Characterization of saline soil for the halophytes of largest inland saline wetland of India using geospatial technology

About 23%of the surface area and 44%of the volume of all the lakes are occupied by saline lakes in the world.Importantly,agricultural diversion,illegal encroachment,pollution,and invasive species could cause these lakes to dry up completely or partially by 2025.Illegal saltpan encroachment is causing Sambhar,India’s largest saline lake,to shrink by 4.23%every decade.This study aims to characterize the soil parameters where halophytes are growing.A literature survey was conducted for halophytes and soil characteristics.The study area was divided into four zones for stratified random sampling.Soil sampling was conducted in February 2021.The soil indicators for halophyte selected were pH,electrical conductivity,moisture,salinity,organic carbon,and organic matter.The obtained results were interpolated in the geospatial platform for soil characteristic mapping.It is found that no research is conducted on halophytes of the lake.Studies on soil are also inconsistent and only six common parameters could be identified.Results show that the pH ranged 9.37-7.66,electrical conductivity was 16.1-0.38,moisture 23.37%-1.2%,organic carbon 3.29%-0.15%,organic matter 5.6%-0.2%,and salinity 8.86%-0.72%.Though these results show improved condition as compared to last few years,in long term,the lake is desiccating.During the UN Decade of Ecosystem Restoration(2021-2030),if these causes are not addressed,the ecosystem may completely dry up.

Vertical Migrating and Cluster Analysis of Soil Mesofauna at Dongying Halophytes Garden in Yellow River Delta

For the first time, we used Tullgren method made a study on vertical migrating and cluster analysis of the soil mesofauna in Dongying Halophytes Garden in the Yellow River Delta （YRD）, Shandong Province. The results showed that the soil mesofauna tended to gather on soil surface in most samples at most times, but the vertical migrating greatly varied in different seasons or environment conditions. Acari was the dominant group. The index of diversity of the soil fauna was correlated with the index of evenness. The Acari＇s number of individuals infected other species and numbers. Dominant group-Aeari made greater contribution to the result of cluster analysis, and there were significant differences between communities in different habitats by cluster analysis with both Bray-Curtis and Jaccard similarity coefficient.

Diversity of cultivable endophytic bacteria associated with halophytes in Xinjiang of China and their plant beneficial traits

Endophytic bacteria from halophytes have a wide range of application prospects in various fields,such as plant growth-promoting,biocontrol activity and stress resistance.The current study aimed to identify cultivable endophytic bacteria associated with halophytes grown in the salt-affected soil in Xinjiang Uygur Autonomous Region,China and to evaluate their plant beneficial traits and enzyme-producing activity.Endophytic bacteria were isolated from Reaumuria soongorica(PalL Maxim.),Artemisia carvifolia(Buch.-Ham.ex Roxb.Hort.Beng.),Peganum harmala L.and Suaeda dendroides(C.A.Mey.Moq.)by using the cultural-dependent method.Then we classified these bacteria based on the difference between their sequences of 16S rRNA(16S ribosomal RNA)gene.Results showed that the isolated bacteria from R.soongorica belonged to the genera Brucella,Bacillus and Variovorax.The bacteria from A.carvifolia belonged to the genera Micromonospora and Brucella.The bacteria from P.harmala belonged to the genera Paramesorhizobium,Bacillus and Peribacillus.The bacteria from S.dendroides belonged to the genus Bacillus.Notably,the genus Bacillus was detected in the three above plants,indicating that Bacillus is a common taxon of endophytic bacteria in halophytes.And,our results found that about 37.50%of the tested strains showed strong protease-producing activity,6.25%of the tested strains showed strong cellulase-producing activity and 12.50%of the tested strains showed moderate lipase-producing activity.Besides,all isolated strains were positive for IAA(3-Indoleacetic acid)production,31.25%of isolated strains exhibited a moderate phosphate solubilization activity and 50.00%of isolated strains exhibited a weak siderophore production activity.Our findings suggest that halophytes are valuable resources for identifying microbes with the ability to increase host plant growth and health in salt-affected soils.

