Two antagonistic gustatory receptor neurons responding to sweet-salty and bitter taste in Drosophila

In Drosophila, gustatory receptor neurons (GRNs) occur within hair-like structures called sensilla. Most taste sensilla house four GRNs, which have been named according to their preferred sensitivity to basic stimuli: water (W cell), sugars (S cell), salt at low concentration (L1 cell), and salt at high concentration (L2 cell). Labellar taste sensilla are classified into three types, l-, s-, and i-type, according to their length and location. Of these, l- and s-type labellar sensilla possess these four cells, but most i-type sensilla house only two GRNs. In i-type sensilla, we demonstrate here that the first GRN responds to sugar and to low concentrations of salt (10-50 mM NaCl). The second GRN detects a range of bitter compounds, among which strychnine is the most potent; and also to salt at high concentrations (over 400 mM NaCl). Neither type of GRN responds to water. The detection of feeding stimulants in i-type sensilla appears to be performed by one GRN with the combined properties of S+L1 cells, while the other GRN detects feeding inhibitors in a similar manner to bitter-sensitive L2 cells on the legs. These sensilla thus house two GRNs having an antagonistic effect on behavior, suggesting that the expression of taste receptors is segregated across them accordingly.     

Taste input from tarsal sensilla is related to egg‐laying behavior in Papilio hospiton

In herbivorous insects, host selection involves various sensory modalities (sight, smell, taste), but the contact chemoreceptors capable of detecting stimuli both from host and non‐host plants play an important role in the final steps of oviposition behavior. Female butterflies scratch and drum the leaf surface and taste the compounds present in plant saps with their tarsal chemosensilla. We assumed that tarsal taste sensitivity may be related to the breadth of host selection in ovipositing females of Papilio hospitonGéné (Lepidoptera: Papilionidae). The spike activity of tarsal taste basiconic sensilla was recorded in response to stimulation with NaCl, bitter compounds, and carbohydrates, with the aim of characterizing the gustatory receptor neurons (GRNs) and of comparing the response patterns in the light of differences in acceptability of host plants. Then we studied the sensitivity of GRNs to saps of the host plants Ferula communis L., Peucedanum paniculatumLoisel, Pastinaca latifolia (Duby) DC. (all Apiaceae), and Ruta lamarmorae Bacch., Brullo et Giusso (Rutaceae), and evaluated the relationship between taste sensitivity and oviposition preference. The results indicate that (1) each sensillum houses sugar‐, bitter‐, and salt‐sensitive cells; (2) the spike activity of the gustatory neurons in response to plant saps produces a different response pattern across all active GRNs; and (3) the number of eggs laid on each plant is highest on F. communis and lowest on R. lamarmorae. These results suggest that the varying activity of the tarsal GRNs may affect host plant acceptability and that ovipositing females of P. hospiton seem to be able to discriminate between host plants.     

Electrophysiological characterization of responses from gustatory receptor neurons of sensilla chaetica in the moth Heliothis virescens

Discrimination of edible and noxious food is crucial for survival in all organisms. We have studied the physiology of the gustatory receptor neurons (GRNs) in contact chemosensilla (insect gustatory organs) located on the antennae of the moth Heliothis virescens, emphasizing putative phagostimulants and deterrents. Sucrose and the 2 bitter substances quinine and sinigrin elicited responses in a larger proportion of GRNs than inositol, KCl, NaCl, and ethanol, and the firing thresholds were lowest for sucrose and quinine. Variations in GRN composition in individual sensilla occurred without any specific patterns to indicate specific sensillum types. Separate neurons showed excitatory responses to sucrose and the 2 bitter substances quinine and sinigrin, implying that the moth might be able to discriminate bitter substances in addition to separating phagostimulants and deterrents. Besides being detected by separate receptors on the moth antennae, the bitter tastants were shown to have an inhibitory effect on phagostimulatory GRNs. Sucrose was highly appetitive in behavioral studies of proboscis extension, whereas quinine had a nonappetitive effect in the moths.     

