Effect of salinity on growth,photosynthesis and mineral composition in leguminous plant Alhagi pseudoalhagi (Bieb.)

Leguminous plant Alhagi pseudoalhagi was subjected to 0 (control), 50, 100, and 200 mM NaCI treatments during a 30 d period to examine the mechanism of tolerance to salinity. Plant dry weight, net CO₂ assimilation rate, leaf stomatal conductance, intercellular CO₂ concentration, and solute concentration in leaves, stems, and roots were determined. Total plant weight in the 50 mM treatment was 170% of that of the control after 10 d of treatment. Total plant weight was lower in the 100 and 200 mM treatments than in the control. The leaf CO₂ assimilation rate was approximately 150% of that of the control in the 50 mM treatment, but was not affected significantly by 100 mM of NaCI, while it was reduced to about 60% of that the control in the 200 mM treatment. Similarly stomatal conductance was consistent with the CO₂ assimilation rate regardless of the treatments. Intercellular CO₂ concentration was lower in the NaCI-treated plants than in the control. Changes in CO₂ assimilation rate due to salinity stress could be mainly associated with stomatal conductance and the carboxylation activity. Although the leaf Na⁺ concentration increased to 900 mmol kg^-1 dry weight in the 200 mM treatment compared to 20 mmol kg^-1 in the control, the plants did not die and continued to grow at such a high leaf Na⁺ concentration. Uptake and transportation rates of Na+, Ca²⁺, Mg²⁺, and K⁺, and the accumulation of N were promoted by 50 mM NaCI. Na⁺ uptake rate continued to increase in response to external NaCI concentration. However, the uptake and transportation rates of Ca²⁺, Mg²⁺, and K⁺ behaved differently under 100 and 200 mM salt stress. The results suggest that A. pseudoalhagi is markedly tolerant to salinity due mainly to its photosynthetic activity rather than to other physiological characteristics.     

Response of Digitalis purpurea plants to temporary salinity

Abstract

The effect of two different levels of salinity upon adult plants of Digitalis purpurea has been studied. Seeds of D. purpurea plants were sown in pots of equal size and moistened with deionized water during one year. Afterwards, different treatments with NaCl were initiated, the concentrations being 100 mM and 200 mM NaCl in irrigation water during 63 days. Growth, measured as dry and fresh weight, and soluble protein contents, were lower in stressed plants than in control plants. Monovalent cation analysis showed that in leaves K⁺ plus Na⁺ (Total M) values did not change with the different treatments, but that in roots these values increased with the increasing salinity stress. On the other hand, proline levels were higher in stressed plants although the accumulation of this amino acid was not significant In leaves, Cl^? levels increased linearly with salinity degree, and the accumulation of this ion was faster than that of Na⁺, whereas in roots, the Cl^? level remained relatively low.

Total cardenolide levels in leaves and roots of the 100 mM NaCl plants were higher than those in 200 mM NaCl and control plants. We infer that moderate salinity conditions lead to raised cardenolide levels, principally in leaves, but the reason for this is not clear.     

Some aspects of salinity,plant density,and nutrient effects on Cressa cretica L.

The effects of salinity, density, and nutrient on the growth, reproduction, and ecophysiology of a perennial halophyte, Cressa cretica L., were studied. Lower salinity concentration (425 mM) promoted the growth, but the highest salinity (850 mM) did not have a significant effect. Plants grew faster and were healthier at low density treatment. Lack of nitrogen (N) in the medium substantially inhibited shoot growth. Higher rhizome length and increased dry weight were some of the symptoms of N‐deficiency. Phosphorus (P)‐free plants also showed higher dry weight and higher ratio of rhizomes to shoots. Reproductive capacity of Cressa cretica plants was not affected by the absence of P. Growth and reproduction of Cressa cretica plants were significantly inhibited by potassium (K) deficiency. Optimal plant growth was recorded in complete nutrient solution. Higher concentrations of oxalate were found in plants growing under low density conditions and in non‐saline controls. Proline concentration increased with the increase in salinity of the medium. Chlorophyll a and b synthesis were inhibited by high salinity treatments whereas changes in density regimes did not have an effect.     

