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High salt concentrations in the growing medium can severely affect the growth and development of plants. It is imperative to understand the different components of salt-tolerant network in plants in order to produce the salt-tolerant cultivars. High-affinity potassium transporter- and myelocytomatosis proteins have been shown to play a critical role for salinity tolerance through exclusion of sodium (Na + ) ions from sensitive shoot tissues in plants. Numerous genes, that limit the uptake of salts from soil and their transport throughout the plant body, adjust the ionic and osmotic balance of cells in roots and shoots. In the present review, we have tried to provide a comprehensive report of major research advances on different mechanisms regulating plant tolerance to salinity stress at proteomics, metabolomics, genomics and transcriptomics levels. Along with the role of ionic homeostasis, a major focus was given on other salinity tolerance mechanisms in plants including osmoregulation and osmo-protection, cell wall remodeling and integrity, and plant antioxidative defense. Major proteins and genes expressed under salt-stressed conditions and their role in enhancing salinity tolerance in plants are discussed as well. Moreover, this manuscript identifies and highlights the key questions on plant salinity tolerance that remain to be discussed in the future., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Salinity represents a medium with high soluble salts where as sodicity represents a medium with high exchangeable sodium, low calcium and highly alkaline pH. Salinity and sodicity commonly occur together in salt-affected soils however physiological studies have mostly considered salinity alone ending up in poor field success of the selected genetic resources. Similarly, the role of root-mediated acidification in salt resistance is not known in wheat. Here six wheat genotypes were exposed to salinity (NaCl: 125 mM), low calcium (25% of non-treated control) and salinity + low calcium in solution culture. There were significant differences among the wheat genotypes for growth and leaf ionic composition under salinity, low calcium and salinity + low calcium treatments. The wheat genotypes SARC-1, 25-SAWSN-42 and Pasban-90 accumulated higher K + and Ca 2+ and lower Na + and Cl - and were resistant to the combined stress of low calcium and salinity. These genotypes also showed higher root-mediated acidification under stress conditions. The wheat genotypes resistant to salinity + low calcium supply in solution culture also performed better in the saline-sodic soil in a lysimeter study. A genotype resistant to salinity alone accumulated lower Ca 2+ and showed lower rhizosphere acidification potential and did not perform good in saline-sodic soil conditions. Therefore, root-mediated acidification potential and resistance to low calcium supply improves resistance of wheat to saline-sodic conditions. It is further suggested that screening of the wheat germplasm for saline-sodic soils should be carried out at salinity + low calcium to better simulate saline-sodic field conditions., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Contamination of soil with salinity and Cd negatively affects growth and productivity of plants. The proposed study has been planned to explore the effects of salinity on Cd uptake, tolerance and phytoremediation potential of conocarpus (Conocarpus erectus L.). One-month-old uniform plants of conocarpus were exposed to 0, 8.9, 44.5, 89 and 178 µM Cd alone or in combination with 0, 100 and 200 mM NaCl in Hoagland's nutrient solution. Results revealed that shoot and root biomasses, leaf water content and pigment content decreased more in response to combination of Cd and salinity compared to Cd alone. The Na + and Cl - concentrations in shoot and root were not affected by Cd alone, but increased in Cd + salinity treatments. The K + concentration decreased by Cd alone as well as Cd combination with salinity. Plant Cd uptake increased in the presence of salinity but its translocation from root to shoot remained unaffected. Exposure of plants to Cd alone and Cd + salinity caused oxidative stress via overproduction of H 2 O 2 and inducing lipid peroxidation. The activities of antioxidant enzymes such as SOD, CAT, POD and APX increased to mitigate this oxidative stress. It is concluded that the tolerance of conocarpus against Cd stress is decreased in the presence of salinity due to increased uptake of toxic ions and intensification of oxidative stress. Moreover, the Cd uptake behavior of this tree indicates its suitability for phytostabilization of Cd contaminated saline and non-saline soils., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Climate change is causing drastic reduction in crop yields around the globe due to increase in soil salinity, drought and heat stress. Quinoa (Chenopodium quinoa Willd) is regarded as a very significant food security crop considering the climate change scenario. Two quinoa genotypes (Puno and Titicaca) were cultivated on salt affected soil under drought stress with different sowing dates. Compared with early sowing, late sowing combined with salinity and drought stress caused drastic decline in plant growth and grain yield due to imposition of heat stress. Plant biomass and grain yield decreased by 26% and 39% in Puno, and by 34% and 49% in Titicaca under late sowing accompanied by salt and drought stress. Relative water contents and stomatal conductance of leaves declined in the same trend in both genotypes. Shoot Na+ concentration was the highest whereas K+ concentration was the lowest in both genotypes when drought and salt stress were combined under late sowing. Grain minerals (Ca, Mg, Fe, Zn, Cu, K, P, N and Mn) and dietary contents (protein, lipids, carbohydrates and fibre) were decreased more under the combination of salinity and drought for late sowing as compared to early sowing. When salinity and drought stress were combined under late sowing, the contents of H2O2 and TBARS were 1.9 and 2.2‐fold higher in Puno and 2.4 and 2.6‐fold higher in Titicaca, respectively. The oxidative stress was mitigated by enhanced activities of antioxidant enzymes (CAT, SOD and POD) more in Puno than Titicaca. Plant biomass and grain yield were higher in Puno with better grain quality than Titicaca. Hence, this genotype should be cultivated on salt affected soils facing drought and high temperatures. [ABSTRACT FROM AUTHOR]

