Response of two sorghum genotypes to soil lime and sodium chloride amendments

Abstract

Salinity affects plants by interaction between sodium (Na) and calcium (Ca). Two sorghum (Sorghum bicolor) genotypes ('Hegari’ and ‘NB‐9040') were studied for the Na x Ca interaction in a soil amended with 2% calcium carbonate (CaCO₃) and with 0, 12.3, 24.6, and 36.9 mmol sodium chloride (NaCl)/kg soil. The two genotypes were similar in their response to soil NaCl in their shoot and root growth but differed in response to lime. The salinity‐tolerant Hegari was suppressed by high Ca concentration in the soil, mainly in the low‐NaCl treatments, and responded by a lower concentration of potassium (K) and magnesium (Mg) in the leaves, which was associated with leaf‐chlorosis. Since Na uptake was reduced by Ca, the main effect of salinity on plant growth was by the accumulation of chloride (Cl) in the leaves.     

INFLUENCE OF SODIUM CHLORIDE AND CALCIUM FOLIAR SPRAY ON HYDROPONICALLY GROWN PARSLEY IN NUTRIENT FILM TECHNIQUE SYSTEM

The effects of salinity [30 or 90 mM sodium chloride (NaCl)] and calcium (Ca) foliar application on plant growth were investigated in hydroponically-grown parsley (Petroselinum crispum Mill). Increasing salinity reduced fresh weight and leaf number. Calcium alleviated the negative impacts of 30 mM NaCl on plant biomass and leaf fresh weight but not in case of 90 mM. Plant height, leaf and root dry weight and root length did not differ among treatments. Total phenols increased with calcium application, chlorophyll b reduced by salinity, while total carotenoids increased with salinity and/or Ca application. Salinity reduced nutrient uptake [nitrate (NO₃), potassium (K), phosphorus (P) and Ca] and elemental content in leaves and roots. Calcium application reduced P but increased Ca content in plant tissues. Increments of Na uptake in nutrient solution resulted in higher Na content in leaves and roots regardless Ca application. These findings suggest that calcium treatment may alleviate the negative impacts of salinity.     

Genotipic responses of olive plants to sodium chloride

The effect of NaCl‐salinity on growth responses and tissue mineral content was investigated for two olive (Olea europaea L.) genotypes of different vigor, Leccino and Frantoio. Forty‐day‐old self‐rooted plants were grown for a 60‐day period in a sand culture system supplied with a 1/2 strength Hoagland solution with the addition of 0,12.5,25,50, and 100 mM NaCl. Plants were harvested at 12‐day intervals, and the dry weights of shoot, and principal and lateral roots were evaluated. Relative growth rate (RGR) was also estimated. At the same time, plant tissues were analysed for N, P, K, Ca, Mg, Na, and Cl content.

Growth inhibition by NaCl treatments was greater for Leccino than Frantoio plants. At the end of the experiment, 50 mM NaCl significantly reduced Leccino growth, while negative effects on Frantoio were detected only when using 100 mM NaCl. Leccino always accumulated more Na and Cl in the leaves than Frantoio. In a similar manner, Na/K ratio was always higher in the Leccino leaves compared to the Frantoio leaves. An inverse relationship between NaCl tolerance and vigor of the genotype emerged.     

EFFECTS OF PLANT GROWTH PROMOTING BACTERIA ON YIELD,GROWTH, LEAF WATER CONTENT,MEMBRANE PERMEABILITY,AND IONIC COMPOSITION OF STRAWBERRY UNDER SALINE CONDITIONS

