scholarly journals Exogenous application of KNO3 elevates the salinity tolerance of Stevia rebaudiana through ion homeostasis mechanism

2019 ◽  
Author(s):  
Mitali Mahajan ◽  
Surbhi Sharma ◽  
Pawan Kumar ◽  
Probir Kumar Pal

AbstractThough relatively little is understood of adaptation, physiological and metabolic changes of Stevia rebaudiana under exposure to salinity stress, it is hypothesized that exogenous application of potassium (K+) could elevates the salinity tolerance through ions homeostasis. Thus, an experiment was conducted with twenty treatment combinations comprising four salinity levels (irrigation with normal water as control and three level of NaCl at 40, 80 and 120 mM) and five different concentrations of KNO3 (0.0, 2.5, 5.0, 7.5, and 10.0 g L−1). Dry leaf yield was not negatively affected with mild salinity (40 mM). However, the detrimental effects were observed at moderate and higher salinity levels (80 and 120 mM). The uptakes of K+, Ca2+, and N were significantly reduced at higher salinity level, whereas accumulations of Na+ and Cl− ions in plant tissues were substantially increased. Proline content in leaf was also increased significantly (P≤0.05) in response to salt stress. Among the foliar application, KNO3 at 5.0 gL−1 registered significantly (P≤0.05) higher dry leaf yield compared with control. Exogenous application of K+ under moderate salinity stress maintained ion balance in cytosol, particularly K: Na. Thus, the salinity tolerance of stevia can be elevated to some extent through exogenous application of K+.HighlightThe detrimental effects of moderate and higher salinity levels on growth and dry leaf yield of stevia were observed. However, tolerance level can be elevated through exogenous application of KNO3.

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.    


2019 ◽  
Author(s):  
Zhiquan Cai ◽  
Qi Gao

Abstract Background: Chenopodium quinoa Willd., a halophytic crop, shows great variability among different genotypesin response to salt. To investigate the salinitytolerance mechanisms, five contrasting quinoa cultivars belonging to highland ecotype were compared for their seed germination (under 0, 100 and 400 mM NaCl) and seedling’s responses under five salinity levels (0, 100, 200, 300 and 400 mM NaCl). Results: Substantial variations were found in plant size (biomass) and overall salinity tolerance (plant biomass in salt treatment as % of control) among the different quinoa cultivars. Plant salinity tolerance was negatively associated with plant size, especially at lower salinity levels (<300 mM NaCl), but salt tolerance between seed germination and seedling growth is was not closely correlated. Except for shoot/root ratio, all measured plant traits responded to salt in a genotype-specific way. Salt stress resulted in decreased plant height, leaf area, root length, and root/shoot ratio in each cultivar. With increasing salinity levels, leaf superoxide dismutase (SOD) activity and lipid peroxidation generally increased, but catalase (CAT) and peroxidase (POD) activities showed non-linear patterns. Organic solutes (soluble sugar, proline and protein) accumulated in leaves, whereas inorganic ion (Na + and K + )increased but K + /Na + decreased in both leaves and roots. Across different salinity levels and cultivars, without close relationships with antioxidant enzyme activities (SOD, POD, or CAT), salinity tolerance was significantly negatively correlated with leaf organic solute and malondialdehyde contents in leaves and inorganic ion contents in leaves or roots ( not except for root K + content), but positively correlated with K + /Na + ratio in leaves or roots. Conclusion: Our results establish indicate ed that leaf osmoregulation, K + retention, Na + exclusion, and ion homeostasis are the main physiological mechanisms conferring salinity tolerance of these cultivars, rather than the regulations of leaf antioxidative ability.As an index of salinity tolerance, K + /Na + ratio in leaves or roots can be used for the selective breeding of highland quinoa cultivars.


2020 ◽  
Author(s):  
Zhiquan Cai ◽  
Qi Gao

Abstract Background: Chenopodium quinoa Willd., a halophytic crop, shows great variability among different genotypesin response to salt. To investigate the salinitytolerance mechanisms, five contrasting quinoa cultivars belonging to highland ecotype were compared for their seed germination (under 0, 100 and 400 mM NaCl) and seedling’s responses under five salinity levels (0, 100, 200, 300 and 400 mM NaCl). Results: Substantial variations were found in plant size (biomass) and overall salinity tolerance (plant biomass in salt treatment as % of control) among the different quinoa cultivars. Plant salinity tolerance was negatively associated with plant size, especially at lower salinity levels (<300 mM NaCl), but salt tolerance between seed germination and seedling growth is was not closely correlated. Except for shoot/root ratio, all measured plant traits responded to salt in a genotype-specific way. Salt stress resulted in decreased plant height, leaf area, root length, and root/shoot ratio in each cultivar. With increasing salinity levels, leaf superoxide dismutase (SOD) activity and lipid peroxidation generally increased, but catalase (CAT) and peroxidase (POD) activities showed non-linear patterns. Organic solutes (soluble sugar, proline and protein) accumulated in leaves, whereas inorganic ion (Na + and K + )increased but K + /Na + decreased in both leaves and roots. Across different salinity levels and cultivars, without close relationships with antioxidant enzyme activities (SOD, POD, or CAT), salinity tolerance was significantly negatively correlated with leaf organic solute and malondialdehyde contents in leaves and inorganic ion contents in leaves or roots ( not except for root K + content), but positively correlated with K + /Na + ratio in leaves or roots. Conclusion: Our results establish indicate ed that leaf osmoregulation, K + retention, Na + exclusion, and ion homeostasis are the main physiological mechanisms conferring salinity tolerance of these cultivars, rather than the regulations of leaf antioxidative ability.As an index of salinity tolerance, K + /Na + ratio in leaves or roots can be used for the selective breeding of highland quinoa cultivars.


