scholarly journals Salt stress and phyto-biochemical responses of plants – a review

2008 ◽  
Vol 54 (No. 3) ◽  
pp. 89-99 ◽  
Author(s):  
A. Parvaiz ◽  
S. Satyawati

The ability of plants to tolerate salts is determined by multiple biochemical pathways that facilitate retention and/or acquisition of water, protect chloroplast functions and maintain ion homeostasis. Essential pathways include those that lead to synthesis of osmotically active metabolites, specific proteins and certain free radical enzymes to control ion and water flux and support scavenging of oxygen radicals. No well-defined indicators are available to facilitate the improvement in salinity tolerance of agricultural crops through breeding. If the crop shows distinctive indicators of salt tolerance at the whole plant, tissue or cellular level, selection is the most convenient and practical method. There is therefore a need to determine the underlying biochemical mechanisms of salinity tolerance so as to provide plant breeders with appropriate indicators. In this review, the possibility of using these biochemical characteristics as selection criteria for salt tolerance is discussed.

1981 ◽  
Vol 8 (3) ◽  
pp. 267 ◽  
Author(s):  
MK Smith ◽  
JA Mccomb

The effect of NaCl on growth was examined for whole plants and callus cultures of a salt-sensitive glycophyte (Phaseolus vulgaris L.), a salt-tolerant glycophyte (Beta vulgaris L.) and two halophytes (Atriplex undulata D. Dietr., which has salt glands, and Suaeda australis (R. Br.) Moq., a succulent). Whole plants were grown in nutrient solution culture at NaCl concentrations of 0.1-250 mM. Callus cultures were initiated from the same seed stock, and similar saline regimes were imposed. Whole plant responses were characteristic for the various types of plants: P. vulgaris showed a decrease in growth with increasing salinity; B. vulgaris showed a slight increase in growth at the intermediate salt level and a decrease at higher levels; A. undulata and S. australis showed well defined growth optima at 62.5 mM and 125 mM NaCl, respectively. Callus cultures of P. vulgaris and the two halophytes grew very poorly when salinity was increased. Callus of B. vulgaris showed the same tolerance to salt as did the whole plants. Thus salt tolerance of the halophytes depends on the anatomical and physiological complexity of the intact plant while callus from B. vulgaris appears to have a mechanism(s) of salt tolerance which operates at the cellular level.


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.


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.


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

Abstract Background Chenopodium quinoa Willd., a halophytic crop, shows great variability among different genotypes in response to salt. To investigate the salinity tolerance mechanisms, five 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 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 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 and inorganic ion contents in leaves or roots (not root K + content), but positively correlated with K + /Na + ratio in leaves or roots.Conclusion Our results established 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.


2013 ◽  
Vol 19 (2) ◽  
pp. 57-65
Author(s):  
MH Kabir ◽  
MM Islam ◽  
SN Begum ◽  
AC Manidas

A cross was made between high yielding salt susceptible BINA variety (Binadhan-5) with salt tolerant rice landrace (Harkuch) to identify salt tolerant rice lines. Thirty six F3 rice lines of Binadhan-5 x Harkuch were tested for salinity tolerance at the seedling stage in hydroponic system using nutrient solution. In F3 population, six lines were found as salt tolerant and 10 lines were moderately tolerant based on phenotypic screening at the seedling stage. Twelve SSR markers were used for parental survey and among them three polymorphic SSR markers viz., OSR34, RM443 and RM169 were selected to evaluate 26 F3 rice lines for salt tolerance. With respect to marker OSR34, 15 lines were identified as salt tolerant, 9 lines were susceptible and 2 lines were heterozygous. While RM443 identified 3 tolerant, 14 susceptible and 9 heterozygous rice lines. Eight tolerant, 11 susceptible and 7 heterozygous lines were identified with the marker RM169. Thus the tested markers could be efficiently used for tagging salt tolerant genes in marker-assisted breeding programme.DOI: http://dx.doi.org/10.3329/pa.v19i2.16929 Progress. Agric. 19(2): 57 - 65, 2008


