N<Subscript>2</Subscript>-fixation along a gradient of long-term disturbance in tropical mangroves bordering the gulf of Mexico

Microbial processes are key elements in determining the productivity of mangroves, and reductions in these processes reflect the loss of microbial biodiversity and function due to fabricated disturbances. Because nitrogen is a major limiting nutrient for the productivity of these ecosystems, the goal of this study was to determine profiles of inorganic nitrogen combined with several environmental parameters, all in relation to the degree of long-term hydraulic impairment of a tropical, monospecific black mangrove (Avicennia germinans) forest that showed degradation ranging from total loss of mangrove cover to no disturbance. N₂-fixation, oxygen levels, and nitrite contents decreased significantly with the severity of the disturbance, and almost null levels were reached in the completely degraded zone, whereas salinity achieved very high values. Concomitantly, total N, ammonium, and P contents and ammonia volatilization increased significantly. Pore-water temperature and pH increased moderately. Other soil physical properties (sand, silt, clay, organic matter, and total C), which varied among the sampling sites, were not correlated with the level of disturbance. Principal component analyses, including environmental and biological parameters, suggested that the most significant finding was the considerable loss of N₂-fixation with increasing impairment, which was concomitant with significant increases in volatilization of ammonia and salinity. The results show that microbial N-cycling processes are highly sensitive to salinity and to man-made disturbances that modify the water level and flow.     

Preliminary studies on the salt tolerance and sodium relations of common ornamental plants

The salinity tolerance of local varieties of five ornamental species Begonia, Chlorophytum, Coleus, Geranium, and Mesembryanthemum was assessed in a medium term pot experiment. The pot grown plants were watered for 50 days with water salinised at 5 dS/m and 15 dS/m and a tap water control. Based on growth parameters and on survival, Begonia was classified as salt sensitive, Coleus, Geranium, and Chlorophtytum as moderately tolerant, and Mesembry‐ anthemum as salt tolerant. Shoot sodium (Na) content was measured at the end of the experiment. It appears that the restriction of Na entry to the shoot is linked to salinity tolerance. Mesembryanthemum seems to be able to control Na entry to the shoot at water salinities above 5 ds/m.     

Mangroves as indicators of coastal change

In view of the unique biological characteristics of mangroves, it is interesting to assess the extent to which these ecosystems can be used as indicators of coastal change or sea-level rise. From recent studies of mangrove mortality at several locations (including Guiana, Gambia, Côte d'Ivoire, Kenya, India and Bangladesh), it appears that these coastal ecosystems are so specialized that any minor variation in their hydrological or tidal regimes causes noticeable mortality. Each species of mangrove (but particularly those belonging to the genera Rhizophora, Bruguiera, Sonneratia, Heritiera and Nypa) occurs in ecological conditions that approach its limit of tolerance with regard to salinity of the water and soil, as well as the inundation regime. If the duration of daily immersion were to be modified by tectonic, sedimentological or hydrological events, the species either readjusts to the new conditions or succumbs to unsuitable conditions. Consequently, the use of remote sensing data for mangrove ecosystems offers excellent potential as a tool for monitoring coastal change.     

不同矿化度咸水在滨海典型植被盐碱地中的入渗特性研究

基于滨海盐碱区典型植被白茅、盐地碱蓬和裸地的土壤性状调查,开展了不同矿化度咸水(0、5、10 g/L)在上述典型地块中的水分入渗试验,以分析滨海盐碱区典型植被对土壤结构特征、咸水入渗特性、水盐分布规律的影响.结果表明:①裸地、盐地碱蓬地和白茅地土壤容重和含盐量依次降低、土壤大粒径水稳性团聚体含量依次增加;②同一地块初始...     

Improvement in the Adaptation of Lygeum Spartum L. to Salinity In the Presence of Calcium

Lygeum spartum L. has been recently introduced in areas where salinity is high in soils. However, there are no studies about the physiological response of these plants to salt excess. The effect of sodium chloride (NaCl) on plant growth and water status was studied. Also, the effect of calcium (Ca) addition to salinity conditions was analyzed because of the coexistence of salinity and calcareous soils. Dry weight (DW), transpiration, and osmotic potential (Ψπ) decreased with elevated NaCl and were restored with Ca²⁺, whereas moderate salinity had no effect. Fresh weight (FW), water potential (Ψω), and root hydraulic conductance (L ₀) decreased with salinity; Ca²⁺ supply had an ameliorative effect at moderate salinity. Sodium (Na⁺) increased in leaf sap at high levels of NaCl and was decreased by Ca²⁺. Lygeum spartum showed a resistance to moderate salinity, but the effect of Ca²⁺ depends on salinity intensity. Thus, the role of Ca²⁺ in the tolerance to salinity was emphasized.     

