scholarly journals Response of Different Cultivars of Wheat Plants (Triticum aestivum L.) to Inoculation by Azotobacter sp. under Salinity Stress Conditions

Author(s):  
Sahar El-Nahrawy ◽  
Mohamed Yassin

Salinity is one of the key restraints to agricultural productivity worldwide and is expected to increase further. Therefore, cope with this problem we should be develop strategies to enhance salinity tolerance in different crops. One of these modern strategies is to use plant growth promoting rhizobacteria (PGPR) which can help plants to withstand under harsh environmental conditions. The present study was evaluated six isolates of Azotobacter sp. (Az1-Az6) which tested in vitro for growth, PGPR traits such as indole-3 acetic acid (IAA) production and nitrogen fixation, germination indicators for different wheat cultivars i.e. Misr 1, Gemmiza 12 and Sakha 95 under different levels of NaCl. Also, the efficacy of inoculation with two superior isolates in different wheat cultivars in a Gnotobiotic Sand System and greenhouse experiment for improving growth dynamics, physiological attributes, nutrient uptake and antioxidant enzymes under different levels salinity of sandy soil (0, 4, 8 and 12 dS m-1). Out of 6 isolates, two isolates (Az2 and Az6) could show salinity tolerance and exhibited PGPR traits as well as improvement germination tests. Both the bacteria could promote growth in 3 cultivars of wheat tested in terms of increase in fresh weight, dry weight, root and shoot length as well as root colonization compared to uninoculated control under Gnotobiotic Sand System experiment.  Under greenhouse experiment conditions, inoculation treatment with Az6 showed a significant increase of vegetative growth, physiological and biochemical parameters of different wheat cultivars under different salinity stress treatments. Also, Az6 treatment recorded the highest N% from wheat plants attained 2.64, 2.51 and 2.43% at 4 dS m-1 for Misr1, Sakha 95 and Gemmiza 12 cultivars, respectively but the highest K+, K+/Na+% and the lowest Na+% were obtained from plants that grown in soil salinized with 8 and 12 dS m-1. The same trend was observed for antioxidant enzymes. Thus, inoculation with Azotobacter isolates Az2 and Az6 could be efficiently used to partially or completely eliminate the effects of salt stress on growth of different wheat cultivars.

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248207
Author(s):  
Zahra Jabeen ◽  
Hafiza Asma Fayyaz ◽  
Faiza Irshad ◽  
Nazim Hussain ◽  
Muhammad Nadeem Hassan ◽  
...  

Salinity is among the major abiotic stresses negatively affecting the growth and productivity of crop plants. Sodium nitroprusside (SNP) -an external nitric oxide (NO) donor- has been found effective to impart salinity tolerance to plants. Soybean (Glycine max L.) is widely cultivated around the world; however, salinity stress hampers its growth and productivity. Therefore, the current study evaluated the role of SNP in improving morphological, physiological and biochemical attributes of soybean under salinity stress. Data relating to biomass, chlorophyll and malondialdehyde (MDA) contents, activities of various antioxidant enzymes, ion content and ultrastructural analysis were collected. The SNP application ameliorated the negative effects of salinity stress to significant extent by regulating antioxidant mechanism. Root and shoot length, fresh and dry weight, chlorophyll contents, activities of various antioxidant enzymes, i.e., catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) were improved with SNP application under salinity stress compared to control treatment. Similarly, plants treated with SNP observed less damage to cell organelles of roots and leaves under salinity stress. The results revealed pivotal functions of SNP in salinity tolerance of soybean, including cell wall repair, sequestration of sodium ion in the vacuole and maintenance of normal chloroplasts with no swelling of thylakoids. Minor distortions of cell membrane and large number of starch grains indicates an increase in the photosynthetic activity. Therefore, SNP can be used as a regulator to improve the salinity tolerance of soybean in salt affected soils.


2014 ◽  
Vol 22 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Omid Younesi ◽  
Ali Moradi

AbstractThe experiment was conducted in order to study effects of seeds priming with gibberellic acid (GA3) at 0, 3, 5 and 8 mM on germination, growth and antioxidant enzymes activity in alfalfa seedlings under salinity stress (200 mM NaCl). All control seeds germinated. The rate of germinated seeds was reduced to 48% in the presence of NaCl, and increased to 76% after seeds priming with 5 mM GA3. Priming with 5 mM GA3 was also correlated with an increase of dry weight of seedlings derived from both stressed and non-stressed seeds as well as with the reduction of electrolyte leakage (EL) and malondialdehyde (MDA) level in salt stressed seedlings. The activity of superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase in primed and non-primed seeds increased in the presence of NaCl and after priming of seeds with 5 mM GA3, whereas only small effect on glutathione reductase activity in both primed and non-primed seeds was observed. The total ascorbate level was higher in both stressed and non-stressed seedlings from primed seeds. These results suggest that GA3 priming might increase the salt tolerance of alfalfa seedlings through enhancing the activities of antioxidant enzymes and reducing the membrane damage as estimated using biomarkers, EL index and MDA content.