Solanaceous crops act as a source of food, nutrition and medicine for humans. Soil salinity is a damaging environmental stress, causing significant reductions in cultivated land area, crop productivity and quality, especially under climate change. Solanaceous crops are extremely vulnerable to salinity stress due to high water requirements during the reproductive stage and the succulent nature of fruits and tubers. Salinity stress impedes morphological and anatomical development, which ultimately affect the production and productivity of the economic part of these crops. The morpho-physiological parameters such as root-to-shoot ratio, leaf area, biomass production, photosynthesis, hormonal balance, leaf water content are disturbed under salinity stress in Solanaceous crops. Moreover, the synthesis and signalling of reactive oxygen species, reactive nitrogen species, accumulation of compatible solutes, and osmoprotectant are significant under salinity stress which might be responsible for providing tolerance in these crops. The regulation at the molecular level is mediated by different genes, transcription factors, and proteins, which are vital in the tolerance mechanism. The present review aims to redraw the attention of the researchers to explore the mechanistic understanding and potential mitigation strategies against salinity stress in Solanaceous crops, which is an often-neglected commodity. [ABSTRACT FROM AUTHOR]

Boron (B) is an essential element for higher plants with a widespread deficiency in agricultural soils. Salinity, another common agricultural problem, aggravates B toxicity in plants. NaCl salinity increases B toxicity symptoms on plants and soluble B concentration in inter- and intracellular compartments in leaves. In many cases salinity and high soil B occur together making the conditions more hostile for the plants e.g. the San Joaquin Valley, California. This study investigates the interactive effects of boron toxicity and different salts including NaCl, Na2SO4 and CaCl2. These three salts were used in three separate experiments and wheat plants were exposed for three weeks to either boron or a salt alone or in combination. Salinity x boron significantly reduced shoot as well as root growth of wheat irrespective of the salt used to develop salinity. Sodium sulphate salinity alone and in combination with boron caused a higher percent reduction in shoot fresh and dry weights followed by sodium chloride and calcium chloride salinity. It shows a differential interaction of these salts with boron that may be due to their differential effect on the uptake of boron or vice versa.

Salinity is one of the major abiotic stresses that is deteriorating soil fertility and reducing essential nutrients acquisition by plants around the world. Among staple food, wheat can be a primary source of micronutrients like Fe and Zn. The saline/saline-sodic and calcareous soils are deficient in Fe and Zn. In these regards, the aim of present study was to screen out wheat genotypes which can efficiently utilize Fe and Zn in saline conditions. Therefore, ten wheat genotypes (i.e., Ujala-2016, Punjab-2011, Galaxy-2013, Faisalabad-2008, Anaj-2017, SARC-I, SARC-VIII, Lasani-2008, Sehar-2006 and Inqalab-91) were exposed to varying rates of Zn (0.2, 0.4 µM) and Fe (25, 50 µM) under saline and normal conditions in a solution culture experiment. Salinity was developed by using NaCl salt, while the sources of Zn and Fe were ZnSO4.7H2O and FeSO4.7H2O, respectively. The data of various wheat growth and ionic parameters including root/shoot dry weight, chlorophyll contents, Zn, Fe, K and Na concentration in root and shoot of wheat genotypes were recorded using standard procedures. The results showed that Fe and Zn application significantly (p ≤ 0.05) increased wheat plant growth under salt stress. Among tested genotypes, Faisalabad-2008 and Galaxy-2013 performed better under saline conditions with maximum biomass production, Zn, Fe and K absorption. Thus, these both genotypes were found to be good source for future wheat breeding programs or can be grown by farmers owing to efficient Fe and Zn utilization as a gateway toward the production of Fe and Zn biofortified wheat under saline conditions. [ABSTRACT FROM AUTHOR]

Soil salinity, drought, and increasing temperatures are serious environmental issues that drastically reduce crop productivity worldwide. Quinoa (Chenopodium quinoa Willd) is an important crop for food security under the changing climate. This study examined the physio-biochemical responses, plant growth, and grain yield of four quinoa genotypes (A7, Titicaca, Vikinga, and Puno) grown in pots containing normal (non-saline) or salt-affected soil exposed to drought and elevated-temperature treatments. Combinations of drought, salinity, and high-temperature stress decreased plant growth and yield more than the individual stresses. The combined drought, salinity, and heat stress treatment decreased the shoot biomass of A7, Puno, Titicaca, and Vikinga by 27, 36, 41, and 50%, respectively, compared to that of control plants. Similar trends were observed for grain yield, chlorophyll contents, and stomatal conductance. The combined application of these three stresses increased Na concentrations but decreased K concentrations in roots and shoots relative to control. Moreover, in the combined salinity, drought, and high-temperature treatment, A7, Puno, Titicaca, and Vikinga had 7.3-, 6.9-, 8-, and 12.6-fold higher hydrogen peroxide contents than control plants. All four quinoa genotypes increased antioxidant enzyme activities (CAT, SOD, and POD) to overcome oxidative stress. Despite A7 producing the highest biomass under stress, it did not translate into increased grain production. We conclude that Puno and Titicaca are more tolerant than Vikinga for cultivation in salt-affected soils prone to drought and heat stress. [ABSTRACT FROM AUTHOR]