Effects of salinity and flooding on the infectivity of salt marsh arbuscular mycorrhizal fungi in<Emphasis Type="Italic"> Aster tripolium</Emphasis> L.

Salt marshes are characterized by the occurrence of combined salinity and flooding stresses. The individual and combined effects of salinity and flooding on the establishment and activity of arbuscular mycorrhizal (AM) colonization in the salt marsh halophyte Aster tripolium L. by indigenous salt marsh AM fungi were evaluated. A. tripolium plants were cultivated in a mixture of sand and salt marsh soil under different salinity concentrations (5%, 50% or 100% artificial seawater) and water regimes (non-flooding, tidal flooding and continuous flooding). Plants were harvested after 3 and 8 weeks and their growth was negatively influenced by increased salinity and water level. Increased salinity level affected the establishment of AM colonization, AM fungal growth and activity (measured as succinate dehydrogenase activity) within roots, and extraradical mycelium growth. The influence of flooding on the establishment of colonization and on intra- and extraradical AM fungal growth was dependent on the water regime. Continuous flooding reduced colonization and AM fungal growth, whereas tidal flooding did not affect these parameters unless combined with intermediate salinity level (50% seawater) at the end of the experiment. The water regime did not influence AM active colonization. The ratio of root to soil AM fungal growth increased as the water level increased. The results of this study demonstrate that the establishment and activity of AM colonization in A. tripolium is more influenced by salinity than by flooding, and suggests that the functionality of salt marsh AM fungi is not affected by flooding.     

EFFECT OF SALINITY ON SEEDLING EMERGENCE OF PROTEA COMPACTA,P. CYNAROIDES,AND P. MAGNIFICA (PROTEACEAE)

Protea compacta, P. cynaroides, and P. magnifica, South African protea species cultivated for cut flowers, were tested in order to determine their salinity tolerance at seedling emergence. The seeds were sown in a mixture of peat-moss and volcanic ash (1:1 v/v). Five water salinity levels (0.5, 1.7, 2.7, 4.8 and 8.2 dS m^?1 for P. cynaroides, and 0.2, 1.3, 2.4, 4.7 and 8.5 dS m^?1 for P. compacta and P. magnifica) were imposed by irrigating with water that contained sodium chloride (NaCl) and calcium chloride (CaCl₂) (normal ratio 2:1). In the Tenerife coastal area, water from wells has a similar or higher sodium (Na)/ calcium (Ca) ratio. Seedling emergence percentages and rates (speed of emergence) were measured. In general, the increased salinity caused a decrease in the percentage of seedling emergence and retarded the emergence process. With regard to seedling emergence rates, the species that showed a greater salinity tolerance was P. cynaroides which had a salinity tolerance index (ST-Index) of 7.93, followed by P. compacta and P. magnifica with ST-Indices of 5.93 and 5.08, respectively. With regard to the seedling emergence percentages, the species that showed a greater salinity tolerance was P. cynaroides which had a ST-Index of 8.01, followed by P. compacta and P. magnifica, with ST-Indices of 7.91 and 6.39, respectively. The calculation of the ST-Indices using the electrical conductivity of the saturated soil extract (EC_e) allowed us to observe that, at seedling emergence, P. compacta, P. cynaroides, and P. magnifica are moderately sensitive to salinity.     

Water deficit and abscisic acid production of Salicornia bigelovii under salinity stress

We investigated the mechanism of growth reduction of dicotyledonous halophyte Salicornia bigelovii under salinity stress by growing it at 0.005 to 500?mol?m^?3 sodium chloride (NaCl). The optimal range for growth of S. bigelovii was between 50 and 200?mol?m^?3 NaCl. A significant correlation was found between growth and water content, which indicated that water deficit was an important factor in growth reduction at both suboptimal and supraoptimal salinities. Abscisic acid (ABA) concentration of the shoot was negatively related to growth and water content, which suggested that ABA induced by water deficit may inhibit growth at both the suboptimal and supraoptimal salinities. The cause of water deficit at supraoptimal salinity might be caused by nutritional imbalance and osmotic stress due to the low osmotic potential of the external solution. However, limited salt uptake may be one of the causes of water deficit under suboptimal salinity. We discuss a sodium ion (Na⁺) specific deficit rather than salt deficit as another possible cause of water deficit.     