Plant growth promoting effects of Bacillus subtilis EY2, Bacillus atrophaeus EY6, Bacillus spharicus GC subgroup B EY30, Staphylococcus kloosii EY37 and Kocuria erythromyxa EY43 were tested on strawberry cv. ‘Fern’ in terms of fruit yield, growth, chlorophyll reading value, leaf relative water content (LRWC), membrane permeability and ionic composition of leaves and roots under saline conditions. Compared with 0 mM sodium chloride (NaCl) treatment, the average decrease of yield and LRWC were 51.6% and 21.0%, respectively, when 35 mM NaCl was applied. However, EY30, EY37, and EY43 treatments under saline condition (35 mM NaCl) significantly increased fruit yield (54.4%, 51.7% and 94.9%) compared with 35 mM NaCl treatment without plant growth promoting bacteria (PGPB). The LRWC increased from 72.0% in 35 mM NaCl treatment to 88.4%, 86.6%, 84.2%, 83.5%, and 86.2% by EY2, EY6, EY30, EY37, and EY43 applications, respectively. The lowest membrane permeability among the bacterial strains was obtained from EY37 treatment (37) while it was 33 and 58 in 0 mM NaCl and 35 mM NaCl treatments, respectively. The concentration of all plant tissue nutrients investigated [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] with the exception of root phosphorus (P) and Mg concentration significantly decreased with 35 mM salt treatment. Nitrogen content of leaves varied between 3.04 and 3.14% in bacterial treatments under saline conditions while it was 2.71% in 35 mM NaCl treatment. In contrast sodium (Na) and chloride (Cl) of leaves and Cl content of roots were significantly decreased by root inoculation with all bacterial treatments in comparison to 35 mM NaCl treatment with no inoculation. Treatment with Bacillus EY30, Staphylococcus EY37 and Kocuria EY43 to strawberry plants can ameliorative the deleterious effect of salt stress on fruit yield, growth and nutrition. These results demonstrate that PGPB treatment could be offer an economic and simple means to increased plant resistance for salinity stress.     

Interactive effects of salinity and macronutrient level on wheat. II. Composition

Results of several studies show interactive effects of salinity and macronutrients on the growth of wheat plants. These effects may be associated with the nutrient status in plant tissues. The objective of this study was to investigate interactive effects of salinity and macronutrients on mineral element concentrations in leaves, stems, and grain of spring wheat (Triticum aestivum L. cv. Lona), grown in hydroponics, and the relation of these effects to yield components. Eight salinity levels were established from 0 to 150 mM NaCl, and 1, 0.2, and 0.04 strength Hoagland macronutrient solution (x HS) were used as the macronutrient levels. Sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chlorine (Cl), and phosphorus (P) in leaves, stems, and grain, NO₃ in leaves and stems, and total nitrogen (N) in grain were determined. Supplemental Ca, Mg, K, and NO₃ added to 0.2 x HS increased mineral concentrations in leaves and stems, but did not improve growth or yield in salinized wheat plants except moderately at 100–150 mM NaCl. In contrast, growth or yield was improved significantly when the concentration of macronutrients was increased from 0.04 to 0.2 × HS. In contrast to leaves and stems, mineral concentrations in grain increased (Na, Cl) or decreased (Ca, Mg, K) only slightly or were not affected (K) by salinity except at high salinity and low macronutrient level. Nitrogen and P concentrations in grain were not affected by salinity. Sodium and Cl concentrations in leaves and stems increased significantly, whereas K and NO₃ decreased significantly, with an increase in salinity regardless of the macronutrient level. The latter was also observed for Ca and Mg in leaves. Extreme Na/Ca ratios in plant tissues negatively affected grain yield production at high salinity with medium or high macronutrient levels and at low macronutrient level together with medium salinity. Even though strong and significant correlations between mineral concentration at grain maturity in leaves, stems, and grain and various yield parameters were observed, our results are inconclusive as to whether toxicity, nutrient imbalance, nutrient deficiency, or all of these factors had a strong influence on grain yield.     

Genotype-Dependent Differential Responses of Three Forage Species to Calcium Supplement in Saline Conditions

Salt toxicity comprises of osmotic and ionic components both of which can severely affect root and shoot growth. In many crop species, supplemental calcium (Ca) reduces the inhibition of growth typical of exposure to salt stress. The objective of this study was to compare whole plant growth and physiological responses to interactive effect of salinity and Ca level on three forage species [African millet (AM), tall wheat grass (TW), and perennial ryegrass (PR)] differing in tolerance to sodium chloride (NaCl) salinity. Plants were grown under glasshouse condition and supplied with nutrient solution containing 0, 100, and 250 mM NaCl supplemented with 0.5, 5, or 10 mM calcium chloride (CaCl₂). Plant growth, ionic concentration, water relations, and solute (proline and glycinebetaine) concentrations of the plants were determined two weeks after the salinity treatments. At 100 mM NaCl, there was a moderate reduction in dry matter (DM) production of all three species. A drastic decrease in DM occurred at 250 mM NaCl. Supplemental Ca reduced the adverse effects of salinity on all three species. The TW showed higher shoot and root growth in 100 and 250 mM NaCl than AM and PR. It also showed the highest DM at 5 and 10 mM Ca supplement. The shoot and root DM of TW increased by about 45 and 15%, respectively compared to the control. Chemical analysis indicated that in TW, Ca restricted both uptake and transport of sodium (Na) from root to shoot. It also increased Ca and potassium (K) concentrations in both organs. The transport of K and Ca from root to shoot of AM and PR were decreased by NaCl, but were restored with increasing Ca in the medium. The opposite occurred for Na. In PR, more K uptake was observed in shoot at 250 mM NaCl with 10 mM Ca supplement. The sap osmotic potential (Ψ_S) was the highest in TW at 10 mM Ca in the presence of 250 mM NaCl. Contribution of various solutes to the difference in Ψ_S among the species from the control and 250 mM salt treatment differed greatly. Supplemental Ca induced decline in the leaf Ψ_S of TW which was predominately due to K, glycinebetaine, Na and proline accumulation. Addition of 10 mM Ca to the growth medium maintained a low Na and a high K level. Accumulation of glycinebetaine and proline in leaf contributed the NaCl tolerance of TW. The presented results suggest that supplement Ca, not only improved ionic relations but also induced plant ability in production of compatible solutes (glycinebetaine and proline) and osmotic adjustment. Accordingly, genotype dependent capacity could be found using supplemental Ca.     

