Characterization of ten date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia using AFLP and ISSR markers

Date palm is the most economically important plant in the Middle East due to its nutritionally valuable fruit. The development of accurate DNA fingerprints to characterize cultivars and the detection of genetic diversity are of great value for breeding programs. The present study explores the usefulness of ISSR and AFLP molecular markers to detect relationships among 10 date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia. Thirteen ISSR primers and six AFLP primer combinations were examined. The level of polymorphism among cultivars for ISSRs ranged from 20% to 100% with an average of 85%. Polymorphism levels for AFLPs ranged from 63% to 84% with an average of 76%. The total number of cultivar-specific markers was 241, 208 of which were generated from AFLP analysis. AJWA cultivar had the highest number of cultivar-specific ISSR markers, whereas DEK, PER, SUK-Q, SHA and MOS-H cultivars had the lowest. RAB and SHA cultivars had the most and least AFLP cultivar-specific markers, respectively. The highest pairwise similarity indices for ISSRs, AFLPs and combined markers were 84% between DEK (female) and PER (female), 81% between SUK-Q (male) and RAB (male), and 80% between SUK-Q (male) and RAB (male), respectively. The lowest similarity indices were 65% between TAB (female) and SUK-Q (male), 67% between SUK-A (female) and SUK-Q (male), and 67% between SUK-A (female) and SUK-Q (male). Cultivars of the same sex had higher pairwise similarities than those between cultivars of different sex. The Neighbor-Joining (NJ) tree generated from the ISSR dataset was not well resolved and bootstrap support for resolved nodes in the tree was low. AFLP and combined data generated completely resolved trees with high levels of bootstrap support. In conclusion, AFLP and ISSR approaches enabled discrimination among 10 date palm cultivars of from Saudi Arabia, which will provide valuable information for future improvement of this important crop.     

Weeds flora demographic analysis of date palm orchards in El-Bahariya,El-Frafra and Siwa oases

Oases are a specific ecosystems which date palm Phoenix dactylifera are the mainly crop growing for its fruits and others tree parts. Palm orchards are infested by many pests, including weeds species and exposed within time to the challenging invasive weeds to control. The heavy incidence of weeds negatively affects palm productivity, especially in small plantation and divergent distances, while the established orchards, palm trees shading cause deprives from the process of weeds photosynthesis to be lower competitive. The survey was conducted in El-Bahariya and El-Frafra than Siwa oases of which 375 plots were taken. Vegetative analysis in oases altogether demonstrate 91 weed specimens were encountered of which 18 perennial, 42 were broad leaved, and 30 narrow leaved as well as one parasitic weed species belonging to 22 families, whereas Poaceae is the most plentiful family displayed by 38.5% from all families, occurred in date palm orchards during the study. The geographical differentiation affected coefficient of similarity whereas, it in oases recorded the highest between El-Bahariya and El-Frafra than Siwa and El-Bahariya, while El-Frafra Oasis was the most diverse and richness than the others which have the middle soil properties, fertility, and structure. The correlation analysis of weed flora between both El-Bahariya and El-Frafra was higher and more than El-Bahariya and Siwa oases. Under the unique closed agroenvironment of oases, weeds population dynamics are a stable approximately. Regardless of the diversity of annual weed species, perennials species represent the highest dominant number and the pattern of grown weeds was more dominant than wild desert and some invasive weed species. The control action should be taken of perennial weeds and proactive as well as long term prevention for invasive species.     