Factors modulating the blood feeding behavior and the electrophysiological responses of labral apical chemoreceptors to adenine nucleotides in the mosquito Aedes aegypti (Culicidae)

The feeding of Aedes aegypti (L.) on blood is induced by the presence of phagostimulants: adenine nucleotides. Three chemoreceptive cells in the labral apical sensilla can distinguish the presence of adenine nucleotides depending on the other stimulus components. This work aims at correlating the sensory information arising from the labral apical sensilla with the feeding behavior in response to the same stimuli. The saline stimulating solution, containing adenine nucleotides, is modulated by changing one of the following components: salt concentration, buffer or pH. Cell 3 that responds to NaCl in a dose dependent manner seems to have another unique modality. The response of this cell is unaffected by ATP when the stimulating solution is NaCl buffered by NaHCO(3). It responds at a higher spike frequency to the presence of ATP in a NaCl solution without NaHCO(3). Thus in the presence of ATP Cell 3 detects whether the NaCl solution is buffered by NaHCO(3). Both the blood feeding response and the sensory information from Cell 2 (which responds at high spike frequencies to the presence of ATP) are modulated by pH in a similar way. Both responses present a bi-modal response, with a major peak at pH 4.0 and a moderate peak at the most alkaline pH value tested.     

Taste discriminating capability to different bitter compounds by the larval styloconic sensilla in the insect herbivore Papilio hospiton (Géné)

Herbivorous animals may benefit from the capability to discriminate the taste of bitter compounds since plants produce noxious compounds, some of which toxic, while others are only unpalatable. Our goal was to investigate the contribution of the peripheral taste system in the discrimination of different bitter compounds by an herbivorous insect using the larvae of Papilio hospiton Géné as the experimental model, showing a narrow choice range of host plants. The spike activity from the lateral and medial styloconic sensilla, housing two and one bitter-sensitive gustatory receptor neurons (GRNs), respectively, was recorded following stimulation with nicotine, caffeine, salicin and quercitrin and the time course of the discharges was analyzed. Nicotine and caffeine activated all three bitter-sensitive GRNs, while salicin and quercitrin affected only two of them. In feeding behavior bioassays, intact larvae ate glass-fiber disks moistened with salicin and quercitrin, but rejected those with nicotine and caffeine, while lateral sensillum-ablated insects also ate the disks with the two latter compounds. The capability to discriminate bitter taste stimuli and the neural codes involved are discussed.     

Electrophysiological responses of the chemoreceptor neurones in the antennal taste sensilla to plant alkaloids and glucosides in a granivorous ground beetle

The electrophysiological response of chemoreceptor neurones from the antennal chaetoid taste sensilla of the omnivorous ground beetle Pterostichus oblongopunctatus to several plant alkaloids and glucosides is investigated. A quinine‐sensitive neurone responding to quinine and quinine hydrochloride is found, most probably related to the granivorous feeding habit of P. oblongopunctatus. The response to quinine hydrochloride is concentration‐dependent at 0.001–50 mm , with the response threshold at 0.01 mm and a maximum rate of firing of 67 spikes/s at 50 mm . The stimulatory effect of caffeine is very weak, where the firing rate increases by only 1.4 spikes/s at a concentration of 10 mm compared with that evoked by a control stimulus. In addition, both quinine and quinine hydrochloride strongly inhibit spike production by the salt‐ and pH‐sensitive neurones when presented in mixtures with 10 mm NaCl. Several tested plant secondary compounds (i.e. salicin, sinigrin, caffeine and nicotine), which have only little or no effect on the firing rate of the quinine‐sensitive neurone, greatly reduce the responses of the salt‐ and pH‐sensitive neurones. The results of the present study suggest that the antennal taste sensilla of P. oblongopunctatus may detect plant defensive compounds both through the activation of a quinine‐sensitive neurone and via peripheral inhibition of other chemoreceptor neurones of the taste sensillum.     

Disulfide bonds and disorder in granulin‐3: An unusual handshake between structural stability and plasticity

Granulins (GRNs) are a family of small (～6 kDa) proteins generated by the proteolytic processing of their precursor, progranulin (PGRN), in many cell types. Both PGRN and GRNs are implicated in a plethora of biological functions, often in opposing roles to each other. Lately, GRNs have generated significant attention due to their implicated roles in neurodegenerative disorders. Despite their physiological and pathological significance, the structure‐function relationships of GRNs are poorly defined. GRNs contain 12 conserved cysteines forming six intramolecular disulfide bonds, making them rather exceptional, even among a few proteins with high disulfide bond density. Solution NMR investigations in the past have revealed a unique structure containing putative interdigitated disulfide bonds for several GRNs, but GRN‐3 was unsolvable due to its heterogeneity and disorder. In our previous report, we showed that abrogation of disulfide bonds in GRN‐3 renders the protein completely disordered (Ghag et al., Prot Eng Des Sel 2016). In this study, we report the cellular expression and biophysical analysis of fully oxidized, native GRN‐3. Our results indicate that both E. coli and human embryonic kidney (HEK) cells do not exclusively make GRN‐3 with homogenous disulfide bonds, likely due to the high cysteine density within the protein. Biophysical analysis suggests that GRN‐3 structure is dominated by irregular loops held together only by disulfide bonds, which induced remarkable thermal stability to the protein despite the lack of regular secondary structure. This unusual handshake between disulfide bonds and disorder within GRN‐3 could suggest a unique adaptation of intrinsically disordered proteins towards structural stability.     

