Water Salinity Stress Research Articles

Characterizing the hysteretic effects of water and salinity stresses on root-water-uptake

Characterizing the effects of previous water and salinity stresses is critical for the evaluation of plant water status, which, in turn, is essential for understanding soil-plant water relations and optimizing irrigation schemes. Recent research has found that hysteresis of plant response following water stress alone can be described by an exponential function of the stress degree on the previous day. To explore and quantify the effects of hysteresis concerning salinity stress and combined water-salinity stress, a hydroponic experiment and a soil column experiment on winter wheat, and a field experiment on cotton were conducted. Like water stress, previous salinity stress and combined water-salinity stress also resulted in hysteretic effects on root-water-uptake. Leaf stomatal conductance and plant transpiration rate of stressed crops could only recover gradually from a previous stressed status after re-watering. When stress was mild, compensatory recovery was found, while incomplete recovery occurred when stress was severe. Although the recovery process was closely related to stress history and type, a recovery coefficient was quantified universally with an exponential function of the stress extent on the previous day (with a coefficient of determination R2 ≥ 0.60). Consideration of hysteresis for water and salinity stresses with a mathematical model led to significant improvement in the simulation of both relative transpiration rate (R2 = 0.94, root mean squared error RMSE = 0.04, maximal absolute error MAE = 0.12) and soil water content (R2 = 0.90, RMSE = 0.01 cm3 cm–3, MAE = 0.03 cm3 cm–3), especially during the recovery periods severely affected by historical stress. Consideration of hysteresis is expected to benefit regulation of soil water and salinity and thus enhance water use efficiency. However, the mechanisms underlying hysteresis, especially the compensatory recovery mechanisms, still need to be further investigated.

Impact of Magnetic Technology on Germination, Seedling vigour, Growth, Yield, and Nutritional value of Groundnut (Arachis Hypogaea L) under Water Salinity Stress Conditions in Sandy Soil

Impact of Magnetic Technology on Germination, Seedling vigour, Growth, Yield, and Nutritional value of Groundnut (Arachis Hypogaea L) under Water Salinity Stress Conditions in Sandy Soil

Effects of Organic Fertilizer on Photosynthesis, Yield, and Quality of Pakchoi under Different Irrigation Conditions.

Water scarcity and the overuse of chemical fertilizers present significant challenges to modern agriculture, critically affecting crop photosynthesis, yield, quality, and productivity sustainability. This research assesses the impact of organic fertilizer on the photosynthetic attributes, yield, and quality of pakchoi under varying irrigation water conditions, including fresh water and brackish water. Findings reveal that the modified rectangular hyperbolic model most accurately captures the photosynthetic reaction to organic fertilization, outperforming other evaluated models. The maximum net photosynthesis rate (Pnmax), yield, soluble sugar (SS), and soluble protein content (SP) all exhibited a downward-opening quadratic parabolic trend with increasing amounts of organic fertilizer application. Specifically, under fresh-water irrigation, the optimal Pnmax, yield, SS, and SP were obtained at organic fertilizer rates of 65.77, 74.63, 45.33, and 40.79 kg/ha, respectively, achieving peak values of 20.71 µmol/(m2·s), 50,832 kg/ha, 35.63 g/kg, and 6.25 g/kg. This investigation provides a foundational basis for further research into the intricate relationship between water salinity stress and nutrient management, with the goal of crafting more sophisticated and sustainable farming methodologies. The insights gained could significantly influence organic fertilizer practices, promoting not only higher yields but also superior quality in agricultural outputs.

