Distinction and characterisation of salinity tolerant and sensitive rice cultivars as probed by the chlorophyll fluorescence characteristics and growth parameters

2014 ◽  
Vol 41 (7) ◽  
pp. 727 ◽  
Author(s):  
Devendra Pratap Singh ◽  
Ramani Kumar Sarkar

Soil salinity is a major abiotic stress that limits rice productivity worldwide. The problem is intense – particularly in areas with extremely dry and hot climatic conditions. Designing an effective phenotyping strategy requires thorough understanding of plant survival under stress. The investigation was conducted using 12 rice cultivars differing in salinity tolerance. Among these cultivars, seedling survival on day 10 of salt treatment (12 dS m–1) was above 85% during wet season and 75% during dry season in FL478, AC39416, Pokkali and Kamini. Highly salt-tolerant cultivars maintained greater proportion of green leaf and chlorophyll content under salt stress. Unlike sensitive cultivars, tolerant cultivars taken up less Na+ and more K+, resulting in lower Na+ : K+ ratio in leaf and sheath. Normalised chlorophyll a fluorescence data revealed that the Fv/Fm and PIABS values decreased on days 3 and 7, respectively, of salt stress in susceptible rice cultivar. Salinity factor index (SFI) calculated by giving different weights to relative PIABS values after variable days of salinity stress clearly distinguished the level of tolerance among rice cultivars. The SFI can be used for grouping of moderately to highly salt-tolerant cultivars based on their tolerance level. We conclude that maintenance of greater proportion of green leaf, and restricted transport of Na+ to sheath and leaf helps the plant to counteract adverse effects of salinity on rice growth.

2018 ◽  
Vol 7 (2) ◽  
pp. 1-12 ◽  
Author(s):  
Tahmina Khanam ◽  
Nahid Akhtar ◽  
MA Halim ◽  
Feroza Hossain

The experiment was conducted to clarify the growth and yield response of two rice cultivars, BR55 and BR43 under salt stress. Six different concentrations of NaCl viz 50, 100, 150, 200, 250 and 300 mM and distilled water (control) were applied on the rice cultivars which were grown under pot culture condition. Growth parameters like plant height, tiller number, leaf number and leaf area were negatively affected by salinity in both cultivars. Salt stress caused a significant reduction in yield in both cultivars of rice. Growth reduction was higher in BR43 than in BR55.The reduction in yield and yield parameters were found to be lower in BR55 than those in BR43. The results obtained in the present study suggest that BR55 showed higher salt tolerance than in BR43. Jahangirnagar University J. Biol. Sci. 7(2): 1-12, 2018 (December)


Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 891 ◽  
Author(s):  
Mobina Ulfat ◽  
Habib-ur-Rehman Athar ◽  
Zaheerud-din Khan ◽  
Hazem M. Kalaji

Salinity is one of the major abiotic stresses prevailing throughout the world that severely limits crop establishment and production. Every crop has an intra-specific genetic variation that enables it to cope with variable environmental conditions. Hence, this genetic variability is a good tool to exploit germplasms in salt-affected areas. Further, the selected cultivars can be effectively used by plant breeders and molecular biologists for the improvement of salinity tolerance. In the present study, it was planned to identify differential expression of genes associated with selective uptake of different ions under salt stress in selected salt-tolerant canola (Brassica napus L.) cultivar. For the purpose, an experiment was carried out to evaluate the growth response of different salt-sensitive and salt-tolerant canola cultivars. Plants were subjected to 200 mM NaCl stress. Canola cultivars—Faisal Canola, DGL, Dunkled, and CON-II—had higher growth than in cvs Cyclone, Ac-EXcel, Legend, and Oscar. Salt-tolerant cultivars were better able to maintain plant water status probably through osmotic adjustment as compared to salt-sensitive cultivars. Although salt stress increased shoot Na+ and shoot Cl− contents in all canola cultivars, salt-tolerant cultivars had a lower accumulation of these toxic nutrients. Similarly, salt stress reduced shoot K+ and Ca2+ contents in all canola cultivars, while salt-tolerant cultivars had a higher accumulation of K+ and Ca2+ in leaves, thereby having greater shoot K+/Na+ and Ca2+/Na+ ratios. Nutrient utilization efficiency decreased significantly in all canola cultivars due to the imposition of salt stress; however, it was greater in salt-tolerant cultivars—Faisal Canola, DGL, and Dunkled. Among four salt-tolerant canola cultivars, cv Dunkled was maximal in physiological attributes, and thus differentially expressed genes (DEGs) were assessed in it by RNA-seq analysis using next-generation sequencing (NGS) techniques. The differentially expressed genes (DEG) in cv Dunkled under salt stress were found to be involved in the regulation of ionic concentration, photosynthesis, antioxidants, and hormonal metabolism. However, the most prominent upregulated DEGs included Na/K transporter, HKT1, potassium transporter, potassium channel, chloride channel, cation exchanger, Ca channel. The RNA-seq data were validated through qRT-PCR. It was thus concluded that genes related to the regulation of ionic concentrate are significantly upregulated and expressed under salt stress, in the cultivar Dunkled.