EFFECTS OF WATER SALINITY ON GROWTH INDICES AND PHYSIOLOGICAL PARAMETERS IN SOME PISTACHIO ROOTSTOCKS

Pistachio is one of the most important horticultural crops in Iran. The majority of the pistachio producing regions is located in arid and semi-arid areas with saline conditions. Therefore, selection of suitable rootstocks is important for increasing yield efficiency of this important nut crop. In this study, the effect of four water salinity levels (0.75, 5, 10 and 15 ds m^?1) on growth indices and physiological parameters of four Pistacia vera L. rootstocks (Badami-e-Zarand A, Badami-e-Zarand B, Qazvini, and Sarakhs) were investigated under greenhouse conditions. After treatment for three months, leaf dry weight was reduced by about 30-50% at an irrigation water electrical conductivity (EC_w) of 10 ds m^?1. Badami-e-Zarand B was the most vigorous rootstock at the highest EC. Decreases in root and stem dry weight (average of all rootstocks combined) occurred at water salinity of 10 ds m^?1. Chemical analysis of shoot and root indicated that the salinity affected the concentration and distribution of sodium (Na⁺), potassium (K⁺), and calcium (Ca²⁺) in pistachio rootstocks. The concentrations of Na⁺ and K⁺ increased with a rise in water salinity levels. Comparison between Na⁺ concentration of shoot and root showed that all examined rootstocks limited the Na⁺ transportation to shoot tissue up-to 15 ds m^-1, and retained it in the roots. However, this ability was less in the Sarakhs rootstock. Based on measured parameters, Badami-e-Zarand B and Sarakhs could be considered as tolerant and sensitive pistachio rootstocks to water salinity, respectively.     

科尔沁沙地南缘樟子松人工林对土壤水盐的影响

为掌握科尔沁沙地南缘樟子松造林40多年对土壤水分、盐度的影响。以科尔沁沙地樟子松林地、草地2020年3月至2021年11月土壤、气象数据为基础，采用双累积曲线法(DCM)验证样地选取的合理性，利用空间代替时间法(STM)研究樟子松林地、草地土壤含水量、盐度的变化规律，以及与气象因子关系的差异。樟子松林地改变了土壤纵向剖面水分、盐度分布规律，二者均趋于正“S”形分布；林地有效提高土壤储水量(p<0.05),降低土壤盐度，缩减水分次活跃层范围；林地土壤水分变异性更高(p<0.05),盐度变异性更低(p>0.05);林地的气象因子与土壤水分、盐度指标各分项之间关联程度与草地不同，减弱与降雨的相关性，增加与水汽压亏缺的相关系数。樟子松林生态系统具有较强的涵养水源、抑制土壤盐渍化的功能。     

毛乌素沙地煤矿开采对植被景观的影响

毛乌素沙地气候干燥,水资源短缺,生态环境十分脆弱,对各种人为扰动极为敏感。该地区煤炭资源的开采势必会增加当地环境负担,使得生态环境恶化。以陕西省神木县大保当煤矿为例,通过实地调查,在查明自然植被种类、类型和分布的基础上,借助地理信息系统技术与地表沉陷预测模型,对煤矿开采造成的植被景观格局变化进行了预测,并分析了斑块数、形状指数、多样性指数等指标。结果表明,煤矿开采后矿区景观破碎度上升,斑块形状复杂化,景观异质性降低,植被生物量减少。矿区植被类型发生变化,原先以叉子圆柏(Sabina vulgaris)、北沙柳(Salix psammophila)、斜茎黄耆(Astragalus adsurgens)为优势种的灌木丛向以黑沙蒿(Artemisia ordosica)为优势种的灌草丛转化。从矿区整体变化程度来看,煤矿开采对区域自然生态系统存在一定的干扰,但未造成其根本性改变,自然生态系统仍存在一定的恢复和调控能力,应采取一系列生物与工程措施引导矿区生态环境向可持续方向发展。     

Effect of Salinity on Seedling Emergence of Seven Banksia Species Cultivated for Cut Flower and Foliage

