Hydrochemical processes and metal composition of Ain Umm-Sabah natural spring in Al-Hassa Oasis Eastern Province, Saudi Arabia

This study was carried out to determine the hydro-chemical processes and the metal concentration of spring water to evaluate its suitability for irrigation and other purposes. A total of 10 water samples were collected from Ain Umm Sabah at different times and from different locations from the spring basin. EC (dS m(-1)), pH, temperature, total cations (Na, Ca, Mg, K) and anions [Cl, CO3, HCO3, SO4, NO3, Fluoride (F)] were determined. Some trace and heavy metals (Al, As, Ba, B, Br, Mo, Ni, Si, Cd, Cu, V, Fe, I, Pb, Mn, Zn, Sr, Se, Sb, La and Se were determined. The Spring water is classified as C4S2 (high salinity with medium sodicity problem water). Chloride (Cl) and nitrate (NO3) concentrations were higher than the permissible limits according to World Health Organization Standards. The Ain Umm Sabah water is Na-Cl dominant water and can create soil sodicity problems and cause Na and Cl ion toxicity to plants if used for irrigation of sensitive crops. The spring water is under-saturated (negative SI) with respect to calcite, dolomite, gypsum, anhydrite, halite, fluorite and aragonite and oversaturated (positive SI) with respect to goethite, siderite and hematite minerals. The concentration of all the estimated trace metals was within the permissible limits for its use as drinking water and other purposes according to WHO. Since the spring water contains high concentration of NO3, hence can not be used for drinking purposes without prior treatment. The study findings suggest careful use and pumping of water from the spring. Further studies are required on regular basis to monitor the depletion in the spring water level and the temporal change in water salinity.     

Chemical control of weeds in transplanted tomatoes in Saudi Arabia

The herbicides metobromuron, diphenamid and dinitramine were tested either singly or in combination with dalapon for the control of weed species in transplanted tomato crops in Saudi Arabia, during 1979 and 1980. All herbicides were effective in controlling Chenopodium murale L., the primary broad-leaved weed in the area. However, they were less effective against other broad-leaved weed species and, even in combination with dalapon, failed to reduce populations of grass weeds. Tomato seedlings showed various degrees of injury: dinitramine was the most phytotoxic herbicide, followed by metobromuron and diphenamid. No toxicity was observed for dalapon. Diphenamid was the most promising herbicide for controlling weeds and producing significantly higher yields of tomatoes.     

Insomnia in chronic renal patients on dialysis in Saudi Arabia

Background  

Studies have shown that insomnia is a common sleep disorder among patients with end-stage renal disease (ESRD). This study aimed to assess the prevalence of insomnia in Saudi patients with ESRD who are on maintenance dialysis.     

Use of pulse trickles to reduce clogging problems in trickle irrigation system in Saudi Arabia

Laboratory experiments were conducted at the Agricultural and Veterinary Training and Research Station, King Faisal University, Al-Hassa, Kingdom of Saudi Arabia to study the effect of pulse irrigation from a line source on sandy soil uniformly packed in soil tank using high flow rates. It was found that the increase in pulsed flows up to six times to that of the equivalent continuous flow can be used with little change to the soil wetting pattern. The water deep percolation reduced and horizontal spread increased with an increase in the pulsed flow up to twelve times to that of continuous flow (control treatment). A strong correlation was obtained between the water application rates and the vertical and horizontal advances which could be expressed as power function. The results showed an excellent potential to increase the emitter sizes up to 2.4-3.5 times and the emitter cross section area up to 6.0-12.0 times than the normal size for reducing the trickle clogging problem. Empirical analysis of the vertical and horizontal advance shows that both of these parameters can be expressed as a power function.     

Preliminary results with sex pheromones to trap potato tuber worm moths in Saudi Arabia

Summary A mixture of sex pheromone PTM₁ (trans-4,cis-7-tridecadien-1-ol acetate) and PTM₂ (trans-4,cis-7,cis-10-tridecatrien-1-ol acetate) on rubber cap dispensers was used to attract adult male tuber moths to water pan traps. Correlation analysis of daily catches made over a 61-day period showed that temperature and relative humidity accounted for 20.5% and 1.4% respectively of catch variability. Further studies are needed to reveal any major components of the 78% residual variability.     

