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.

Floral Species as Environmental Quality Indicators in Jordan: High Salinity and Alkalinity Environments

In this study the occurrence and ecology of plant assemblages are investigated, mainly for use as indicator plants of saline grounds in several locations in Jordan. High alkalinity and H2S-rich water tolerant species of plants are also discussed. Plants growing on salty grounds have distinct composition regarding their place in the taxonomic system. Plant assemblages and their degree of tolerance to salinity as in Karama area in the Jordan Valley are found to be distinct from that of Azraq Sabkha (Cental Jordan) with salt-tolerant flora. Karama area provides the living space for Mesembryanthemum on the saltiest ground, Suaeda further up on wetter surrounding and Salicornia succeeding on moist and less salty grounds. Drier places with rather salty grounds have bushes of Arthrocnemum, while slightly less salty places are preferred by Tamarix tetragyna. When Prosopis bushes appear, salt is only present periodically in the ground, as is also the case with Atriplex halimus and Capparis. In Azraq the former beach of a temporal lake is characterized by two species of Spergularia in its saltier parts and by Tamarix passerinoides. It was recognized that Tamarix, Phragmites, Chenopodium, and Inula represented alkaline water tolerant plants. The study concludes that the salt concentration in the ground is reflected in the composition of the flora growing on it. On the other hand, plants are also found vulnerable to fluctuation in the salt concentration of their environments with different resistance degrees. This makes them excellent bioindicators of salty environments.

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.

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.

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.

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.

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.

Effects of salinity and desalination on seed germination of six annual weed species

The effects of various salinities and desalination on seed germination of six annual glycophytes （Artemisia sieversiana, A. scoparia, Chloris virgata, Eragrostis pilosa, Chenopodium acuminatum and Chenopodium glaucum） were studied in Horqin Sandy Land, Inner Mongolia, China. NaCl solutions of five concentrations （0 mM, as the control, and 50, 100, 200 and 300 mM） were used for saline stress and desalination treatments. Increasing salinity significantly reduced germination percentages of A. sieversiana, A. scoparia, Ch.virgata and Ch. acuminatum, but had no effect on the germination percentages of E. pilosa. Lower salinity levels （50 mM） significantly increased germination percentage of Ch. glaucum. High salinity might be a precondition for germi- nation after desalination for five of the six species, excepting E. pilosa at NaCl concentration of 300 mM in comparison with non-primed seeds. Higher salinity （200 mM） led to some specific ion toxicity and reduced seed viability of A. sieversiana. No specific ion toxicity but an osmotic effect limited the germination of other five species was observed The final germination percentages （salinity stress and desalination） of the six species showed three variations in comparison with the controls, namely, indiscrimination, stimulation, and reduction. Germination responses to salinity and desalination suggested that the six species were separated into three categories. Three species （A. sieversiana, Ch. virgata and Ch. acuminatum） showed similar germination responses to salinity with those of halophyte, but also showed a lower tolerance limit than most halophytes, although this was not always the case. A. scoparia and Ch. glaucum exhibited some ‘salt stimulation’ in seed germination percentages after desalination, whereas E. pilosa did not show any obvious responseto salinity. Therefore, salinity usually induces dormancy of seeds with strong germination capacity in fresh water, but has few, or even positive, effects on seeds with strong innate dormancy.

Photosynthetic Behaviour and Mineral Nutrition of Tamarix gallica Cultivated Under Aluminum and NaCl Combined Stress

The lack of knowledge of plant tolerance and differential response to aluminum(Al)encouraged many researchers,in the last decade,to elucidate Al toxicity and tolerance mechanisms.The current study reported the impact of Al,a toxic element with negative effects on plant growth and development,in halophytic plant Tamarix gallica.Plants were subjected to different Al concentrations(0,200,500 and 800μM)with or without NaCl(200 mM)supplementation.Growth,photosynthesis and mineral content were assessed.Al stress had a significant decrease on shoots’biomass production between 19 to 41%,and a little variation on chlorophyll content and photosynthetic efficiency(Fo,Fm,Fv fluorescence’s and Fv/Fm).Furthermore,the Al-treatments did not affect significantly the content of potassium,calcium,and magnesium in different plant parts,whereas NaCl addition to the medium induced a decrease in these elements’concentrations.Our results have shown that T.gallica is able to accumulate the high levels of Al in shoots and roots,6288μg.g^(-1) DW and 7834μg.g^(-1) DW respectively.It is considered as a hyperaccumulator plant of Al.In addition,Na+contents in shoots and roots exceed 23000μg.g^(-1) DW.Therefore,T.gallica presents a high tolerance at the same time to Al and NaCl phytotoxicity,so it is interesting to use in phytoremediation programs.

Marine Species Introduced on the French Channel-Atlantic Coasts: A Review of Main Biological Invasions and Impacts

The impacts of anthropogenisation modify permanently the distribution patterns of brackish and marine species. Globalization leads to a rapid increase of the numbers of introduced species anywhere in the world. Biological invasions often result in significant losses in the economic value, biological diversity and function of invaded ecosystems. This review presents the main pathways of introduction of non-indigenous species and the main benthic taxonomic groups being established and/or invasive along the French Channel-Atlantic coasts. A focus is put on main invasive marine species in the intertidal and subtidal zones of Brittany (France), among macroalgae (Sargassum muticum, Grateloupia turuturu, Undaria pinnatifida, Codium fragile and Gracilaria vermiculophylla), halophytes (Spartina alterniflora) and benthic invertebrates (Mollusks: Crepidula fornicata, Crassostrea gigas and Venerupis philippinarum). The species biology, introduction vectors, reproductive and dispersal capacities are considered, together with proliferation patterns along the Channel-Atlantic coasts. The ecological impacts of these species on the environment are also described, as well as the European regulations existing to limit alien species introduction and some examples of struggle against the invaders including eradication trials and biomass valorization. Last, the on-going impacts of global changes on alien species invasiveness along the Channel-Atlantic coasts are discussed.