Silicon modulates the activity of antioxidant enzymes and nitrogen compounds in sunflower plants under salt stress

Sunflower (Helianthus annuus L.) is an important oilseed crop with clear sensibility to salt stress. In this study, we evaluated silicon (Si) effect on the nitrogen metabolism and antioxidant enzyme activity in sunflower plants subjected to salinity. A 4 × 4 factorial arrangement of treatments in a completely randomized design with four replicates was used, consisting of four concentrations of Si (0.0; 1.0; 1.5; and 2.0 mM) and four concentrations of NaCl (0; 50; 100; and 150 mM) in the nutrient solution. The salinity reduced the nitrate content, but the increasing Si concentration in the medium improved the nitrate uptake, leading this ion to accumulate in salt-stressed plants, particularly in the roots. The nitrate reductase activity and the proline and soluble N-amino contents were also significantly increased by Si in salt conditions. The salinity increased electrolyte leakage and reduced the activity of enzymes superoxide dismutase, ascorbate peroxidase and catalase in sunflower plants, but these decreases were reversed by Si at 2 mM, thus alleviating the effects of salinity on these variables. We conclude that Si is able to positively modulate nitrogen metabolism and antioxidant enzyme activities in sunflower plants in order to alleviate the harmful effects of salinity.     

EFFECTS OF SALINITY AND THE INTERACTION BETWEEN THYMUS VULGARIS AND LAVANDULA ANGUSTIFOLIA ON GROWTH,ETHYLENE PRODUCTION AND ESSENTIAL OIL CONTENTS

This study evaluated the effects of salinity on thyme (Thymus vulgaris) and lavender (Lavandula angustifolia) plants grown alone and in combination with each other. After transplanting, two-month-old plants received nutrient solutions supplemented with 0, 50, and 100 mM sodium chloride (NaCl) for 21 d. Thyme and lavender grown alone were each more tolerant to salt stress than thyme and lavender grown together. In the 100 mM NaCl treatment, all lavender plants grown with thyme died. In thyme, the carbon (C) and nitrogen (N) contents of the roots increased. Ethylene production in thyme was stimulated by salinity only in plants that interacted with lavender. However, in lavender, ethylene production was not influenced by the presence of thyme. The production of essential oils (EOs) was increased by salinity in thyme plants, whereas the EO production of lavender plants depended on the presence of thyme.     

Influence of sodium chloride on the growth and mineral nutrition of pepper cultivars

The response of four cultivars of pepper (Capsicum annuum L.), Yolo Wonder, HDA 103, HDA 174, and SC 81 to sodium chloride (NaCl) salinity was studied in hydroponic culture by comparing three different NaCl concentrations: 0 mM, 50 mM, and 100 mM. For all cultivars, growth was reduced when NaCl concentration in the growth medium increased. However, cultivar behavior as a function of the NaCl concentration was not homogenous. The HDA 174 displayed the best growth when NaCl concentration was high, while Yolo Wonder was the most sensitive to salinity. The SC 81 showed intermediate behavior since its growth was low at all treatment levels, but it reacted only slightly to increasing salinity. The analytical results showed that growth was very closely linked to the zinc (Zn) content of the blade: the best growth was observed when the percentage of Zn in the blade was low, whereas high Zn content was linked to sharp reduction in growth. The most tolerant cultivar, HDA 174, showed an original response: the sodium (Na) was strongly accumulated in the leaf blade, whereas the other cultivars tended to avoid Na accumulation. This corresponded to an adaptation observed for halophyte plants.     