Evaluation of Some Okra and Molokhia Landraces under Irrigation Water Salinity Stress

Aims: Evaluate eight landraces of okra and five landraces of molokhia, collected from different region of Egypt, under different levels of irrigation water salinity.
 Study Design: The experimental design used was a split-plot in a randomized complete blocks design with three replicates, where the four irrigation water salinity concentrations were arranged in the main plots, whereas, landraces of okra or molokhia were arranged in the sub plots.
 Place and Duration of Study: This investigation was carried out during the two successive summer seasons of 2021 and 2022 at Soil Salinity Laboratory Research, Alexandria Governorate, Agricultural Research Center.
 Methodology: Four levels of saline irrigation water were applied having EC of 625 (tap water as a control), 2000, 4000 and 6000 ppm which was applied as necessary according to soil field capacity (27.85%).
 Results: Generally, all the studied traits, of okra and molokhia, decreased as the salinity level increased except for the spines of edible pods which was in contrast, in both seasons. There were significant differences among the studied eight landraces of okra and the studied five landraces of molokhia for all the studied traits in both seasons. Edible pods yield/plant of Behera landrace was not significantly affect by irrigation at salinity levels up to 2000 ppm of salinity level in 2022 season. Moreover, Alexandria and Gharbya landraces were the least affected by increasing salinity levels comparing with the rest of landraces in both seasons. With respect to molokhia, Fresh leafy yield/plot of Alexandria landrace was not significantly affected by irrigation at salinity levels up to 2000 ppm of salinity level in the first seasons.
 Conclusion: It can be recommended to cultivate Behera, Alexandria and Gharbya landraces of okra and Alexandria and Kafr Elsheikh landraces of molokhia when irrigation with relatively high levels of salinity, as these landraces were relatively less affected by increasing salinity concentration. These landraces can also be introduced into breeding programs to improve them or develop new varieties that are more salt-tolerant.

The Effect of Salinity (NaCl) Stress and Different Magnetic Applications on The Germination of Cucumber Seeds (Cucumis sativus L.)

Salinity stress is one of the main factors that limit seed germination and plant growth. Therefore, magnetic water was used because it had a positive effect on seed germination. This study was conducted to investigate the effect of magnetic (MT1, MT2, MT3, MT4, and MT5) treatment of water passing through magnets 1, 2, 3, 5, and 8 times respectively, and non-magnetic (NMT) treatment on the germination of cucumber seeds (Cucumis sativus L.) under salinity stress (NaCl) (S1 = 0.38 dSm-1, S2 = 4.0 dSm-1, S3 = 8.0 dSm-1). The experiment was conducted by the design of a one-way ANOVA with three replications. The results showed that water salinity stress a significantly decrease in the final germination percentage (FGP), germination index (GI), coefficient of the velocity of germination (CVG), germination percentage 4th day (GP), and germination rate index (GRI), while the mean germination time (MGT) increased significantly. In addition, the FGP, GP, GI, CVG, and GRI were significantly increased and the MGT was significantly decreased when using magnetic water compared to non-magnetic water. The highest values of FGP, GP, GI, CVG, and GRI were at S1 while they decreased by 7.8%, 10.0%, 15.8%, 2.4% and 16.2%, respectively in S3 (8.0 dSm-1), compared to S1 (0.38 dSm-1). The highest FGP values of 92.20% at MT4 were obtained with S1 salinity (0.38 dSm-1) and the lowest FGP value of 72.20% at NMT with water salinity S3 (8.0 dSm-1). The results of the research showed that magnetic water treatment has a positive effect on the germination of cucumber seeds and that salinity stress reduced the germination of seeds. Finally, it can be recommended to apply MT4 (water passed through the magnetic 5 times) to achieve the best germination of cucumber seeds.

Assessment of irrigation water salinity effects on red beet under Mediterranean conditions

Plant tolerance to salinity stress is vital for irrigation scheduling, decision-making, planning and operation, and most critically, water resource management. Although there are numerous scientific data on the response of various plants to salinity stress, there are few studies on red beet in the literature, and specifically under Mediterranean conditions. This study aimed to investigate the effects of water salinity stress on water use, growth, yield parameters, and salinity threshold and slope values of red beet in Mediterranean conditions. In addition to control (0.6 dS m-1), five irrigation water salinity levels including low (1.5 dS m-1), medium-low (3.0 dS m-1), medium (4.5 dS m-1), medium-high (6.0 dS m-1) and high salinity (8.0 dS m-1) stresses were used as treatments. Increased water salinities caused increases in electrical conductivity and pH values of saturated soil paste extracts and drainage waters, while decreases in water use affected plant height storage root yield and water use efficiency. The salinity threshold and slope values of red beet were determined as 3.10 dS m-1 and 4.42% per dS m-1.