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.

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.

Antioxidant and Antibacterial Properties of <i>Mesembryanthemum crystallinum</i>and <i>Carpobrotus edulis</i>Extracts

The two halophyte plants Mesembryanthemum crystallinum and Carpobrotus edulis (Family: Aizoaceae, Order: Cary-ophyllales), widely used in the traditional medicine, were chosen for this study. There is no much information about the antioxidant and antibacterial activities of the two plants growing in the Tunisian coasts. The most of studies conducted confirmed the responses of these plants to the abiotic stresses. We demonstrate a high antioxidant activity in the two plant extracts by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The two plant extract also exhibited antibacterial activity by using the minimal inhibitory concentration (MIC) against bacterial strains;Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923). The different medicinal properties can be attributed in part to the presence of polyphenolics compounds in the two plant extracts.

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.

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.

Endophytic bacteria associated with halophyte Seidlitzia rosmarinus Ehrenb.ex Boiss.from saline soil of Uzbekistan and their plant beneficial traits

Endophytic bacteria of halophytic plants play essential roles in salt stress tolerance.Therefore,an understanding of the true nature of plant-microbe interactions under extreme conditions is essential.The current study aimed to identify cultivable endophytic bacteria associated with the roots and shoots of Seidlitzia rosmarinus Ehrenb.ex Boiss.grown in the salt-affected soil in Uzbekistan and to evaluate their plant beneficial traits related to plant growth stimulation and stress tolerance.Bacteria were isolated from the roots and the shoots of S.rosmarinus using culture-dependent techniques and identified by the 16S rRNA gene.RFLP(Restriction Fragment Length Polymorphism)analysis was conducted to eliminate similar isolates.Results showed that the isolates from the roots of S.rosmarinus belonged to the genera Rothia,Kocuria,Pseudomonas,Staphylococcus,Paenibacillus and Brevibacterium.The bacterial isolates from the shoots of S.rosmarinus belonged to the genera Staphylococcus,Rothia,Stenotrophomonas,Brevibacterium,Halomonas,Planococcus,Planomicrobium and Pseudomonas,which differed from those of the roots.Notably,Staphylococcus,Rothia and Brevibacterium were detected in both roots and shoots,indicating possible migration of some species from roots to shoots.The root-associated bacteria showed higher levels of IAA(indole-3-acetic acid)synthesis compared with those isolated from the shoots,as well as the higher production of ACC(1-aminocyclopropane-1-carboxylate)deaminase.Our findings suggest that halophytic plants are valuable sources for the selection of microbes with a potential to improve plant fitness under saline soils.

Homologous cloning, characterization and expression of a new halophyte phytochelatin synthase gene in Suaeda salsa

The halophyte Suaeda salsa can grow in heavy metal-polluted areas along intertidal zones having high salinity.Since phytochelatins can effectively chelate heavy metals,it was hypothesized that S.salsa possessed a phytochelatin synthase(PCS) gene.In the present study,the cDNA of PCS was obtained from S.salsa(designated as SsPCS) using homologous cloning and the rapid amplification of cDNA ends(RACE).A sequence analysis revealed that SsPCS consisted of 1 916 bp nucleotides,encoding a polypeptide of 492 amino acids with one phytochelatin domain and one phytochelatin C domain.A similarity analysis suggested that SsPCS shared up to a 58.6%identity with other PCS proteins and clustered with PCS proteins from eudicots.There was a new kind of metal ion sensor motif in its C-terminal domain.The SsPCS transcript was more highly expressed in elongated and fibered roots and stems(P<0.05) than in leaves.Lead and mercury exposure significantly enhanced the mRNA expression of SsPCS(P<0.05).To the best of our knowledge,SsPCS is the second PCS gene cloned from a halophyte,and it might contain a different metal sensing capability than the first PCS from Thellungiella halophila.This study provided a new view of halophyte PCS genes in heavy metal tolerance.

In Vitro Propagation, Isolation and Expression Studies of Suaeda edulis Genes Involved in the Osmoprotectants Biosynthesis

Halophytes are an excellent choice for the study of genes conferring salt tolerance to salt-sensitive plants and,they are suitable for reclamation and remediation of saline soil.We develop an in vitro plant propagation protocol and studies of genes involved with GB and Pro biosynthesis in Suaeda edulis.Axillary buds were used as explants and cultured in different treatments on Murashige and Skoog(MS)medium supplemented with different concentrations and combinations of plant growth regulators.The highest number of multiple shoots was on MS medium containing 1 mg/L Benzyladenine(BA)and/or 2 g/L activated carbon with 5.5±06 shoots per explant.The identification and expression analysis of genes involved in glycine betaine(GB)biosynthesis were S-adenosyl-methionine synthetase(SAMS),choline monooxygenase(CMO)and betaine alde-hyde dehydrogenase(BADH),and for proline(Pro)was pyrroline 5-carboxylate synthetase(P5CS).These sequences shared 90–95%of identity with others plant homologous in public databases.The amino acids sequence analysis showed that all these peptides contain some of the conserved motifs of those kinds of enzymes.The qRT-PCR analysis revealed a higher expression of SeBADH,SeCMO,and,SeP5CS genes in the roots and leaves from plants collected in the field in contrast with from in vitro plants.However,the expression level of SeSAMS was higher only in the leaves of plants collected in the field when com-pared to those cultivated in vitro.

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.

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.