Einfluß von NaCI-Salinität auf die CO2-Assimilation und auf den Einbau von 14C in verschiedene Inhaltsstoffe bei jungem Sommerweizen

Effect of NaCI salinity on CO₂ assimilation and incorporation of ¹⁴C in various chemical fractions of young wheat plants The effect of an increasing NaCI salinity on CO₂ assimilation and on the distribution of ¹⁴C in various chemical fractions of young wheat plants was studied. Increasing salinity restricted growth and in particular ¹⁴CO₂ assimilation being measured at the end of the experimental period. Correspondingly the amounts of ¹⁴C found in the various chemical fractions (amino acids, organic anions, carbohydrates, proteins, lipids, insoluble residue) were decreased with an increase in salinity. The relative distribution of ¹⁴C in the chemical fractions also was affected by salinity. At low salinity level a relatively low ¹⁴C concentration was found in the low molecular fractions, while the high molecular fractions showed a relatively high ¹⁴C concentration. At high salinity level this tendency was only weakly evident. Increasing salinity had no major impact on the nutrient concentrations (N, P, K, Ca, Mg) in the shoots, whereas the concentration of Na and especially of CI was remarkably raised. It is assumed that this excessive Na and CI concentrations in the shoots are resulting in the yield depression.     

Calcium Sulfate Improves Salinity Tolerance in Rootstocks of Plum

ABSTRACT

Three vegetative rootstocks of plum (Prunus domestica), Marianna GF 8-1 (Prunus cerasifera × munsoniana), Myrobolan B (P. Cerasifera) and Pixy (P. Insititia) were grown in pots containing sand and irrigated with complete nutrient solution to investigate the effect of calcium sulfate supplied to the nutrient solution on plants grown under salt stress. Treatments were (1) control (C): nutrient solution alone; (2) S (salinity stress): 40 mM NaCl; (3) S+Ca1: 40 mM NaCl +2.5 mM calcium (Ca) and (4) S+Ca₂: 40 mM NaCl + 5 mM Ca. Calcium was supplied as CaSO₄. The plants grown under 40 mol L^?1 NaCl produced less dry matter and had lower chlorophyll content than those without NaCl. Supplementary CaSO₄ at both 2.5 and 5 mM concentrations ameliorated the negative effects of salinity on plant dry matter and chlorophyll content. Salt treatment impaired membrane permeability by increasing electrolyte leakage. The addition of calcium sulfate partially maintained membrane permeability. Sodium (Na) concentration in plant tissues increased in both leaves and roots of plants under the high NaCl treatment. Pixy had much lower Na. The CaSO₄ treatments lowered significantly the concentrations of Na in both leaves and roots. Pixy was more tolerant to salinity than the other two rootstocks. The accumulation of Na in leaves and roots indicates a possible mechanism whereby Pixy copes with salinity in the rooting medium, and/or may indicate the existence of an inhibition mechanism of Na transport to leaves. Concentrations of Ca and K were lower in the plants grown at high NaCl than in those under the control treatment, and these two element concentrations were increased by calcium sulfate treatments in both leaves and roots, but remained lower than control values in most cases.     

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.     

Responses of Batis maritima plants challenged with up to two‐fold seawater NaCl salinity

Batis maritima is a promising halophyte for sand‐dune stabilization and saline‐soil reclamation. This species has also applications in herbal medicine and as an oilseed crop. Here, we address the plant response to salinity reaching up to two‐fold seawater concentration (0–1000 mM NaCl), with a particular emphasis on growth, water status, mineral nutrition, proline content, and photosystem II integrity. Plant biomass production was maximal at 200 mM NaCl, and the plants survived even when challenged with 1000 mM NaCl. Plant water status was not impaired by the high accumulation of sodium in shoots, suggesting that Na⁺ compartmentalization efficiently took place in vacuoles. Concentrations of Mg²⁺ and K⁺ in shoots were markedly lower in salt‐treated plants, while that of Ca²⁺ was less affected. Soluble‐sugar and chlorophyll concentrations were hardly affected by salinity, whereas proline concentration increased significantly in shoots of salt‐treated plants. Maximum quantum efficiency (F_v/F_m), quantum yield of PSII (Φ_PSII), and electron‐transport rate (ETR) were maximal at 200–300 mM NaCl. Both nonphotochemical quenching (NPQ) and photochemical quenching (qP) were salt‐independent. Interestingly, transferring the plants previously challenged with supraoptimal salinities (400–1000 mM NaCl) to the optimal salinity (200 mM NaCl) substantially restored their growth activity. Altogether, our results indicate that B. maritima is an obligate halophyte, requiring high salt concentrations for optimal growth, and surviving long‐term extreme salinity. Such a performance could be ascribed to the plant capability to use sodium for osmotic adjustment, selective absorption of K⁺ over Na⁺ in concomitance with the stability of PSII functioning, and the absence of photosynthetic pigment degradation.     