The influence of daylength on final leaf number in spring wheat

The influence of daylength on final leaf number was determined in four field-sown wheat cultivars with no vernalisation requirement. Leaf and primordium appearance was monitored in plots sown at two-month intervals during an annual cycle. The timing of the response to daylength varied substantially among cultivars. In one, final commitment of the last leaf primordium occurred close to the time of initiation of that primordium while, in another cultivar, commitment did not occur until terminal spikelet or later. In the other two cultivars, commitment occurred midway through spikelet initiation. Late timing of response to daylength is a useful adaptation that allows cultivars with no vernalisation response sown autumn to set more leaves than when sown in spring, and hence to delay flowering. Based on the analysis, a simple iterative procedure was developed that successfully predicted final leaf number, the dates of appearance of the flag ligule and anthesis for one of the cultivars grown in an independent experiment.     

Genetic analysis of field resistance to tan spot in spring wheat

Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs., is an important constraint to wheat (Triticum aestivum L.) yield in many countries. Since the inheritance of field resistance to tan spot is poorly understood, this study was conducted to determine the genetic control of resistance in the field. Resistance was measured as disease severity caused by P. tritici-repentis race 1 in four crosses involving five wheat parents: parent 1 (P₁) = catbird; parent 2 (P₂) = Milan/Shanghai-7; parent 3 (P₃) = Alondra/Coc//Ures; parent 4 (P₄) = Bcb//Dundee/Gul/3/Gul); parent 5 (P₅) = ND/VG9144//Kal/BB/3/Yaco/4/Chil. P₁, P₂ and P₃ were resistant and P₄ was moderately resistant, whereas P₅ was susceptible to tan spot. The F₂-derived F₃ families and the parents were field evaluated at El Batán, Mexico, in 1996. When all the plants within a F₃ family expressed low levels of disease severity similar to that of the resistant parent it was classified resistant (R), otherwise the progeny was classified as susceptible (S). The progeny of the three crosses of the susceptible parent with the resistant and moderately resistant parents P₂, P₃, and P₄ segregated as 3R:13S whereas the progeny in the cross with P₁ showed a segregation ratio of 1R:15S. This suggests that each resistant parent possessed two genes conditioning resistance to tan spot severity caused by P. tritici-repentis race 1. Information on the inheritance of resistance measured as disease severity on adult plants under field conditions is of practical importance for wheat breeding programs seeking improvement in tan spot resistance.     

Leaf development of spring wheat cultivars in an irrigated heat-stressed environment

Wheat (Triticum aestivum L.) is expanding into lower latitudes of the Nile Valley Region, where maximum air temperature can reach 38–40°C during the short growing season. Genotype and environment, particularly temperature, affect the rate of leaf appearance. Field experiments were conducted at the Gezira Research Station, Wad Medani, Sudan in 1992–94. The study aimed to determine the effect of high temperature (by manipulating sowing dates) on leaf and tiller appearance and growth of nine spring wheat cultivars. Linear response was found between rate of leaf appearance and thermal time and it was faster before double-ridge stage than after double ridge. Phyllochron ranged between 99°C d and 122°C d. Differences in phyllochron interval (PI) were pronounced among cultivars and early-maturing cultivars had faster leaf appearance compared with late-maturing ones. Mean final leaf number on the main stem ranged from 8.1 to 12.2 and it was highly correlated with thermal time from sowing to double ridge stage (r=0.71**). Genetic constitution of cultivars had larger effect on number of leaves per main-stem than temperature. Tillers were initiated at leaf stage 2.9 and cultivars differed in their tillering capacity and only 1.5–2.0 reproductive tillers per plant were produced. About 810°C d were needed to produce tillers 1 and 2 and about 1140°C d for tillers 3 and 4. Leaf senescence started at leaf stage 6.1 for cv. Wadi El Neil and 4.2 for Debeira. Cultivars sown late exhibited delayed senescence of their leaves. High temperature accelerated maturity and the cultivars suited for the irrigated tropical environment were found to be early-sown late-maturing types.     

Tiller mortality and its relationship to grain yield in spring wheat

Spikeless tillers of wheat (Triticum aestivum L.) affect grain yield because of less than optimum effective plant population. This study was conducted to examine the genetic variability for tiller mortality, and its relationship to grain yield in diverse wheat lines. Twenty lines were evaluated in replicated field tests in 4 years at Rampur, Nepal. The characters investigated were maximum number of tiller produced, the number of reproductive tillers, tiller mortality, and grain yield. The lines differed significantly for all characters. The tiller mortality ranged from 7 to 30%. There were substantial effects of environment on all four characters. The entry-by-year interactions were significant for all traits, primarily because of changes in the relative genotypic differences for these traits in the four years. However, certain lines consistently ranked low or high for tiller mortality. There was a significant negative correlation between tiller mortality and grain yield in 3 out of 4 years. There was a positive correlation of highest tiller number with reproductive tiller number and with tiller mortality. Grain yield showed a nonsignificant positive correlation with maximum tiller number. The reproductive tiller number was positively correlated with grain yield. Results of this study indicate that spikeless tillers contribute negatively to grain yield and that genetic variation exists for tiller mortality in spring wheat.     

