Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress

2012 ◽  
Vol 92 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Cheng-Wu Jin ◽  
Yan-Lin Sun ◽  
Dong-Ha Cho

Jin, C.-W., Sun, Y.-L. and Cho, D.-H. 2012. Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress. Can. J. Plant Sci. 92: 311–319. As irrigation water salinization has become a serious constraint for crop production, as well as soil salinity, the selection and use of salt-tolerant species is urgently required. In this study, we describe the salt responses of three kenaf (Hibiscus cannabinus L.) cultivars and select the cultivar with high salt tolerance. Responses to salt stress were investigated in terms of growth, water potentials, photosynthesis, and proline contents. Photosynthesis, evaluated by net CO2 assimilation rate, stomatal conductance, and intercellular CO2 concentration, did not show any significant effects among the cultivars. Leaf water potential decreased depending on salt concentration and salt treatment period. Proline accumulation was enhanced, particularly depending on salt concentration, but not salt treatment period. As salt concentration increased, seedling growth was inhibited to a certain extent, and the inhibition of growth depended mainly on salt concentration. At the early stage of treatment, Dowling was more tolerant to salt stress than Everglade-41 and Tainung-2. Although Dowling showed a lower decrease in fresh weight, Tainung-2 always maintained a relatively high vegetative yield, even under high salt stress. Tainung-2, having greater salt adaptation, was therefore considered an ideal cultivar for popularization and farm cultivation.

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 845
Author(s):  
Helena Hnilickova ◽  
Kamil Kraus ◽  
Pavla Vachova ◽  
Frantisek Hnilicka

In this investigation, the effect of salt stress on Portulaca oleracea L. was monitored at salinity levels of 100 and 300 mM NaCl. At a concentration of 100 mM NaCl there was a decrease in stomatal conductance (gs) simultaneously with an increase in CO2 assimilation (A) at the beginning of salt exposure (day 3). However, the leaf water potential (ψw), the substomatal concentration of CO2 (Ci), the maximum quantum yield of photosystem II (Fv/Fm), and the proline and malondialdehyde (MDA) content remained unchanged. Exposure to 300 mM NaCl caused a decrease in gs from day 3 and a decrease in water potential, CO2 assimilation, and Fv/Fm from day 9. There was a large increase in proline content and a significantly higher MDA concentration on days 6 and 9 of salt stress compared to the control group. After 22 days of exposure to 300 mM NaCl, there was a transition from the C4 cycle to crassulacean acid metabolism (CAM), manifested by a rapid increase in substomatal CO2 concentration and negative CO2 assimilation values. These results document the tolerance of P. oleracea to a lower level of salt stress and the possibility of its use in saline localities.


2021 ◽  
Vol 948 (1) ◽  
pp. 012049
Author(s):  
Y R E Wulandari ◽  
T Triadiati ◽  
Y C Sulistyaningsih ◽  
A Suprayogi ◽  
M Rahminiwati

Abstract Mulberry (Morus sp.) plant is used to feed silkworms, and the leaves contain compounds with medicinal properties of secondary metabolites. However, the content of these compounds tends to increase under stress conditions, for instance, salt stress. This study, therefore, aimed to determine the accessions of mulberry with tolerance for salt stress. The stem cuttings of seven accessions from 5 regions, Bogor, Pati, Situbondo, Bali, and Gowa, were planted following a factorial randomized block design with 3 replications. Subsequently, the first factor using the accessions, and the second factor using NaCl solution (0.0%, 0.2%, 0.3%, and 0.4% concentrations) were performed. The variables observed were growth (leaves number, plant height, and shoots number), photosynthesis rate, total chlorophyll, and proline content. The results showed that the M6 accession exhibited tolerance under high salt stress, based on the leaves number, plant height, shoot number, photosynthesis rate, and proline content. Furthermore, an increase in salt concentration was discovered to cause a decrease in growth, photosynthesis rate, and total chlorophyll content. Also, proline accumulation stimulated by high salt stress possibly plays an important role in salinity tolerance.


2018 ◽  
Vol 1 ◽  
pp. 19-25 ◽  
Author(s):  
Ja'afar Umar ◽  
Adamu Aliyu ◽  
Kasimu Shehu ◽  
Lawal Abubakar