Alleviation of salt stress by arbuscular mycorrhizal in zucchini plants grown at low and high phosphorus concentration

With the aim of determining whether the arbuscular mycorrhizal (AM) inoculation would give an advantage to overcome salinity problems and if the phosphorus (P) concentration can profoundly influence zucchini (Cucurbita pepo L.) plant responses to AM, a greenhouse experiment was carried out with AM (+AM) and non-AM (−AM). Plants were grown in sand culture with two levels of salinity (1 and 35 mM NaCl, giving electrical conductivity values of 1.8 and 5.0 dS m⁻¹) and P (0.3 and 1 mM P) concentrations. The percentages of marketable yield and shoot biomass reduction caused by salinity were significantly lower in the plants grown at 0.3 mM P, compared to those grown at 1 mM P. However, even at high P concentration, the absolute value of yield and shoot biomass of +AM zucchini plants grown under saline conditions was higher than those grown at low P concentration. The +AM plants under saline conditions had higher leaf chlorophyll content and relative water content than −AM. Mycorrhizal zucchini plants grown under saline conditions had a higher concentration of K and lower Na concentration in leaf tissue compared to −AM plants. The P content of zucchini leaf tissue was similar for +AM and −AM treatments at both low and high P concentrations in the saline nutrient solution. The beneficial effects of AM on zucchini plants could be due to an improvement in water and nutritional status (high K and low Na accumulation).     

Effects of three commercial rootstocks on mineral nutrition,fruit yield,and quality of salinized tomato

Tomato (Solanum lycopersicum Mill. cv. Belladona F₁) plants were either self‐rooted, self‐grafted, or grafted onto the commercial rootstocks “Beaufort”, “He‐Man”, and “Resistar” and grown in a recirculating hydroponic system. Three nutrient solutions differing in NaCl‐salinity level (2.5, 5.0, and 7.5 dS m^–1, corresponding to 0.3, 22, and 45 mM NaCl) were combined with the five grafting treatments in a two‐factorial (3 × 5) experimental design. At the control NaCl level (0.3 mM), fruit yield was not influenced by any of the grafting treatments. However, at low (22 mM NaCl) and moderate (45 mM NaCl) salinity levels, the nongrafted and the self‐grafted plants gave significantly lower yields than the plants grafted onto He‐Man. The plants grafted onto the other two rootstocks gave higher yields only in comparison with the nongrafted plants, and the differences were significant only at low (Beaufort) or moderate (Resistar) salinity. Yield differences between grafting treatments at low and moderate salinity arose from differences in fruit number per plant, while mean fruit weight was not influenced by grafting or the rootstock. NaCl salinity had no effect on the yield of plants grafted onto He‐Man but restricted the yield in all other grafting treatments due to reduction of the mean fruit weight. With respect to fruit quality, salinity enhanced the titratable acidity, the total soluble solids, and the ascorbic acid concentrations, while grafting and rootstocks had no effect on any quality characteristics. The leaf Na concentrations were significantly lower in plants grafted onto the three commercial rootstocks, while those of Cl were increased by grafting onto He‐Man but not altered by grafting onto Beaufort or Resistar in comparison with self‐grafted or nongrafted plants. Grafting onto the three tested commercial rootstocks significantly reduced the leaf Mg concentrations, resulting in clear Mg‐deficiency symptoms 19 weeks after planting.     

