首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
In this study, 19 sites representing different habitats in Hail region were regularly visited for two years, in each site 2–5 stands were selected for investigating floristic composition and vegetation types in the area. A total of 124 species representing 34 families were recorded. The family Asteraceae is represented by the highest number of species (21 species) followed by the Poaceae (17 species) and the Brassicaceae (10 species) whereas, 15 families including Acanthaceae, Convolvulaceae, Moraceae, Nyctaginaceae and Primulaceae, are represented by a single species each. Chronological analysis of the vegetation in the area revealed the domination of Saharo-Sindian elements in the wild vegetations and of weedy species in the cultivated plots. Therophytes and chamaephytes are the dominating life forms of the vegetation spectra; therophytes represent 49.20% and chamaephytes represent 29.00% of the total species in the study area. Application of TWINISPAN and DECORANA classification and ordination techniques to the data produced seven vegetation groups. Ruderal habitats comprised two small groups A and F dominated by Phragmites australis and Imperata cylindrical (A), Euphorbia peplus and Sisymbrium irio (F), respectively. Two vegetation groups (B and G) have been recognized in the mountains and slopes dominated by Launaea mucronata, Trigonella stellata (B) and Ficus palmate and Fagonia bruguieri (G). Other two groups (C and E) inhabit the desert and mountainous wadies; these are represented by Gymnocarpos decandrus and Ochradenus baccatus (C) and Senecio glaucus subsp. coronopifolius and Rumex equisetiforme (E). On the other hand, one group (D) inhabits the cultivated plots and is represented by Plantago albicans and Rumex vesicarius, the last group also includes species restricted to the sand dune habitat of the Al-Nafud desert north of Hail city and represented by Calligonum polygonoides and Halyxolon salicornicum. The vegetation analysis indicated the invasion of Hail Flora by some foreign weeds such as Solanum nigrum, Lactuca serriola and Amaranthus lividus. The presence of these weeds points out the need to monitor the vegetation change in Hail region, and also other regions of Saudi Arabia, in order to elucidate the human impact on the wild plants diversity as human activities change with the fast development in the kingdom.  相似文献   

2.
This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) followed by Habronema muscae (22.2%). Trichostrongylus axei and Oxyuris equi were less common at (11.1%) and (8.8%), respectively. Habronema megastoma and Setaria equine were found in two horses only (4.4%). Gasterophilus intestinalis larvae were recovered from 39 horses (86.6%) and Gasterophilus nasalis larvae were found in 17 horses (37.7%). Season had a significant effect on the prevalence of P. equorum and G. nasalis, while age of horses had a significant effect only on the prevalence of P. equorum. The husbandry in Saudi Arabia appears to be conductive to parasites transmitted in stables or by insects rather than in pasture.  相似文献   

3.
Fungi inhabiting household environments in the West, East and Central localities of Riyadh city were screened. The screened area included bedrooms, drawing rooms, living rooms, kitchens and bathrooms. The common genera of fungi isolated wereAlternaria, Aspergillus, Cercospora, Chaetomium, Cladosporium, Curvularia, Drechslera, Embellisia, Fusarium, Mucor, Penicillium, Rhizopus, Scytalidium, Trichoderma, Torula andUlocladium. Two uncommon generaNodulosporium andOidiodendron for Saudi Arabian mycoflora were also isolated. In all the localities, the highest number of fungal colonies per plate or per gram were found in the living rooms, followed by bedrooms. The number of colonies per plate or per gram was in general higher in densely populated than in less populated areas.  相似文献   

4.
This study was conducted to investigate phytophagous and predatory mites associated with vegetable plants in Riyadh, Saudi Arabia. Eight phytophagous and 10 predacious mites were collected from 14 species of vegetable crops covering five major production localities. Out of these 18 mite species, 13 species are new to the mite fauna of Saudi Arabia. In addition, the two species, Tenuipalpus punicae and Agistemus exsertus, are reported for the first time on vegetable crops in Saudi Arabia. For each mite species found, notes on host plant association and occurrence period are given. An illustrated key for the identification of the 18 mite species reported in this study is provided and this can be used to improve the IPM programs by applying the local natural predatory mites in controlling mite pests in Saudi Arabia.  相似文献   