Many plants accumulate high levels of free proline content (pro) and glycine betaine (GB) in response to abiotic stress, Pro and GB act as an osmoprotectant. Generally, these levels are high than those required to be used in protein synthesis. Salinity inhibition of plant growth is the result of osmotic and ionic effect and different plant species have developed different mechanisms to cope with those effects. In this study, accumulation of osmolytes of twenty tomato genotypes was evaluated in response to salinity stress. The seedlings of each genotype were divided into three groups, Sodium chloride (NaCl) dissolved in irrigation water to make variant concentration of 30 and 60 mg/L of salt concentration using electrical conductivity meter which were used to water the plants. Level of free proline and glycine betaine were measured. Data obtained were subjected to one way analysis of variance using SPSS (20) Statistical Software. Dry mass accumulation decreased with increased salt concentration in all the genotypes. However, the result differ significantly (P< 0.05). The highest dry mass accumulations at control were recorded on Tropimech and Giofranco F. with 6.00 and 5.97. The lowest dry mass accumulations were recorded on plant treated with 60mg/L of salt. Dangainakawa recorded the least accumulation of dry mass on plants treated with 60mg/l of salt with 0.90g followed by Dan Gombe with 1.47g respectively. The highest free proline content of 1.46 µmolg-1was recorded on Dan gainakawa at plant treated with 60 mg/L of NaCl. The lowest proline content was recorded at control on Giofranco F. with 0.17 µmolg-1The highest GB content in all the plants were recorded at plants treated with 60 mg/L. However, the highest GB content (1.67) among the 20 (P<0.05) were recorded at 60 mg/L in Rio Grande followed by Bahaushe with 1.50 µmolg-1. In conclusion, GB and Pro are osmoregulators produced by tomato in response to stress so as to alleviate the consequence effects of salt stress.


2021 ◽  
Vol 12 ◽  
Author(s):  
Pu-Sheng Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu

Salinity is one of the strongest abiotic factors in nature and has harmful effects on plants and microorganisms. In recent years, the degree of soil salinization has become an increasingly serious problem, and the use of plant growth-promoting rhizobacteria has become an option to improve the stress resistance of plants. In the present study, the salt tolerance mechanism of the rhizosphere bacterium Rahnella aquatilis JZ-GX1 was investigated through scanning electron microscopy observations and analysis of growth characteristics, compatible solutes, ion distribution and gene expression. In addition, the effect of JZ-GX1 on plant germination and seedling growth was preliminarily assessed through germination experiments. R. aquatilis JZ-GX1 was tolerant to 0–9% NaCl and grew well at 3%. Strain JZ-GX1 promotes salt tolerance by stimulating the production of exopolysaccharides, and can secrete 60.6983 mg/L of exopolysaccharides under the high salt concentration of 9%. Furthermore, the accumulation of the compatible solute trehalose in cells as the NaCl concentration increased was shown to be the primary mechanism of resistance to high salt concentrations in JZ-GX1. Strain JZ-GX1 could still produce indole-3-acetic acid (IAA) and siderophores and dissolve inorganic phosphorus under salt stress, characteristics that promote the ability of plants to resist salt stress. When the salt concentration was 100 mmol/L, strain JZ-GX1 significantly improved the germination rate, germination potential, fresh weight, primary root length and stem length of tomato seeds by 10.52, 125.56, 50.00, 218.18, and 144.64%, respectively. Therefore, R. aquatilis JZ-GX1 is a moderately halophilic bacterium with good growth-promoting function that has potential for future development as a microbial agent and use in saline-alkali land resources.


1981 ◽  
Vol 61 (3) ◽  
pp. 543-548 ◽  
Author(s):  
N. J. TYLER ◽  
D. B. FOWLER ◽  
L. V. GUSTA

The effect of salt stress on the cold acclimation of winter wheat plants grown in nutrient solution was determined. The presence of salts reduced crown moisture content, leaf osmotic and water potential, and decreased the rate of plant cold acclimation. Plants acclimated for 30 days in solutions with conductivities of < 1.0 (control), 6.0, 12.0 and 18.0 mmhoscm had LT50 of −19, −16, −4 and −4 °C, respectively, as determined from controlled freeze tests. Salt concentration of the hydroponic media also influenced crown potassium, sulfur, magnesium, sodium and nitrogen contents.


2021 ◽  
Vol 12 ◽  
Author(s):  
Li Li ◽  
Naiwei Li ◽  
Xiwu Qi ◽  
Yang Bai ◽  
Qiutong Chen ◽  
...  

Glehnia littoralis is a medicinal halophyte that inhabits sandy beaches and has high ecological and commercial value. However, the molecular mechanism of salt adaptation in G. littoralis remains largely unknown. Here, we cloned and identified a non-specific phospholipase C gene (GlNPC3) from G. littoralis, which conferred lipid-mediated signaling during the salt stress response. The expression of GlNPC3 was induced continuously by salt treatment. Overexpression of GlNPC3 in Arabidopsis thaliana increased salt tolerance compared to wild-type (WT) plants. GlNPC3-overexpressing plants had longer roots and higher fresh and dry masses under the salt treatment. The GlNPC3 expression pattern revealed that the gene was expressed in most G. littoralis tissues, particularly in roots. The subcellular localization of GlNPC3 was mainly at the plasma membrane, and partially at the tonoplast. GlNPC3 hydrolyzed common membrane phospholipids, such as phosphotidylserine (PS), phosphoethanolamine (PE), and phosphocholine (PC). In vitro enzymatic assay showed salt-induced total non-specific phospholipase C (NPC) activation in A. thaliana GlNPC3-overexpressing plants. Plant lipid profiling showed a significant change in the membrane-lipid composition of A. thaliana GlNPC3-overexpressing plants compared to WT after the salt treatment. Furthermore, downregulation of GlNPC3 expression by virus-induced gene silencing in G. littoralis reduced the expression levels of some stress-related genes, such as SnRK2, P5SC5, TPC1, and SOS1. Together, these results indicated that GlNPC3 and GlNPC3-mediated membrane lipid change played a positive role in the response of G. littoralis to a saline environment.