Salicylic Acid–Induced Salinity Redressal in Hydroponically Grown Strawberry

The present study was conducted to evaluate shoot and root mineral composition of salt-stressed Selva strawberry under application timing of salicylic acid (SA). Treatments included plants sprayed with 0.5 or 1 mM SA, plants exposed to 40 mM sodium chloride (NaCl), and plants sprayed with 0.5 or 1 mM SA 1 week before, simultaneously, or after initiation of 40 mM salinity. Results indicated that under saline conditions, sodium (Na) and chloride (Cl) contents increased along with decrease in nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn) in shoot and root of plants. In plants treated with SA at 1 mM concentration, 1 week before salinity application, root Mg and shoot Ca were greater in comparison to salt-stressed plants treated with the same SA concentration 1 week after their exposure to salt stress. Thus, earlier SA application appears to be a better strategy for optimized protection against deleterious influence of salinity.     

Influence of Salinity on Chlorophyll,Leaf Water Potential,Total Soluble Sugars,and Mineral Nutrients in Two Young Olive Cultivars

The effect of salinity (NaCl) on chlorophyll, leaf water potential, total soluble sugars, and mineral nutrients in two young Iranian commercial olive cultivars (‘Zard’ and ‘Roghani’) was studied. One-year-old trees of these cultivars were planted in 10-L plastic pots containing equal ratio of sand-perlite mixture (1:1). Sodium chloride at concentrations of 0, 40, 80, 120, or 160 mM plus Hoagland's solution were applied to these pots for 150 days. The results showed that chlorophylls (a), (b), and (a+b) reduced with increasing of salinity up to 40 mM. There was no difference between cultivars for chlorophylls (b) and (a+b) while ‘Roghani’ showed more decreased in content of chlorophyll (a) than did ‘Zard’. Total soluble sugars in leaves increased with an increase in salinity up to 80 mM but decreased with additional increase in salinity. Salinity stress reduced water potential equally in both cultivars. The concentrations of sodium (Na) and chloride (Cl) and Na/potassium (K) ratio were increased and K decreased with increasing of salinity up to 80 mM in leaves and roots. Concentrations of K, magnesium (Mg), calcium (Ca), phosphorus (P), and nitrogen (N) reduced significantly in leaves, shoots and roots with increasing salinity.     

Partitioning of Chlorine,Sodium, and Potassium and Shoot Growth of Three Pomegranate Cultivars Under Different Levels of Salinity

Salinity is a major problem in a wide pomegranate-growing area of central Iran. Effects of four levels of salinity on leaf and root chlorine (Cl), sodium (Na), and potassium (K) partitioning and shoot growth in three major commercial cultivars of pomegranate (Punica granatum), namely ‘Alak Torsh,’ ‘Malas Torsh,’ and ‘Malas Shirin,’ under climatic conditions of central Iran were investigated. Pomegranate cuttings were rooted and planted in plastic pots containing 1:1 sand:perlite medium and irrigated immediately with complete Hoagland's solution immediately. Four salinity levels of irrigation water (0, 40, 80, and 120 mM NaCl) were used. Final concentrations of NaCl were achieved after three weeks and continued for 80 d. Growth characteristics (i.e., length of the main stem, length and number of internodes, and leaf surface) were measured during the experiment. At harvest, concentrations of Na, K, and Cl in root and apical and basal leaves of the three cultivars were determined separately. In ‘Malas Torsh’ and ‘Alak Torsh’ cultivars, increasing salinity was proportional to NaCl concentration and reduced the length of stem, the length and number of the internodes, and leaf surface. There was an increase in the growth rate of the ‘Malas Shirin’ cultivar with increasing salinity up to 40 mM, but a decline in growth rate occurred at salinity levels higher than 40 mM. With increasing salinity level, the tissue concentration of Na and Cl increased while the K/Na ratio decreased. No significant differences were observed among the three cultivars in Na, Cl, and K concentrations of roots or apical or basal leaves. These results show that ‘Malas Shirin’ grew better under saline conditions compared with the ‘Malas Torsh’ and ‘Alak Torsh’ cultivars.     