Salinity and water stress are serious environmental issues that reduced crop production worldwide. The current research was initiated (2012) in the wirehouse of the Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan to investigate the growth, stress tolerance, and physiological responses of guava to salinity and water shortage. Guava was grown for one year in pots containing soil with Eight treatments (control, 10 dS m−1, 20 dS m−1, 40 dS m−1, control + water stress (WS), 10 dS m−1 + WS, 20 dS m−1 + WS, 40 dS m−1 + WS) in a completely randomized design. The results indicated that plant growth, stress tolerance, and physiological parameters declined at higher salinity and water stress and could not survive at 40 dS m−1. The 20 dS m−1 + WS caused a > 70% decline in dry weights of shoot and root regarding control. Similarly, the highest decrease in stress tolerance was noticed in 20 dS m−1 + WS followed by the 20 dS m−1 treatment than control. Our findings validated that guava can be cultivated on soils having salinity ≤ 10 dS m−1 but it could not be cultivated on soils having salinity ≥ 20 dS m−1 with limited water supply. [ABSTRACT FROM AUTHOR]

Salinity stress is a major abiotic stress limiting the crop production worldwide. Salt accumulation in root zone and uptake of toxic ions (i.e., Na+ and Cl- ) causes disturbance in water uptake by osmotic stress, oxidative stress, salt injury of roots and specific ion toxicity to the plants reducing the crop growth and production. Silicon (Si) treatment to stressed plants exhibits positive effect on growth, physiology and ionic homeostasis of plants. A study was conducted to check the varietal response of bread wheat genotypes against moderate (75 mM NaCl) and strong (150 mM NaCl) saline conditions in hydroponics and stressed plants were treated with exogenous silicon (2 mM) to evaluate it against saline stress in wheat seedling. Fifty days old wheat seedling showed negative response to saline stress under both levels but when treated with Si, its growth traits, tissue health parameters and ionic homeostasis were improved. Exogenous silicon application improved growth traits shoot and root length, fresh and dry weight upto 75% and tissue health parameter i.e., membrane stability index and relative water contents upto 61% as compared to salinity stress. It improved the ionic homeostasis in wheat seedling by decreasing the Na+ uptake upto 43 and 84% and increasing the K+ concentration by 26 to 39% respectively under moderate to strong saline conditions. Different genotypes showed different response against salinity and exogenous Silicon application. Faisalabad-08 and Anaj-17 performed best in all growth, physiological and ionic parameters and also ranked as top varieties in Principle component analysis on the basis of salt tolerance index. It was concluded that Faisalabad-08 and Anaj-17 has higher salt tolerance among all wheat genotypes tested, and silicon treatment to stressed plants increases the salt tolerance and improves growth traits, tissue health and ionic homeostasis in all wheat genotypes. [ABSTRACT FROM AUTHOR]

Soil salinization is a serious environmental problem worldwide. To explore the comparative effects of soil salinity and sodicity on physiological, biochemical and nutritional quality attributes of four quinoa genotypes (A1, A7, Puno, Vikinga), pot and field experiments were performed on non‐saline soil and two types of salt‐affected soils designated as SS1 (saline) and SS2 (saline‐sodic). The results of both the experiments showed similar reduction pattern in biomass (11%–44%), chlorophyll content (10%–36%), stomatal conductance (18%–32%) and grain yield (30%–47%) of four genotypes on SS2 compared with SS1. Higher sodicity level of SS2 resulted in more Na accumulation (23%–40%) and oxidative damage (12%–35% decrease in membrane stability) leading to an increase in the activities of antioxidant enzymes (SOD, POD, CAT) in all the genotypes. Grain mineral contents (except Na and Mg) were decreased more in SS2 than SS1. Multivariate analysis revealed that grain Na content has negative correlation with all the nutritional quality attributes except Mg and fibre contents. Genotypes A1 and A7 were more salt tolerant with better grain nutritional quality than Puno and Vikinga. It is concluded that soil sodicity is more detrimental than salinity, and quinoa genotypes A1 and A7 are better than Puno and Vikinga for cultivation on saline and saline‐sodic soils. [ABSTRACT FROM AUTHOR]