2019 ◽  
Vol 55 (No. 2) ◽  
pp. 61-69 ◽  
Author(s):  
Dorsaf Allel ◽  
Anis BenAmar ◽  
Mounawer Badri ◽  
Chedly Abdelly

Soil salinity is one of the main factors limiting cereal productivity in worldwide agriculture. Exploitation of natural variation in local barley germplasm is an effective approach to overcome yield losses. Three gene pools of North African Hordeum vulgare L. grown in Tunisia, Algeria and Egypt were evaluated at the reproductive stage under control and saline conditions. Assessment of stress tolerance was monitored using morphological, yield-related traits and phenological parameters of reproductive organs showing significant genetic variation. High heritability and positive relationships were found suggesting that some traits associated with salt tolerance could be used as selection criteria. The phenotypic correlations revealed that vegetative traits including shoot biomass, tiller number and leaf number along with yield-related traits such as spike number, one spike dry weight, grain number/plant and grain number/spike were highly positively correlated with grain yield under saline conditions. Hence, these traits can be used as reliable selection criteria to improve barley grain yield. Keeping a higher shoot biomass and longer heading and maturity periods as well as privileged filling ability might contribute to higher grain production in barley and thus could be potential target traits in barley crop breeding toward improvement of salinity tolerance. Multiple selection indices revealed that salt tolerance trait index provided a better discrimination of barley landraces allowing selection of highly salt-tolerant and highly productive genotypes under severe salinity level. Effective evaluation of salt tolerance requires an integration of selection indices to successfully identify and characterize salt tolerant lines required for valuable exploitation in the management of salt-affected areas.  


2019 ◽  
Vol 70 (19) ◽  
pp. 5355-5374 ◽  
Author(s):  
Dandan Zang ◽  
Jingxin Wang ◽  
Xin Zhang ◽  
Zhujun Liu ◽  
Yucheng Wang

Abstract Plant heat shock transcription factors (HSFs) are involved in heat and other abiotic stress responses. However, their functions in salt tolerance are little known. In this study, we characterized the function of a HSF from Arabidopsis, AtHSFA7b, in salt tolerance. AtHSFA7b is a nuclear protein with transactivation activity. ChIP-seq combined with an RNA-seq assay indicated that AtHSFA7b preferentially binds to a novel cis-acting element, termed the E-box-like motif, to regulate gene expression; it also binds to the heat shock element motif. Under salt conditions, AtHSFA7b regulates its target genes to mediate serial physiological changes, including maintaining cellular ion homeostasis, reducing water loss rate, decreasing reactive oxygen species accumulation, and adjusting osmotic potential, which ultimately leads to improved salt tolerance. Additionally, most cellulose synthase-like (CSL) and cellulose synthase (CESA) family genes were inhibited by AtHSFA7b; some of them were randomly selected for salt tolerance characterization, and they were mainly found to negatively modulate salt tolerance. By contrast, some transcription factors (TFs) were induced by AtHSFA7b; among them, we randomly identified six TFs that positively regulate salt tolerance. Thus, AtHSFA7b serves as a transactivator that positively mediates salinity tolerance mainly through binding to the E-box-like motif to regulate gene expression.


2021 ◽  
Author(s):  
Yamato Ishida ◽  
Takuya Kobayashi ◽  
Shuhei Chiba ◽  
Yohei Katoh ◽  
Kazuhisa Nakayama

