scholarly journals Characteristics of Azotobacter sp. strain AC11 and their effects on the growth of tomato seedlings under salt stress

Author(s):  
Honglian Ge

This study was aimed to investigate the potential of Azotobacter sp. strain AC11 in promoting growth and enhancing resistance to salinity stress in tomato seedlings. In this study, we measured the ability of strain AC11 to fix nitrogen and solubilize phosphorus and potassium, as well as its production of indole-3-acetic acid (IAA) and siderophores. A greenhouse pot experiment was conducted to investigate whether strain AC11 promoted tomato seedlings’ growth and enhanced their salt resistance. The results showed that strain AC11 produced IAA and siderophores, fixed nitrogen, and solubilized potassium and phosphorus. In pot trials, strain AC11 increased the shoot height, root length, and dry and fresh weights of tomato seedlings, and also increased their chlorophyll, soluble protein, and soluble sugar content. Furthermore, the bacteria induced the activities of superoxide dismutase (SOD; EC: 1.15.1.1), peroxidase (POD; EC: 1.11.1.7), and catalase (CAT; EC: 1.11.1.6), while it reduced the malondialdehyde (MDA) content and rate of O2- generation in tomato seedlings under salt stress. In summary, Azotobacter sp. strain AC11 promoted the growth of tomato seedlings and induced resistance to salt stress by producing IAA and siderophores, promoting the activities of antioxidant enzymes, and increasing the content of osmotic adjustment substances as well as enhancing the availability of the macronutrients N, P, K, and Fe3+ in the soil.

2014 ◽  
Vol 1010-1012 ◽  
pp. 1225-1229
Author(s):  
Ming Xia Zhu ◽  
Feng Jin ◽  
Xi Wen Shao ◽  
Xian Ying Gao ◽  
Yan Qiu Geng ◽  
...  

Taking Changbai 9 and Changbai 22 as experiment material, using pot experiment, to study of different concentration effect of saline alkali stress on physiological characteristics of rice in different growth periods. The results showed that, effect of saline alkali stress on the physiological characteristics of the same rice variety and soil characteristics of different resistant rice varieties are different. Weak salt resistance of Changbai 22 of chlorophyll , soluble sugar and MDA of salt stress more sensitive than saline resistance strong of Changbai 9,and the change trend of the physiological indexes of two cultivars under saline alkali stress is consistent, with the increasing concentration of salt stress, leaf chlorophyll content, soluble sugar content and soluble protein content firstly increased and then decreased,while the MDA concentration showed an increasing trend. At the same time with the increase of salt stress concentration, accumulation of soluble sugar in leaves of Changbai 9 increased even more than Changbai 22,indicating the Changbai 9 may be mainly through the accumulation of soluble sugar to alleviate the toxic effects of osmotic stress. This study can be used as an important reference index for soda saline alkali soil rice planting, soil improvement and comprehensive utilization.


2015 ◽  
Vol 26 (2) ◽  
pp. 21-25 ◽  
Author(s):  
Marcelina Krupa-Małkiewicz ◽  
Beata Smolik ◽  
Dominik Ostojski ◽  
Maja Sędzik ◽  
Justyna Pelc

AbstractThe aim of this study is to determine the effect of both NaCl and KCl alone and in comparison to AsA on the morphological and some biochemical parameters of Oxheart and Vilma cultivars of tomato under laboratory and field conditions. A combination of salt applied in the laboratory experiment caused a significant effect on seed germination and root and shoot length and a significant reduction of Chl a, Chl b and Car contents in 14-day-old tomato seedlings. However, seedlings of cultivar Vilma were characterised by higher tolerance to applied salt stress.NaCl caused a significant decrease in Chl a, Chl b and Car, and an increase in Pro and MDA content in the leaves of Vilma cultivar under field conditions. Besides, tomato plants cv. Vilma treated with NaCl alone or NaCl with ascorbic acid developed longer roots, from 48 to 73%, compared to the control.