ABSTRACT

Seven Banksia species were tested in order to determine their salinity tolerance at seedling emergence. Five water salinity levels (0.5, 1.7, 2.7, 4.8, and 8.2 dS m^?1 for B. burdettii, B. hookeriana, B. menziesii, and B. victoriae; and 0.2, 1.3, 2.4, 4.7, and 8.5 dS m^?1 for B. coccinea, B. occidentalis, and B. speciosa) were imposed by irrigating with water that contained sodium chloride (NaCl) and calcium chloride (CaCl₂) (normal ratio 2:1). With regards to seedling emergence rates, the species that showed greater salinity tolerance were B. menziesii and B. occidentalis. With regards to the seedling emergence percentages, B. speciosa was the most salinity-tolerant. The calculation of the thresholds expressed as electrical conductivity of saturated soil extract gave that, at seedling emergence, B. speciosa and B. occidentalis are moderately tolerant to salinity, B. menziesii, B. coccinea, and B. hookeriana are moderately sensitive to salinity, and B. burdettii and B. victoriae are sensitive to salinity.     

Effect of salt stress on photosynthesis and related physiological characteristics of Lycium ruthenicum Murr

Halophytes could withstand the hyper-salinity soil and survive widely in areas where soil salt content is high because they can endure salt stress to a certain extent. Lycium ruthenicum Murr (LRM), with significant nutritional and medicinal values, is one of the most important native halophytes in the arid oasis-desert transition zone of northwestern China. In recent years, artificially planting LRM has been being popular since it can improve saline-alkalized soil and increase the income of local farmers as well. More efforts about the artificial planting of LRM are put in enhancing the productivity and quality, but survivorship of LRM seedling by appropriate saline irrigation is still unclear in arid areas. A field experiment was conducted to explore the responses of LRM to four levels of saline water irrigation (Ec of irrigation water: 2.00?μs?cm^?1 (T₁), 4.51?μs?cm^?1 (T₂), 6.89?μs?cm^?1 (T₃), and 9.00?μs?cm^?1 (T₄)) during the growing seasons in 2014 and 2015. The average soil electrical conductivity (Ec_a) in 0–60 cm depth increased while the biomass of LRM decreased with increasing Ec of irrigation water, and the differences of Ec_a among treatments decreased with increasing salinity level. In contrast to previous research findings, salt stress had more significant effect on photosynthesis and chlorophyll fluorescence of LRM, in which great changes were caused by a threshold following the increased salinity. Most of the light energy absorbed by LRM was used for photosynthesis and heat dissipation when soil salinity was low, what was used for chlorophyll fluorescence when soil salinity was high. The results of the experiment indicate that T₂ was the most suitable irrigation method for artificially planting LRM in the field, and it’s the key to save freshwater resources in arid areas and improve the production of saline-alkali land.     

Interactive Effects of Salinity and ZnO Nanoparticles on Physiological and Molecular Parameters of Rapeseed (Brassica napus L.)

Salinity is considered as the main factor limiting the yield of crops in arid and semi-arid regions. There are still many uncertainties about the nanotechnology and its potential applications, as well as doubts about its efficacy and safety in the long term. The aim of this study was to examine the alleviative effects of ZnO NPs (nanoparticles) (0, 20 and 80 mgL^?1) on toxicity damage caused by NaCl (0, 50 and 100 mM) at physiological and molecular parameters in Rapeseed. Rapeseed plants were treated at the rosette stage by different levels of salinity and ZnO NPs based on a completely randomized design (CRD) with three replications. At the physiological level, salinity stress significantly increased root ion leakage and decreased relative water content (RWC), stomata density and Hill reaction while application of ZnO NPs improved Hill reaction, and reduced ion leakage. At the molecular level, salinity stress significantly reduced the expression of ARP, MYC and SKRD2 genes compared to non-stressed plants while MPK4 gene expression increased under a high level of NaCl imposition. Foliar spraying of ZnO NPs considerably decreased the expression of MYC, MPK4, and SKRD2 genes and increased the expression of the ARP gene. It can be concluded that ZnO NPs had the ability to reduce the toxicity created under salinity stress at the optimal concentration (20 mgL^?1) in rapeseed and could play an important role in increasing the resistance of rapeseed plants to salinity stress.     