A mitochondrial molecular marker of resistance to Bayoud disease in date palm

We have previously shown that two circular plasmid-like DNAs (the S and the R plasmids) can be found in the mitochondria of date palm (Phoenix dactylifera L.), a dioecious monocotyledonous tree. The two plasmids differ essentially by the absence, in the R plasmid, of a 109-bp DNA segment. Using 36 date palm varieties and employing a PCR-based approach, we show that the simultaneous presence of the R plasmid and absence of the S plasmid can be considered as a reliable molecular marker of resistance to a vascular wilt (Bayoud disease) caused by the fungus Fusarium oxysporum f. sp. albedinis. Conversely, the simultaneous presence of the S plasmid and absence of the R plasmid is correlated to Bayoud disease susceptibility The availibility of this diagnostic tool for plasmid characterization should subsequently allow simple, rapid and efficient selection of Bayoud-resistant individuals from the large number of date palms obtained by natural crosses which display good date quality. Received: 14 August 2000 / Accepted: 10 November 2000     

Purification and characterization of membrane-bound peroxidase from date palm leaves (Phoenix dactylifera L.)

Peroxidase from date palm (Phoenix dactylifera L.) leaves was purified to homogeneity and characterized biochemically. The enzyme purification included homogenization, extraction of pigments followed by consecutive chromatographies on DEAE-Sepharose and Superdex 200. The purification factor for purified date palm peroxidase was 17 with 5.8% yield. The purity was checked by SDS and native PAGE, which showed a single prominent band. The molecular weight of the enzyme was approximately 55 kDa as estimated by SDS–PAGE. The enzyme was characterized for thermal and pH stability, and kinetic parameters were determined using guaiacol as substrate. The optimum activity was between pH 5–6. The enzyme showed maximum activity at 55 °C and was fairly stable up to 75 °C, with 42% loss of activity. Date palm leaves peroxidase showed K_m values of 0.77 and 0.045 mM for guaiacol and H₂O₂, respectively. These properties suggest that this enzyme could be a promising tool for applications in different analytical determinations as well as for treatment of industrial effluents at low cost.     

An assessment of level of heavy metals pollution in the water,sediment and aquatic organisms: A perspective of tackling environmental threats for food security

Pollution is severely threatening the wetland habitats. Heavy metals are one among of the major pollutants in wetland habitats. The cadmium (Cd), copper (Cu), chromium (Cr), cobalt (Co), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn), were assessed in the water, sediment, benthic species (polychaetes, mollusc and crustaceans), prawn and fishes. The assessment of heavy metals was done by using double-beam Atomic Absorption Spectrophotometer (AAS). The Hg, Cr and Co were greater in sediment, Ni and Cd were higher in polychaetes and molluscs respectively. However, the Cu and Pb greater in crabs and the Zinc was greater in fishes. The concentration of metals showed significant differences among the various sources examined (P < 0.05) except Cr (P > 0.05). The inter-correlational analysis among the metals assessed from the various sources showed that the Cr and Pb not correlated among the eight metals examined. However, the Cu and Co were correlated with Hg (r = 0.307) and (r = 0.788) respectively. The nickel was correlated with Hg (r = 0.367), Cu (r = 0.362) and Co (r = 0.432). The Zinc was correlated with the Cd (r = 0.331) and Hg (r = 0.737). However, correlation of metals among the different sources shown that the metals of polychaetes correlated with sediment r = 0.637, the metals of crabs correlated with the sediment and polychaetes r = 0.630 and r = 842 respectively, the metals of molluscs was also correlated with sediment (r = 0.636), polychaetes (r = 0.889) and crabs (r = 0.894). In addition to that the metals of prawns was correlated with the polychaetes (r = 839), crabs (r = 0.628) and molluscs (r = 0.634). The metals of fishes correlated with polychaetes (r = 0.529), crabs (r = 0.710), molluscs (r = 0.493) and prawns (r = 0.593). Indeed the multiple regression model explained that the metals of sediments influence the accumulation of metals in biotic species such as polychaetes, molluscs, crustaceans, prawns and fishes with 84% (F = 21.079; p < 0.001).The order of the heavy metals in the water, sediment and biotic species was Hg > Pb > Ni > Cr > Zn > Co > Cu > Cd. The study found that the level of heavy metals at various sources in the sanctuary is showing considerable warning and the sanctuary is required intensive assessment on various aspects of pollution since the Point Calimere Wildlife Sanctuary is supporting several species of migratory and endangered shorebirds seasonally.     