Mango performance as affected by the soil application of zeolite and biochar under water salinity stresses

This study was carried out during two consecutive seasons, 2020 and 2021, on 12-year-old mango (Mangifera indica L.). cv. Ewaise grown in region Idku, El Beheira Governorate, Egypt. The trees were planted at 5 × 4 m apart and grafted on “Sokary” root stock to study the influence of zeolite and biochar on growth, yield, and fruit quality of “Ewaise” mango cultivar irrigated by agricultural drainage water. The trees were treated by the following treatments: zeolite or biochar solely at 1, 2, and 3 kg for tree and their different combinations such as 1 kg zeolite + 1 kg biochar; 1 kg zeolite + 2 kg biochar; 1 kg zeolite + 3 kg biochar; 2 kg zeolite + 1 kg biochar; 2 kg zeolite + 2 kg biochar; 2 kg zeolite + 3 kg biochar; 3 kg zeolite + 1 kg biochar; 3 kg zeolite + 2 kg biochar; and 3 kg zeolite + 3 kg biochar as well as control zero soil application. The obtained results showed that the soil application of zeolite or biochar gave a positive effect on improving the soil characteristics which reflects on the tree trunk thickness, shoot length and thickness, number of inflorescences, yield in kg per tree, and fruit quality. The greatest positive effect on the previous mentioned parameters was obtained by the combined application of the soil application of 2 kg zeolite + 3 kg biochar; 2 kg zeolite + 2 kg biochar; 3 kg zeolite + 2 kg biochar; and 3 kg zeolite + 3 kg biochar over the rest-applied treatments or control in the two seasons.

Effect of water salinity stress on dates biometric and biochemical characteristics

The problem of salinity of irrigation water in palm groves has led us to conduct this study based on the comparison of the quality of dates Deglet Nour and Ghars from two farming systems in the region of El-Oued according to the EC irrigation water. Salt stress in El'Ghout causes in both varieties a regression of biometric characteristics, pH, EC, water content and dry matter, while total sugars are high. The dates of the farm are more voluminous, less acidic, with high ash content, dry matter and high electrical conductivity. According to standards Algerian of date classification reveals that the characteristics of Deglet Nour dates of El'Ghout are more damaged by the salinity of the environment. The two varieties of the farm have better characteristics than those of El'Ghout. It also appears that the salinity of water improves the sugar content of dates

Modelling the relationships between the yield and evapotranspiration of maize under salinity stress and nitrogen deficiency

AbstractUnderstanding the intraseasonal sensitivity of crop evapotranspiration (ET) to stresses allows for accurate modelling of crop yield. In this research, the effects of water salinity stress and soil nitrogen deficiency on evapotranspiration (in the growth stages) and maize yield in 2017 and 2018 were investigated. Four treatments of saline water levels of 0.5 (S0), 2.1 (S1), 3.5 (S2) and 5.7 (S3) dS m−1 were combined with four nitrogen fertilization levels of 100% (N0), 75% (N1), 50% (N2) and 25% (N3). The maize ET amounts from the S0N0 to S3N3 treatments decreased from 80 to 55 mm (in the initial stage), 202 to 129 mm (in development), 127 to 80 mm (in the mid) and 14.5 to 10.5 mm (in the late). The dry biomass yield of maize from the S0N0 to S3N3 treatments was equal to 15.3 to 9.23 t.ha−1. The relative yield of maize was modelled by the additive models of Blank, Stewart and Singh and the multipliable models of Jensen, Rao and Minhas. The results showed that the Stewart and Jensen models were selected as the optimal models. By using the optimal models, the relative yield of maize can be modelled based on the evapotranspiration rate (in the growth stages) under salinity stress and nitrogen deficiency.