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.     

RESPONSE OF SALT STRESSED STRAWBERRY PLANTS TO FOLIAR SALICYLIC ACID PRE-TREATMENTS

Salinity has deleterious effects on plant growth and development through membrane stability, photosynthetic activity, protein content, and ionic composition; however, salicylic acid (SA) could restore these properties in plants. The objective of this study was to determine the ameliorative effects of SA as foliar pre-treatments on membrane permeability, proline and protein contents, chlorophyll a, b and total chlorophyll and ionic composition of strawberry cv. ‘Camarosa’ under saline conditions. Membrane permeability and proline content significantly increased and protein and chlorophyll contents significantly decreased by 6 mS cm^?1 application without SA treatment compared with the control (2 mS cm^?1) treatment. Membrane permeability decreased from 6.9 in 0 mM SA treatment to 5.2 by application of 1.0 mM SA under saline conditions and same to the control (5.2). Compared with 0 mM SA treatment, the average increases of proline and protein contents were 66.7% in 0.25 mM SA treatment and 62.2% in 0.1 mM SA treatment in 6 mS cm^?1 level, respectively. Chlorophyll b and total chlorophyll significantly increased by 0.25 mM SA treatments under saline conditions. The lowest and the highest chlorophyll b and total chlorophyll were obtained from 0 mM SA treatment (19.6 and 44.5 mg L^?1) and 0.25 mM SA treatment (28.6 and 52.9 mg L^?1) in 6 mS cm^?1 salinity level. Ionic compositions of leaves were significantly affected by salinity and SA treatments. Nitrogen in 1.0 mM SA treatment and P contents of leaves in 0.1 mM SA treatment significantly increased but Na and Cl contents of leaves significantly decreased by SA treatments in 6 mS cm^?1 salinity level. The results of this study were clearly indicated that the SA application on strawberry plants could ameliorate the deleterious effect of salt stress on membrane permeability, proline, protein, and chlorophyll contents. Therefore, SA treatment could offer an economic and simple application to salinity stress.     

Response of Cherry Rootstocks to Boron and Salinity

ABSTRACT

The objective of the present research was to study the effects of boron (B) and potassium chloride (KCl) induced salinity on growth, nutritional status, and chlorophyll content of the cherry rootstocks CAB 6P (Prunus cerasus L.) and Gisela 5 (Prunus cerasus L. × Prunus canescens L.). Plants produced the longest shoots, more leaves, and the greatest fresh weights of shoots and leaves when treated with 0.025 mM B combined with the lower level of salinity (0.75 dS m^?1). CAB 6P plants retained most of their leaves until the end of the experiment, whereas Gisela 5 plants showed higher leaf shedding. Irrigation of plants with solutions containing 0.2 mM B and electrical conductivities (EC) of 4 dS m^?1 resulted in lower leaf chlorophyll contents (SPAD units) when compared with all other treatments. Nitrogen (N) concentrations of leaves from both rootstocks decreased as the EC of the nutrient solution increased from 0.75 to 4 mM. Potassium (K) concentrations of leaves from both rootstocks increased as salinity levels increased.     

EFFECTS OF SOIL SALINITY IN THE GROWTH OF AMBROSIA ARTEMISIIFOLIA BIOTYPES COLLECTED FROM ROADSIDE AND AGRICULTURAL FIELD