5.
Fungi causes most plant disease. When fruits are stored at suboptimal conditions, fungi grows, and some produce mycotoxin which can be dangerous for human consumption. Studies have shown that the Penicillium and Monilinia species commonly cause spoilage of fruits, especially apples. Several other genera and species were reported to grow to spoil fruits. This study was conducted to isolate and identify fruit spoilage by fungi on apples collected in Riyadh, Saudi Arabia and conduct a molecular identification of the fungal isolates. Thus, we collected 30 samples of red delicious and Granny Smith apples with obvious spoilage from different supermarkets between February and March of 2012 in Riyadh, Saudi Arabia. Each apple was placed in a sterile plastic bag in room temperature (25–30 °C) for six days or until fungal growth was evident all over the sample. Growth of fungal colonies on PDA was counted and sent for molecular confirmation by PCR. Six fruit spoilage fungi were isolated, including Penicillium chrysogenum, Penicillium adametzii, Penicillium chrysogenum, Penicillium steckii, Penicillium chrysogenum, and Aspergillus oryzae. P. chrysogenum was the most frequent isolate which was seen in 14 of a total of 34 isolates (41.2%), followed by P. adametzii and A. oryzae with seven isolates each (20.6%) and the least was P. steckii with six isolates (17.6%). Penicillium species comprised 27 of the total 34 (79.4%) isolates. Sequence analysis of the ITS regions of the nuclear encoded rDNA showed significant alignments for P. chrysogenum, P. adametzii and A. oryzae. Most of these fungal isolates are useful and are rarely pathogenic; however they can still produce severe illness in immune-compromised individuals, and sometimes otherwise healthy people may also become infected. It is therefore necessary to evaluate the possible production of mycotoxins by these fungi to determine a potential danger and to establish its epidemiology in order to develop adequate methods of control.  相似文献   

6.
The present study sought to assess the potential of the cestode Hymenolepis diminuta as a bioindicator for lead accumulation in two industrial areas of the city of Riyadh, Saudi Arabia. Rats (Meriones libycus) were collected from two sites (industrial area II and Salbukh) in Riyadh. In the industrial area II, the mean levels of lead concentrations were found to be 1.96, 1.92, 1.4 and 30.72 μg/g in the rats’ liver, kidney and intestine, and in H. diminuta, respectively. In Salbukh, meanwhile, the lead concentrations were 1.63, 1.52, 1.20 and 21.31 μg/g in the rats’ liver, kidney, and intestine, and in H. diminuta, respectively. In addition, in industrial area II, compared with the liver, kidney and intestine of their host, the bioconcentration factors of lead were found to be, respectively, 15.6, 16 and 21.9 times higher in H. diminuta, and were 7.5, 8, and 10.2 times higher in the same organs compared to H. diminuta in Salbukh. The present study, therefore, proved that H. diminuta could be used as a bioindicator for heavy metal contamination in the industrial areas of the city of Riyadh.  相似文献   

7.
Saudi Arabia rangeland ecosystems have undergone intense processes of degradation for many decades because of extreme climate and human activities such as overgrazing and socioeconomic changes. In this study, Hail and Qassim Regions of Saudi Arabia covering an area about 79610.73 km2 were selected to study the rangeland vegetation and condition. Haloxylon salicornicum was the most dominant species, covering more than 56% of the total area. The second prominent community was Acacia-Lycium shawii, which covers about 21% of total area. It was found that about 65% of vegetation in the surveyed area is in good or very good condition compared with about 31% in poor or deteriorated condition. Effective measures such as determination of carrying capacities and development of grazing systems have to be implemented to ensure resources sustainably.  相似文献   

8.
Airborne Pollen grains and Spores of three different cities viz., Al-Khobar (1987–1988), Abha (1991–1992) and Hofuf (1992–1993) in Saudi Arabia were studied using Burkard Volumetric Seven-Day Spore Trap. The data were analyzed in relation to their allergenic capability and one-year pollen and spore calendars were designed to correlate the patients’ symptoms as well as for selection of appropriate allergen extracts for diagnosis and treatment of allergic diseases. Amongst pollen group, Amaranthus viridis, Plantago spp., Chenopodium album, Ricinus communis, Rumex vesicarius, Juniperus spp., Parkinsonia aculeata, Prosopis spp., and Phoenix dactylifera were some of the frequent types. Amongst the fungal spores group Cladosporium, Smuts spores, Colored basidiospores, Alternaria, Ulocladium and Drechslera were the dominant types.  相似文献   