Optimizing agricultural water use through simulation of soil water content and water uptake under soil moisture and irrigation water salinity stresses: Case study of corn roots using SWAP model

In order to evaluate soil water content and water uptake by corn plant roots (Single cross 260) under different soil moisture and water salinity stresses using the agro-hydrological Soil–Water–Atmosphere–Plant (SWAP) model, an experiment was conducted in 2015 at the green house of the Agriculture Research Center of Shahrood, Iran. The statistical model employed was a split plot based on a randomized complete block design with three replications. The main plots consisted of three levels of irrigation; 50 (I1) (full irrigation as the control), 75 (I2) and 100% (I3) of Total Available Water (TAW) depletion while the sub-plots consisted of three levels of salinity of irrigation water; 2 (S1), 4 (S2) and 6 (S3) ds.m-1. The results showed a good correspondence between the simulated soil moisture, water uptake and measured values. The normalized root mean square error (nRMSE) and the root mean square error (RMSE) values of the predicted soil moisture were 4.58 and 24.96 and for the water uptake by the roots were 23.37 and 35.48, respectively. The R2 of coefficient of simulation for water uptake by roots in different treatments were 0.38 to 0.8. The dataset of the predicted and measured values were close to the 1:1 scale line for both soil moisture and water uptake. This study indicated that the SWAP model can be used as a powerful tool to simulate field water cycle and evaluate irrigation practices. Accordingly, taking into account the existing conditions of the region such as weather and soil type and preparing scenarios based on possible management options, management strategies can be optimized according to the results achieved for the SWAP model simulation.

Evaluation of Some Sugar Beet Varieties under Water Salinity Stress in New Reclaimed Land

In line with sustainable agriculture that depends on modern methods and new sources of non-traditional irrigation, a field experiment was conducted at a privet farm behind Cairo-Alexandria Desert Road, Giza, Egypt during two seasons to evaluate five sugar beet varieties under water salinity stress condition. The present work included 15 treatments; represent five sugar beet varieties: viz. Multi-germs (Amina, Farida, and Faten) and Mono-germs (Unners and Sharleston), in combinations with two salinity treatments (Magic-Sal (13% humic acid + 20% carboxylic acid) and Sal-Wax (50% carboxylic acid) components) compared to control application. Results indicated that salinity treatments help in early stages to increase the emergency percentage of sugar beet varieties under high salinity water stress. As compared to control treatment, salinity treatments significantly increase proline accumulation, leaf relative water content (LRWC %),and root yield, but, it caused a reduction in quality parameters (sucrose, purity, and extractable sugar percentages) in both seasons. On the other hand, variety (Amina) overpassed the other varieties under salinity water stress with respect to germination ratio, proline content, LRWC%,and root yield (ton/fed) in both seasons. While, Sharelston variety surpassed significantly the other studied varieties with respect to sucrose, purity, and extractable sugar percentage (ES%) in both seasons.The distribution of stomata density of leaf increased as salinity water stress level increased. Results also showed that five sugar beet varieties under two salinity treatments (Magic-Sal or Sal-Wax) had positive effects and increased stomata area, but stomata density and its index as well as stomata closure% decreased compared with non-use.

Interactive effects of water salinity stress and chitosan foliar-spray application on vegetative and flowering growth aspects and chemical constituents of pot marigold (Calendula officinalis L.) plant.