2018 ◽  
Vol 15 (3) ◽  
pp. 797-808 ◽  
Author(s):  
Yuewei Guo ◽  
Yunge Zhao

Abstract. Mosses, as major components of later successional biological soil crusts (biocrusts), play many critical roles in arid and semiarid ecosystems. Recently, some species of desiccation-tolerant mosses have been artificially cultured with the aim of accelerating the recovery of biocrusts. Revealing the factors that influence the vegetative propagation of mosses, which is an important reproductive mode of mosses in dry habitats, will benefit the restoration of moss crusts. In this study, three air-dried desiccation-tolerant mosses (Barbula unguiculata, Didymodon vinealis, and Didymodon tectorum) were hermetically sealed and stored at five temperature levels (0, 4, 17, 25, and 30 °C) for 40 days. Then, the vegetative propagation and physiological characteristics of the three mosses were investigated to determine the influence of storage temperature on the vegetative propagation of desiccation-tolerant mosses and the mechanism. The results showed that the vegetative propagation of the three mosses varied with temperature. The most variation in vegetative propagation among storage temperatures was observed in D. tectorum, followed by the variation observed in B. unguiculata. In contrast, no significant difference in propagation among temperatures was found in D. vinealis. The regenerative capacity of the three mosses increased with increasing temperature from 0 to 17 °C, accompanied by a decrease in malondialdehyde (MDA) content, and decreased thereafter. As the temperature increased, the chlorophyll and soluble protein contents increased in B. unguiculata but decreased in D. vinealis and D. tectorum. As to storage, the MDA and soluble sugar contents increased after storage. The MDA content of the three mosses increased at each of the investigated temperatures by more than 50 % from the initial values, and the soluble sugar content became higher than before in the three mosses. The integrity of cells and cell membranes is likely the most important factor influencing the vegetative propagation of desiccation-tolerant mosses. A 40-day storage period caused cell injury. Our results suggest that storage temperature can enhance or suppress such injury and change the regenerative capacity of the three mosses. The data indicate that the suitable storage temperature is 4 °C for B. unguiculata and 17 °C for both D. vinealis and D. tectorum.


2020 ◽  
Author(s):  
Xiaolin Zhu ◽  
Meifei Su ◽  
Xiaohong Wei ◽  
Yu Long ◽  
Baoqiang Wang ◽  
...  

AbstractTomato is a model crop, as well as important food worldwide. In the arid areas, aggravation of soil salinity has become the primary problem that threatens the high yield in tomato production. As a second messenger substance, cyclic guanosine monophosphate (c-GMP) plays an indispensable role in plant response to salt stress through regulating cell processes to promote plant growth and development. However, this mechanism has not been fully explored in tomato seedlings. In this experiment, the tomato seeds were cultured in distilled water (CK), 20 μM c-GMP (T1), 50 mM NaCl (T2), 20 μM c-GMP + 50 mM NaCl (T3). The results show that 20 μM c-GMP effectively alleviated the inhibition of 50 mM NaCl on tomato growth and development, inducing the expression of 1580 DEGs. 95 DEGs were up-regulated and 442 DEGs were down-regulated (CK vs T1), whereas in the T2 vs T3 comparison 271 DEGs were up-regulated and 772 DEGs were down-regulated. Based on KEGG analysis, the majority of DEGs were involved in metabolism; exogenous c-GMP induced significant enrichment of pathways associated with carbohydrates, phenylpropanoids and fatty acid metabolism. Most PMEs, acCoA, PAL, PODs, FADs, and AD were up-regulated, and GAPDHs, PL, PG, BXL4, and β-G were down-regulated, which reduced susceptibility of tomato seedlings to salt and promoted their salt adaptation. The application of c-GMP promoted soluble sugar, flavonoids and lignin content, reduced accumulation of MDA, and enhanced the activity of POD. Thus, our results provide insights into the molecular mechanisms associated with salt tolerance of tomato seedlings.