Seagrass beds and mangroves as potential nurseries for the threatened Indo-Pacific humphead wrasse, Cheilinus undulatus and Caribbean rainbow parrotfish, Scarus guacamaia

The importance of seagrass beds and mangroves as a juvenile habitat as opposed to other shallow water habitat types is investigated using a single sampling method on four islands in the western Indian Ocean for Cheilinus undulatus, and on one island in the southern Caribbean Sea for Scarus guacamaia. Both species occur on the Red list of threatened species. Juveniles of Cheilinus undulatus were predominantly found on seagrass beds while adults were limited to the coral reef. The presence of seagrass beds resulted in significantly higher densities of the species on coral reefs in front of these habitats, indicating the importance of seagrass beds as a juvenile habitat. For Scarus guacamaia, juveniles were exclusively observed in mangroves while adults only occurred on the coral reef. Adult S. guacamaia occurred on all coral reefs along the sheltered coast of the island containing mangroves, but no relationship with distance to mangroves was observed. This could indicate the importance of mangroves for the occurrence of adults of this species on the scale of an entire island.     

利用15N揭示滴灌区盐旱胁迫对土壤氮素分布与棉花生长的影响

为了探究盐旱胁迫对土壤中氮素分布和棉花生长的影响,通过测坑试验研究滴灌区不同盐分、干旱条件下土壤全氮、硝氮、氨氮的分布和棉花生长情况。试验设置3种盐分梯度的土壤（电导率,EC）：3,6,9 dS/m,分别用T1、T2、T3表示;3个灌水量：2 700,3 600,4 500 m³/hm²,分别用W1、W2、W3表示（4 500 m³/hm²为当地推荐灌水量）。结果表明：当土壤盐分梯度> 3 dS/m时土壤全氮累积量显著高于低盐土壤（P<0.05）,且土壤盐分对棉花花期生长影响较大。土壤的氨氮挥发量和土壤盐分梯度成正比。土壤硝态氮的淋失与灌水量呈正比,与正常灌水量的硝态氮淋失相比,水分胁迫对棉花产量的影响更为严重（P<0.01）。随土层深度的增加,土壤碱解氮以每20 cm土层8%的速度减少。各处理土壤¹⁵N残留率为11%~40%,随土壤盐度增加而增加,随灌水量增加而减少,与土壤全氮含量呈正比,与棉花产量呈反比。综上所述,T1W3处理更有利于棉花对氮肥的利用和产量的提高,推荐滴灌区棉花土壤盐度<3 dS/m,灌水量4 500 m³/hm²,可在花期适当提高施肥量以稳定产量。     

Mapping Slight and Moderate Saline Soils in Irrigated Agricultural Land Using Advanced Land Imager Sensor (EO-1) Data and Semi-Empirical Models

Around the world, especially in semi-arid regions, millions of hectares of irrigated agricultural land are abandoned each year because of the adverse effects of irrigation, mainly secondary salinity and sodicity. Accurate information about the extent, magnitude, and spatial distribution of salinity and sodicity will help create the sustainable development of agricultural resources. In Morocco, south of the Mediterranean region, the growth of the vegetation and potential yield are limited by the joint influence of high temperatures and water deficit. Consequently, the overuse of surface and ground water, coupled with agricultural intensification, generates secondary soil salinity. Knowing when, where, and how salinity may occur is very important to the sustainable development of any irrigated production system. Remedial actions require reliable information to help set priorities and to choose the type of action that is most appropriate in each situation. Ground-based electromagnetic measurements of soil electrical conductivity (EC) are generally accepted as the most effective method for quantification of soil salinity. Unfortunately, these methods are expensive, time consuming, and need considerable human resources for land surveying. Moreover, the dynamic nature of soil salinity in space and time makes it more difficult to use conventional methods for comparisons over large areas. A major challenge of remote sensing, as a potential alternative technique, is to detect different levels of soil salinity. The main aim of this research is to assess the potential of the Advanced Land Imager (ALI) sensor on board the Earth Observing-1 (EO-1) satellite, with its rich infrared bands, for the discrimination and mapping of slight and moderate soil salinity in the Tadla’s irrigated agricultural perimeter in Morocco. To achieve this goal, semi-empirical predictive models developed in a previous study using second order regression analysis between the EC of salt-affected soils and different spectral salinity indices were applied to the ALI image. This was atmospherically corrected and the radiometric sensor drift was calibrated. Visual comparisons and statistical validation of these models using ground truth were undertaken in order to identify the best semi-empirical model for slight and moderate salinity mapping. The obtained results show that the model based on the Normalized Difference Salinity Index (NDSI) does not give any results. The model based on the Salinity Index-1 (SI-1) and the SI-Advanced Space-borne Thermal Emission and Reflection Radiometer (SI-ASTER) confuses vegetation with high soil salinity, although the model does bring out areas of lower salinity. Both R² of 0.67 for the SI-1 and 0.65 for the SI-ASTER further reinforce that these models cause too much confusion to be used with accuracy for salt-affected soil detection. The semi-empirical model based on Soil Salinity and Sodicity Index-1 (SSSI-1) performs better than the two last models. However, there is a relative confusion between the classes in the slight and moderate salinity and in areas that are shown by the validation map; the higher class of salinity does not appear to contain higher levels of salinity. The statistical validation of this model reinforces what is seen on the derived map with only an R² = 0.68. The model based on the SSSI-2 clearly provides the best results in comparison to the ground truth. Its derived map gives the closest overall visual approximation of the EC map, with a whole range of values. With a statistical validation of R² = 0.97 to the ground truth, it is by far the best performance of any of the other models, and the different classes are statistically well separated, which further reinforces the accuracy of the visual analysis.     