2021 ◽  
Author(s):  
ARUN SHANKAR ◽  
O P Choudhary ◽  
Kuldeep Singh

Salinized hydroponic culture experiment with three salinity levels (EC control, 6 and 12 dS/m) was performed to screen salt tolerant mutants of aerobic rice cultivar Nagina 22 and to study the nature of salt tolerance from a total of 432 EMS induced M4 mutants. Plants were harvested 30 days after sowing. Growth parameters viz. root weight, shoot weight, root length, shoot length, Na and K concentrations in shoot and roots were measured. Combined Factor scores of growth parameters was computed by Principle Component Analysis using Minitab software. At EC 12 dS/m 10 mutants out of 432 were able to survive. At moderate salinity, some mutant lines produced higher shoot weight compared to their respective control showing inverse trend and the effectiveness of EMS induced mutation in inducing salinity tolerance to these mutants. At high salinity only10 mutants survived (remained green) up to the time of 30 days harvest. These mutants performed well in terms of overall growth recording 2.1-2.5 times higher factor score and 8-14 times higher shoot weight compared to the N 22 check. One mutant N22-L-1010 almost completely excluded Na at xylem parenchyma level. Two other mutants N22-L-1013 and N22-L-806 maintained Na exclusion compared to the N22 check. N22 check and mutant N22-L-1009 maintained similar degree of Na exclusion though the N22 check died because it cannot maintain adequate K in shoot. We conclude that EMS has induced salinity tolerance in some mutants. The study can be advanced further to characterize the putative mutants through molecular genetics approaches.


HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 374-376 ◽  
Author(s):  
Kenneth B. Marcum

Relative salinity tolerance of 33 creeping bentgrass (Agrostis palustris Huds), one colonial bentgrass (A. capillaris L.), and one velvet bentgrass (A. canina L.) cultivars were determined via hydroponics in a controlled-environment greenhouse. After gradual acclimation, grasses were exposed to moderate salinity stress (8 dS·m-1) for 10 weeks to determine tolerance to chronic salinity stress. Relative dry weight of leaf clippings (RLW), percentage of green leaf area (GL), root dry weight (RW), and root length (RL) were all effective parameters for predicting salinity tolerance. Following 10 weeks of salinity stress, RLW was correlated with GL (r = 0.72), with RW (r = 0.71), and with RL (r = 0.66). The range of salinity tolerance among cultivars was substantial. `Mariner', `Grand Prix', `Seaside', and `Seaside II' were salt-tolerant, `L-93', `Penn G-2', `18th Green', and `Syn 96-1' were moderately salt tolerant, and `Avalon', `Ambrosia', `SR1119', `Regent', `Putter', `Penncross', and `Penn G-6' were salt sensitive.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 940
Author(s):  
Raddi ◽  
Mariotti ◽  
Martini ◽  
Pierguidi

The effect of salinity on seed germination/emergence in narrow-leaved ash (Fraxinus angustifolia) was studied both under field and laboratory conditions, in order to detect critical values to NaCl exposure. Research Highlights: Novel statistical methods in germination ecology has been applied (i) to determine the effects of chilling length and salinity (up to 150 mM NaCl) on Fraxinus angustifolia subsp. oxycarpa seed emergence, and (ii) to estimate threshold limits treating germination response to salinity as a biomarker. Background and Objectives: Salinity cut values at germination stage had relevant interest for conservation and restoration aims of Mediterranean floodplain forests in coastal areas subjected to salt spray exposure and/or saline water introgression. Results: Salinity linearly decreased germination/emergence both in the field and laboratory tests. Absence of germination was observed at 60 mM NaCl in the field (70–84 mM NaCl depending on interpolation model) and at 150 mM NaCl for 4-week (but not for 24-week) chilling. At 50 mM NaCl, germination percentage was 50% (or 80%) of control for 4-week (or 24-week) chilling. Critical values for salinity were estimated between freshwater and 50 (75) mM NaCl for 4-week (24-week) chilling by Bayesian analysis. After 7-week freshwater recovery, critical cut-off values included all tested salinity levels up to 150 mM NaCl, indicating a marked resumption of seedling emergence. Conclusions: Fraxinus angustifolia is able to germinate at low salinity and to tolerate temporarily moderate salinity conditions for about two months. Prolonged chilling widened salinity tolerance.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tingting Sun ◽  
Tingting Pei ◽  
Lulu Yang ◽  
Zhijun Zhang ◽  
Mingjun Li ◽  
...  