Peripheral coding of bitter taste in Drosophila

Taste receptors play a crucial role in detecting the presence of bitter compounds such as alkaloids, and help to prevent the ingestion of toxic food. In Drosophila, we show for the first time that several taste sensilla on the prothoracic legs detect bitter compounds both through the activation of specific taste neurons but also through inhibition of taste neurons activated by sugars and water. Each sensillum usually houses a cluster of four taste neurons classified according to their best stimulus (S for sugar, W for Water, L1 and L2 for salts). Using a new statistical approach based on the analysis of interspike intervals, we show that bitter compounds activate the L2 cell. Bitter-activated L2 cells were excited with a latency of at least 50 ms. Their sensitivity to bitter compounds was different between sensilla, suggesting that specific receptors to bitter compounds are differentially expressed among L2 cells. When presented in mixtures, bitter compounds inhibited the responses of S and W, but not the L1 cell. The inhibition was effective even in sensilla where bitter compounds did not activate the L2 cell, indicating that bitter compounds directly interact with the S and W cells. Interestingly, this inhibition occurred with latencies similar to the excitation of bitter-activated L2 cells. It suggests that the inhibition in the W and S cells shares similar transduction pathways with the excitation in the L2 cells. Combined with molecular approaches, the results presented here should provide a physiological basis to understand how bitter compounds are detected and discriminated.     

Taste sensitivity and divergence in host plant acceptance between adult females and larvae of Papilio hospiton

On the island of Sardinia the lepidopteran Papilio hospiton uses Ferula communis as exclusive host plant. However, on the small island of Tavolara, adult females lay eggs on Seseli tortuosum, a plant confined to the island. When raised in captivity on Seseli only few larvae grew beyond the first–second instar. Host specificity of lepidopterans is determined by female oviposition preferences, but also by larval food acceptance, and adult and larval taste sensitivity may be related to host selection in both cases. Aim of this work was: (i) to study the taste sensitivity of larvae and ovipositing females to saps of Ferula and Seseli; (ii) to cross‐compare the spike activity of gustatory receptor neurons (GRNs) to both taste stimuli; (iii) to evaluate the discriminating capability between the two saps and determine which neural code/s is/are used. The results show that: (i) the spike responses of the tarsal GRNs of adult females to both plant saps are not different and therefore they cannot discriminate the two plants; (ii) larval L‐lat GRN shows a higher activity in response to Seseli than Ferula, while the opposite occurs for the phagostimulant neurons, and larvae may discriminate between the two saps by means of multiple neural codes; (iii) the number of eggs laid on the two plants is the same, but the larval growth performance is better on Ferula than Seseli. Taste sensitivity differences may explain the absence of a positive relationship between oviposition preferences by adult females and plant acceptance and growth performance by larvae.     

Bitter substances suppress afferent responses to an appetitive mixture: Evidence for peripheral integration of chemosensory stimuli

The processes that lead from detection of chemicals, transduction, and coding with the appropriate message to initiate ingestion of a palatable meal or to reject a potentially noxious substance are poorly understood in vertebrates owing to the complex organization of the taste system. As a first step in elucidating the cellular basis of the behavioral differences elicited by appetitive stimuli and bitter compounds, we recorded from the afferent nerves conveying peripheral chemosensory information to the CNS in the head of the leech, Hirudo medicinalis. Superfusion of the chemosensory region of the lip of Hirudo with a mixture of NaCl (150 mM) and arginine (1 mM), an appetitive solution that elicits ingestion, increased the neuronal activity in the afferent cephalic nerves, for example (Zhang X, Wilson RJ, Li Y, Kleinhaus AL. 2000. Chemical and thermal stimuli have short‐lived effects on the Retzius cell in the medicinal leech. J Neurobiol 43:304–311.). In the present paper we show that superfusing the lip with quinine or denatonium reduced the basal neural activity in the afferents. Furthermore, these bitter substances in the appetitive solution counteracted the increased activity the appetitive solution evoked in the cephalic nerves. Thus, the neural activity evoked by the application of appetitive and aversive stimuli to the chemosensory area of the lip paralleled the opposite behavioral responses to the same chemicals. The results suggest that individual leech taste cells possess receptors for both types of stimuli. Therefore, the leech may be a good model system in which to study peripheral taste events in cells that may possess multiple receptors and transduction mechanisms that interact to integrate information. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 255–263, 2001     