2021 ◽  
Author(s):  
Shahab Hatamipoor ◽  
Leila Shabani ◽  
Sadegh Farhadian

Abstract Background The exogenous application of priming molecules to plants helps them to develop tolerance against salinity stress. In the present study, we used exogenous naringenin (0.5 mM) pretreatment before the stress in safflower seedlings under 25 mM NaCl to elucidate the role of naringenin to alleviate oxidative conditions associated with salinity complications. Results Our results showed biomass, leaf relative water content, chlorophyll content, K+ content, and K+/Na+ ratio were negatively affected by 25 mM NaCl. However, the H2O2 accumulation, malondialdehyde (MDA) content, antioxidant enzymes and Na+ content of NaCl-stressed safflower seedlings were remarkably increased. The results obtained in the present study showed the beneficial effects of the pre-treatment of naringenin in safflower seedlings under non-salinity stress condition with respect to increasing plant biomass, total phenolic compound, radical scavenging activity (RSA), soluble sugar content, proline, glutathione, enzymatic antioxidants, and K+ content. Also, the results showed that naringenin pre-treatment can (partly) be overcome NaCl-induced stress on safflower seedlings, probably due to higher accumulation of plant biomass, total phenolic compound, RSA, catalase (CAT) activity, and K+/Na+ ratio as well as lowering the H2O2 and MDA content in the leaves. Conclusions Generally, it could be concluded that, pre-treatment of naringenin before stress could partly diminish NaCl-caused oxidative stress in safflower seedlings, probably due to improvement in enzymatic and non-enzymatic antioxidant and reduced cell membrane damage.


Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 220 ◽  
Author(s):  
Huifang Cen ◽  
Tingting Wang ◽  
Huayue Liu ◽  
Danyang Tian ◽  
Yunwei Zhang

Alfalfa (Medicago sativa L.) is an important and widely cultivated forage grass. The productivity and forage quality of alfalfa are severely affected by salt stress. Melatonin is a bioactive molecule with versatile physiological functions and plays important roles in response to various biotic and abiotic stresses. Melatonin has been proven efficient in improving alfalfa drought and waterlogging tolerance in recent studies. In our reports, we applied melatonin exogenously to explore the effects of melatonin on alfalfa growth and salt resistance. The results demonstrated that melatonin application promoted alfalfa seed germination and seedling growth, and reduced oxidative damage under salt stress. Further application research found that melatonin alleviated salt injury in alfalfa plants under salt stress. The electrolyte leakage, malondialdehyde (MDA) content and H2O2 content were significantly reduced, and the activities of catalase (CAT), peroxidase (POD), and Cu/Zn superoxide dismutase (Cu/Zn-SOD) were increased with melatonin pretreatment compared to control plants under salt stress with the upregulation of genes related to melatonin and antioxidant enzymes biosynthesis. Melatonin was also involved in reducing Na+ accumulation in alfalfa plants. Our study indicates that melatonin plays a primary role as an antioxidant in scavenging H2O2 and enhancing activities of antioxidant enzymes to improve the salt tolerance of alfalfa plants.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
G. H. Yu ◽  
X. Zhang ◽  
H. X. Ma

The SbPIP1 gene is a new member of the plasma membrane major intrinsic gene family cloned from the euhalophyteSalicornia bigeloviiTorr. In order to understand the physiological responses in plants that are mediated by the SbPIP1 gene, SbPIP1-overexpressing wheat lines and WT plants of the wheat cv. Ningmai 13 were treated with salt stress. Several physiological parameters, such as the proline content, the malondialdehyde (MDA) content, and the content of soluble sugars and proteins, were compared between SbPIP1-transformed lines and WT plants under normal growth or salt stress conditions. The results indicate that overexpression of the SbPIP1 gene can increase the accumulation of the osmolyte proline, decrease the MDA content, and enhance the soluble sugar biosynthesis in the early period but has no influence on the regulation of soluble protein biosynthesis in wheat. The results suggest that SbPIP1 contributes to salt tolerance by facilitating the accumulation of the osmolyte proline, increasing the antioxidant response, and increasing the biosynthesis of soluble sugar in the early period. These results indicate SbPIP1 plays an important role in the salt stress response. Overexpression of SbPIP1 might be used to improve the salt tolerance of important crop plants.


2021 ◽  
Author(s):  
Longtian Zhang ◽  
Guozhang Bao ◽  
Mengyu Zhang ◽  
Zihang Yu ◽  
Tao Guan ◽  
...  