Morphological differences were observed between roadside (R) and agricultural field (F) biotypes of Ambrosia artemisiifolia, in which R-type seedlings were shorter and produced larger and heavier seeds under greenhouse grown conditions. Previous findings indicated that A. artemisiifolia R-types exhibited greater salt tolerance with respect to germination. However, the impact of biotype and salt tolerance on morphological variation has not been investigated in A. artemisiifolia plants. After performing replicated greenhouse experiments with both biotypes, it was shown that salinity level was a critical factor influencing both seedling and mature plant size and this response was dependent upon biotype. The R-type exhibited slight but significant increases in growth at low/mild salinity levels (50–100 mM) compared with non-saline conditions, while the F-type exhibited significantly reduced growth at the low/mild salinity levels. The reductions in growth of F-type plants in low/mild salinity were similar to those reductions of R-types observed in non-saline conditions. As both biotypes produced seeds at low/mild salinity levels, we conclude that low/mild salinity affects A. artemisiifolia plant size and overall growth rate, and secondly, certain F-type plants may acclimate to the roadside environment over time by reducing their size while producing larger seed under saline conditions. It is possible that this species may exhibit changes in morphology after several generations of exposure to saline roadside conditions. Toxicity due to salt treatment at high salinity (400 mM) was observed in both biotypes, whereas the R-type was more tolerant to both low and high salinity levels with respect to seed germination. Differential A. artemisiifolia growth responses which occur from seed germination to plant maturity may be partially attributed to its ability to tolerate saline soil conditions both under greenhouse and field conditions. This ability to tolerate saline conditions may be especially important in early spring when roadside soils experience increased salinity, caused by de-icing salt treatments applied during the winter season.     

Growth Responses and Nitrogen-15 Absorption of Desert Saltgrass Under Salt Stress

Abstract

Saltgrass [Distichlis spicata (L.) Greene var. stricta (Gray) Beetle], accession WA-12, collected from a salt playa in Wilcox, AZ, was studied in a greenhouse to evaluate its growth responses in terms of shoot and root lengths, shoot dry-matter yield, and nitrogen (N) (regular and ¹⁵N) absorption rates under control and salt (sodium chloride, NaCl) stress conditions. Plants were grown under a control (no salt) and three levels of salt stress (100, 200, and 400 mM NaCl, equivalent to 5850, 11700, and 23400 mg L^{? 1} sodium chloride, respectively), using Hoagland solution in a hydroponics system. Ammonium sulfate [(¹⁵NH₄)₂SO₄], 53% ¹⁵N (atom percent ¹⁵N) was used to enrich the plants. Plant shoots were harvested weekly, oven-dried at 60°C, and the dry weights measured. At each harvest, both shoot and root lengths were also measured. During the last harvest, plant roots were also harvested and oven-dried, and dry weights were determined and recorded. All harvested plant materials were analyzed for total N and ¹⁵N. The results showed that shoot and root lengths decreased under increasing salinity levels. However, both shoot fresh and dry weights significantly increased at 200 mM NaCl salinity relative to the control or to the 400 mM NaCl level. Shoot succulence (fresh weight/dry weight) also increased from the control (no salt) to 200 mM NaCl, then declined. The root dry weights at both 200 mM and 400 mM NaCl salinity levels were significantly higher than under the control. Concentrations of both total-N and ¹⁵N in the shoots were higher in NaCl-treated plants relative to those under the control. Shoot total-N and ¹⁵N contents were highest in 200 mM NaCl-treated plants relative to those under the control and 400 mM salinity.     

Comparison of growth and mineral accumulation of two solanaceous species,Solanum scabrum Mill. (huckleberry) and S. melongena L. (eggplant), under salinity stress