Scanning ion‐selective electrode technique and X‐ray microanalysis provide direct evidence of contrasting Na+ transport ability from root to shoot in salt‐sensitive cucumber and salt‐tolerant pumpkin under NaCl stress

Grafting onto salt‐tolerant pumpkin rootstock can increase cucumber salt tolerance. Previous studies have suggested that this can be attributed to pumpkin roots with higher capacity to limit the transport of Na⁺ to the shoot than cucumber roots. However, the mechanism remains unclear. This study investigated the transport of Na⁺ in salt‐tolerant pumpkin and salt‐sensitive cucumber plants under high (200 mM) or moderate (90 mM) NaCl stress. Scanning ion‐selective electrode technique showed that pumpkin roots exhibited a higher capacity to extrude Na⁺, and a correspondingly increased H⁺ influx under 200 or 90 mM NaCl stress. The 200 mM NaCl induced Na⁺/H⁺ exchange in the root was inhibited by amiloride (a Na⁺/H⁺ antiporter inhibitor) or vanadate [a plasma membrane (PM) H⁺‐ATPase inhibitor], indicating that Na⁺ exclusion in salt stressed pumpkin and cucumber roots was the result of an active Na⁺/H⁺ antiporter across the PM, and the Na⁺/H⁺ antiporter system in salt stressed pumpkin roots was sufficient to exclude Na⁺. X‐ray microanalysis showed higher Na⁺ in the cortex, but lower Na⁺ in the stele of pumpkin roots than that in cucumber roots under 90 mM NaCl stress, suggesting that the highly vacuolated root cortical cells of pumpkin roots could sequester more Na⁺, limit the radial transport of Na⁺ to the stele and thus restrict the transport of Na⁺ to the shoot. These results provide direct evidence for pumpkin roots with higher capacity to limit the transport of Na⁺ to the shoot than cucumber roots.     

Sodium chloride stress induces nitric oxide accumulation in root tips and oil body surface accompanying slower oleosin degradation in sunflower seedlings

Present work highlights the involvement of endogenous nitric oxide (NO) in sodium chloride (NaCl)‐induced biochemical regulation of seedling growth in sunflower (Helianthus annuus L., cv. Morden). The growth response is dependent on NaCl concentration to which seedlings are exposed, they being tolerant to 40 mM NaCl and showing a reduction in extension growth at 120 mM NaCl. NaCl sensitivity of sunflower seedlings accompanies a fourfold increase in Na⁺/K⁺ ratio in roots (as compared to that in cotyledons) and rapid transport of Na⁺ to the cotyledons, thereby enhancing Na⁺/K⁺ ratio in cotyledons as well. A transient increase in endogenous NO content, primarily contributed by putative NOS activity in roots of 4‐day‐old seedlings subjected to NaCl stress and the relative reduction in Na⁺/K⁺ ratio after 4 days, indicates that NO regulates Na⁺ accumulation, probably by affecting the associated transporter proteins. Root tips exhibit an early and transient enhanced expression of 4,5‐diaminofluorescein diacetate (DAF‐2DA) positive NO signal in the presence of 120 mM NaCl. Oil bodies from 2‐day‐old seedling cotyledons exhibit enhanced localization of NO signal in response to 120 mM NaCl treatment, coinciding with a greater retention of the principal oil body membrane proteins, i.e. oleosins. Abolition of DAF positive fluorescence by the application of specific NO scavenger [2‐phenyl‐4,4,5,5‐tetramethyllimidazoline‐1‐oxyl‐3‐oxide (PTIO)] authenticates the presence of endogenous NO. These novel findings provide evidence for a possible protective role of NO during proteolytic degradation of oleosins prior to/accompanying lipolysis.     