Author(s):  
Satavisha Mullick ◽  
Ramesh Kumar Kushwaha

Background: Green gram (Vigna radiata) also known as moong bean is an annually cultivated in East Asia, Southeast Asia and Indian subcontinent. V. radiata is very important source for the protein as in our regular diet and it proved essential amino acid such as phenylalanine, leucine, isoleucine, valine, lysine, arginine, methionine, threonine and tryptophan. Methods: Here, we studied the influence of seed endophytes on germination and development under salinity stress condition. Seeds were treated with sodium hypochlorite for 30 min under shaking condition at 100 rpm for surface sterilization and treated with 70% ethanol for 2 min and followed five times rinse with autoclaved water. Surface sterilised seeds were homogenised in autoclaved water with the help of mortal-pestle. Homogenised seed solution made serial dilution and spreaded over nutrient agar for endophytic bacterial growth. Seeds were treated with bacteriocide and fungicide to make endophytes free, followed by sown for germination at 0mM, 50mM, 100mM and 150mM NaCl concentration. Result: Endophyte free seedlings were more susceptible against salt stress over normal seedlings. Therefore endophyte free seedling shoot and root biomass was 23.5% and 65.7% lower than control seedling biomass at 0mM salt respectively, while root length was 70% lower than control seedling root at 0mM salt concentration. Proline content in shoot and root observed an increase with increase of salt concentration. At 0mM salt, proline content was 0.00782±0.00043 and 0.00648±0.00017 (µmol/mg) in root of normal and endophyte free seedling respectively, while in shoot, it was non-significant difference. Glycine betaine content found to be increasing upto 100mM, followed by decreasing at 150mM in both root and shoot tissue. Glycine betaine content in endophyte free and control seedling shoot was 74.2±2.5 and 96.0±2.73 (µg/200mg) respectively at 100mM salt concentration. This result suggests, not only heritable genomic DNA but also endophytes associated with seed are very much important for the seedling growth and development which is also finally helps to combat abiotic stress situation.


2019 ◽  
Vol 14 (4) ◽  
pp. 319-328
Author(s):  
Antar Mahmud Badran ◽  
Igor Yuryevich Savin

Bitter almond rootstock is considered one of the most vital rootstocks for stone fruit species but it is classified as a plant sensitive to salinity. This experiment was carried out to study the effect of salt stress on vegetative growth and photosynthetic pigments of bitter almond rootstock as an attempt to sustain growth and increase its tolerance to high salt concentrations. However, the seeds were soaked in salt solution of NaCl as 1, 3, and 5 dsm-1 for 48 hours before stratification. After that, nuts were sown in perlite and treated with different saline solutions subsequently stratified at 6 ℃ for eight weeks. Sprouted seeds were cultivated in pots with a mixture of peat and perlite and treated only with the highest salt concentration 5 dsm-1. The treatments were arranged in a complete randomized block design with three replications. Vegetative traits and photosynthetic pigments content were estimated. The results revealed that soaking and pre-treating seed of bitter almond rootstock by means of high salt concentration 5dsm-1 during the germination period and subsequently after planting produced stronger transplants that had hardening, adaptation and could avoid the hyperosmotic shock of salt stress after planting. It is obvious throughout; increment of stem diameter, plant height, total number of leaves\plant, fresh and dry weight of leaves, photosynthetic pigments and total carbohydrate content of such transplants. While other coming seedlings from low salt concentrations were exposed to hyperosmotic shock and salt injury therefore inhibit growth rate of such plants, increased falling of leaves and finally reduced photosynthetic pigments content in the resulting seedlings.


2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4090
Author(s):  
Morteza Sheikhalipour ◽  
Behrooz Esmaielpour ◽  
Gholamreza Gohari ◽  
Maryam Haghighi ◽  
Hessam Jafari ◽  
...  

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles (Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and 200 mg L−1) and Cs–Se NPs (0, 10 and 20 mg L−1) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L−1) and Cs–Se NPs (20 mg L−1) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO2 (100 mg L−1) and Cs–Se NPs (20 mg L−1). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L−1 TiO2 NPs and 20 mg L−1 Cs–Se could be considered as promising agents in combating high levels of salinity in the case of stevia.


Sign in / Sign up

Export Citation Format

Share Document