Studying the effects of heavy metal on chlorophyll and sugar in one year-old seedlings organs of Acer velutinum specie

Pollution is one of the most important factors inhibiting growth in the environment; therefore the effects of zinc pollution were studied in Acer velutinum specie. Two years old seedlings of Acer velutinum specie were prepared from nursery, the concentrations of zero and one hundred and thirty mg per liter of zinc chloride solution were added to the soil of seedlings pots after calculating and after passing a three-month period of seedling growth, the plant organs were removed, then the amount of zinc concentration in the samples was determined and data were analyzed. The results of the analysis showed that the highest amount of accumulation on the stem, root and soil in treatment concentrations is 87.75, 65.68 and 24.78 mg per kg and accumulation of zinc in total chlorophyll and sugar in treatment concentrations is 4.61 and 0.6028 mg per g, respectively, and accordingly Acer velutinum specie is suitable for refinement of soils contaminated with zinc.     

Anti-hypercholesterolemic impacts of barley and date palm fruits on the ovary of Wistar albino rats and their offspring

A high cholesterol diet is related to ovarian dysfunction and infertility which has been increased among young ages consuming processed food products. The present study was conducted to evaluate the role of a high cholesterol diet on the ovaries of young female rats via assessments of histopathology, immunohistochemistry, oxidative stress and apoptic markers. Also, mating of hypercholesterolemic female rats was carried out to measure the fertility and numbers of their offspring. At the same time, phytotherapy was carried out through supplementing the diet with barley and/ or date palm fruits (10%) during the experiment to assess the phyto-therapeutic impacts in attenuation of drastic hypercholesterolemic effects.Hypercholesterolemic diet-fed rats exhibited damage of the ovarian follicles and increased follicular atresia. Furthermore, expression of cleaved caspase-3 was upregulated, while PCNA was downregulated in granulosa, theca and stroma cells. Hypercholesterolemic female rats showed marked depletion of antioxidative enzymes, increased lipid peroxidation and apoptotic markers. Alterations to the female serum hormones were detected. Offspring maternally fed on hypercholesterolemic diet showed a significant decrease of body weight and altered sex ratio. However, concomitant supplementation of barley and or date fruits to hypercholesterolemic groups revealed marked improvement of ovarian structure and function.On the basis of these evidences, it is believed that the enhanced synergistic effects of barley and/or date palm fruits in the amelioration of ovarian structure and functions were elicited by the potential antioxidant activity of their phytomicronutrients, polyphenols, β-glucan and trace elements. These materials scavenge free radicals from inflamed cells that can be used to establish an effective and novel therapeutic strategy for activating ovarian cell regeneration.     

Comparison of the toxicity of heavy metals to cabbage growth

Summary Cabbage plants were grown for 55 days with a nutrient solution containing 1 and 10 ppm of V, Cr(III), Cr(VI), Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg(I), orHg(II). A comparison of the plant growth and chemical analysis revealed that Cr(VI), Cu, Cd, and Hg(II) in the solution are most toxic to the plant growth (hence detrimental to the cabbage-head formation) and Mn, Fe, and Zn are less toxic than other heavy metals, and that Mn, Zn, Co, Ni, and Cd and translocated into all the plant organs while V, Cr(III), Cr(VI), Fe, Cu, Hg(I), and Hg(II) are accumulated in the roots.     