9.
The hot and arid lowlands of southwestern Saudi Arabia are home to two common lianas, Cocculus pendulus and Leptadenia arborea. This paper attempts to relate the adaptation of these two climbing woody perennials to such a harsh environment to the anatomy and hydraulic characteristics of their wood. The stems of these lianas have wood with wide xylem vessels and high hydraulic conductivity which should enhance water flow to the upper canopy despite their severe twisting. Hydraulic conductivity is further helped by the simple perforation plates of xylem vessels. The circular thickening of xylem walls gives them strength and reduces the risk of their collapse and the ensuing embolism in the advent of high tension created by severe water deficit and high evapo-transpiration demand. Wide vessels, on the other hand, are more susceptible to embolism. This problem may be overcome by reducing the solute potential of xylem sap by hydrolysis of starch grains which were found to be abundant in the vicinity of the vessels. This should help absorb water by the deep roots from the capillary fringes of the typically shallow water table in this particular habitat. Furthermore, the abundance of ray parenchyma cells between xylem groups of both lianas provides great flexibility with minimum damage to water conduits in the stem during climbing and twisted growth. It was concluded that these wood features in both lianas are crucial for survival under the harsh conditions of arid Tihama plains of southwestern Saudi Arabia.  相似文献   

10.
This study surveyed 205 wetland sites in the Southwestern Saudi Arabia. We found seven species of amphibians (Anura), which belong to four families: Bufonidae; which includes four species, Sclerophrys tihamica; S. Arabica, Duttaphrynus dhufarensis, and Bufotes viridis; Hylidae, represented by only one species, the tree frog Hyla savignyi; Ranidae, which represented by one species, Pelophylax ridibundus and finally the Dicroglossidae, represented by one species, Euphlyctis ehrenbergii. The reasonable amount of rain received in southwest Arabia, and habitat diversity contribute to the relative abundance of amphibians in the region. Five types of wetland habitats were found in the study area. Valley streams, irrigated farms, seasonal ponds, dam reservoir and lagoons of treated sewage water. The current study revealed the wide spread of amphibians in southwestern Saudi Arabia than what had been reported earlier and confirmed the presence of the Bufotes viridis at three new sites in Asir Heights. It also showed the wide spread of S. arabica in all types of habitats in the southwestern region of Saudi Arabia. Habitat degradation was evident in the region, which might lead to species loss.  相似文献   

11.
A collection of snakes in Turaif region, Kingdom of Saudi Arabia, an area that has been poorly documented for reptiles, consists of 28 specimens representing 11 species belonging to 4 families (Colubridae, Elapidae, Viperidae and Atractaspididae). This study presents the first comprehensive inventory of the herpetofauna of the Turaif province of Saudi Arabia. Co-ordinates: Latitude, longitude and altitude, of the collected specimens were mapped using GPS. Three of the snake species Lytorhynchus diadema, Pseudocerastes fieldi and Walterinnesia morgani reported by the authors in the present survey proved to be new records for Turaif region of Saudi Arabia.  相似文献   

12.
We report morphometric data for 133 specimens of Diplometopon zarudnyi (Squamata: Trogonophidae) collected across its range within Riyadh province of Saudi Arabia. One-way analyses of variance revealed that differences exist in most characters. Snout-vent length and vent-tail length showed slight and inconsistent differences among samples. D. zarudnyi is characterized by 164–175 body annuli; 165–178 dorsal annuli; 13–17 caudal annuli with absence of caudal autotomy. In addition, 2–4 lateral annuli; 45–54 mid-body segments; 39–50 posterior segments; 4–5 head’s plates and 4–6 pre-cloacal pores were recorded in both males and females without gender difference. The present study revealed the widespread distribution of this species in the studied region, since land topography in this area is characterized by the absence of any natural barriers which could restrict the spread of this amphisbaenian lizard D. zarudnyi.  相似文献   

13.
Plant species composition patterns and vegetation types were investigated along Elevational Gradients in Al Baha region, Saudi Arabia. Sandy plain, wadis, drainage lines, rocky outcrops, hills and fallow lands occur over a wide geographic range encompassing variation in plant species and communities among these different ecological sites. To provide a quantitatively based classification of the vegetation we used Multi Variant Statistical Package (MVSP) software, followed by the re-arrangement of a matrix of the similar plant species in rows and similar sample sites in columns. Plant density and environmental variables were measured and recorded in each quadrat. Two-way indicator species analysis and Canonical Correspondence Analysis (CCA) were used to analyze the relationships between vegetation and environmental variables, while Arc Map was used to analyze the pattern of plant species density. A total of 59 sample plots (25 × 25 m), stratified, randomly-placed relevés were collected in Al Baha region, along a cross section running from south-west to north-west. About 190 plant species belonging to 59 families were recognized. This study showed that these plant species formed 15 vegetation types that primarily correspond mainly to different combinations of elevation, and topography. The study concluded that this research has provided the first quantitative and systematic survey of the vegetation in Al Baha region.  相似文献   