Abstract Background: As a biennial plant, Secale cereale L is usually harvested in the autumn in the northern part of China where the temperature difference between day and night is of great disparity Through the pot experiment, the seedlings were cut to 2, 6 and 10 cm stubble height, and the simulated freeze-thaw (FT) stress (10/-5℃) was carried out after 6 days regrowth. The physiological effects of FT with different stubble height were revealed by analyzing the relative water content (RWC), osmotic adjustment substance concentration (soluble sugar and protein), membrane peroxidation (MDA) and catalase (CAT) activity. Results: The results demonstrated that under freeze stress (-5℃), the content of soluble protein and MDA decreased and the seedlings of 2 cm treatment kept higher level of soluble protein and MDA, while the seedlings of 6 and 10 cm treatments kept higher level of the RWC, soluble sugar content, and CAT activity. After FT stress, the content of soluble sugar and protein, RWC in the 6 cm treatment were higher than those in 2 cm and 10 cm treatments, and the CAT activity in 10 cm treatment was the highest while the MDA content is lower.Conclusion: These data suggest that keeping high stubble height is more adaptive for short-term FT stress.


2018 ◽  
Vol 19 (7) ◽  
pp. 2062 ◽  
Author(s):  
Ling He ◽  
Yin-Huan Wu ◽  
Qian Zhao ◽  
Bei Wang ◽  
Qing-Lin Liu ◽  
...  

WRKY transcription factors (TFs) play a vital part in coping with different stresses. In this study, DgWRKY2 was isolated from Dendranthema grandiflorum. The gene encodes a 325 amino acid protein, belonging to the group II WRKY family, and contains one typical WRKY domain (WRKYGQK) and a zinc finger motif (C-X4-5-C-X22-23-H-X1-H). Overexpression of DgWRKY2 in chrysanthemum enhanced tolerance to high-salt stress compared to the wild type (WT). In addition, the activities of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT)), proline content, soluble sugar content, soluble protein content, and chlorophyll content of transgenic chrysanthemum, as well as the survival rate of the transgenic lines, were on average higher than that of the WT. On the contrary, hydrogen peroxide (H2O2), superoxide anion (O2−), and malondialdehyde (MDA) accumulation decreased compared to WT. Expression of the stress-related genes DgCAT, DgAPX, DgZnSOD, DgP5CS, DgDREB1A, and DgDREB2A was increased in the DgWRKY2 transgenic chrysanthemum compared with their expression in the WT. In conclusion, our results indicate that DgWRKY2 confers salt tolerance to transgenic chrysanthemum by enhancing antioxidant and osmotic adjustment. Therefore, this study suggests that DgWRKY2 could be used as a reserve gene for salt-tolerant plant breeding.


2019 ◽  
Vol 17 (1) ◽  
pp. 1352-1360 ◽  
Author(s):  
Huijuan Guo ◽  
Zhiqiang Hu ◽  
Huimin Zhang ◽  
Wei Min ◽  
Zhenan Hou

AbstractThis pot experiment was to evaluate how salts (NaCl, Na2SO4) and alkali (Na2CO3+NaHCO3) affect the physiological and biochemical characteristics during the seedling stage of two cotton cultivars (salt-tolerant, L24; salt-sensitive, X45). Salt and alkali stress reduced seedling emergence rate, relative biomass, and chlorophyll content, however, the REC and MDA content increased. Salt and alkali stress increased markedly superoxide dismutase (SOD) activity. Peroxidase (POD) activity increased first and then decreased as the increase of salt and alkali stress. Catalase (CAT) activity initially increased and then decreased as NaCl stress increased. In addition, the SOD activity, REC, and MDA content was markedly higher in salt stress than that in alkali stress. The proline content of L24 was higher than that of X45 under salt and alkali stress. However, glycine betaine and soluble sugar content of L24 was lower than that of X45 under alkali stress. The REC and MDA content of L24 were lower than those of X45, however, the relative biomass, chlorophyll content, SOD, POD, CAT, and Pro were higher than those of X45. In conclusion, salt tolerant cotton cultivars may possess a superior protection effect by increasing antioxidant enzymes activity under salt and alkali stress.


Sign in / Sign up

Export Citation Format

Share Document