A pot experiment was conducted during the two successive seasons of 2018/2019 and 2019/2020 at west of Somosta, Beni-Suef governorate, Egypt, to explore the effect of both saline water and foliar application of chitosan treatments on growth parameters for vegetative and flowering and on some chemical constituents of Calendula officinalis L. In contrast to control plants which were irrigated with tap water, the plants were irrigated with saline water containing NaCl at concentrations of 1000, 2000, 3000, 4000 and 5000 ppm. They were treated also by chitosan as foliar spray application at 100, 200 and 400 ppm, as well as, the interaction between them were involved. The higher salinity levels (4000 and 5000 ppm NaCl) caused significant decreases in all vegetative and flowering growth measurements of pot marigold plants compared to control. Maximum reduction was observed at 5000 ppm NaCl which showed higher increase of the free proline content, sodium and chloride percentages. Meanwhile, the increase in the concentration of salt in the irrigation water resulted in a decrease in the total chlorophylls in leaves and carotene content in flowers. Foliar application of chitosan at concentrations 200 and 400 ppm alleviated the adverse effect of salinity condition thereby vegetative, flowering characters and also chemical constituents were improved. The best level of foliar application of chitosan was at 400 ppm Whereas, non-significant effects were found on the vegetative and floral parameters and some chemical components as a result of the interaction between both aspects studied in comparison with untreated treatment.

ALLEVIATION OF SALINITY STRESS THROUGH MAGNETIC WATER AND NANO ZINC AND MAGNESIUM TREATMENT OF LEMONGRASS PLANT (Cymbopogen citratus L.)

The effect of magnetic water compared with saline water , nano-Mg at 100 and 200 ppm and nano-Zn at 50 and 100 ppm treatments and their combinations on lemongrass plants (Cymbopogen citratus L.) was studied during 2018/2019 and 2019/2020.Vegetative growth parameters including plant height, number of tillers/ plant, leaf area, herb fresh and dry weights were greatly affected by both studied factors. Magnetic water treatments recorded the highest values of all vegetative growth parameters compared with saline water. However, all nanoparticles of Mg and Zn treatments were superior than control in promoting vegetative growth parameters and the treatments of 100 ppm nano-Zn and 200 ppm nano-Mg recorded the maximum values of vegetative growth parameters. The combined treatments showed that the highest values of vegetative growth measurements were obtained in plants irrigated with magnetic water and sprayed with 100 ppm nano-Zn, in both cuts In 1st and 2ndseasons.N, P, K and Mg contents were significantly higher in lemongrass plants irrigated with magnetic water than those irrigated with saline water. Moreover, the treatments of 100 ppm nano-Zn exhibited the highest significant values of N, P, K, whereas 100 and 200 ppm of nano-Mg treatments were superior in recording the highest values of Mg content, in the two seasons. The combination treatments of lemongrass plants irrigated with magnetic water and sprayed with 100 ppm nano-Zn or 200 ppm nano-Mg produced the richest values of N, P and K% D.W., whereas, the treatments of magnetic water combined with 100 or 200 ppm of nano-Mg produced the best Mg content.A great effect of magnetic water irrigation on increasing Fe and Zn contents than saline water treatments. The treatments of 50 and 100 ppm of nano-Zn were more effective than control and other treatments in maximizing Fe and Zn levels. The combined treatments of lemongrass plants irrigated with magnetic water and sprayed with 100 ppm of nano-Zn exhibited the highest values of Fe and Zn% D.W. in most cases. Additionally, total chlorophyll greatly increased in lemongrass plants irrigated with magnetic water than those irrigated with saline water, whereas the treatment of 200 ppm nano-Mg increased it than others. Interaction effect showed that, plants irrigated with magnetic water and sprayed with nano-Mg at 200 ppm exhibited the highest values of total chlorophyll.Proline and glycine betaine contents were greatly decreased with magnetic water treatment compared with saline water. Meanwhile, all applied treatments were effective in decreasing the levels of both constituents than control, which considered a good indicator to alleviation of water salinity stress on lemongrass plants through magnetic water and nanoparticles of Mg and Zn applications. Finally, volatile oil %, was greatly increased in lemongrass plants irrigated with magnetic water, especially the treatment of nano-Zn at 100 ppm as compared of others in this respect in both cuts and the two studied seasons. The interaction between the two studied factors was significant which means that both factors act together in improving volatile oil content in lemongrass herb