Abstract Background Soil salinity is a critical threat to global agriculture. In plants, the accumulation of xanthine activates xanthine dehydrogenase (XDH), which catalyses the oxidation/conversion of xanthine to uric acid to remove excess reactive oxygen species (ROS). The nucleobase-ascorbate transporter (NAT) family is also known as the nucleobase-cation symporter (NCS) or AzgA-like family. NAT is known to transport xanthine and uric acid in plants. The expression of MdNAT is influenced by salinity stress in apple. Results In this study, we discovered that exogenous application of xanthine and uric acid enhanced the resistance of apple plants to salinity stress. In addition, MdNAT7 overexpression transgenic apple plants showed enhanced xanthine and uric acid concentrations and improved tolerance to salinity stress compared with nontransgenic plants, while opposite phenotypes were observed for MdNAT7 RNAi plants. These differences were probably due to the enhancement or impairment of ROS scavenging and ion homeostasis abilities. Conclusion Our results demonstrate that xanthine and uric acid have potential uses in salt stress alleviation, and MdNAT7 can be utilized as a candidate gene to engineer resistance to salt stress in plants.


Author(s):  
Sabrina Raddi ◽  
Barbara Mariotti ◽  
Sofia Martini ◽  
Alberto Pierguidi

The effect of salinity on seed germination/emergence in narrow-leaved ash (Fraxinus angustifolia) was studied both under field and laboratory conditions, in order to detect critical values to NaCl exposure. Research Highlights: Novel statistical methods in germination ecology has been applied (i) to determine the effects of chilling length and salinity (up to 150 mM NaCl) on Fraxinus angustifolia subsp. oxycarpa seed emergence, and (ii) to estimate threshold limits treating germination response to salinity as a biomarker. Background and Objectives: Salinity cut values at germination stage had relevant interest for conservation and restoration aims of Mediterranean floodplain forests in coastal areas subjected to salt spray exposure and/or saline water introgression. Results: Salinity linearly decreased germination/emergence both in the field and laboratory tests. Absence of germination was observed at 70 mM NaCl in the field and at 150 mM NaCl for 4-week (but not for 24-week) chilling. At 50 mM NaCl germination percentage was 50% (or 80%) of control for 4-week (or 24- week) chilling. Critical values for salinity were estimated between freshwater and 50 (75) mM NaCl for 4-week (24-week) chilling by Bayesian analysis. After 7-week freshwater recovery, critical cut-off values included all tested salinity levels up to 150 mM NaCl, indicating a marked resumption of seedling emergence. Conclusions: Fraxinus angustifolia is able to germinate at low salinity and to tolerate temporarily moderate salinity conditions for about two months. Prolonged chilling widened salinity tolerance.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2576
Author(s):  
Tauqeer Ahmad Yasir ◽  
Ayesha Khan ◽  
Milan Skalicky ◽  
Allah Wasaya ◽  
Muhammad Ishaq Asif Rehmani ◽  
...  

Soil salinity disrupts the physiological and biochemical processes of crop plants and ultimately leads to compromising future food security. Sodium nitroprusside (SNP), a contributor to nitric oxide (NO), holds the potential to alleviate abiotic stress effects and boost tolerance in plants, whereas less information is available on its role in salt-stressed lentils. We examined the effect of exogenously applied SNP on salt-stressed lentil plants by monitoring plant growth and yield-related attributes, biochemistry of enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) amassing of leaf malondialdehyde (MDA) and hydrogen peroxide (H2O2). Salinity stress was induced by NaCl application at concentrations of 50 mM (moderate salinity) and 100 mM (severe salinity), while it was alleviated by SNP application at concentrations of 50 µM and 100 µM. Salinity stress severely inhibited the length of roots and shoots, the relative water content, and the chlorophyll content of the leaves, the number of branches, pods, seeds, seed yield, and biomass per plant. In addition, MDA, H2O2 as well as SOD, CAT, and POD activities were increased with increasing salinity levels. Plants supplemented with SNP (100 µM) showed a significant improvement in the growth- and yield-contributing parameters, especially in plants grown under moderate salinity (50 mM NaCl). Essentially, the application of 100 µM SNP remained effective to rescue lentil plants under moderate salinity by regulating plant growth and biochemical pathways. Thus, the exogenous application of SNP could be developed as a useful strategy for improving the performance of lentil plants in salinity-prone environments.


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