Evaluation of extraction methods for the identification of proteins from date palm (Phoenix dactylifera L.) seed and flesh

Date fruits are well known to be very nutritious. Nevertheless, the protein contents of the fruit, particularly the seed and flesh, are still understudied, largely due to their difficult physical characteristics. This study was conducted to compare three different protein extraction methods which were the trichloroacetic acid (TCA)-acetone (TCA-A), phenol (Phe), and TCA-acetone-phenol (TCA-A-Phe), and to perform proteomic analysis on date palm seed and flesh. Phe extraction method showed the highest protein yields for both seed (8.26?mg/g) and flesh (1.57?mg/g). Through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Phe, and TCA-A-Phe extraction methods were shown to be efficient in removing interfering compounds and gave well-resolved bands over a wide range of molecular weights. Following liquid chromatography–tandem mass spectrometry analysis, about 50–64% of extracted proteins were identified with known functions including those involved in glycolysis, Krebs cycle, defense, and storage. Phe protein extraction method was proven to be the optimal method for date flesh and seed.     

Migration of heavy metals in two Japanese soils

Summary The migration of common bio-toxic heavy metals in two typical soils of Japan under the influence of various leaching solutions was investigated.The results of the present study have indicated that the Pb and Cu ions were less mobile than those on Zn and Cd. Thus, the former two ions have largely been concentrated in the surface horizon while the latter two have been localised in the sub-surface layers. Ni has exhibited greater mobility than other heavy metals under all the leaching stress in both the soils. It is clear from the present study that Ni, Cd and Zn might pose a greater threat of ground water pollution than Cu and Pb. The specific migration properties of each metal ion varied depending on the nature of the ion and leaching solutions. The major soil factors governing the mobility of heavy metals in the soils have been discussed in the light of the results of the present investigation.     

Traffic and industrial activities around Riyadh cause the accumulation of heavy metals in legumes: A case study

The objective of this study was to analyse the effect of the continuously increasing anthropogenic activities around Riyadh, Saudi Arabia on the accumulation of heavy metals in leguminous crops. This study determined whether four legume crops, Pisum sativum L., Vicia faba L., Glycine max and Vigna sinensis, could accumulate the heavy metals Cu, Mn, Pb and Zn in their leaves, pods and grains during the summer when grown under conditions with ambient air pollution from heavy traffic and industrial activities in Riyadh, Saudi Arabia. The effect of the air pollution was examined by quantifying the protein and trace element Cu, Mn, Pb and Zn concentrations in the leaves, pods and grains of the four plant species. Analysis of the results indicated that air pollution significantly increased the heavy metal concentrations in the leaves, pods and grains. Toxic concentrations of the heavy metals were found in the plants grown at L3, L4 and L5. In conclusion, the air pollution increases as the traffic, industrial activities and population density increase.     

Molecular phylogeny of date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia by DNA fingerprinting

Genetic diversity among 13 different cultivars of date palm (Phoenix dactylifera L.) of Saudi Arabia was studied using random amplified polymorphic DNA (RAPD) markers. The screening of 140 RAPD primers allowed selection of 37 primers which revealed polymorphism, and the results were reproducible. All 13 genotypes were distinguishable by their unique banding patterns produced by 37 selected primers. Cluster analysis by the unweighted paired group method of arithmetic mean (UPGMA) showed two main clusters. Cluster A consisted of five cultivars (Shehel, Om-Kobar, Ajwa, Om-Hammam and Bareem) with 0.59–0.89 Nei and Li's coefficient in the similarity matrix. Cluster B consisted of seven cultivars (Rabeeha, Shishi, Nabtet Saif, Sugai, Sukkary Asfar, Sukkary Hamra and Nabtet Sultan) with a 0.66–0.85 Nei and Li's similarity range. Om-Hammam and Bareem were the two most closely related cultivars among the 13 cultivars with the highest value in the similarity matrix for Nei and Li's coefficient (0.89). Ajwa was closely related with Om-Hammam and Bareem with the second highest value in the similarity matrix (0.86). Sukkary Hamra and Nabtet Sultan were also closely related, with the third highest value in the similarity matrix (0.85). The cultivar Barny did not belong to any of the cluster groups. It was 34% genetically similar to the rest of the 12 cultivars. The average similarity among the 13 cultivars was more than 50%. As expected, most of the cultivars have a narrow genetic base. The results of the analysis can be used for the selection of possible parents to generate a mapping population. The variation detected among the closely related genotypes indicates the efficiency of RAPD markers over the morphological and isozyme markers for the identification and construction of genetic linkage maps.Communicated by H.F. Linskens     

Identification and sequencing of Date-SRY Gene: A novel tool for sex determination of date palm (Phoenix dactylifera L.)