Status of mineral nutrient in plant body play an important role in improving its response to any environmental hazard like water stress, salt stress and heavy metal stress etc. Along with other mineral nutrients, potassium has an important task regarding plants endurance under salt stress condition. It is very important for maintaining turgor and membrane potential, balancing osmotic potential, controlling stomatal movement and activating enzymes. Addition of potassium in growing medium improved salinity tolerance in rice, wheat and corn. Results of previous research depicted that high concentration of potassium in plant body greatly reduced the production of reactive oxygen species. With the objective to combat salinity stress in maize a pot study to investigate the effect of K application on the growth and Fe/Zn use efficiency of salt-tolerant and sensitive maize genotypes. In this experiment two maize {Zea mays L.) genotypes, one salinity sensitive and one salinity tolerant (on the basis of study I) were used. Seeds of each cultivar were sterilized in HgCb solution (0.1%) for 10 min and after rinsing these seeds with distilled water they were sown in plastic pots containing well washed gravels. The seedlings were allowed to grow for 15 days. Uniform sized seedlings were transferred to a hydroponic system comprising of plastic tubs filled with Hoagland's nutrient solution (half strength). The treatments in this experiment include different levels of NaCl and potassium. The concentrations of potassium were 1 and 1.5 mM of the Hoagland nutrient solution with 0 or 100 mM NaCl. The salinity treatment was developed by adding sodium chloride (NaCl) to the nutrient solution after four days of transplantation to the hydroponic system. There were four replications of each treatment. The plants were allowed to grow in the treatment solutions for 28 days and at harvest the data regarding root/ shoot lengths, root/shoot fresh and dry weights were recorded. The oven dried shoot samples were analyzed for ion contents including Zn, Fe, Na+ and K+. It was concluded that in saline soil maize yield may improve by the application of K and increase of the concentration in maize grains can improve human nourishment. [ABSTRACT FROM AUTHOR]

Soil salinization is a serious environmental menace that reduces the development, growth and yield of most of the plants. Growing halophyte crops such as quinoa (Chenopodium quinoa Willd.) is a promising way of productive utilization of saline soils. The present study was conducted during 2018-19, in which we investigated the comparative salt tolerance potential of two genotypes of quinoa (Puno and A1) on the basis of growth, ionic and physiological attributes. Five-week-old seedlings of both genotypes were exposed to different levels of salinity (0, 100, 200 and 400 mM NaCl) developed in Hoagland's nutrient solution. Results revealed that root and shoot growth, chlorophyll contents, membrane stability and relative water content remained unchanged at lower level of NaCl (100 mM). However, these attributes decreased significantly at higher level of NaCl (400 mM). The Na+ concentrations increased, whereas K+ concentrations and the ratio of K+: Na+ showed an inverse relation to the increasing salinity levels. The comparison of both genotypes indicated that physiological attributes and plant biomass were higher in A1 than Puno due to less uptake of Na+ ions and higher K+: Na+ ratio. Therefore, A1 is more suitable genotype than Puno to be grown on saline soils in arid regions of Pakistan. [ABSTRACT FROM AUTHOR]

Both salinity and cadmium (Cd) contamination of soils are the most critical issues of global food security. Soil application of biochar could decrease toxic metal and sodium (Na) uptake by plants in the season, but its long-term residual effects on metal uptake in latter crops need evaluation. A pot experiment with rice was conducted under ambient conditions in a Cdcontaminated soil which was used in an earlier experiment on wheat where soil was treated with different rates of biochar (0, 3, and 5% w/w) and irrigated with water having different salinity levels (0, 25, and 50 mM). Further treatments were not applied in the current study. The results revealed that plant growth and photosynthesis reduced while Cd and Na concentrations and oxidative stress were increased in plants under combined Cd and salinity. Biochar application reduced the Cd and Na concentrations and increased the potassium (K) concentrations in plants while diminished the oxidative stress in salt-stressed rice. Biochar positively affected the plant growth and physiology in a soil treated with 0, and 25 mM salt stress. However, plant growth and photosynthesis were reduced with biochar amendments under 50 mM NaCl stress. Soil AB-DTPA extractable Cd was higher in salinized soil without biochar addition, while biochar reduced the Cd extractability. It can be concluded that all biochar amendments had a significant residual effect on decreasing Cd and Na uptake while plant growth was negatively affected at higher biochar and salinity levels. [ABSTRACT FROM AUTHOR]

Salinity is an important abiotic stress affecting agricultural productivity in Pakistan. In order to meet the country's requirement, the sustainability of crop production is pre-requisite. A hydroponic experiment was conducted to check the response of wheat cultivars against salinity with salicylic acid application. There were four wheat varieties (Lasani-2008, MH-97, SARC-1 and Iqbal-2008), two levels of NaCl (75 mM and 150 mM) and two levels of salicylic acid (0.25 mM and 0.50 mM) along with their respective controls. This experiment was conducted in a completely randomized design with factorial arrangement and five replications of each. After one month of transplanting in hydroponic culture, plant growth parameters and chlorophyll contents were determined. The results showed that plant growth was highly affected at both levels of NaCl treatments, while a decrease in chlorophyll contents and K+ concentration was observed. However, the application of salicylic acid (0.25 mM and 0.50 mM) overcame the adverse effects of salinity and improved the plant growth significantly (P≤0.05) by increasing superoxide dismutase and catalase activities. The application of 0.25 mM salicylic acid in the presence of 75 mM NaCl enhanced shoot dry weight by 21% and 30.68% in Lasani-2008 and Iqbal- 2008, respectively as compared to their respective control. The activity of superoxide dismutase was enhanced from 2.67 to 3.15 (gmol/g Fw) in SARC-1 when salicylic acid was applied in the presence of 150 mM NaCl. Under tested condition, SARC-1 performed better than others tested wheat genotypes. In conclusion, salicylic acid improved the performance of wheat varieties in saline conditions. [ABSTRACT FROM AUTHOR]