2020 ◽  
Author(s):  
Xiu Jing ◽  
Ping Mi ◽  
Xianzhi Xie ◽  
Baoshan Wang

Abstract Background: Salt stress, one of the most important abiotic stresses, severely reduces crop yields. Identifying salt-tolerant rice germplasm resources at the germination stage, developing salt tolerance indicators, and cultivating salt-tolerant rice cultivars are crucial for improving rice production in saline soil.Results: We measured the germination parameters of 140 japonica rice cultivars on the 7 day after sowing (DAS) in 0 and 150 mmol L−1 NaCl. To accurately assess salt tolerance and identify reliable indicators of salt tolerance, we measured the shoot length (SL), root length (RL), root fresh weight (RFW), shoot fresh weight (SFW), total fresh weight (TFW) and salt tolerance (STI) index after 7 days of salt-stress treatment. The 140 rice cultivars were divided into four categories based on the mean MFVs: highly salt tolerant (HST: 19 cultivars), salt tolerant (ST: 74 cultivars), weakly salt tolerant (WST: 43 cultivars), and salt sensitive (SS: 4 cultivars). Based on the physiological indicators, we established a mathematical model to accurately evaluate salt tolerance in japonica rice cultivars. STI of TFW under 150 mmol L−1 NaCl treatment showed the highest correlation with salt tolerance during the germination stage.Conclusions: We determined the optimum NaCl concentration (150 mmol L−1) for evaluating salt tolerance in japonica rice at the germination stage. We identified 19 HST, 74 ST, 43 WST, and 4 SS japonica rice cultivars during the germination stage and proposed a mathematical model to evaluate salt tolerance. STI of TFW is a reliable, accurate indicator for evaluating salt tolerance in japonica rice. These findings should greatly facilitate the evaluation of japonica rice cultivars during seed germination and the breeding of salt-tolerant rice cultivars.


2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Denver I. Walitang ◽  
Chang-Gi Kim ◽  
Kiyoon Kim ◽  
Yeongyeong Kang ◽  
Young Kee Kim ◽  
...  

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Shamim Ahmed ◽  
Tae-Young Heo ◽  
Aritra Roy Choudhury ◽  
Denver I. Walitang ◽  
Jeongyun Choi ◽  
...  

AbstractSalinization of agricultural lands, particularly rice paddies, results in the drastic decline of crop yields. Soil salinization impacts the plant physiology by inducing salt stress which may leads to osmotic stress, ionic stress and water-related nutrient imbalance. These imbalances necessitate the need for plants to produce osmolytes including proline and glycine betaine. This study aimed to elucidate the dynamic changes in proline and glycine betaine accumulation modulated by the inoculation of Brevibacterium linens RS16 in salt-sensitive and moderately salt-tolerant rice plants under salt stress conditions. This study showed the interaction of four major factors including rice genotypes with differing tolerance to salt stress, length of exposure to salt stress, level of salt stress and effects of inoculation. Salt stress resulted in significant reduction in plant growth parameters with the salt-sensitive rice genotype (IR29) having a more significant growth reduction. Both the salt-sensitive and salt-tolerant rice genotypes increased in total proline and glycine betaine accumulation at 3 days and 10 days after subjecting under 50 mM and 150 mM salt stress conditions. A significant increase in proline and glycine betaine was observed in the salt-sensitive genotype after 10 days under 50 mM and 150 mM salt stress conditions. Inoculation of the rice genotypes with B. linens RS16 resulted in the improvement of plant growth parameters in both rice genotypes, and total proline and glycine betaine accumulation, especially in IR29. This study showed that proline and glycine betaine are compatible osmolytes of rice under salt stress, and that inoculation of rice genotypes with B. linens RS16 mediated salt tolerance through improvement of plant growth parameters and proline and glycine betaine accumulation in rice plants.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Geetika Mehta ◽  
Senthilkumar K. Muthusamy ◽  
G. P. Singh ◽  
Pradeep Sharma