Effect of Sulfur and Potassium Application under Salinity Stress on Productivity and Fruit Quality of Swelling Peach Cultivar

This study was conducted during two successive seasons (2016 and 2017) at El-Sheikh Zwayed, North Sinai Governorate, Egypt. The aim of this research was to investigate the effect of three anti-salt stress materials (Nile fertile, elemental sulfur and potassium sulfate) on Swelling peach cultivar under irrigation water saline stress. In this experiment Nile fertile was applied at (0, 500 and 1000 gm/ tree), elemental sulfur (95% S) as soil application at three levels (0, 500 and 750 g / tree) and potassium sulphate as foliar application on three concentrations (0, 2, and 4 g/l.) and combination of them. The obtained results revealed that all anti-salt stress substances have a positive effect on vegetative growth parameters, fruit set, and yield/tree. The highest significant value of the final fruit set, yield/tree was obtained with Nile fertile treatment followed by elemental sulfur and potassium sulphate in both seasons of this study. On the other hand, there was no significant differences between the three materials on fruit length, fruit diameter, flesh and pit fruit weight, total soluble solids, total acidity and leaf content of N%, P% and k% during both seasons of the study and leaf content of Fe (ppm) in the 1st season. While the interaction effect between the three investigated factors shows clearly significant effects in improving vegetative growth, final fruit set no. of fruits /tree, fruit weight, crop yield, fruit physical and chemical parameters. Thus, the combination between Nile fertile 1000g/tree + elemental sulfur 750g/tree + potassium sulphate at (4g/L) gave the best results on shoot length, leaf area, initial, final fruit set %, fruit length and diameter, flesh weight (g), pit weight (g), maximum yield/tree, TSS, lowest acidity%. In addition to N, P, K, Fe, Zn and Mn in leaves in both seasons. On the other hand, untreated trees recorded the lowest values in previous studied parameters in this respect.

Salinity impacts on experimental fodder sorghum production

Field experiment was conducted at research station of Soil, Water & Environment Discipline, Khulna University, during the dry season to see the growth performance of sorghum (Sorghum bicolor L. cv. Morokoshi) irrigating with saline water. For irrigation, river water (RW) containing EC value of 14.04 dS m-1 was collected from the Rupsha river, Khulna and mixed with tap water [TW] containing EC value of 0.78 dS m-1at three different ratios (3:1, 1:1 and 1:3 v/v). After mixing, water containing five different EC values (0.78, 4.19, 7.18, 10.79 and 14.04 dS m-1) were obtained and considered as salinity treatment. Harvesting and sampling was done 83 days after transplanting (DAT) by cutting four sorghum plants randomly selected from each plot. Different morphological parameters such as plant height, leaf number, leaf length, leaf width, stem diameter and plant biomass were measured and recorded. Soil samples were also collected from each plot. Under water salinity stress, all the agronomic attributes and plant biomass showed a decreasing tendency with increasing salt concentration in irrigation water but the growth was not harmfully affected at lower levels of salinity. Plant height and biomass was significantly decreased irrigating with water containing salinity 10.79 dS m-1.After harvest it was found that irrigation with saline water up to 10.79 dS m-1 did not show any increase of soil salinity. It was probably due to rainfall during the monsoon which was occurred at the later stage of the growing period. So, the fodder sorghum plant might be cultivated in the coastal regions of Bangladesh where fresh water irrigation is limited due to salinity problem as well as might be grown irrigating with saline water up to 10.79 dS m-1.SAARC J. Agri., 16(1): 145-155 (2018)

Proline and ions accumulation in four Passiflora species under water-saline stress