In this study, we explored the effect of salinity on cadmium (Cd) tolerance and phytoremediation potential of Acacia nilotica. Two-month-old uniform plants of A. nilotica were grown in pots contaminated with various levels of Cd (0, 5, 10, and 15 mg kg−1), NaCl (0%, 0.5%, 1.0% (hereafter referred as salinity), and all possible combinations of Cd + salinity for a period of six months. Results showed that shoot and root growth, biomass, tissue water content and chlorophyll (chl a, chl b, and total chl a+b) contents decreased more in response to salinity and combination of Cd + salinity compared to Cd alone. Shoot and root K concentrations significantly decreased with increasing soil Cd levels, whereas Na and Cl concentrations were not affected significantly. Shoot and root Cd concentrations, bioconcentration factor (BCF) and translocation factor (TF) increased with increasing soil Cd and Cd + salinity levels. At low level of salinity (0.5%), shoot and root Cd uptake enhanced, while it decreased at high level of salinity (1.0%). Due to Cd tolerance, high shoot biomass and shoot Cd uptake, this tree species has some potential for phytoremediation of Cd from the metal contaminated saline and nonsaline soils. [ABSTRACT FROM AUTHOR]

Boron (B) is an essential nutrient required in very small amount by crop plants and it can become toxic to plants when present in slightly higher amount. Increasing concentration of B is often found in association with salinity. The presence of salinity and high B may result in synergistic or antagonistic effects on plant growth. A hydroponic trial was conducted to evaluate the influence of various levels of B on the growth, physiological and biochemical responses of salt tolerant and sensitive wheat genotypes under saline conditions. The present study comprised of twelve treatments including four rates of B (control, 0.5, 1 and 1.5 mM) and three levels of salinity (control, 100 and 200 mM NaCl). Two salt tolerant (SARC-I and Sehar-2006) and two salt sensitive (Koistan-90 and MH-97) wheat genotypes were used. The tested salt tolerant and sensitive wheat genotypes showed significant variations and responded differently to salinity and B individually as well as in combination. The salt tolerant genotypes showed better growth due to high antioxidant activity, maintenance of photosynthesis and stomatal conductance and low leaf Na, B and Cl concentration in the presence of individual and combined stresses of salinity and high B as compared to sensitive genotypes. The highest level of salinity and B in combination caused the highest reduction in plant growth as compared to their respective controls. However the interactive effect of salinity and boron was antagonistic as increasing salinity reduced boron toxicity while increasing boron reduced harmful effects of salinity on growth and physiological attributes of wheat. [ABSTRACT FROM AUTHOR]

A field experiment was conducted under two natural field conditions at the Research Farm (normal soil) and Proka Farm (salt-affected soil) of The Institute of Soil and Environmental Sciences (ISES), University of Agriculture, Faisalabad, Pakistan, to evaluate the performance of 11 rice genotypes in normal and salt-affected conditions. The experiment was laid out in randomized complete block design (RCBD) with three replications. The gas exchange attributes were measured at vegetative stage whereas the grain and straw yields and the yield components were recorded at maturity. After harvesting, the ionic parameters including sodium (Na+) and potassium (K+) were determined. Afterward, grain quality in terms of length, width, milling recovery, broken fraction, and chalkiness was also determined for the selected genotypes. Salt-affected conditions adversely affected the physiology, yield, and quality of the tested genotypes. The genotypes KS-282 followed by Shaheen Basmati showed significantly higher photosynthetic rate, transpiration rate, and stomatal conductance under both normal and salt-affected conditions, whereas the genotypes 99404 followed by 99417 showed minimum values of gas exchange attributes. The grain and straw yields were the highest in the case of KS-282 at both sites, whereas the lowest grain and straw yields were observed in the case of 99440 followed by 99417 under both normal and salt-affected conditions. Regarding the quality attributes, Super Basmati produced longer grains but with higher broken fraction and lower milling recovery, whereas the reverse was observed in the case of KS-282. [ABSTRACT FROM AUTHOR]

Soil salinity is considered a serious environmental issue in many countries of the world, including Pakistan. A hydroponic experiment was carried out to study different mechanisms of salinity tolerance in two Acacia species, namely Acacia stenophylla A. Cunn. ex Benth. and Acacia albida Delile. Uniform seedlings of both species were grown for 28 days in half-strength Hoagland's nutrient solution with 0, 100, or 200 mmol·L−1 NaCl concentrations. The results revealed that shoot biomass decreased by 21% and 29% at the lower salinity level (100 mmol·L−1 NaCl) and by 44% and 55% at the higher salinity level (200 mmol·L−1 NaCl) in A. stenophylla and A. albida, respectively. The respective reductions in root biomass of both species were 20% and 29% at the lower salinity level and 36% and 54% at the higher salinity level. The physiological attributes such as chlorophyll and relative water contents decreased to a greater extent in A. albida than in A. stenophylla. As a result of oxidative stress, membrane stability index (MSI) decreased in both species, with a greater reduction in A. albida. Among different antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), the highest increase (sixfold) was observed in SOD activity in A. stenophylla. This study concludes that A. stenophylla is more salinity tolerant than A. albida as it maintained better ionic balance and higher activities of antioxidant enzymes and, as a result, higher biomass production. [ABSTRACT FROM AUTHOR]