AbstractSalt stress adversely affects the global wheat production and productivity. To improve salinity tolerance of crops, identification of robust molecular markers is highly imperative for development of salt-tolerant cultivars to mimic yield losses under saline conditions. In this study, we mined 171 salt-responsive genes (including 10 miRNAs) from bread wheat genome using the sequence information of functionally validated salt-responsive rice genes. Salt-stress, tissue and developmental stage-specific expression analysis of RNA-seq datasets revealed the constitutive as well as the inductive response of salt-responsive genes in different tissues of wheat. Fifty-four genotypes were phenotyped for salt stress tolerance. The stress tolerance index of the genotypes ranged from 0.30 to 3.18. In order to understand the genetic diversity, candidate gene based SSRs (cg-SSRs) and MIR gene based SSRs (miR-SSRs) were mined from 171 members of salt-responsive genes of wheat and validated among the contrasting panels of 54 tolerant as well as susceptible wheat genotypes. Among 53 SSR markers screened, 10 cg-SSRs and 8 miR-SSRs were found to be polymorphic. Polymorphic information content between the wheat genotypes ranged from 0.07 to 0.67, indicating the extant of wide genetic variation among the salt tolerant and susceptible genotypes at the DNA level. The genetic diversity analysis based on the allelic data grouped the wheat genotypes into three separate clusters of which single group encompassing most of the salt susceptible genotypes and two of them containing salt tolerance and moderately salt tolerance wheat genotypes were in congruence with penotypic data. Our study showed that both salt-responsive genes and miRNAs based SSRs were more diverse and can be effectively used for diversity analysis. This study reports the first extensive survey on genome-wide analysis, identification, development and validation of salt-responsive cg-SSRs and miR-SSRs in wheat. The information generated in the present study on genetic divergence among genotypes having a differential response to salt will help in the selection of suitable lines as parents for developing salt tolerant cultivars in wheat.


2014 ◽  
Vol 69 (5-6) ◽  
pp. 226-236 ◽  
Author(s):  
Renlei Wang ◽  
Shaohua Liu ◽  
Feng Zhou ◽  
Chunxia Ding

The effects of exogenous ascorbic acid (AsA) and reduced glutathione (GSH) on antioxidant enzyme activities [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)] and the contents of malondialdehyde (MDA) and H2O2, as well as of endogenous AsA and GSH, in the chloroplasts of two rice cultivars, the salt-tolerant cultivar Pokkali and the salt-sensitive cultivar Peta, were investigated. Exogenous AsA and GSH enhanced SOD, APX, and GR activities, increased endogenous AsA and GSH contents, and reduced those of H2O2 and MDA in the chloroplasts of both cultivars under salt stress (200 mM NaCl), but the effects were significantly more pronounced in cv. Pokkali. GSH acted more strongly than AsA on the plastidial reactive oxygen scavenging systems. These results indicated that exogenous AsA and GSH differentially enhanced salinity tolerance and alleviated salinity-induced damage in the two rice cultivars


2012 ◽  
Vol 137 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Rashad M. Balal ◽  
Muhammad M. Khan ◽  
Muhammad A. Shahid ◽  
Neil S. Mattson ◽  
Tahira Abbas ◽  
...  