Evaluating germinability of eight desert halophytes under long-term seed storage: Implications for conservation

Ex situ conservation in seed banks is a potential complementary conservation strategy for native plant species.It is well established that ex situ seed banking of native wild plants prolongs seed viability and thereby preserves genetic and species diversity for future use.We evaluated ex situ storage potential of eight halophytic species from deserts in the United Arab Emirates(UAE)by studying seed germination.Specifically,we examined the germinability of freshly collected seeds and seeds stored for three years in a seed bank.We also examined the effect of light conditions on fresh and stored seed germination.Fresh seeds of seven of the eight species tested had a higher germination rates under 12/12 h light/dark fluctuations than did those exposed to total darkness.Storage reduced light sensitivity in Halocnemum strobilaceum,Suaeda aegyptiaca,Salsola drummondii and Salsola imbricata,but increased the requirement for light in Arthrocnemum macrostachyum.In Anabasis setifera,storage decreased germination percentage when there was a 12-hour light/dark fluctuation,but increased germination rate when exposed to the dark treatment.Storage significantly reduced germination in both the light/dark and dark treatments in Suaeda vermiculata and S.aegyptiaca.Germination speed also responded differently to storage;whereas Timson's index significantly increased in A.macrostachyum and H.strobilaceum,it significantly decreased for S.drummondii,S.aegyptiaca and S.vermiculata.Germination of these species at a range of temperatures requires further testing;additionally,we strongly suggest that these laboratory findings be complemented by field studies.

Effects of Different Halophytes on Soil Microflora and Enzyme Acti-vities of Saline-alkali Soil

In the pot experiment,seven varieties of halophytes were grown in saline-alkali soil to investigate the responses of microflora and soil enzymes in the rhizosphere.The results showed that compared to the control,the population of bacterial colony(84.8%-95.6%),actinomycetes colony(12.0%-14.5%)and fungi colony(0.5%-1.1%)increased significantly(P<0.05).The population of ammonia bacteria,aerobic cellulose decomposition bacteria in the soil of Vicia sativa L.(201.99%and 395.49%),Medicago sativa(152.43%and 319.90%)and Sesbania cannabina(Retz.)Pori(193.14%and 396.08%)were higher significantly than that of Panicum virgatum L.(49%and 60%),Sorghum bicolor(L.)Moench(99%and 210%),Amaranthus hypochondriacus L.(75%and 36%)and Aneurotepidimu chinense(75%and 77%)(P<0.05).However,Sorghum bicolor(L.)Moench was evidently higher than Panicum virgatum L.,Amaranthus hypochondriacus L.and Aneurotepidimu chinense(P<0.05)in the soil.The population of ammonia bacteria and aerobic cellulose-decomposing bacteria was significantly correlated with the five enzymes(P<0.05),which could improve the microenvironment in saline-alkali soil to accelerate the element cycling and promote the sustainable development of agriculture through cultivating Medicago sativa,Vicia sativa L.,Sesbania cannabina(Retz.)Pori and Sorghum bicolor(L.)Moench.

Study of Halophytes Dispersion in the North-West Region of Algeria

To know the mode of distribution of halophytes species in the western region of Algeria, it was considered useful to undertake a study based on the achievement of identified linear. Two areas were considered, Northern Tlemcen (Beni Saf and Rachgoun) and Northwest Oran (Sabkha). The trend of climate aridity which is more pronounced in the study area may have influences on floristic halophytes. The study of the floristic composition showed the importance of indicator halophitisation species such as Atriplex halimus, Tamarix gallica, Salicornia fruticosa, Arthrocnemum glaucum and was accompanied by various therophytes such as Sinapis arvensis, Erodium moschatum, Malva sylvestris and Plantago lagopus. ANOVA (analysis of variance) has highlighted the factors that influence the spatial distribution of some halophytes species at five stations studied;some are dispersed aggregates (Tamarix gallica, Suaeda fruticosa) with a coefficient of variation (Cv) greater than 10%;others are regularly dispersed (Atriplex halimus) with a coefficient of variation (Cv) less than 10%.