Salinity and drought are two important environmental problems responsible for the reduction of growth and yield of many plant species. The present study was conducted to evaluate the tolerance potential of A. nilotica and A. ampliceps against salinity and water shortage in the pots. Different salinity levels (control, 10, 20 and 30 dS m-1) were developed in the pots by adding calculated amount of NaCl. Three months old nursery plants of both species were transplanted in these pots. After two weeks of transplantation, water stress was continuously applied till the end of the experiment. After four months, data regarding shoot and root growth, nodulation, chlorophyll and relative water contents were determined following standard methods. Ionic composition (Na+, K+ and Cl-) of shoot and root was determined by wet digestion. The results demonstrated that A. ampliceps was more tolerant to salinity due to better ionic composition and physiological attributes but when salinity was combined with water stress; its tolerance potential was decreased. On the other hand, A. nilotica performed better under water stress and when salinity was combined with water stress. [ABSTRACT FROM AUTHOR]

Salinity causes decrease in maize growth and production. Maize occupies an important position in fodder and food crops of Pakistan. Recently, maize has been designated as silicon (Si) accumulator which can alleviate the salinity damage, a major constraint to agricultural crop production. With the objective to combat salinity stress in maize by Si applications using silicic acid Si(OH)4, an experiments was conducted on two contrasting maize genotypes (salt sensitive; Pak-Afgoee and salt tolerant; Ev-5098), under normal and saline conditions. Three different levels of Si (0, 1 and 3 mM) were optimized for salinity tolerance on the basis of plant morphological characters especially dry weight in hydroponics. These Si-level was further used to investigate its effect on maize in hydroponic (0 mM NaCl) and saline (100 mM NaCl). The evaluation was done on the basis of various morphological, physiological, biochemical and growth traits during the experiments. Silicon supplementation into the solution culture significantly improved the K+: Na+ with reduced Na+ and increased K+ uptake. Plant water relations with higher water potential, increase in chlorophyll fractions and its ratios, enhanced stomatal conductance. It was concluded that Ev-5098 is better than Pak-Afgoee under salt stress and silicon inclusion into the any growth medium is beneficial for maize and can improve crop growth by maintaining plant water status, better K+: Na+ and recovering the plant defense system adversely influenced by salt stress. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental stress that is reducing crop yield, particularly in arid and semi-arid regions of the world. It is responsible for many physiological and biochemical disorders in plants. To investigate its effects on two acacia species, namely Acacia ampliceps Maslin and Acacia nilotica L., a solution-culture experiment was conducted in which both species were exposed to NaCl concentrations of 100 and 200 mmol·L-1. After four weeks of salinity stress, plants were harvested, and physical-growth data were recorded. The membrane stability index and activities of antioxidants enzymes such as superoxide dismutase, peroxidase, and catalase were determined using standard methods. Root exudates were collected for the analysis of organic acids, i.e., citric acid and tartaric acid. Root ash alkalinity was also measured. The results indicated that salinity stress caused a significant increase in the activities of antioxidant enzymes and in the release of organic acids in both species. Higher activities of antioxidant enzymes resulted in less damage to membranes and produced more shoot and root biomass in A. ampliceps than in A. nilotica. Likewise, having more rhizosphere acidification enabled A. ampliceps to respond in a better way to salinity stress than A. nilotica. [ABSTRACT FROM AUTHOR]

Salt stress reduces grain yield of maize ( Zea mays L.) due to poor kernel setting but not due to decreased grain filling. In the present study, it was tested whether acid invertase activity is decreased in developing kernels of maize under salt stress, and if assimilate supply is limited. The relatively salt-sensitive maize hybrid Pioneer 3906 was compared with the more salt-resistant hybrid SR 12. Salt stress caused a significant decrease in grain yield which was due to a 50% decrease in kernel number. No source limitation was observed, as the sucrose concentrations in kernels were significantly increased under salt stress for both genotypes. In contrast, glucose and fructose concentrations in kernels were significantly decreased. Salt stress caused a significant inhibition of soluble acid invertase activity to 19% in hydroponics 5 d after pollination (5 DAP) and to 50% in the soil culture experiment (2 DAP). The decrease in enzyme activity was the same for both genotypes. In the soil experiment, the highest soluble acid invertase activity was found 2 DAP with a steep decline until 8 DAP in Pioneer 3906. It is concluded that a decrease in acid invertase activity is a key factor associated with limited kernel setting under salt stress but additional factors may be responsible for genotypic differences. [ABSTRACT FROM AUTHOR]