Water-saline stress is one of the factors limiting growth and crop production, with the induction of morphological, structural and metabolic changes in higher plants. This study aimed to evaluate the response of four species with ten accessions of Passiflora to saline stress and drought stress, and the accumulation of proline and content of cationic macronutrients and their relationships with sodium. The plants were grown under controlled conditions for seven months, watered with nutrient solution with additions of NaCl (100 mM) to achieve the desired conductivities (1.5, 2.5, 4.0, and 5.5 dS m-1) and constant substrate humidity of 100%, 66% and 33%. The concentrations of Na+, K+, Ca++, Mg++ and proline in the leaves were determined. Proline accumulation increased in salinized plants, especially in young leaves. Proline increase was evident in accessions tolerant and moderately tolerant to salinity. These results indicate that tolerance to salinity and water stress in Passiflora relates to an improved ability to exclude sodium and greater ability to accumulate proline for osmotic adjustment. The increased salinity of the nutrient solution increased sodium contents, relations Na+/Ca++, Na+/Mg++, Na+/K+, and decreased Ca++, Mg++ and K+ levels, reflecting the nutritional imbalance caused by progressive saline stress.

IMPROVING PRODUCTIVITY OF WILD MINT (Mentha longifolia L.) PLANTS BY USING HUMIC ACID UNDER SALINE WATER IRRIGATION CONDITIONS

This study was carried out on Mentha longifolia L. Fam. Lamiaceae (Labiatae) at the Farm of North Sinai Research Station, El-Sheikh Zwaid city during the two successive seasons of 2014/2015 and 2015/2016 to improve growth, productivity and oil production as well as chemical composition of Mentha longifolia L. plant under North Sinai conditions by using humic acid (0, 3 and 6 Litre.fed-1) under different levels of saline water (Tap water, 2048 ppm and 4224 ppm). Generally the highest values of vegetative growth parameters, oil production and chemical composition were obtained by using tap water and fertilizing with humic acid at 6 l.fed-1 in first experiment. But under arid and semi-arid conditions like North Sinai Governorate, humic acid could offer an economical and simple application to salt sensitive plant, it can be use saline water at 2048 ppm + humic acid at 6 l.fed-1 to decrease water salinity stress without decreasing in yield or oil production of Mentha longifolia L.

Changes in the growth, humoral and mucosal immune responses following β-glucan and vitamin C administration in red sea bream, Pagrus major

In order to study the effects of dietary β-glucan (BG), vitamin C (VC) and their combination (BG/VC) on growth, humoral and mucosal immune responses of red sea bream (Pagrus major) and its resistance to low water salinity stress, 240 healthy fish with initial body weight of 1.98±0.01g were randomly divided into four groups: a control group fed with basal diet and three treated groups fed with basal diets supplemented with 1000mgkg−1 BG, 800mgkg−1 VC, and the combination of 500mgkg−1 BG+400mgkg−1 VC, respectively. The obtained results showed that, compared with the control, the final body weight, weight gain and specific growth rate, feed and protein efficiency ratio, body protein content, nitro blue tetrazolium (NBT), total serum protein and tolerance against low salinity stress increased in fish fed BG or/and VC supplementations with the highest being in fish fed both BG and VC supplements while body moisture content, plasma glucose, triglyceride and malondialdehyde (MDA) contents decreased (P<0.05); body lipid content, hematocrit, serum and mucus lysozyme activities, superoxide dismutase (SOD), alternative complement pathway and mucus secretion also significantly increased in fish fed BG and VC supplements (P<0.05). Moreover, the fish fed BG diet had better improvement (P<0.05) in mucus bactericidal activity than the VC group. Furthermore, fish fed BG diet exhibited higher serum peroxidase activity (PA), however, fish fed VC diet showed higher mucus PA than the control group (P<0.05). Thus, the basal diet supplemented with BG or/and VC could promote the growth, antioxidant capacity, humoral and mucosal immune responses of red sea bream, and enhance the resistance to low salinity stress. Statement of relevanceA combination of β-glucan and vitamin C presented an additive effect on inducing the growth, immune responses and oxidative status of red sea bream. We recommend that treatment of 500mg of β-glucan and 400mg of vitamin C per kg diet is the appropriate concentration of inducing the red sea bream immune response.