A study was conducted to investigate the morphological, physiobiochemical, enzymatic, and ionic differences among four cultivated citrus (Citrus sp.) rootstocks with different salt tolerances. Two salt-tolerant rootstocks [Rangpur lime (C. limonia) and Rubidoux (C. trifoliata)] and two salt-sensitive rootstocks [Carrizo citrange (Citrus sinensis × C. trifoliata) and Sanchton citrumello (C. trifoliata × C. paradisi)], were subjected to NaCl stress in greenhouse conditions. The 9-month-old plants were exposed to four different NaCl levels (0, 30, 60, or 90 mm) in sand culture for 3 months. Plant biomass (fresh weight, dry weight, root length, shoot length, and leaf thickness), physiological attributes [number of stomata, stomatal size, number of epidermal cells, photosynthesis rate, stomatal conductance (gS), water use efficiency, and transpiration rate]. and ion content (Na+, K+, Ca+2, Mg+2, and Cl–) were adversely affected by salt stress, but salt-tolerant cultivars were comparatively less affected. Salt stress also enhanced antioxidant enzyme activity (superoxide dismutase, catalase, and peroxidase), particularly in salt-tolerant cultivars. The salt-sensitive cultivars accumulated the greatest content of Na+ and Cl– in their leaves, whereas the salt-tolerant cultivars accumulated the greatest content of Na+ and Cl– in their roots, an adaptation to combat the highly saline conditions. Overall, it was concluded that the salt tolerance of rootstocks is associated with a greater antioxidant enzyme activity and differing accumulation patterns of Na+, K+, Cl–, Mg+2, and Ca+2 in leaves and roots; these can be considered potential indicators of a cultivar's sensitivity to salt stress.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2433
Author(s):  
Shenghai Ye ◽  
Zhibo Huang ◽  
Guibin Zhao ◽  
Rongrong Zhai ◽  
Jing Ye ◽  
...  

Soil salinity is a key source of abiotic stress in the cultivation of rice. In this study, two currently cultivated japonica rice species—Zhegeng 78 (salt-tolerant) and Zhegeng 99 (salt-sensitive)—with similar backgrounds were identified and used to investigate their differential responses to salt stress at the post-germination and seedling stages. Quantitative RT-PCR analysis demonstrated that the expression of OsSOS1, OsHAK1, and OsHAK5 at the post-germination stage, and the expression of OsHKT1,1, OsHTK2,1, and OsHAK1 at the seedling stage, were significantly higher in the salt-tolerant Zhegeng 78 compared with those of the salt-sensitive Zhegeng 99 under salt stress. The significantly lower Na+ net uptake rate at the post-germination and higher K+ net uptake rates at the post-germination and seedling stages were observed in the salt-tolerant Zhegeng 78 compared with those of the salt-sensitive Zhegeng 99 under salt stress. Significantly higher activity of peroxidase (POD) and the lower hydrogen peroxide (H2O2) accumulation were observed in the salt-tolerant Zhegeng 78 compared with those of salt-sensitive Zhegeng 99 under salt stress at the seeding stage. The salt-tolerant Zhegeng 78 might be valuable in future cultivation in salinity soils.


HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1820-1826 ◽  
Author(s):  
Ozlem Altuntas ◽  
H. Yildiz Dasgan ◽  
Yelderem Akhoundnejad

Salt stress is a major problem worldwide because it decreases yields of many important agricultural crops. Silicon is the second-most abundant element in soil and has numerous beneficial effects on plants, particularly in alleviating stress-related impacts. Pepper is an important crop in the Mediterranean region, but pepper varieties differ in their salinity tolerances. The objective of this research was to test the ability of silicon to mitigate effects of salt stress in both salt-sensitive and salt-tolerant cultivars. Salt damage was evaluated by measuring biomass, photosynthetic-related variables, leaf water potential, and membrane damage. We found that the addition of silicon solute to a growth medium was highly effective in improving plant growth by enhancing photosynthesis, stomatal conductance (gS), leaf water status, and membrane stability, which in turn led to higher biomass production in salt-stressed pepper plants, especially in a salt-sensitive cultivar. From an agronomic viewpoint, application of Si may provide economically relevant productivity improvements for salt-sensitive pepper genotypes grown under moderate salinity conditions and for salt-tolerant genotype grown under higher-salinity conditions.


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