Characteristics of mineral elements in shoots of three annual halophytes in a saline desert, Northern Xinjiang

Halophytes are valuable salt-, alkali- and drought-resistant germplasm resources. However, the char- acteristics of mineral elements in halophytes have not been investigated as intensively as those in crops. This study attempted to investigate the characteristics of mineral elements for annual halophytes during their growth period to reveal their possible physiological mechanisms of salt resistance. By using three native annual halophytes （Salsola subcrassa, Suaeda acuminate and Petrosimonia sibirica） distributed in the desert in Northern Xinjiang of China, the dynamic changes in the mineral element contents of annual halophytes were analyzed through field sampling and laboratory analyses. The results demonstrated that the annual halophytes were able to absorb water and mineral nutrients selectively. In the interaction between the annual halophytes and saline soil, the adaptability of the annual halophytes was manifested as the accumulation of S, Na and CI during the growth period and maintenance of water and salt balance in the plant, thus ensuring their selective absorption of N, P, K, Ca, Mg and other mineral nutrients according to their growth demand. By utilizing this property, halophyte planting and mowing （before the wilting and death periods） could bioremediate heavy saline-alkali soil.

Climate and topography regulate the spatial pattern of soil salinization and its effects on shrub community structure in Northwest China

Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub community structure at the ecosystem scale.Therefore,we conducted a transect sampling of desert shrublands in Northwest China during the growing season(June–September)in 2021.Soil salinization(both the degree and type),shrub community structure(e.g.,shrub density and height),and biodiversity parameters(e.g.,Simpson diversity,Margalf abundance,Shannon-Wiener diversity,and Pielou evenness indices)were used to assess the effects of soil salinization on shrub community structure.The results showed that the primary degree of soil salinization in the study area was light salinization,with the area proportion of 69.8%.Whereas the main type of soil salinization was characterized as sulfate saline soil,also accounting for 69.8%of the total area.Notably,there was a significant reduction in the degree of soil salinization and a shift in the type of soil salinization from chloride saline soil to sulfate saline soil,with an increase in longitude.Regional mean annual precipitation(MAP),mean annual evapotranspiration(MAE),elevation,and slope significantly contributed to soil salinization and its geochemical differentiation.As soil salinization intensified,shrub community structure displayed increased diversity and evenness,as indicated by the increases in the Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices.Moreover,the succulent stems and leaves of Chenopodiaceae and Tamaricaceae exhibited clear advantages under these conditions.Furthermore,regional climate and topography,such as MAP,MAE,and elevation,had greater effects on the distribution of shrub plants than soil salinization.These results provide a reference for the origin and pattern of soil salinization in drylands and their effects on the community structure of halophyte shrub species.

Predicting changes in the suitable habitats of six halophytic plant species in the arid areas of Northwest China

