activity compared to P. fluorescens and hydro-priming under different times. Therefore, in order to improve germination indices and seedling vigour index, biopriming with P. putida bacteria can be recommended.

In order to evaluation the effects of mycorrhiza, plant growth promoting rhizobacteria and nano zinc oxide foliar application on effective traits at grain filing of triticale under soil salinity condition, a factorial experiment was conducted based on randomized complete block design with three replications in research greenhouse of Faculty of Agriculture Sciences, University of Mohaghegh Ardabili in 2014. Factors experiment were included soil salinity in four levels (non-salinity, salinity 20, 40 and 60 mM NaCl), biofertilizers in four levels (no application of biofertilizers, application of mycorrhiza, Azotobacter chrocoocoum strain 5 Psedomunas putida strain 186, both application PGPR mycorrhiza) and nano zinc oxide in three levels (without nano zinc oxide, application of 0.4 and 0.8 g lit-1). Results showed that grain yield per plant, yield components, grain filling rate, grain filling period and effective grain filling period decreased with increasing of soil salinity. While proline and soluble sugars content increased. Means comparison showed that the highest of yield per plant (3.64 g. plant-1), grain filling rate (0.00196 g day-1), grain filling period (52.75 days) and effective grain filling period (36.62 days) were obtained at both application of PGPR and mycorrhiza, foliar application 0.8 g lit-1 nano zinc oxide and no-salinity. The highest content of soluble sugars (99.48 mg g-1 FW) was obtained at both application of PGPR and mycorrhiza, foliar application 0.8 g.lit-1 nano zinc oxide and salinity of 60 mM. Salinity of 20, 40 and 60 mM NaCl decreased 8.9%, 22.11% and 32.34% respectively from grain yield and application of biofertilizers and nano zinc oxide compensated 40.17%, 49.74% and 40% respectively from yield reduction. Based on the results, it seems that application of biofertilizers and nano zinc oxide can be recommended for profitable triticale production under soil salinity condition.

The current experiment was designed to evaluate the effect of plant growth promoting rhizobactria (PGPR) on chlorophyll fluorescence and some physiological parameters in basil (Ocimum basilicum L.) leaf under salinity stress. The experiment was conducted in factorial arrangement based on completely randomized design. Treatments were four levels of salt stress (0, 40, 80 and 120 mM of NaCl) and three levels of PGPR inoculation (control, coinoculation with either Azotobacter̺Ⲧ⫢陛 or Azospirillum㻇깶覨鶫㸅Ꜣ陛). The results showed that increasing salinity stress significantly increased both minimum and maximum fluorescences (Fo and Fm) and quantum yield of non-regulated non-photochemical quantum efficiency [Y(NO)], while decreased variable fluorescence (Fv), maximum photochemical quantum yield of photosystem II (Fv/Fm) and photochemical quantum yield of photosystem II [Y(II)]. The trend of chlorophyll content and chlorophyll a and b (in control treatment) increased at low and medium level of salinity while decreased at higher salinity levels. However, with increasing the salinity level the relative water content (RWC) as well as the amount of carotenoids decreased and electrolyte leakage increased. Inoculation of basil plants with PGPR significantly reduced Fo and Y(NO) while increased Fv, Fv/Fm and NPQ as compared to the uninoculted control. Among the biological treatments, Azospirillum㻇깶覨鶫㸅Ꜣ陛 by 12% increase in Y(II) and 16% decrease in Y(NO), showed the most positive effects on plant photosynthetic system. Biological treatment also improved chlorophyll content, chlorophyll a and RWC and reduced electrolyte leakage. In conclusion, the current results indicated that the ameliorate effect of PGPR particularly coinoculation of Azospirillum㻇깶覨鶫㸅Ꜣ陛 on chlorophyll fluorescence and physiological parameters improvement of basil seedling leaves under salinity stress.

Plant diseases damage to agricultural crops in every year. Different approaches may be used to prevent the growth and reduce damage of plant diseases gents. Including methods is using of biological control. That is an environmentally sound and effective means of reducing plant diseases effects. Actually, the rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth, which could be used by these organisms for biological control of plant pathogens. Among the plant growth-promoting factors can be named as Trichoderma sp. fungus and strains of Bacillus sp. and Pseudomonas sp. had widely used in biological control of plant diseases. These biological agents make use of different mechanisms to control plant diseases, such as activate defense responses, antibiosis, stimulate plant growth, antibiotics production, increase nutrient uptake, siderophore and HCN production. Therefore, propagation and inoculation of these biological agent to plants, can decrease usage of chemical fertilizers and pesticides. Integrating mechanistic and ecological knowledge on these microorganism populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture

Application of plant growth promoting rhizobacteria and foliar application of Nano-Zinc oxide are proper and cheap method for increasing of Triticale yield. So، in order to study of the effects of nano-zinc oxide and seed inoculation with plant growth promoting rhizobacteria (PGPR) on contribution of dry matter remobilization and stem reserves in grain yield، chlorophyll content، stomata conductance and some physiological indices of Triticale، a factorial experiment was conducted based on randomized complete block design with three replications in research greenhouse of the Faculty of Agriculture، University of Mohaghegh Ardabili in 2013. Factors were: foliar application of Nano-Zinc oxide at five levels (0 as control، 0. 25، 0. 5، 0. 75 and 1 g/lit) and seed inoculation with plant growth promoting rhizobacteria in four levels (without inoculation as control، seed inoculation with Azotobacter chrocoococum strain 5، Azosprillium lipoferum strain OF and Psedomunas putida strain 9). The highest contribution of dry matter remobilization and stem reserves in grain yield was obtained at no application of Nano-Zinc oxide and no seed inoculation with PGPR. Means comparison showed that maximum of yield and yield components، chlorophyll content، stomata conductance، total dry matter and crop growth rate was obtained at application of 1 g/lit Nano-Zinc oxide×seed inoculation with Azotobacter and Azosprillium and minimum of they were recorded at no application of Nano-Zinc and no seed inoculation with PGPR. So، it can be suggested that in order to increasing of grain yield، chlorophyll content، stomata conductance and some physiological indices such as total dry matter and crop growth rate be applied seed inoculation of Triticale with Azotobacter and Azosprillium ×application of 1 g/lit Nano-Zinc oxide.

In order to study of the effects of biofertilizers on growth indices and contribution of dry matter remobilization in wheat grain yield, a factorial experiment was conducted based on randomized complete block design with three replications. Factors were: nitrogen application time at three levels, (1/3 planting, 1/3 tillering and stem elongation, 1/3 before flowering), (1/4 planting, 1/2 tillering and stem elongation stages,1/4 before flowering) and (1/4 planting, 1/4 emergence, 1/4 stem elongation, 1/4 flowering) as N1, N2 and N3 respectively. Seed inoculation treatments with PGPR containing control (without inoculation) seed inoculation with Azotobacter chrocoococum strain 5, Psedomunas strain 41 and 186. Maximum of dry matter remobilization per plant was obtained in nitrogen application time as N1 without seed inoculation and the least was obtained in nitrogen application as N3 and seed inoculation with Azotobacter. Grain yield per plant, number of grains per spike, hundred seed weight, plant height, root weight and protein content (%) increased at nitrogen application as N1 and seed inoculation with PGPR. Dry matter accumulation increased slowly at all treatment combinations until 40 days after sowing (DAF), then increased rapidly till 70 (DAF). Then it decreased till harvest time due to aging of leaves. So, it can be suggested that in order to increase grain yield and other growth indices, nitrogen should be applied as N1 in combination with seed inoculation with Azotobacter.