Abstract Primary cilia contain specific proteins to achieve their functions as cellular antennae. Ciliary protein trafficking is mediated by the intraflagellar transport (IFT) machinery containing the IFT-A and IFT-B complexes. Mutations in genes encoding the IFT-A subunits (IFT43, IFT121/WDR35, IFT122, IFT139/TTC21B, IFT140, and IFT144/WDR19) often result in skeletal ciliopathies, including cranioectodermal dysplasia (CED). We here characterized the molecular and cellular defects of CED caused by compound heterozygous mutations in IFT144 [the missense variant IFT144(L710S) and the nonsense variant IFT144(R1103*)]. These two variants were distinct with regard to their interactions with other IFT-A subunits and with the IFT-B complex. When exogenously expressed in IFT144-knockout (KO) cells, IFT144(L710S) as well as IFT144(WT) rescued both moderately compromised ciliogenesis and the abnormal localization of ciliary proteins. As the homozygous IFT144(L710S) mutation was found to cause autosomal recessive retinitis pigmentosa, IFT144(L710S) is likely to be hypomorphic at the cellular level. In striking contrast, the exogenous expression of IFT144(R1103*) in IFT144-KO cells exacerbated the ciliogenesis defects. The expression of IFT144(R1103*) together with IFT144(WT) restored the abnormal phenotypes of IFT144-KO cells. However, the coexpression of IFT144(R1103*) with the hypomorphic IFT144(L710S) variant in IFT144-KO cells, which mimics the genotype of compound heterozygous CED patients, resulted in severe ciliogenesis defects. Taken together, these observations demonstrate that compound heterozygous mutations in IFT144 cause severe ciliary defects via a complicated mechanism, where one allele can cause severe ciliary defects when combined with a hypomorphic allele.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 712
Author(s):  
Md Sarowar Alam ◽  
Mark Tester ◽  
Gabriele Fiene ◽  
Magdi Ali Ahmed Mousa

Salinity is one of the most significant environmental stresses for sustainable crop production in major arable lands of the globe. Thus, we conducted experiments with 27 tomato genotypes to screen for salinity tolerance at seedling stage, which were treated with non-salinized (S1) control (18.2 mM NaCl) and salinized (S2) (200 mM NaCl) irrigation water. In all genotypes, the elevated salinity treatment contributed to a major depression in morphological and physiological characteristics; however, a smaller decrease was found in certain tolerant genotypes. Principal component analyses (PCA) and clustering with percentage reduction in growth parameters and different salt tolerance indices classified the tomato accessions into five key clusters. In particular, the tolerant genotypes were assembled into one cluster. The growth and tolerance indices PCA also showed the order of salt-tolerance of the studied genotypes, where Saniora was the most tolerant genotype and P.Guyu was the most susceptible genotype. To investigate the possible biochemical basis for salt stress tolerance, we further characterized six tomato genotypes with varying levels of salinity tolerance. A higher increase in proline content, and antioxidants activities were observed for the salt-tolerant genotypes in comparison to the susceptible genotypes. Salt-tolerant genotypes identified in this work herald a promising source in the tomato improvement program or for grafting as scions with improved salinity tolerance in tomato.


2011 ◽  
Vol 38 (3) ◽  
pp. 187 ◽  
Author(s):  
Brynne E. Lazarus ◽  
James H. Richards ◽  
Phoebe E. Gordon ◽  
Lorence R. Oki ◽  
Corey S. Barnes

We investigated genetic differences in salinity tolerance among 20 saltgrass (Distichlis spicata (L.) Greene) genotypes, including constitutive, gender-based and phenotypic plasticity traits, to better understand the basis of adaptation and acclimation by saltgrass in diverse environments. On average, the plants survived NaCl treatments up to ~1 M, with reductions in growth and health that varied with genotype. For these 20 genotypes in a greenhouse study, we showed that greater plasticity in one salt tolerance mechanism was physiologically linked to lesser plasticity in another. Under various levels of constant salinity stress, genotypes employing a strategy of greater plasticity in foliar Na and lesser plasticity in both foliar K : Na and Na turnover rate were better able to substitute Na for K in some cellular functions, especially osmotic adjustment, leading to increased salinity tolerance. Although we observed gender segregation with salinity in the Owens (Dry) Lake Playa (Inyo County, CA, USA) population planted for dust control, from which the genotypes were collected, we did not observe gender differences in salinity tolerance in the greenhouse. Significant physiological plasticity tradeoffs among genotypes, however, did affect overall salinity tolerance and may be important for this species survival in diverse managed and natural habitats.


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