Dioecism has always been an issue in many plant species with its numerous disadvantages, especially in woody trees such as date palms. As one of the most important crops in the Middle Eastern countries, researchers are having problems identifying of sex of the plant in its early stages of development. Hence, proper population stands in the male: female ratio for maintenance is almost impossible in the field for better production. In this study, sex determination of date palm (Phoenix dactilyfera L.) were identified in regions of the Y chromosome (Date-SRY) gene, the pivotal gene that initiates sex determination, using a new technique and thus an economically desirable objective, which will significantly impact profits in seed based cultivations. Partial sequences of the Date-SRY were taken and amplified by nested polymerase chain reaction (PCR). According to the results, the exact sex of date palm was identified in all the tested plants, while amplified regions of the Date-SRY gene closely matched with the human and papaya sequences. In addition, a primer pair was designed to amplify the sequences of the SRY-date gene with confidence that it will identify male date palms. These primer sequences include SRY-date Forward 5′- cggccctctaagtatctgtgcgcaacg-3′ (SRY-date F) and the SRY-date Reverse 5′- gtttgcacttcgaagcagag-3′ (SRY-date R). The complete sequence of the DNA has been registered and deposited in GenBank (BankIt1598036 DPSRY1 KC577225 thenKJ873056).     

Effect of GA3 and 2,4-D foliar application on the anatomy of date palm (Phoenix dactylifera L.) seedling leaf

Two concentrations (10-5M and 10-3M) of both GA3 and 2,4-D were used as foliar spray to evaluate the response of date palm (Phoenix dactylifera L.) cv. Khedri seedlings. They affected some of the anatomical characteristics of the first leaf emerging after the beginning of the spray. The high concentration of GA3 increased the size of the midrib and its vascular bundle numbers. Both low and high concentrations of 2,4-D inhibited the formation of the midrib. 2,4-D in both low and high concentrations decreased the number of vessels in both protoxylem and metaxylem and also decreased their diameters, where as GA3 in low and high concentrations have less effect on the number of vessels and its diameters. GA3 in high concentration increased the number of vascular bundles in 1mm long of the leaf blade, while 2,4-D in low and high concentrations decreased their numbers. 10-3M of 2,4-D increased the size and layers of special hypodermal cells.     

Biotechnological strategies applied to the decontamination of soils polluted with heavy metals

Soils have been submitted to several contaminants that vary in concentration and composition. Heavy metals can be widely spread and accumulated in those environments due to some inappropriate actions. In this present review some remediation techniques to remediate soils are presented, focusing on the use of plants that are capable of surviving in soils with heavy metals along with the function of some microorganisms in the restoration process.     

食品中重金属的存在形态及其与毒性的关系

简要介绍了近年来有关食品中重金属形态及其毒性关系的研究进展,归纳了食品中重金属的化学形态特征、不同类型食品中重金属的存在形态、食品中重金属形态与生物有效性和毒性的关系,以及该领域中急需研究解决的问题．     