Solanum scabrum Mill. (huckleberry) is widespread in West, East and Central Africa, where it constitutes one of the most important leafy vegetables. However, the salinity tolerance of this crop has not yet been assessed. The objective of this study was to assess the response of huckleberry to salinity stress in comparison with eggplant (S. melongena L.). Four-week-old seedlings of both species were subjected to two levels of salinity stress, 50 mM and 150 mM sodium chloride (NaCl), for 14 d. Leaf water potential of both species decreased with increasing salinity stress. This decrease was lower in huckleberry than in eggplant. Total dry weight and total leaf area were also decreased by salinity, and the reductions of total dry weight and total leaf area under the 50 mM treatment compared with the control were 25 and 18% in huckleberry, while they were 47 and 55% in eggplant, respectively. The increases in leaf sodium (Na) accumulation in the 50 and 150 mM treatments compared with the control were 65 and 66% for eggplant and 18 and 36% for huckleberry, respectively. Na accumulation in stem and root in huckleberry was higher than that of leaf, whereas it was the reverse in eggplant under both salinity treatments. Huckleberry accumulated less Na in the leaves than eggplant, suggesting that huckleberry might reduce the transport of Na to its leaves more effectively than eggplant. The decrease of potassium (K) accumulation and the increase of Na in leaves by salinity resulted in a higher Na/K ratio in leaves, but this trend was greater in eggplant than in huckleberry. The calcium (Ca) concentration in leaves of huckleberry was also increased by salinity, whereas that of eggplant was decreased. These results indicate that huckleberry is more tolerant to salinity than eggplant, and less decrease in leaf area associated with lower leaf Na and increased Ca concentrations may be important in enhancing quality and sustaining productivity of the crop under this stress.     

Lavandula multifida response to salinity: Growth,nutrient uptake,and physiological changes

Fern leaf lavender (Lavandula multifida L.) is a perennial shrub native to Almería with known medicinal properties, which grows in saline soils that are increasingly present in the Mediterranean region. However, the effects of salinity on the mineral nutrition and physiology of L. multifida are unknown. In the present study, we evaluated the salt resistance of this species and compared it with other members of the Lamiaceae . Plants of L. multifida were grown in pots in a mixture of sphagnum peat‐moss and Perlite, and treated with five different NaCl concentrations [10 (control), 30, 60, 100, and 200 mM NaCl] over a period of 60 d. The effects of different levels of salinity on mineral nutrient and osmolyte concentrations and on biomass were evaluated. Our results show that L. multifida plants were able to grow with 60 mM NaCl without significant biomass reduction. Na⁺ and Cl⁻ were the main contributors to the osmotic potential in both roots and leaves, whereas total soluble sugars (TSS) and proline made only a small contribution. The concentrations of TSS and proline showed different trends in the different organs: in roots, both showed the highest concentrations at 60 mM NaCl, whereas in leaves TSS increased and proline decreased with increasing salt stress. To survive salinity, L. multifida plants increased salt excretion (Na⁺ and Cl⁻) by leaves at 100 and 200 mM NaCl and leaf succulence at 60, 100, and 200 mM NaCl. Excessive accumulation of Na⁺ and Cl⁻ was avoided by shedding leaves. Our results indicate that L. multifida is better adapted to salinity compared to other members of the Lamiaceae ¸ a consideration that is particularly relevant for their growth in arid saline areas.     

Salt tolerance and mineral relations for celery

To invertigate the relationship between salt tolerance and plant mineral status in celery (Apium graveolens L.) growth and the concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), and chloride (Cl) in different tissues were determined in plants grown in hydroculture with nutrient solutions containing 5 (control), 50,100, and 300 mM sodium chloride (NaCl) for four weeks. At salinity levels of 50 and 100 mM NaCl, there was a moderate, albeit significantly, reduction of growth, while a drastic decrease in both fresh and dry weight was obtained at 300 mM NaCl. Regardless of the salinity level, growth resumed promptly and completely once the stress was ceased. Sodium chloride stress reduced the accumulation of nitrate (NO₃)‐N in all plant tissues, but there were no relevant effects on the concentration of reduced N and P. The concentration of K in roots and leaf petioles was unaffected by NaCl treatment, but it gradually declined with increasing salinity in leaf blades. This reduction was less pronounced in the young leaves as compared to the mature ones. Increasing the NaCl concentration decreased the concentration of Ca in all tissues, but it prevented the occurrence of black‐heart, a typical Ca‐related physiological disorder which affected severely the controls. Salt‐stressed plants absorbed large amounts of Na and Cl which accumulated in the mature leaves, particularly in the oldest leaves. These findings suggest that the relatively high salt tolerance of celery relies on the ability to maintain an adequate nutritional status and to protect the shoot meristem from salt toxicity.