Soil salinity is a major environmental issue in arid and semiarid regions of the world. Acacia has very important role for salt affected barren lands due to its high salinity tolerance potential. The aim of the present study was to explore the genetic differences among Acacia ampliceps and Acacia nilotica regarding their response to salinity. Three-weeks old seedlings of both species were transplanted in half strength Hoagland nutrient solution having five salt levels (control,100, 200, 300 and 400 mM NaCl) with four replications in completely randomized design with factorial arrangement. After eight weeks of transplantation, the plants were harvested and data for shoot and root length and their fresh and dry weights were recorded. Na+, K+ and Cl-concentration of both root and shoot was determined. All the growth parameters of both species declined significantly in response to salinity. Acacia ampliceps was more salt tolerant than Acacia nilotica with better growth owing to higher K+: Na+ ratio in plant tissues. [ABSTRACT FROM AUTHOR]

Soil salinity is a major problem of agriculture in Pakistan. Permanent solution of salinity problem is removal of salts by leaching and drainage whic is expensive. So research efforts should involve profitable utilization of these lands through biological approaches. Considering these observations, this study was designed with the objectives to explore changes in growth and physiological attributes of different sunflower genotypes under interactive effect of salinity and boron. Vigorous seeds of selected genotypes (two tolerant, two sensitive) were sown in gravels. One week old seedlings were transplanted to ½ strength Hoagland's nutrients solution. Three days after transplantation the requisite salinity (control and 100 mM NaCl) and boron levels (0.05 mM B, 0.5 mM B and 1.0 mM B as H₃BO₃) were established in three installments. The arrangement of the experiment was split plot with three replications. The data regarding shoot and root fresh weights, relative water contents (RWC), membrane stability index (MSI), and leaf area (LA) were recorded. The results revealed that salinity and boron adversely affected the growth and physiology of sunflower genotypes with a higher effect in the case of combined stress. This study also showed that the growth reduction was more in the salt susceptible genotypes (Hysun-33, Hysun-38) than in the salt tolerant genotypes (SF-187, S-278). [ABSTRACT FROM AUTHOR]

Arsenic (As) is a toxic metalloid and its widespread contamination in agricultural soils along with soil salinization has become a serious concern for human health and food security. In the present study, the effect of cotton shell biochar (CSBC) in decreasing As-induced phytotoxicity and human health risks in quinoa (Chenopodium quinoa Willd.) grown on As-spiked saline and non-saline soils was evaluated. Quinoa plants were grown on As contaminated (0, 15 and 30 mg kg−1) saline and non-saline soils amended with 0, 1 and 2% CSBC. Results showed that plant growth, grain yield, stomatal conductance and chlorophyll contents of quinoa showed more decline on As contaminated saline soil than non-saline soil. The application of 2% CSBC particularly enhanced plant growth, leaf relative water contents, stomatal conductance, pigment contents and limited the uptake of As and Na as compared to soil without CSBC. Salinity in combination with As trigged the production of H 2 O 2 and caused lipid peroxidation of cell membranes. Biochar ameliorated the oxidative stress by increasing the activities of antioxidant enzymes (SOD, POD, CAT). Carcinogenic and non-carcinogenic human health risks were greatly decreased in the presence of biochar. Application of 2% CSBC showed promising results in reducing human health risks and As toxicity in quinoa grown on As contaminated non-saline and saline soils. Further research is needed to evaluate the role of biochar in minimizing As accumulation in other crops on normal as well as salt affected soils under field conditions. [Display omitted] • Role of cotton shell biochar (CSBC) in reducing As toxicity in quinoa was explored. • Grain yield and physiological attributes severely declined in the absence of CSBC. • 2% CSBC enhanced plant growth, grain yield and limited the uptake of As and Na. • CSBC ameliorated the oxidative stress via overexpression of antioxidant enzymes. • CSBC reduced the human health risks due to consumption of As contaminated grains. Application of 2% CSBC showed promising results in reducing human health risks and As toxicity in quinoa grown on As contaminated normal and saline soils. [ABSTRACT FROM AUTHOR]

This study reports the relationship of the leaf ionic composition with the grain yield and yield components of wheat in response to salinity x sodicity and salinity alone. The study was conducted in soil culture in pots with three treatments including control (ECe 2.6 dS m- 1 and SAR 4.53), salinity (ECe 15 dS m- 1 and SAR 9.56), and salinity x sodicity (ECe 15 dS m- 1 and SAR 35). The soil was treated before being put in the pots and the pots were arranged in a completely randomized factorial arrangement with five replications. The seeds of three wheat genotypes were sown directly in the pots and the study was continued till the crop maturity. At booting stage, the leaf second to the flag leaf of each plant was collected and analyzed for sodium (Na+), potassium (K+), and chloride (Cl-). At maturity, plants were harvested and data regarding grain yield and yield components were recorded. This study shows that salinity and sodicity in combination decreases the grain yield of wheat more than the salinity alone with a greater difference in the sensitive genotype. This study also shows that as for salinity, the maintenance of lower Na+ and higher K+ concentrations and higher K+: Na+ ratio in the leaves relates positively with the better development of different yield components and higher grain yield in saline sodic soil conditions. Although, the leaf Cl- concentration was increased significantly by salinity as well as salinity x sodicity and would have affected the growth and yield, yet it does not seem to determine the genotypic tolerance or sensitivity to either salinity or salinity x sodicity. [ABSTRACT FROM AUTHOR]