K+ and Ca++ in the receptor lymph of arthropod cuticular mechanoreceptors

Summary Two types of cuticular strain detectors, the campaniform sensilla on the haltere of the blowfly,Calliphora vicina, and the slit sensilla on the tibia of the spider,Cupiennius salei, were investigated. In campaniform sensilla a transepithelial voltage (43.6±10.7 mV), which depends on an intact metabolism, occurs. In spider slit sensilla no transepithelial voltage exists. The occurrence and the lack of a transepithelial voltage is paralleled with differences in the ionic composition of the receptor lymph in the two arthropod sensilla. We used double-barrelled ion-selective microelectrodes to measure potassium and calcium content in the receptor lymph with respect to the hemolymph. The potassium concentration in campaniform sensilla (121±15 mM) is five times larger than that of the wing hemolymph (25±7 mM) and nine times larger than that of the haltere hemolymph (13±3 mM). These differences are statistically significant. The calcium concentration in campaniform sensilla (0.8±0.5 mM) does not differ significantly from that of the hemolymph (1.2±0.7 mM). In spider slit sensilla no significant difference occurs between the potassium concentration of the receptor lymph (9.5 mM±5.5 mM) and that of the hemolymph (8±3 mM). The calcium concentration of the hemolymph (1.6±0.9mM) is 3 times higher than that of the receptor lymph (0.6±0.3 mM). This difference is significant.Abbreviation TEV transepithelial voltage     

Cross-talk between salicylic acid and NaCl-generated reactive oxygen species and nitric oxide in tomato during acclimation to high salinity

Hydrogen peroxide (H₂O₂) and nitric oxide (NO) generated by salicylic acid (SA) are considered to be functional links of cross‐tolerance to various stressors. SA‐stimulated pre‐adaptation state was beneficial in the acclimation to subsequent salt stress in tomato (Solanum lycopersicum cv. Rio Fuego). At the whole‐plant level, SA‐induced massive H₂O₂ accumulation only at high concentrations (10^?3–10^?2M), which later caused the death of plants. The excess accumulation of H₂O₂ as compared with plants exposed to 100 mM NaCl was not associated with salt stress response after SA pre‐treatments. In the root tips, 10^?3–10^?2M SA triggered the production of reactive oxygen species (ROS) and NO with a concomitant decline in the cell viability. Sublethal concentrations of SA, however, decreased the effect of salt stress on ROS and NO production in the root apex. The attenuation of oxidative stress because of high salinity occurred not only in pre‐adapted plants but also at cell level. When protoplasts prepared from control leaves were exposed to SA in the presence of 100 mM NaCl, the production of NO and ROS was much lower and the viability of the cells was higher than in salt‐treated samples. This suggests that, the cross‐talk of signalling pathways induced by SA and high salinity may occur at the level of ROS and NO production. Abscisic acid (ABA), polyamines and 1‐aminocyclopropane‐1‐carboxylic acid, the compounds accumulating in pre‐treated plants, enhanced the diphenylene iodonium‐sensitive ROS and NO levels, but, in contrast to others, ABA and putrescine preserved the viability of protoplasts.     

Effect of salinity on growth of four strains of Rhizobium and their infectivity and effectiveness on two species of Acacia

Two Rhizobium strains (WU1001 and WU1008) were isolated from nodules of Acacia redolens growing in saline areas of south-west Australia, and two strains selected from the University of Western Australia's culture collection (WU429 isolated from A. saligna and WU433 from A. cyclops). The growth of each in buffered, yeast extract mannitol broth culture was largely unaffected by salt up to 300 mM NaCl. A slight increase in lag time occurred at concentrations of 120 mM NaCl and above, but cell number at the static phase was not affected. Each of the four Rhizobium strains tested accumulated Na⁺ but showed decreasing levels of sugar with increasing salt in the external medium. Amino acid levels also increased, in some cases by more than tenfold. However, the relative proportion of each remained fairly constant in the bacteria, irrespective of salt treatment. Only trace quantities of proline were detected and there was no increase in this amino acid with salt. Acidic amino acids (glutamate and aspartate) remained as a constant proportion.Rhizobium strains WU429, WU1001 and WU1008 produced effective nodules on both A. cyclops and A. redolens grown in sand with up to 80 mM NaCl (added in nutrient solutions free of nitrogen). Strain WU433 was highly infective on both Acacia species tested at low salt concentrations (2–40 mM NaCl), but infection was sensitive to salt levels at 120 mM NaCl and above. Nodules formed with strain WU433 were, however, ineffective on both A. redolens and on A. cyclops and showed nil or negligible rates of acetylene reduction at all salt concentrations. Strains WU429, WU1001 and WU1008 in combination with a highly salt-tolerant provenance of A. redolens formed symbioses which did not vary significantly in nodule number and mass, specific nodule activity or total N content irrespective of salt level up to 160 mM NaCl. On a more salt sensitive provenance of A. redolens and on A. cyclops the infectivity and effectivity of the Rhizobium strains tested usually decreased as the external salt concentration increased. These data are interpreted to indicate that tolerance of the legume host was the most important factor determining the success of compatible Rhizobium strains in forming effective symbioses under conditions of high soil salinity.     