In the context of changes in global climate and land uses,biodiversity patterns and plant species distributions have been significantly affected.Soil salinization is a growing problem,particularly in the arid areas of Northwest China.Halophytes are ideal for restoring soil salinization because of their adaptability to salt stress.In this study,we collected the current and future bioclimatic data released by the WorldClim database,along with soil data from the Harmonized World Soil Database(v1.2)and A Big Earth Data Platform for Three Poles.Using the maximum entropy(MaxEnt)model,the potential suitable habitats of six halophytic plant species(Halostachys caspica(Bieb.)C.A.Mey.,Halogeton glomeratus(Bieb.)C.A.Mey.,Kalidium foliatum(Pall.)Moq.,Halocnemum strobilaceum(Pall.)Bieb.,Salicornia europaea L.,and Suaeda salsa(L.)Pall.)were assessed under the current climate conditions(average for 1970-2000)and future(2050s,2070s,and 2090s)climate scenarios(SSP245 and SSP585,where SSP is the Shared Socio-economic Pathway).The results revealed that all six halophytic plant species exhibited the area under the receiver operating characteristic curve values higher than 0.80 based on the MaxEnt model,indicating the excellent performance of the MaxEnt model.The suitability of the six halophytic plant species significantly varied across regions in the arid areas of Northwest China.Under different future climate change scenarios,the suitable habitat areas for the six halophytic plant species are expected to increase or decrease to varying degrees.As global warming progresses,the suitable habitat areas of K.foliatum,S.salsa,and H.strobilaceum exhibited an increasing trend.In contrast,the suitable habitat areas of H.glomeratus,S.europaea,and H.caspica showed an opposite trend.Furthermore,considering the ongoing global warming trend,the centroids of the suitable habitat areas for various halophytic plant species would migrate to different degrees,and four halophytic plant species,namely,S.salsa,H.strobilaceum,H.glomeratus,and H.capsica,would migrate to higher latitudes.Temperature,precipitation,and soil factors affected the possible distribution ranges of these six halophytic plant species.Among them,precipitation seasonality(coefficient of variation),precipitation of the warmest quarter,mean temperature of the warmest quarter,and exchangeable Na+significantly affected the distribution of halophytic plant species.Our findings are critical to comprehending and predicting the impact of climate change on ecosystems.The findings of this study hold significant theoretical and practical implications for the management of soil salinization and for the utilization,protection,and management of halophytes in the arid areas of Northwest China.

Detecting soil salinity with arid fraction integrated index and salinity index in feature space using Landsat TM imagery

Modeling soil salinity in an arid salt-affected ecosystem is a difficult task when using remote sensing data because of the complicated soil context （vegetation cover, moisture, surface roughness, and organic matter） and the weak spectral features of salinized soil. Therefore, an index such as the salinity index （SI） that only uses soil spectra may not detect soil salinity effectively and quantitatively. The use of vegetation reflectance as an indirect indicator can avoid limitations associated with the direct use of soil reflectance. The normalized difference vegetation index （NDVI）, as the most common vegetation index, was found to be responsive to salinity but may not be available for retrieving sparse vegetation due to its sensitivity to background soil in arid areas. Therefore, the arid fraction integrated index （AFⅡ） was created as supported by the spectral mixture analysis （SMA）, which is more appropriate for analyzing variations in vegetation cover （particularly halophytes） than NDVI in the study area. Using soil and vegetation separately for detecting salinity perhaps is not feasible. Then, we developed a new and operational model, the soil salinity detecting model （SDM） that combines AFⅡ and SI to quantitatively estimate the salt content in the surface soil. SDMs, including SDM1 and SDM2, were constructed through analyzing the spatial characteristics of soils with different salinization degree by integrating AFⅡ and SI using a scatterplot. The SDMs were then compared to the combined spectral response index （COSRI） from field measurements with respect to the soil salt content. The results indicate that the SDM values are highly correlated with soil salinity, in contrast to the performance of COSRI. Strong exponential relationships were observed between soil salinity and SDMs （R2〉0.86, RMSE〈6.86） compared to COSRI （R2=0.71, RMSE=16.21）. These results suggest that the feature space related to biophysical properties combined with AFII and SI can effectively provide information on soil salinity.

Unlocking the in vitro anti-Trypanosoma cruzi activity of halophyte plants from the southern Portugal

Objective:To evaluate the in vitro anti-Trypanosoma cruzi（T.cruzi） activity of organic extracts prepared from halophyte species collected in the southern coast of Portugal（Algarve）,and chemically characterize the most active samples.Methods:Acetone,dichloromethane and methanol extracts were prepared from 31 halophyte species and tested in vitro against trypomastigotes and intracellular amastigotes of the Tulahuen strain of T.cruzi.The most active extract was fractionated by preparative HPLC-DAD,affording 11 fractions.The most selective fraction was fully characterized by 1H-NMR.Results:From 94 samples tested,one was active,namely the root dichloromethane extract of Juncus acutus(IC50 < 20 μg/mL).This extract was fractionated by HPLC,affording 11 fractions,one of them containing only a pure compound（juncunol）,and tested for anti-parasitic activity.Fraction 8(IC50 = 4.1 μg/mL) was the most active,and was further characterized by 1H-NMR.The major compounds were phenanthrenes,9,10-dihydrophenanthrenes and benzocoumarins.Conclusion:Our results suggest that the compounds identified in fraction 8 are likely responsible for the observed anti parasitic activity.Further research is in progress aiming to isolate and identify the specific active molecules.To the best of our knowledge,this is the first report on the in vitro anti T.cruzi activity of halophyte species.