Ion distribution in leaves of varying age in salt‐tolerant lines of alfalfa under salt stress

Two lines of alfalfa (Medicago sativa L.), a salt‐tolerant AZ‐Germ Salt II and a salt‐sensitive Mesa Sirsa, were grown for three weeks in solution culture containing 0 or 100 mol/m³ sodium chloride (NaCl) in half‐strength Hoagland nutrient solution. Distribution of cations and chloride (Cl) in the leaves of varying ages was determined. The older leaves (age‐dependent) of both lines contained more sodium (Na) in the laminae and petioles than the younger leaves at the salt treatment, whereas the reverse was true for potassium (K) in the laminae. Age‐dependent Cl distribution was only found in the laminae of AZ‐Germ Salt II. Distribution of calcium (Ca) in the lamina and petioles was strongly age‐dependent in both lines, but such a pattern was not found for magnesium (Mg) concentrations. AZ‐Germ Salt II accumulated considerably higher concen‐ trations of Na and Cl in the laminae compared with Mesa Sirsa. The lower Na and Cl concentrations in the laminae of Mesa Sirsa were due to relatively higher accumulation of these ions in the stems. It is concluded that distribution of Na, Cl, and Ca in the leaf laminae is age dependent. Salt tolerance in alfalfa is related to inclusion of Na and Cl in the leaf laminae.     

EFFECTS OF SALINITY AND CALCIUM ON THE GROWTH AND CHEMICAL COMPOSITION OF PISTACHIO SEEDLINGS

Poor quality of irrigation water (high salinity) has reduced the yields of pistachio over recent years, especially in Kerman. The effects of four salinity levels [0, 30, 60, and 90 mM sodium chloride (NaCl)] and three calcium (Ca) levels [0, 0.5, and 1 mM Ca as calcium nitrate (Ca(NO₃)₂.4H₂O)] on growth and chemical composition of pistachio seedlings cv. ‘Badami’ were studied in sand culture under greenhouse conditions in completely randomized design (CRD) with four replications. After 170 days, leaf area, leaf number, shoot and root dry weights were determined. Also shoot and root sodium (Na), potassium (K), Ca, and magnesium (Mg) concentrations were measured. Results showed salinity decreased all growth parameters. Ca application increased shoot and root Ca concentrations and root K concentration, while Ca application decreased shoot K concentration and shoot and root Mg concentrations. Salinity decreased shoot Ca, root K, and root Mg concentrations, while salinity increased shoot and root total sodium uptake, and shoot and root Cl concentrations.     

Effects of Sodium Chloride-Induced Salinity on Mineral Nutrients and Soluble Sugars in Three Commercial Cultivars of Pomegranate

Abstract

The effect of sodium chloride (NaCl)-induced salinity on concentration and translocation of ions and soluble sugars in three commercial cultivars, ‘Alak Torsh,’ ‘Malas Torsh,’ ‘Malas Shirin,’ of pomegranate (Punica granatum L.) was studied. After rooting of cuttings, they were planted in the plastic pots contained sand:perlite (1:1) medium and irrigated with complete Hoagland^’s solution immediately. After three weeks, plants were treated with different concentration (0, 40, 80, and 120 mM) of NaCl solution. These treatments continued during 80 days with irrigation water. Finally, uptake and transport of ions [Na, potassium (K), calcium (Ca), magnesium (Mg), nitrogen (N), and Cl) and soluble sugars in these three cultivars were measured. With increasing NaCl concentration in irrigation water, the amount of Na, Cl, and K of the tissues increased, but amount of Ca, Mg, and N of the tissues decreased. No cultivar differences were observed in the rate of uptake of tested minerals. Soluble sugars decreased as NaCl concentrations in irrigation water increased.     