棉铃虫幼虫对人类呈味物质的取食反应

利用叶碟法在室内测定了棉铃虫对人类酸、甜、苦、咸4种基本呈味物质和麻、辣味2种植物提取物的取食反应。正交试验结果表明,棉铃虫幼虫对用甜味、苦味和辣味物质(蔗糖、奎宁和辣椒提取物)处理过的烟叶取食选择率较高,对这3种呈味物质表现出有较好的适应性;而幼虫对咸味、酸味和麻味物质(氯化钠、柠檬酸和花椒提取物)处理过的烟叶取食量较少,这3种呈味物质表现出较强的拒食活性。在选择性条件下,幼虫的取食量与花椒提取物剂量显著相关;而在非选择性条件下,幼虫的取食量与氯化钠剂量显著相关。     

Salt‐stress induced modulation of chlorophyll biosynthesis during de‐etiolation of rice seedlings

Chlorophyll biosynthesis in plants is subjected to modulation by various environmental factors. To understand the modulation of the chlorophyll (Chl) biosynthesis during greening process by salt, 100–200 mM NaCl was applied to the roots of etiolated rice seedlings 12 h prior to the transfer to light. Application of 200 mM NaCl to rice seedlings that were grown in light for further 72 h resulted in reduced dry matter production (–58%) and Chl accumulation (–66%). Ionic imbalance due to salinity stress resulted in additional downregulation (41–45%) of seedling dry weight, Chl and carotenoid contents over and above that of similar osmotic stress induced by polyethylene glycol. Downregulation of Chl biosynthesis may be attributed to decreased activities of Chl biosynthetic pathway enzymes, i.e. 5‐aminolevulinic acid (ALA) dehydratase (EC‐2.4.1.24), porphobilinogen deaminase (EC‐4.3.1.8), coproporphyrinogen III oxidase (EC‐1.3.3.3), protoporphyrinogen IX oxidase (EC‐1.3.3.4), Mg‐protoporphyrin IX chelatase (EC‐6.6.1.1) and protochlorophyllide oxidoreductase (EC‐1.3.33.1). Reduced enzymatic activities were due to downregulation of their protein abundance and/or gene expression in salt‐stressed seedlings. The extent of downregulation of ALA biosynthesis nearly matched with that of protochlorophyllide and Chl to prevent the accumulation of highly photosensitive photodynamic tetrapyrroles that generates singlet oxygen under stress conditions. Although, ALA synthesis decreased, the gene/protein expression of glutamyl‐tRNA reductase (EC‐1.2.1.70) increased suggesting it may play a role in acclimation to salt stress. The similar downregulation of both early and late Chl biosynthesis intermediates in salt‐stressed seedlings suggests a regulatory network of genes involved in tetrapyrrole biosynthesis.     

Differential growth of some grapevine varieties in Syria in response to salt <Emphasis Type="Italic">in vitro</Emphasis>

Summary Growth sensitivity of four local grapevine (Vitis vinifera) varieties, Ashlamesh, Helwani, Kassofee, and Khoudeiry, were evaluated for salt. They were cultured on DSD1 medium until rooting stage, then they were transferred to a liquid DSD1 medium containing 0, 10, 20, 30, 40, 80, 120, or 150 mM NaCl for 30 d. The shoot length and leaf number of Ashlamesh, Helwani, and Kassofee were significantly increased at 10 and/or 30 mM NaCl, whereas, 150 mM NaCl decreased shoot length of all varieties except Kassofee. The presence of NaCl at 80 mM or higher concentrations decreased the chlorophyll content and root number of all varieties, while 30 mM NaCl increased root number of Kassofec.