14.
Toxoplasma 3 main clonal lineages are designated as type I, II, and III; however, atypical and mixed genotypes were also reported. This study was conducted for detection of Toxoplasma gondii genotypes in rats (Rattus rattus) in Riyadh region, Saudi Arabia. PCR test on T. gondii B1 gene was conducted on ELISA IgM positive samples for confirmation of the infection. However, genetic analysis of the SAG2 locus was performed to determine T. gondii genotypes using PCR-RFLP technique. PCR test on T. gondii B1gene showed that 22 (81.5%) out of the 27 ELISA IgM positive samples have T. gondii DNA. Genotypic analysis shows that, of the total 22 PCR positive samples, only 13 (59.1%) were of type II, 7 (31.8%) were of type III, and 2 (9.1%) were of an unknown genotype. It is obvious that the prevalence of both type II and III is high in rats. No reports have been available on T. gondii genotypes among rats in Riyadh region, and only little is known about its seroprevalence in rats. Future studies on T. gondii genotypes in rats using multi-locus markers is needed in Riyadh region, Saudi Arabia for better understanding of T. gondii pathogenesis and treatment in humans and animals.  相似文献   

15.
One hundred and forty mammals of fifteen different species belonging to nine families, collected during one-year survey period in Turaif province of Saudi Arabia, are reported. Collections were made during studying the diversity of land vertebrate fauna of Turaif area at the northern province of Saudi Arabia. Cricetidae (n?=?64) was the most common family. Jaculus jaculus vocator (n?=?34) was recorded the highest number of events for any mammal in the surveyed area followed by Gerbillus nanus (n?=?23). Two species of mammals namely G. nanus (n?=?23) and Felis margarita (n?=?3) were reported for the first time in the study area. The geographical distribution of the collected species within this province was mapped.  相似文献   

16.
17.
Wadi Al-Jufair, a tributary of Wadi Nisah, is one of the important wadis of Najd region (Saudi Arabia) sheltering a rich diversity of higher plants. The study area is extended into approximately 15 km2 encompassing the commonest geomorphological features encountered in desert wadis. The wadi supports several rare plants, including Maerua crassifolia Forssk., a regionally endangered tree, and Acacia oerfota (Forssk.) Schweinf., a rare shrub with restricted distribution. The present study aims to analyze the vegetation of wadi Al-Jufair and propose its designation as an important plant reserve. The vegetation type is fundamentally of chamaephytic nature with some phanerophytes, and distinguished into associations where the dominant perennial species give the permanent character of plant cover in each habitat. Four vegetation groups were identified with the application of TWINSPAN, DCA and CCA programs and named after the characteristic species as follows: Lycium shawii; A. oerfota; Acacia raddianaRhazya stricta and Artemisia monosperma. These plant associations demonstrate significant variation in soil texture, moisture, organic matter, pH, EC, and minerals of Wadi Al-Jufair.  相似文献   

18.
Turaif area located in the Northern border region of Saudi Arabia is one of the most important regions of the Kingdom. This work was proposed to throw light on the diversity of lizard fauna investigated through the collection and subsequent identification of specimens from different localities of Turaif region of Kingdom of Saudi Arabia. Sixteen species of lizards belonging to 5 families (Agamidae, Gekkonidae, Lacertidae, Scincidae and Varanidae) were recorded. Lacertidae was the most common family. Three species of lizards namely Acanthodactylus orientalis, Acanthodactylus scutellatus and Acanthodactylus grandis were reported for the first time in the Turaif region of Saudi Arabia. The geographical distribution of the collected species within this province was mapped.  相似文献   

19.
20.
The conservation of five traditional crops is an important aspect of achieving national food security. In the present study, we aimed to collect and conserve germplasm of five local crops from the Jazan region of southwestern Saudi Arabia: Sorghum: Sorghum bicolor (L.) Moench); Barley (Hordeum vulgare L.) Millet (Pennisetum glaucum (L.) R. Br.); Sesame (Sesamum indicum L.) and Guar (Cyamopsis tetragonoloba (L.) Taub). Forty-one seed accessions of these five crops were collected and tested to determine seed moisture content (MC%) and quality as indicators of their potential to survive during long-term dry storage at ?18 °C (i.e. ex-situ conservation of genetic resources). Seed viability was assessed using germination tests, the tetrazolium chloride (TZ) test and X-ray imaging. Seeds of the five crops had very low MC% and high viability (fully developed embryos and germination >91%), indicating that they were of good quality and had high potential for long-term survival in gene banks. The genetic resources of these crops (seeds) have now been preserved at the gene-bank of King Abdulaziz City for Science and Technology (KACST-BGB), Riyadh, Saudi Arabia.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号