Department of Biology

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    Botanical and Chemical Studies on Solenostemma Argel (Del) Hayne Grown in Khartoum
    (University of Khartoum, ) Elkamali, Hatil Hashim Ahmed ; Abdella Elkhidir Medani
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    Growth and Osmotic Adjustment in Cultivars of C3(Groundnut, Arachis hypogaea ) and C4 ( Sorghum, Sorghum bicolor L.Moench ) Species in Response to Water Stress
    (UOFK, 2015-09-15) Mohammed, Mazahir Sanosi ; Dr. Eltayeb Elhag Ali Ahmed ; Biology
    A field experiment was conducted for two seasons at the Demonstration farm , Faculty of Agriculture, University of Khartoum during 2009/2010 and 2010/2011 to study osmotic adjustment in two cultivars of Groundnut (C3 plant) Gibaish and Madani and two cultivars of sorghum (C4 plant ) , Tabat and Arfa Gadamak in response to water stress during growth and development . The design was split plot with three replicates . Water stress was induced by watering treatments at intervals of 7 days (W1) ,14 days (W2) and 21 days (W3). Data were recorded on the following vegetative and reproductive traits :Plant height , number of leaves per plant , leaf area per plant , stem diameter , number of tillers , head length , head weight , number of seeds per head , weight of seeds , number of pods per plant in groundnut and weight of pods . For the content of some minerals and osmotic adjustment ,leaves were collected at random for osmotic adjustment (O.A) measurement after 7 , 11 and 15 weeks of growth for each treatment . The results showed that water stress significantly reduced plant height in both seasons. Mean plant height for the two seasons under W1, W2 , and W3 respectively was 72.2 , 63.9 , and 45.8cm for sorghum genotypes . For groundnut genotypes it was 15.8 , 14.5 , and 10.6cm under W1 , W2 , and W3 respectively. Mean number of leaves was significantly reduced in both seasons in both sorghum and groundnut . The mean ranged from 8.7 , 9.0 and 7.8 under W1, W2 , and W3 respectively for sorghum genotypes it was 7.3 , 6.3 , and 5.9 cm under W1 , W2 , and W3 respectively for groundnut. Leaf area was also significantly reduced in both sorghum and groundnut genotypes. Mean leaf area ranged from 249.2 , 160.2 and 110.1cm2 under W1, W2 , and W3 respectively for sorghum genotypes .For groundnut genotypes it ranged from 50.1 , 34.0 , and 24.2cm2 under W1, W2 , and W3 respectively . Number of seeds was significantly reduced by water stress in both seasons for sorghum genotypes .It ranged from 466.1 , 219.9 and 133.3 under W1, W2 , and W3 respectively. The weight of 1000 grains in sorghum genotypes was significantly reduced by different irrigation intervals in both seasons. Mean weight of 1000 grains was 41.5 , 25.6 , and 23.41g under W1, W2 , and W3 respectively. Calcium , phosphorus and magnesium concentrations in leaves of sorghum and groundnut genotypes were significantly reduced by water stress in both seasons .Potassium concentrations was significantly reduced in the first season but in the second season it was significantly increased by water stress in all genotypes except Gibaish . In all genotypes of sorghum and groundnut nitrogen and protein concentrations were significantly reduced in both seasons. Watering treatments had significant effect on osmotic potential (O.P) of genotypes of sorghum and groundnut resulting in significant increases in O.P (becoming more negativ) . In sorghum genotypes , results revealed that the mean O.P was -0.3 , -0.3 and -0.7 Mpa under W1, W2 , and W3 respectively after 7 weeks of growth . After 15 weeks of growth the mean was -0.3 , -0.3 and -0.5 Mpa under W1, W2 , and W3 respectively . In groundnut genotypes the means O.P was -0.3 , -0.3 and -0.6 Mpa under W1, W2 , and W3 respectively after 7 weeks of growth . After 15 weeks of growth the means was -0.3 , -0.3 and -0.5 Mpa under W1, W2 , and W3 respectively . In this study the highest (more negative ) O.P (-0.8 Mpa) was measured after 7 weeks of growth in Tabat under the 21_day irrigation interval in the first season . Tabat may have therefore more capacity for osmotic adjustment . It would seem that C4 plants ( sorghum ) in this study have a higher capacity for osmotic adjustment that C3 plants (groundnut)
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    The effect of Pulicaria crispa (forssk) Oliv., and Citrullus colocynthis (L.) Schrad. , Aquaous Extracts against Anopheles arabiensis and Culex quinquefasciatus.