Stomatal Abundance and Distribution in <i>Prosopis strombulifera</i>Plants Growing under Different Iso-Osmotic Salt Treatments

Changes in several environmental parameters are thought to affect stomatal development. Under salt stress, plants can regulate their transpiration flux through a better control of the stomatal opening (as a short-term response) and through modifications of leaf anatomy (as a long-term response). We investigate how leaf micromorphology (stomatal abundance and distribution) of the halophyte Prosopis strombulifera (a spiny shrub particularly abundant in high-salinity areas of central Argentina) responds to different water status when plants are subjected to different salt treatments (NaCl, Na2SO4 and their iso-osmotic mixture). Different salt treatments on P. strombulifera plants influenced leaf micromorphological traits differently. In this study, Na2SO4-treated plants showed an increase in stomatal density (SD) and epidermal cell density (ECD) (with smaller stomata) at moderate and high salinity (-1.9 and -2.6 MPa), whereas in NaCl and NaCl + Na2SO4 treated plants, a decrease in these variables was observed. In Na2SO4-treated plants, transpiration was the highest at moderate and high salinity, with the highest content of ABA registered. A possible explanation is that, despite of these high ABA levels, there is no inhibition in stomatal opening, resulting in increased water loss, growth inhibition, and acceleration of senescence processes. We demonstrate that P. strombulifera responds to progressive salt stress by different salts changing the leaf development, particularly in Na2SO4-treated plants, leading to structural modifications in leaf size and micro-morphology of leaf cells.

Biodiversity of Halophytic Vegetation in Chott <i>Zehrez</i>Lake of Djelfa (Algeria)

Mediterranean large lakes play an important role in providing a range of ecosystem functions and supporting biodiversity. The conservation and management of these lakes require more detailed knowledge of their ecology and environment-vegetation relationships. Chotts are probably the most poorly understood lake ecosystems. Chott Zehrez (Djelfa) as a large, shallow lake ecosystem in Algerian steppes, where wetlands are important part of their productivity. Despite the status of chott Zehrez lake as a Ramsar site, the main threat to its conservation is the private nature of surrounding land holdings in addition to the lack of knowledge and awareness by the local population of the importance of lake ecosystems. A wealth of halophytic flora exists which can be exploited for an array of uses like fodder, fuel wood, oilseed, medicines, landscaping, and environment conservation through carbon sequestration. A total 112 species belonging to 26 families and 39 genera were recorded. The sabkha flora includes 9 endangered and endemic species such as Avena bromoides, Cutandia divaricata, Herniaria mauritanica and Salicornia arabica. In this paper we mainly discussed characteristics and importance of Chott Zehrez lake ecosystem, its vegetation potentialities and economic usages will be also presented and discussed. Finally conservation strategy and restoration of this ecosystem are suggested.