Biosorption of heavy metals from aqueous solutions with tobacco dust

A typical lignocellulosic agricultural residue, namely tobacco dust, was investigated for its heavy metal binding efficiency. The tobacco dust exhibited a strong capacity for heavy metals, such as Pb(II), Cu(II), Cd(II), Zn(II) and Ni(II), with respective equilibrium loadings of 39.6, 36.0, 29.6, 25.1 and 24.5 mg of metal per g of sorbent. Moreover, the heavy metals loaded onto the biosorbent could be released easily with a dilute HCl solution. Zeta potential and surface acidity measurements showed that the tobacco dust was negatively charged over a wide pH range (pH > 2), with a strong surface acidity and a high OH⁻ adsorption capacity. Changes in the surface morphology of the tobacco dust as visualized by atomic force microscopy suggested that the sorption of heavy metal ions on the tobacco could be associated with changes in the surface properties of the dust particles. These surface changes appeared to have resulted from a loss of some of the structures on the surface of the particles, owing to leaching in the acid metal ion solution. However, Fourier transform infrared spectroscopy (FTIR) showed no substantial change in the chemical structure of the tobacco dust subjected to biosorption. The heavy metal uptake by the tobacco dust may be interpreted as metal–H ion exchange or metal ion surface complexation adsorption or both.     

Incidence of heavy metals in the mangrove flora and sediments in Kerala, India

The mangroves of Kerala on the south-west coast of India are fast disappearing due to land reclamation and other anthropogenic disturbances. There are very few ecosystem level studies made in these much threatened biotopes in Kerala. The present study involves the measurement of heavy metals in the mangrove flora and sediments of three mangrove habitats along the Kerala coast. Sampling was carried out for a period of one year at bi-monthly intervals, with concentrations of Fe, Mn, Cu,Zn,Pb and Co analysed using atomic absorption spectrophotometry. An appreciable variation was observed in metal concentrations indifferent mangrove species. Cu, Zn and Pb were found to be in higher concentrations in Avicennia officinalis whereas higher levels of Fe, Mn and Co were observed in the species Barringtonia racemosa. The analysis of heavy metals indicated a high level of metal pollutants such as Fe, Cu, Zn and Pb in the mangrove habitats of Quilon and Veli compared to the relatively uncontaminated areas of Kumarakom. This revised version was published online in August 2006 with corrections to the Cover Date.     

Bacterial resistance and detoxification of heavy metals

Microbial cells have resistances to essentially all of the toxic heavy metals of the Periodic Table. In bacterial cells, the genetic determinants of these resistances are frequently found on small extrachromosomal plasmids and transposons. Sometimes the resistances are associated with detoxifying enzymes. This is true for the Hg²⁺ → Hg⁰ reductase, the As³⁺ → As⁵⁺ oxidase and the Cr⁶⁺ → Cr³⁺ reductase. In other cases, such as As⁵⁺, Ag⁺ and Cd²⁺, no change in redox state occurs but, rather, uptake and transport differences accompany resistance determinants. This article summarizes what is known of bacterial metal resistances for which enzymatic detoxification is known to be the mechanism of resistance. The characteristics and functions of the enzymes are described, as well as a summary of the newer DNA sequence analysis (basic science) and bench-scale efforts (applied science) for the mercuric resistance system.     

Distribution of heavy metals in the hippocampal region of the guinea pig

Summary With the present modification of Timm's sulfide silver method all parts of the hippocampal region show a distinctly stratified staining pattern, suggesting large regional differences in the content of heavy metals.The stain is largely confined to distinct grains, partly associated with neuronal somata and partly dispersed in the neuropil. Work in progress supports the idea that the grains in the neuropil are synaptic boutons, as has been shown previously for the mossy fibre layer.The staining pattern has been compared in detail with the fields and layers of the hippocampal region as delineated by cyto- and fibroarchitectonics. Previous concepts of the subdivision of this cortical region are confirmed and supplemented.The sulfide silver pattern of the guinea pig hippocampal region is fundamentally similar to that of the rat. However, the entorhinal area, the regio inferior hippocampi, and the dentate area show notable differences in the staining pattern between the two species.We are indebted to Mrs. E. Kjaer Hansen, Mrs. L. Knudsen, Mr. B. Krunderup, Mr. A. Meier, Mr. Th. Nielsen, Mrs. B. Sørensen, and Miss M. Sørensen for skilful technical assistance.This study was supported in part by U.S.P.H.S. Grant NS 07998.Permanent address: Anatomical Institute, University of Oslo, Norway