    (UOFK, 2015-06-15) Amna Hamid Imam, Babiker ; Dr. El-naeim Ibrahim Abd-Elkarim ; Department of Biology
    The aim of present study is to investigate the potential larvicidal activity of aqueous extract from leaves of two selected indigenous plants, and their subsequent effects upon egg hatching, adult emergence inhibition and oviposition deterrent activity of the mosquitoes A. arabiensis (the main vector of malaria in Sudan) and C. quinquefasciatus (the main vector of Filariasis in Sudan). Laboratory experiments were conducted in the Department of Biology, Faculty of Education, University of Khartoum and Insectary of Health National Laboratory (ISTAC) during the period 2008-2011. Experiments were as follows: The larvicidal activity of leaves aqueous extract of both P. crispa (Altager) and C. colocynthis (Alhandel) were tested against the 2nd, 3rdand 4th instars larvae of A. arabiensis and C. quinquefasciatus. Twenty-five laboratory reared each of A.arabiensis and C. quinquefasciatus second, third and fourth instar larvae were exposed to a wide range of test concentrations (2500, 5000, 10000, 15000, 20000 and 25000ppm) and a control using dechlorinated tap water. Four replicates of each of the concentrations of each plant water exract seperately, were undertaken for each of the two mosquito species to find out the activity range of the extract of leaves of the tested plants. The larval mortality for each stage was determined at 48 hours and by using log dosage–probit mortality analysis, regression line using computer software programs to determine the values of each of the lethal concentrations, 50% (LC50) and 90% (LC 90). The larvae in the toxic aqueous extracts exhibited behavioral responses and intoxication symptoms that vary in degree according to the type and concentration of the extract. The current study revealed toxic and lethal effect doses of both plant leaf extracts on larvae. In all cases the, 2nd instar was more susceptible to the effect of the extract than the 3rd instar and the latter was more susceptible than the 4th instar. The pupal stage was not affected by the extracts even at a high concentration of 25000 ppm. The aqueous extract of C. colocynthis was more effective than P. crispa against the two species of mosquitoes. A. arabiensis was more susceptible than C. quinquefasciatus to P. crispa (Altager) and C. colocynthis (Alhandel). Hundred freshly laid eggs of Culex quinquefasciatus were exposed to five concentrations of leaf extracts of P. crispa and C. colocynthis in de-chlorinated tap water. Each concentration was replicated three times and a control was used. The hatching rate was assessed 5 days later. Both plant exracts showed remarkable effects on the rates of eggs hatching and larvae development. The eggs were found more susceptible than 3rd and 4th instar larvae. Oviposition deterrent tests were designed using five cages and placed side by side A, B, C, D and E. For bioassay, 50 gravid females each of A. arabiensis and C. quinquefasciatus were transferred to seperate mosquito cage (2 day after blood feeding). The concentrations of leaf extracts of both plants, showed high, moderate and low mortality against 3rd instar. The leaves extract of both plants showed 100% oviposition deterrence and effective repellence against both mosquitoes especially at high larvicidal concentration and a choice of control (treated - control). Eggs laying avoidance was not abserved when the control was not offered. It was observed that maximum egg laying accorded at low larvicidal concentrations. In cases of high larvicidal concentration egg laying was avoided completely or at least reduced to very low number. The correlation between the dose and its effect (mortality) was found to be more or less perfect (r2 W76;1.0). The current study revealed that plant leaves extracts have high efficacy in the control of A. arabiensis and C. quinquefasciatus. Consequently, these water extract can be induded in programs of biological control of mosquitoes after its effect on other aquatic organisms and ite safety to man are tested
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    Chemotaxonomic Study on the Genus Ziziphus Tourn. ex L. in the Sudan
    (University of Khartoum, 2011) Nuha Mohammed Elhassan ; Abdel Gabar Nasir Gumaa ; Department of Biology
    This research is composed of two parts: a taxonomic and a chemical study on the genus Ziziphus in the Sudan. The objectives of this study were: identification, classification and documentation of the species of the genus Ziziphus in the Sudan, determination of the major chemical components of the fruits of the genus, construction of taxonomic keys based on morphology and chemical components of fruits and the survey of the various uses of the genus in the Sudanese rural areas. Plant materials were collected from different parts of the Sudan, with special reference to the states of Gezira, Kordofan, Darfur and the White Nile. The collected plants were identified and synonymy was updated. Brief botanical species descriptions have been given with notes on geographical distribution and common uses. The species were photographed by digital camera. Fruits were chemically analyzed according to the methods adopted by the A.O.A.C. (1965 ; 1984). These methods were used for the determination of the following contents: moisture , ash, crude protein, fat, , crude fiber , carbohydrates, reducing sugars , sucrose and the elements Ca, Mg , Fe, and P. High performance liquid chromatography (HPLC) was used for the determination of citric and ascorbic acid contents. Results of chemical data were analyzed using the variance ratio test (F- test) with a probability of 5% . XII The major findings of this study were: • Five Ziziphus spp. were identified , namely: Z.spina-christi, Z.abyssinica, Z.mauritiana, Z.mucronata and Z.pubescens. • Ziziphus spp. are multipurpose and have many uses such as food, medicine, rituals and often superstitions. • The fruit provides good famine food at times of food scarcity. • Ziziphus spp. occur even in arid or semi-arid regions , and are thus considered as drought- resistant plants. Results of statistical analysis of chemical data showed that: • There are significant differences among the Ziziphus spp. in their chemical components . • There are significant differences among the chemical components of Z.mauritiana , on one hand, and those of Z.spina-christi and Z.abyssinica on the other hand. This study recommends the following: • Propagation and domestication of Ziziphus spp. in all arid and semi-arid areas of the Sudan. • Introduction of Ziziphus spp. in food security and desertification programs in the Sudan. • Development of packaging and preservation methods of Z.mauritiana fruits exported to some Arab countries.