Perspective Plant Species for Stabilization of Sand Dunes on the Exposed Aral Sea Bed

A new salty and sandy desert of ca 5 million ha has emerged on the exposed Aral Sea bed. Every year, 170-200 tons of salt and dust rise into the air and fall on the territory of the Republic of Karakalpakstan. A number of experiments have been cond.ucted in order to study the salt tolerance of plants and select drought- and salt-resistant plant species, which show a wide ecological range, to fix quick-sand dunes on the exposed Aral Sea bed. Among the studied species of Calligonum genus C. caput-medusae Schrenk was the most resistant to the saline solution. At the end of the vegetation experiment, the survivability of individuals constituted 44.1% at the concentration of 1.0% of sodium chloride. Artemisiaferganensis Krasch. ex Poljak. and Salsola richteri （Moq.） Kar. ex Litv. showed a good resistance to the concentration of saline solution as high as 150 ram, at which no dried plants were recorded. As the concentration grew to 300 mM, the survivability of Artemisiaferganensis dropped to 40.0% while 66.7 Salsola richteri individuals were developing successfully. An almost similar result was obtained during the experiment on Nitraria schoberi L.. The survivability ofKrascheninnikovia ewersmanniana （Stschegl. ex Losinsk.） Grub. individuals significantly decreased at the concentration of 200 mm （33.4%）, while for Agropyron cristatum the concentration of 300 mm was threshold, at which the survivability of individuals was below 3.3%. The most resistant to the deflation of sands on the exposed bed were Salsola richteri and Calligonum caput-medusae, whose survivability on the sandy dunes was 17%-41%.

Differences in Response of Suaeda spp.to Salt Stress between Two Habitats

Suaeda spp.are a type of halophytes with salinity tolerance,and they have good bioremediation function on saline soil.Starting from relevant indicators such as seed germination,growth and development,photosynthetic characteristics,pigment content,ion content and absorption,this paper summarizes the research progress on the differences in response of Suaeda spp.to salinity between two habitats of inland saline-alkali land and intertidal zone,so as to elaborate the similarities and differences in the physiological mechanism of Suaeda spp.to salinity between two habitats and reveal their different salt tolerance mechanisms.

Ecology of Indigenous Plants in Abandoned Agricultural Areas in Tabuk Region, Saudi Arabia

Due to drought, low soil fertility, little rain fall, elevated levels of evapotranspiration, salinization of the soil and a lack of ground water, the problem of desertion of agricultural areas has developed in KSA in recent years (e.g. Tabuk region). In the Saudi Arabia, agricultural land abandonment’s negative impact on the composition of perennial vegetation, soil quality, and the structure of population was investigated. In the several abandoned fields of the research region, eleven species of perennial plants pertaining to nine families, eleven genera were found. Following the use of the ordination of detrended correspondence analysis (DCA), four plant communities were found. Zygophyllum hamiense, Prosopis farcta, Seidlitzia rosmarinus, Traganum nudatum. The indicators were Pulicaria undulate, Calligonum comosum. Populations of Calligonum comosum and Zygophyllum hamiense were found to be either negatively skewed or inversely J-shaped, indicating fast-growing populations with strong reproductive potential, according to demographic research. Traganum nudatum, Prosopis farcta and S. Rosmarinus, on the other hand, have a nearly symmetrical size-frequency distribution (like a bell in shape). The current research highlights the importance of managing deserted agricultural fields in order to restore and improve range lands having adapted native plants to regional conditions like little water demand.

Phytoecological and phytoedaphological characterization of steppe plant communities in the south of Tlemcen(western Algeria)

In Algeria, the steppe areas of southern Sebdou between Tlemcen, El-Aricha and Mecheria are the scene of an adverse and continuous ecological imbalance often caused by the strong support of human pressure in these ecosystems. In arid and semi-arid regions, salinity remains a constraint for the development of plants. This study focuses on the realization of floristic surveys, where attention was paid to areas occupied by the dominant perennial species (Tamarix gallicaL.). A correspondence analysis by Minitab 15 software has allowed us to individualize the groups of species attracted by some parameters (edaphic, nitrates, humidity), and ecological gradients appear to affect the distribution of these taxa. The study of plant diversity shows the dominance of biological type of therophytes (41%) and morphological type of the Chenopodiaceaes with (25%). For geographical types, the strict Mediterranean and circum-Mediterranean element predominates.