Author(s):  
Rajiv Pathak ◽  
Vipassana Paudel ◽  
Anupama Shrestha ◽  
Janardan Lamichhane ◽  
Dhurva. P. Gauchan

Phosphorous (P) is an essential macronutrient and most soils contain high levels of P. However, its availability to plant is limited by rapid immobilization of phosphorous compounds to insoluble forms and hence plant available forms of P in soils are found in low amounts. Phosphate solubilizing bacteria provide an eco-friendly alternative to convert insoluble phosphates into plant available forms. In the present study, three phosphate solubilizing bacterial isolates (PB-1, PB-4 and VC-01) with visually significant phosphate solubilizing abilities were isolated from tomato rhizosphere soil. In-vitro study in pikovskaya’s agar revealed that isolate PB-1 had the highest phosphate solubilizing ability with a phosphate solubilizing index of 2.08±0.07 followed by isolate VC-01 (1.31±0.09) and PB-4 (1.24±0.08). Isolates were used as bacterial inoculum to assess their ability to promote tomato (Lycopersicon esculentum var. Srijana) seedling and plant growth in in-vitro and greenhouse experiment respectively. Isolate PB-4 showed best growth promotion in seedling assay whereas isolate PB-1 and VC-01 also promoted seedling growth compared to control. In greenhouse experiment however, isolates VC-01 and PB-1 significantly enhanced all parameters (shoot length, root length, shoot and root dry weight) compared to uninoculated control whereas isolate PB-4 had a positive effect on all parameters except root length.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page: 61-70


2018 ◽  
Vol 6 (2) ◽  
pp. 214
Author(s):  
Md. Isfatuzzaman Bhuyan ◽  
K M. Mehadi Hassan ◽  
Nowrose Jahan Lipi ◽  
Md Rafiq Uddin ◽  
Md Monirul Islam ◽  
...  

A study was conducted in the Department of Agronomy, Bangladesh Agricultural University (BAU), Mymensingh from April to August 2012 to examine the salinity tolerance of eight jute varieties (CVE-3, C-83, CVL-1, BJC-7370, O-795, O-9897, OM-1, O-72) and two kenaf varieties (HC-95 and HC-2). Initially germination of these varieties were evaluated under six salinity levels viz. 0mM, 20mM, 40mM, 60mM, 80mM, and 100mM NaCl in the seed laboratory of the Department of Agronomy. Afterwards, all the varieties was grown in pots in the net house under four salinity levels viz. 0mM, 25mM, 50mM, and 75mM. The results from the germination study revealed that under control condition (0mM NaCl) all the jute varieties showed germination more than 80% both at 7 and at 14 days after seed sowing, whereas kenaf varieties had germination a little less than 80%. Among the jute varieties, O-72 showed the highest germination (92%), which was statistically similar with those of OM-1(91%), O-795 (90%), and C-83(87%). Salinity stress decreased germination drastically in all of the jute and kenaf varieties. A salinity level of 100mM caused the highest germination inhibition (74.70%) in jute variety CVL-1, which was very close to those of BJC-7370 and O-72. On the other hand, the lowest germination inhibition (51.11%) was recorded in jute variety O-795. The results of the pot trail showed that the plant characters of jute and kenaf varieties were affected significantly by salinity stress. All the varieties produced their respective plant height, number of leaves per plant, and plant dry weight under control condition (no salinity). Among these varieties, CVE-3 produced the highest plant height (145.2cm), and total dry weight (22.55g), whereas O-72 produced the highest number of leaves per plant (24.67). All these plant characters decreased sharply due to salinity stress irrespective of variety. However, the rate of decrease of plant characters occurred differentially in the jute and kenaf varieties. The highest rate of decrease in number of leaves (74.22%) was found from the variety CVE-3, whereas the lowest one was recorded from the variety HC-2 (51.68%). Salinity stress caused the highest decrease in total plant dry weight (73.68%) in the variety CVL-1 and plant height (73.64%) also in the variety CVL-1. On the contrary, the lowest decrease in plant dry weight (50.99%) was found in the variety O-9897 and plant height also in variety O-9897 (50.88%). Based on the results from germination test and pot trail, it can be inferred that jute variety O-9897 appeared to be the most salt tolerant followed by O-795, HC-2, HC-95, CVE-3, O-72, C-83, BJC-7370, OM-1, and CVL-1.    


HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1882-1884 ◽  
Author(s):  
Kenneth B. Marcum ◽  
Mohammad Pessarakli

Relative salinity tolerance of 32 perennial (Lolium perenne L.) and three intermediate (Lolium ×hybridum Hausskn.) ryegrass turf cultivars was determined by measuring turf leaf clipping dry weight, root weight, rooting depth, and percent green leaf canopy area relative to control (non-salinized) plants. After gradual acclimation, grasses were exposed to moderate salinity stress (6 dS·m−1) for 6 weeks through solution culture in a controlled environment greenhouse. Shoot parameters were highly correlated, being mutually effective predictors of salinity tolerance. After 6 weeks of salinity stress, percent green leaf canopy area (GL) was correlated with relative (to control) final week leaf clipping weight (LWREL) (r = 0.90) and with linear slope of decline of weekly leaf clipping weight over the 6-week exposure to salinity (LWSLOPE) (r = 0.66). Rooting parameters root dry weight (RW) and rooting depth (RD), although significantly correlated with all shoot parameters, were only moderately effective in predicting relative salinity tolerance. ‘Paragon’ was the most salt-tolerant as indicated by all parameters. Other salt-tolerant cultivars included Divine and Williamsburg. Intermediate ryegrass cultivars (Froghair, Midway, and Transist) were invariably found within the most salt-sensitive category for all parameters.


2020 ◽  
Vol 224 ◽  
pp. 04013
Author(s):  
T M Tabatskaya ◽  
O S Mashkina ◽  
O M Korchagin

This paper examines the salinity stress effect in vitro culture of microshoots of 10 birch clones: Betula pendula L., B. pendula Roth var. carelica (Mercklin) Hämet-Ahti, B. pendula f. ’dalecarlica’ (L.f.) Schneid., B. pubescens Ehrh. We used economically valuable and genetically diverse (various species, varieties, hybrids, polyploids) birch material from in vitro clone collection. We tested 3 in vitro selection methods on 1/2 MS hormone-free nutrient medium: mild – with a prolonged exposure to 0.2% NaCl; gradual – with a step-by-step increase in osmotic concentration (from 0.2% to 1%); severe – with a sublethal (1%) NaCl concentration. We established that the gradual method of NaCl exposure according to the following pattern: 0.2% → 0% → 0.5% → 0% → 0.75% → 0% → 1.0% resulted in the best selective effect for birch, as it provides a clear differentiation of clones in terms of their salinity tolerance. We identified that the genotype had a significant impact on the preservation of the explants and their ability to regenerate under salinity stress. The study showed that tetraploid clones of downy birch and a triploid clone of Karelian birch of a pronounced mixoploid nature had the greatest salinity tolerance.


2021 ◽  
Author(s):  
Maryam Nekoee Mehmandar ◽  
Farzad Rasouli ◽  
Mousa Torabi Giglou ◽  
Seyed Morteza Zahedi ◽  
Mohammad Ali Aazami

Abstract Water deficit in first growth stages of melon (Cucumis melo L.) in formation of first true leaves after germination can be a factor limiting production. The first step for resolve the problem is genotypes evaluation and identification of drought tolerant melons. An effective method to achieve the goal is use of osmotic solution in tissue culture. Responses of Iranian melon landraces to drought was evaluated using sorbitol at 0.1, 0.2 and 0.4 M or polyethyleneglycol (PEG 6000) at 0.009, 0.012 and 0.015 M concentrations, and MS medium without treatment as the control. Coleoptile length, fresh and dry weight of shoots and roots, photosynthetic pigments, protein, proline, malondialdehyde (MDA) and antioxidant enzymes superoxide dismutase, guaiacol peroxidase and ascorbate peroxidase were measured. The PEG or sorbitol decreased coleoptile length, fresh weight and photosynthetic pigments, and led to enhancement of proline and MDA. Contents of protein and antioxidant enzymes was completely dependent on genotype and type and concentration of osmotic material. The in vitro culture for screening and identification of tolerant and sensitive drought genotypes could be rapid, useful and effective, with sorbitol mimicing drought better than PEG. After in vitro evaluation, the genotype responses to induced water deficit need to be confirmed under field conditions.