Ion compartmentation in salinity‐stressed alfalfa seedlings growing under different temperature regimes

Abstract

The compartmentation of ions in salinity‐stressed 6‐week‐old alfalfa seedlings was investigated in two cultivars, Batini (moderately salinity tolerant) and Hunter River (salinity sensitive). Both cultivars were grown under field conditions during the cool season (20–25°C) and the warm season (35–46°C). Two saline solutions (6.4 and 12.2 dS m^‐1) were prepared by dissolving the required quantity of NaCl in half‐strength Hoagland solution. Tap water (0.8 dS m^‐1) served as control. Plants were irrigated twice a week with saline solutions, commencing 3 weeks after seedling emergence. The seedlings were separated into leaf (including petiole), stem, and root after 6 weeks of growth and analysed for phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), chloride (Cl), and micronutrients [copper (Cu), boron (B), zinc (Zn), manganese (Mn), and iron (Fe)]. The concentration of P and K in the plant tissue increased with increase in temperature, while Ca and Mg concentrations were depressed. Increase in salinity, in general, resulted in decreased accumulation of all ions, including micronutrients. Hunter River maintained the same pattern of ion compartmentation (root<stem<leaf) for Na and Cl, whereas in Batini a different pattern was obtained for Na (stem<leaf<root). Since the compartmentation pattern of ions in Batini is different for Na and not Cl, it appears that compartmentation of Na may be an important factor in salt tolerance.     

Growth and nutrient composition of tomato and cucumber seedlings as affected by sodium chloride salinity and supplemental calcium

The effect of three levels of salinity (2.0,4.0, and 8.0 mS/cm) on growth and ion composition of tomato and cucumber seedlings was examined with and without addition of 7.4 meq/L calcium chloriode (CaCl₂). The corresponding sodium/calcium (Na/Ca) ratio of the irrigation solution were 4.0 and 1.8 at salinity level 4.0 mS/cm, and 12 and 4.8 at salinity level 8.0 mS/cm. Seedlings growth of tomato and cucumber was generally reduced with increasing salinity level. Cucumber was more salt‐sensitive than tomato. Shoot and root dry weight of cucumber was increased by decreasing Na/Ca ratio at 4.0 mS/cm salinity. Sodium and chloride (Cl) accumulation was increased and Ca was decreased in salinized plants. Reducing Na/Ca ratio under saline condition reduce the accumulation of Na in tomato roots. The effect of salinity on the uptake of nitrogen (N), phosphorus (P), potassium (K), Na, Ca, chloride (Cl), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) in the root and shoot was also determined.     

Effect of salinity on stomatal resistance,proline, and mineral composition of pepper

Pepper (Capsicum annuum L.) plants grown in pots were irrigated with the nutrient solutions containing 50, 75, and 100 mM NaCl or a control solution. Salinity markedly decreased plant growth. Increasing salinity levels increased stomatal resistance and sodium (Na), chloride (Cl), proline contents of the plants. Potassium (K), total‐nitrogen (N), and chlorophyll content of the plants were decreased under high salinity conditions.     

Salinity and nitrogen fertilization affecting the macronutrient content and yield of sweet pepper plants

The effects of salinity due to sodium chloride (NaCl) and nitrogen (N) concentration in the nutrient solution were studied with sweet pepper plants. Four saline treatments combined with two N fertilization were used. Nitrate‐nitrogen (NO₃ ^‐‐N) presence in the nutrient solution produced an increase of sodium (Na) and potassium (K) contents in leaves as well as N. Salinity promoted a reduction of K, phosphorus (P) and Ca and increased the Na concentration in leaves. Calcium (Ca) concentrations were lower in the higher NO₃ ^‐‐N treatment although N level was reached adding calcium nitrate and salinity increased P, K, Na, Ca, and magnesium (Mg) contents in fruits. Yield was increased in the highest N treatment.     