The information of soil compaction effects on growth and yield of crops for saline and waterlogged soils is scanty. A pot experiment was conducted on a sandy clay loam soil during 2001–2002 to study the interactive effects of soil compaction, salinity and waterlogging on grain yield and yield components of two wheat (Triticum aestivum) genotypes (Aqaab and MH-97). Compaction was achieved at 10% moisture level by dropping 5 kg weight, controlled by a tripod stand for 20 times from 0.6 m height on a wooden block placed inside the soil filled pots. Soil bulk density of non-compact and compact treatments was measured as 1.21 and 1.65 Mg m−3, respectively. The desired salinity level (15 dS m−1) was developed by mixing the required amount of NaCl in soil before filling the pots. Waterlogging was developed by flooding the pots for 21 days both at tillering and booting stages. Compaction aggravated the adverse effect of salinity on grain yield and different yield components of both the wheat genotypes. Average reduction in grain yield was 44% under non-compact saline conditions against 76% under compact saline conditions. Similarly, the reduction was about 20% more for 100 grain weight and shoot length, 30% more for number of spikelets per spike, 37% more for number of tillers per plant, and 32% more for straw weight in compact saline treatment than in non-compact saline treatment. Compaction alone caused a reduction of 36% in grain yield. The effect of waterlogging on grain yield and yield components was mostly not changed significantly due to compaction. Rather waterlogging mitigated the effect of compaction for most of the yield components except for number of spikes per plant. Therefore, as for normal soils, the cultivation of salt-affected soils should employ implements and techniques which minimize compaction of root zone soil. The effect of soil compaction can also be minimized by light irrigations with short intervals and by using a stress tolerant crop genotype. [Copyright &y& Elsevier]

Soil compaction affects plant growth by causing increased resistance to root penetration and a decreased uptake of water and ions. A pot experiment was conducted to study the effect of soil compaction in conjunction with the soil salinity and waterlogging on root growth and leaf ionic composition of two wheat genotypes (Aqaab and MH-97). Compaction was achieved at a 10% soil moisture content by dropping 5 kg weight, controlled by a tripod stand for 20 times from 0.6 m height on a wooden block placed inside the soil-filled pots. Soil bulk density of non-compact and compact treatments was measured as 1.21 and 1.65 Mg m−3, respectively. The desired salinity level (15 dS m−1) was developed by mixing required amount of NaCl in the soil before filling the pots. Waterlogging was developed by flooding the pots for 21 days both at tillering and booting stages. Compaction significantly reduced the root length density (RLD) of both the wheat genotypes while the combined effect of compaction×salinity was more drastic on root length density than compaction alone. Waterlogging however, did not decrease the root length density, rather it mitigated the effect of compaction. Compaction decreased the concentration of K+ and K+:Na+ ratio in leaves. Salinity also decreased the concentration of K+ and K+:Na+ ratio, but increased the concentrations of Na+ and Cl− in the crop leaves. Salinity and compaction interacted to cause a greater reduction in K+ concentration and the K+:Na+ ratio, while there was lesser increase in the concentrations of Na+ and Cl− compared with salinity alone. Waterlogging also decreased the concentration of K+ and K+:Na+ ratio in leaves. It intensified the effect of salinity but decreased the effect of compaction on leaf ionic composition. Therefore, the effect of compaction on root growth and ion uptake is more severe under salt-affected soil conditions than under normal soil conditions while occasional waterlogging of a compact soil for a few days makes the soil conditions favorable for root growth both under non-saline as well as saline soil conditions. Also, the performance of a genotype in stressed environment is related to maintenance of higher root length density, leaf K+ concentration and K+:Na+ ratio and lower leaf Na+ and Cl− concentrations. [Copyright &y& Elsevier]

Salinity and drought stress, singly or in combination, are major environmental menaces. Jatropha curcas L. is a biodiesel plant that can tolerate long periods of drought. However, the growth performance and stress tolerance based on physical, chemical, and physiological attributes of this plant have not yet been studied. To address this question, J. curcas seedlings were grown in a completely randomized design in plastic pots filled with soil to evaluate the effects of salinity and drought stresses on growth, ionic composition, and physiological attributes. The experiment consisted of six treatments: control (without salinity and drought stress), salinity alone (7.5 dS m−1, 15 dS m−1), drought, and a combination of salinity and drought (7.5 dS m−1+ Drought, 15 dS m−1+Drought). Our results revealed that, compared with the control, both plant height (PH) and stem diameter (SD) were reduced by (83%, 80%, and 77%) and (69%, 56%, and 55%) under salinity and drought combination (15 dS m−1+Drought) after three, six, and nine months, respectively. There was 93% more leaf Na+ found in plants treated with 15 dS m−1+Drought compared with the control. The highest significant average membrane stability index (MSI) and relative water content (RWC) values (81% and 85%, respectively) were found in the control. The MSI and RWC were not influenced by 7.5 dS m−1 and drought treatments and mostly contributed towards stress tolerance. Our findings imply that J. curcas is moderately tolerant to salinity and drought. The Na+ toxicity and disturbance in K+: Na+ ratio were the main contributing factors for limited growth and physiological attributes in this plant. [ABSTRACT FROM AUTHOR]