Performance of some under‐explored crops under saline irrigation in a semiarid climate in Northwest India

Growing salt‐tolerant under‐explored crops utilizing saline ground water can provide for an economic use of abandoned semiarid lands. Field trials were conducted between 1999 and 2003 on a calcareous soil in a semiarid region of northwest India. Woody perennials were planted at the sill of furrows and irrigated with water of high salinity (EC 10–28 dS m⁻¹), low salinity (EC 5–9 dS m⁻¹) and alternately with these two waters. Woody species included Azadirachta indica, Cordia rothii, Salvadora persica, Jatropha curcas, J. gossipifolia, Ricinus communis, Catharanthus roseus, Adhatoda vasica and Aloe barbadensis. Most of these could be grown successfully but S. persica—a highly salt‐tolerant halophyte—though it produced huge biomass, could not yield mature fruit due to frost injury. The salinity build up in the soil was greater during low‐rainfall years, but a good rainfall year, e.g. 714 mm in 2001, helped to leach out the accumulated salts. The uptake of Na⁺ in plants was greater when irrigated with water of high salinity, while K⁺ accumulation was greater with water of low salinity. Na⁺ accumulation was higher in roots as compared to other parts except in Jatropha and Salvadora, while K⁺ accumulation was greater in leaves. There was a negative correlation between Na⁺ and K⁺ accumulation and a positive correlation between Ca²⁺ and Mg²⁺. Thus, saline water (ECiw 12 dS m⁻¹) can successfully be used for growing several under‐explored crops of high economic value. Copyright © 2006 John Wiley & Sons, Ltd.     

Salt tolerance of two lemon scions measured by leaf chloride and sodium accumulation

Effects of salinity on growth, ion content, water relationships, and chlorophyll and proline levels were measured on one‐year‐old ‘Verna’ and ‘Fino’ lemon (Citrus limon [L] Burm. F.) scions budded to either Sour orange (C. aurantium L.) or macrophylla (C. macrophylla Wester) rootstock. Trees were grown in nutrient solutions containing 2 (control), 40, or 80 mol m^‐3 NaCl for 75 days.

Growth of all combinations was reduced by salinity, but this effect was greater for both scions budded on macrophylla. Leaf chloride and sodium concentrations were lower in both scions budded on Sour orange. Leaf salt concentration was scion dependent. Leaves of ‘Fino’ lemon had higher levels of both chloride and sodium than did leaves of ‘Verna’ lemon, regardless of the rootstock considered.

Despite an accumulation of chloride and sodium in the leaves of salinized trees, leaf water potential and leaf water content increased above the control level. However, stomatal conductance declined in all rootstock/scion combinations.

Chlorophyll contents were markedly reduced by salt treatment; greater reductions were seen in ‘Fino’ lemon than in ‘Verna’ lemon on both rootstocks. Chlorophyll reductions were highly correlated with both chloride and sodium concentrations in the leaves. Free proline increased with salinity in leaves of both scions budded on Sour orange, but was unaffected on macrophylla.

Differences in the parameters determined in response to salinity were attributed to the different capacity of each specific rootstock/scion combination to import chloride and sodium into leaves.