NUTRITIONAL RESPONSES OF CITRUS ROOTSTOCKS TO SALINITY: PERFORMANCE OF THE NEW HYBRIDS FORNER-ALCAIDE 5 AND FORNER-ALCAIDE 13

This study assesses the nutritional behavior of the new citrus rootstocks Forner-Alcaide no.5 (FA-5) and Forner-Alcaide no.13 (FA-13) under saline conditions compared to that of their parents, Cleopatra mandarin (CM) and Poncirus trifoliata (PT). Eighteen month-old plants grafted with Valencia orange scions were used in the experiment. The plants were grown in a greenhouse and irrigated over an eight-week period with nutrient solutions to which different amounts of sodium chloride (NaCl) had been added, namely 0, 20, 40 and 60 mM. Relative growth and the uptake of major mineral elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] were then determined. It was noted that the reduction in relative growth caused by salt treatment was greater in plants grafted on PT than those on FA-13, FA-5 and CM. Increasing the salt level in the growth medium reduced the absorption of the above mineral elements in all scion-rootstock combinations. However, this decrease was generally more marked in plants grafted on PT than in those on CM and FA-5. Plants on FA-13 showed an intermediate behavior. Positive correlations were found between growth and mineral element uptake by salt treated plants. Nutrient uptake was also plotted against chloride (Cl) and sodium (Na) concentrations in leaves and roots at increasing salt levels. This showed that N absorption was closely correlated (inversely) with Cl content in leaves, whereas K, Ca and Mg uptakes were correlated (inversely) with Na concentration in roots. This suggests that the accumulation of saline ions impacts growth and nutrient uptake by citrus plants.     

GROWTH,NUTRIENT ACQUISITION,AND PHYSIOLOGICAL RESPONSES OF HYDROPONIC GROWN TOMATO TO SODIUM CHLORIDE SALT INDUCED STRESS

□ Growth and nutrient acquisition of tomato (Lycopersicon esculentum L.) cv ‘Amani’ were studied under induced salt stress in Hoagland's solution. The plants were treated for 37 days with salinity induced by incorporating different concentrations [0.0 (control), 50, 100, 150, or 200 mM] of sodium chloride (NaCl) to the nutrient solution. Slight reduction was obtained in growth represented by (shoot length and number, leaf number, and dry weight) when seedlings were directly exposed to NaCl stress from 0.0 to 100 mM. At higher concentrations (150 or 200 mM), growth parameters were adversely affected and seedlings died thereafter. Elevated salinity significantly reduced crude protein and fiber in shoots and roots. Tomato shoot and root contents of potassium (K), iron (Fe), and ash were reduced significantly in response to increased levels of salinity. Tissue contents of sodium (Na) and chloride (Cl) increased with elevated salinity treatments.     

Effect of sodium arsenite and sodium chloride on bean plant nutrition (macronutrients)

The effects of different levels of arsenic (As) and salinity on bean plant (Phaseolus vulgaris L., cv. Buenos Aires) nutrition were investigated. We studied the processes of absorption and accumulation of macronutrient elements: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). The experiment was performed in soilless culture at two levels of As: 2 and 5 mg AsL^‐1 (added as sodium arsenite, NaAsO₂), and three saline levels [only sodium chloride (NaCl) was added]: 1, 2, and 4 dS‐m^‐1. Sodium arsenite and NaCl significantly affected macronutrients allocation within bean plant at concentration levels used in this study. Arsenite depressed K, Na, and Mg concentrations in root, whereas root N, and Ca levels were increased. Nitrogen, P, K, and Na concentrations were significantly higher in As‐stressed plants compared with controls. The addition of NaCl increased Ca concentration in roots and decreased that of K. Salinity tended to increase leaf concentrations of K, Na, Ca, and Mg; whereas leaf N and P levels decreased with increasing salinity.     

ARBUSCULAR MYCORRHIZAL COLONIZATION DOES NOT ALLEVIATE SODIUM CHLORIDE-SALINITY STRESS IN VINCA [CATHARANTHUS ROSEUS (L.) G. DON]

We conducted a study to determine if inoculation with arbuscular mycorrhizal fungi (AMF) would enhance the tolerance of vinca [Catharanthus roseus (L.) G. Don] plants to sodium chloride (NaCl)-induced salinity in irrigation water. Vinca tolerated salinity levels up to 40 mM. Chlorophyll concentration, proline synthesis, and total antioxidant activity were increased with saline irrigation, while leaf potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and boron (B) content decreased, suggesting a detrimental salinity effect. Despite the limited effect of increasing salinity on N content, NaCl-stressed vinca plants showed a marked decrease in nitrate reductase activity, which was associated with decreased leaf K and Fe total content. Mycorrhizal inoculation resulted in reduced growth when compared to non-AMF plants, regardless of salinity level. The K/sodium (Na) ratio decreased dramatically with increasing salinity regardless of AMF treatment. Suggesting, that the AMF isolate was not able to selectively uptake K and Ca, and avoid uptake of Na.