Effect of Nitrate on Root Development and Nitrogen Uptake of Suaeda physophora Under NaCl Salinity

The effects of NaCl salinity and NO^-3 on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl （1, 150, 300, and 450 mmol L^-1） and three NO^-3 levels （0.05, 5, and 10 mmol L^-1） in solution culture for 30 d. Addition of NO^-3 at 10 mmol L^-1 significantly improved the shoot （P 〈 0.001） and root （P 〈 0.001） growth and the promotive effect of NO^-3 was more pronounced on root dry weight despite the high NaCl concentration in the culture solution, leading to a significant increase in the root：shoot ratio （P 〈 0.01）. Lateral root length, but not primary root length, considerably increased with increasing NaCl salinity and NO^-3 levels （P 〈 0.001）, implying that Na^＋ and NO3^- in the culture solution simultaneously stimulated lateral root growth. Concentrations of Na^＋ in plant tissues were also significantly increased by higher NaCl treatments （P 〈 0.001）. At 10 mmol L^-1 NO^-3, the concentrations of NO^-3 and total nitrogen and nitrate reductase activities in the roots were remarkably reduced by increasing salinity （P 〈 0.001）, but were unaffected in the shoots. The results indicated that the fine lateral root development and effective nitrogen uptake of the shoots might contribute to high salt tolerance of S. physophora under adequate NO^-3 supply.

Soil Salinity Mapping and Monitoring in Arid and Semi-Arid Regions Using Remote Sensing Technology: A Review

Soil salinity is a serious environmental problem especially in arid and semiarid areas. It either occurs naturally or is human-induced. High levels of soil salinity negatively affect crop growth and productivity leading land degradation ultimately. Thus, it is important to monitor and map soil salinity at an early stage to enact effective soil reclamation program that helps lessen or prevent future increase in soil salinity. Remote sensing has outperformed the traditional method for assessing soil salinity offering more informative and professional rapid assessment techniques for monitoring and mapping soil salinity. Soil salinity can be identified from remote sensing data obtained by different sensors by way of direct indicators that refer to salt features that are visible at the soil surface as well as indirect indicators such as the presence of halophytic plant and assessing the performance level of salt-tolerant crops. The purposes of this paper are to 1) discuss some soil salinity indicators;2) review the satellite sensors and methods used for remote monitoring, detecting and mapping of soil salinity, particularly in arid and semi-arid regions;3) review various spectral vegetation and salinity indices that have been developed and proposed for soil salinity detection and mapping, with an emphasis on soil salinity mapping and assessment in arid and semi-arid regions;and 4) highlight the most important issues limiting the use of remote sensing for soil salinity mapping, particularly in arid and semi-arid regions.

Maternal salinity environment affects salt tolerance during germination in Anabasis setifera： A facultative desert halophyte

The effects of maternal salinity and light incubation on the salinity tolerance of the facultative halophyte Anabasis setifera during their germination stages were assessed. Seeds were collected from non-saline habitats in Egypt and saline habitats in the United Arab Emirates （UAE）. The seeds of the two populations were germinated in 0, 100, 200, 400, 600 and 800 mM NaCI, and incubated at 25℃/15℃ in both 12-h light and 12-h darkness regimes and continuous darkness. Significantly more seeds germinated in the Egyptian population than in the UAE population. Salinity tolerance was significantly greater with the Egyptian population than with the UAE population, especially under the conditions of higher salinities. The difference in salinity tolerance between the seeds of two populations was attributed to their seed mass. In addition, germination was significantly faster for the Egyptian population than for the UAE population. Most of the saline treated seeds were able to recover their germination when transferred to distilled water, but this depended on their maternal salinity and light incubation. Recovery from higher salinities was significantly better for the seeds under darkness than for those under light in the UAE population, but the reverse was true for the seeds in the Egyptian population. The higher salinity tolerance for the A. setifera seeds from the non-saline Egyptian population and the lower salinity tolerance for the seeds from the saline UAE population cannot explain their natural distribution. Further studies about other possible roles, such as levels of different promoting and inhibiting phytohormones, are needed to understand the importance of salinity as an environmentally induced maternal effect.