Invasion Potential of Two Tropical Physalis Species in Arid and Semi-Arid Climates: Effect of Water-Salinity Stress and Soil Types on Growth and Fecundity.

Invasive plants are recognized for their impressive abilities to withstand adverse environmental conditions however, all invaders do not express the similar abilities. Therefore, survival, growth, nutrient uptake and fecundity of two co-occurring, invasive Physalis species were tested under water and salinity stresses, and different soil textures in the current study. Five different water stress levels (100, 75, 50, 25, and 12.5% pot water contents), four different soil salinity levels (0, 3, 6, and 12 dSm-1) and four different soil textures (67% clay, 50% clay, silt clay loam and sandy loam) were included in three different pot experiments. Both weeds survived under all levels of water stress except 12.5% water contents and on all soil types however, behaved differently under increasing salinity. The weeds responded similarly to salinity up till 3 dSm-1 whereas, P. philadelphica survived for longer time than P. angulata under remaining salinity regimes. Water and salinity stress hampered the growth and fecundity of both weeds while, soil textures had slight effect. Both weeds preferred clay textured soils for better growth and nutrient uptake however, interactive effect of weeds and soil textures was non-significant. P. angulata accumulated higher K and Na while P. philadelphica accrued more Ca and Mg as well as maintained better K/Na ratio. P. angulata accumulated more Na and P under salinity stress while, P. philadelphica accrued higher K and Mg, and maintained higher K/Na ratio. Collectively, highest nutrient accumulation was observed under stress free conditions and on clay textured soils. P. philadelphica exhibited higher reproductive output under all experimental conditions than P. angulata. It is predicted that P. philadelphica will be more problematic under optimal water supply and high salinity while P. angulata can better adapt water limited environments. The results indicate that both weeds have considerable potential to further expand their ranges in semi-arid regions of Turkey.

Salicylic Acid Efficacy on Resistance of Garlic Plants (Allium sativum, L.) to Water Salinity Stress on Growth, Yield and its Quality

This experiment was conducted and replicated during both winter seasons of 2013/2014 and 2014/2015, respectively at Soil Salinity Laboratory, Alexandria. This research was conducted to study the effects of water salinity and the application of salicylic acid (SA) on garlic growth performance, yield and its quality. Four levels of saline irrigation water treatments were used; i.e., 435 (fresh tap water as a control), 1500, 3000 and 4500 ppm. Three levels of salicylic acid treatments were foliar applied on garlic plants at the rates of 0, 150 and 300 ppm. The spraying was applied biweekly. The results indicated that the vegetative characters, yield and yield quality were; negatively, affected with increasing saline water levels from 435 up to 4500 ppm. Spraying SA on the leaves garlic plants led to decrease the negatively effects of the saline water on the tested characters. The best results were given when salicylic acid was sprayed at the concentration of 300 pm. The interaction between saline water salinity and SA concentrations did not show any significant effects on all the studied garlic characters. Also, data appeared that spraying garlic plants with SA at the concentration of 300 ppm exhibited the highest values for bulb fresh weight (g/plant), average clove weight (g), no. of cloves per bulb, bulb diameter (cm) and nick bulb diameter (cm) with any of the tested saline water levels. Spraying garlic plants with SA resulted in relatively increasing potassium concentration in comparison to sodium content and this result might be indicated that SA application improved the performance of garlic plant to the stress of irrigation with saline water. The recommendation of this research; based on the obtained results under the conditions of this study, is spraying garlic plants with SA at the concentration of 300 ppm biweekly when having to irrigate with saline water to reduce the adverse effect of saline water on the economic characteristics of the garlic crop.