Agriculture ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 166 ◽  
Author(s):  
Maha Abdelaziz ◽  
Tran Xuan ◽  
Ahmad Mekawy ◽  
Hongliang Wang ◽  
Tran Khanh

Rice is a staple crop for over 50% of the world’s population, but its sensitivity to salinity poses a threat to meeting the worldwide demand. This study investigated the correlation of salinity tolerance to Na+ exclusion, proline accumulation, and the activity of antioxidant enzymes in some rice cultivars originating from Egypt. Giza 182 was shown to be the most tolerant of the five cultivars, as judged by visual symptoms of salt injury, growth parameters, and patterns of Na+ accumulation, while Sakha 105 appeared to be highly susceptible. In detail, Giza 182 accumulated the lowest Na+ concentration and maintained a much lower Na+/K+ ratio in all plant organs in comparison to Sakha 105. The salinity-tolerant varieties had higher accumulation of proline than the salinity-susceptible cultivars. The salinity-tolerant Giza 182 accumulated a higher concentration of proline, but the lipid peroxidation (MDA) level was significantly reduced compared to in the salinity-susceptible Sakha 105. In addition, Giza 182 had stronger activity of both catalase (CAT) and ascorbate peroxidase (APX) compared to Sakha 105. The findings of this study reveal that the salinity tolerance in rice is primarily attributable to Na+ exclusion, the accumulation of proline in rice organs, a low Na+/K+ ratio, and a low level of lipid peroxidation. The levels of the antioxidant enzymes CAT and APX and the accumulation of proline may play important roles in salinity tolerance in rice. However, the comparative involvement of individual antioxidant enzymes in salinity stress in rice should be further investigated. Giza 182 has the potential to be cultivated in salinity-affected areas, although the effects of salinity stress on its grain yield and quality should be evaluated during the full crop cycle.


2010 ◽  
Vol 8 (2) ◽  
pp. 132-141 ◽  
Author(s):  
Kumari Neelam ◽  
Vijay K. Tiwari ◽  
Nidhi Rawat ◽  
Sangharsh K. Tripathi ◽  
Gursharn S. Randhawa ◽  
...  

Graminaceous plants including staple cereals secrete certain phytosiderophores (PS) in calcareous soils with lower iron and zinc availability to enhance their uptake and translocation to the leaves and grains. A few Triticum aestivum cultivars and accessions of six Aegilops species were investigated for release of PS in vitro under iron- and zinc-sufficient and -deficient conditions, and for root and shoot iron and zinc concentrations. All the Aegilops species had three to four times higher release of PS than the wheat cultivars under both nutrient-sufficient and -deficient conditions. The maximum rate of increase of PS was observed on days 11 and 14 under iron- and zinc-deficient conditions, respectively, which levelled off rapidly among the wheat cultivars and continued to be high among Aegilops species till the end of the experiment. The absolute amount of iron and zinc expressed on dry weight basis after 18 d under iron- and zinc-deficient conditions showed nearly three times higher concentration in both roots and shoots of Aegilops species than that of the wheat cultivars. A significantly high correlation between concentrations of iron (r = 0.94) and zinc (r = 0.91) in roots and the PS released was found. The higher grain iron and zinc contents in the Aegilops species reported earlier may be attributed to their diverse and efficient mechanism(s) for PS-mediated micronutrient uptake and translocation system, which could be exploited for biofortification of wheat.


2017 ◽  
Vol 142 (6) ◽  
pp. 476-483 ◽  
Author(s):  
Xin Song ◽  
Suo-min Wang ◽  
Yiwei Jiang

Perennial ryegrass (Lolium perenne) is a popular cool-season and forage grass around the world. Salinity stress may cause nutrient disorders that influence the growth and physiology of perennial ryegrass. The objective of this study was to identify the genotypic variations in growth traits and nutrient elements in relation to salinity tolerance in perennial ryegrass. Eight accessions of perennial ryegrass [PI265351 (Chile), PI418707 (Romania), PI303012 (UK), PI303033 (The Netherlands), PI545593 (Turkey), PI577264 (UK), PI610927 (Tunisia), and PI632590 (Morocco)] were subjected to 0 (control, no salinity) and 300 mm NaCl for 10 d in a greenhouse. Across accessions, salinity stress decreased plant height (HT), leaf fresh weight (LFW), leaf dry weight (LDW), leaf water concentration (LWC), and concentration of N, C, Ca2+, Cu2+, K+, Mg2+, and K+/Na+ ratio and increased Na+ concentration. Negative correlations were found between C and Na+, whereas positive correlations of K+/Na+ with C and N were found under salinity treatment. The principal component analysis (PCA) showed that the first, second, and third principal components explained 40.2%, 24.9%, and 13.4% variations of all traits, respectively. Based on loading values from PCA analysis, LWC, Na+ concentration, and K+/Na+ ratio were chosen to evaluate salinity tolerance of accessions, and eight accessions were divided into the tolerant, moderate, and sensitive groups. The tolerant group had relatively higher LWC and K+/Na+ ratio and concentrations of C, P, and Fe2+ and lower Na+ concentrations than the other two groups, especially the sensitive groups. The result suggested that lower Na+ accumulation and higher K+/Na+ ratio and LWC were crucial strategies for achieving salinity tolerance of perennial ryegrass.


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