New records of eriophyoid mites (Acari: Prostigmata: Eriophyoidea) from Saudi Arabia

A field study was conducted to investigate eriophyoid mites associated with some fruit trees in Riyadh, Saudi Arabia. The survey was carried out in four localities (El-Waseel, Al-Beer, Al-Haiyer and El-Deriya) and included seven species of fruit trees, namely olives (Olea europea), fig (Ficus carica), grapes (Vitis vinifera), apple (Malus domestica), citrus (Citrus spp.), pomegranate (Punica granatum) and pear (Pyrus communis). Seven new records of eriophyoid species (Aceria benghalensis Soliman and Abou-Awad, A. olivi Zaher and Abou-Awad, Caleptrimerus baileyi K., Colomerus oculivitis (Attiah), Oxycenus niloticus (Zaher and Abou-Awad), Rhynchaphytoptusficifolia (Keifer) and Tegolophus hassani (Keifer)), belonging two families, Eriophyidae and Diptilomiopidae, were collected from four species of fruit crops covering four different production localities in Riyadh. An illustrated identification key for these mites is provided. The present study is the first scientific study on Saudi eriophyoid mites.     

Growth and development in tall and dwarf isogenic lines of spring wheat

The objective of the experiments reported here was to analyse the nature of the effects of the Rht dwarfing genes on yield potential in spring wheats, using near-isogenic lines of Yaqui 50 and Ciano 67 grown controlled environments. Although tall and dwarf lines had similar relative growth rates at all stages, the taller plants were consistently larger throughout due to faster and more uniform germination. Stem weight at anthesis-whether total or residual-was reduced by the Rht genes in proportion to height. Leaf length and area were much less affected by the Rht genes than was stem length, and later-formed leaves of dwarf plants could even be larger than in their tall counterparts at cool temperatures. Peak photosynthetic rates were similar in talls and dwarfs, the small differences usually reflecting differences in leaf size or specific leaf weight. Root weight was initially heavier in the taller lines, but after the stage of rapid stem elongation it tended to be heavier in the dwarfs. Tillering could be greater or less in the dwarfs depending on environmental conditions, stage, and genotype.Inflorescence initiation was somewhat earlier in the dwarf lines and their inflorescences were therefore initially heavier, and remained so up to anthesis under low irradiance and warm temperatures. But under high irradiance and/or cool temperatures, after an initially slower start the inflorescences of the taller lines eventually became the heavier. Ear weight at anthesis was closely correlated with grain number per ear at maturity and with grain yield per ear in Yaqui 50, but less closely in Ciano 67 lines, in which grain set was reduced at lower temperature when additional Rht genes were present. No evidence was found for a specific effect of the Rht genes in raising grain number. Ear weight at anthesis was relatively less affected than stem weight by adverse conditions, especially in the shorter lines. Nevertheless, across all conditions there was a close relation between stem and ear weights at anthesis, which differed between lines of different height but which closely fitted one regression when ear weight was related to the weight per unit length of stem. Under low irradiance and high temperature the greater stem growth of the taller lines was associated with smaller ears, but at high irradiance and cool temperatures both ears and stems were heavier in the taller lines.Treatments with GA₃ or CCC, to which only the tall lines responded, showed that ear weight at anthesis did not vary with large increase or decreases in stem weight, but grain set and kernel weight could be changed substantially.The yield-determining effects of the Rht genes thus varied with stage of development and environmental conditions, and with genetic background, which may have to be adjusted in order to optimise the effects of the Rht genes on yield potential, suggesting that comparisons of isogenic lines may not always provide a satisfactory indication of the potential value of major genes in breeding programs.     

Effects of clear plastic film mulch on yield of spring wheat

This paper explores the possibility of improving yields of spring wheat (Triticum aestivum) by using plastic film mulching. Field experiments compared three mulching treatments viz. for 20 d (M1), 40 d (M2), and 60 d (M3) after sowing (DAS), with a non-mulch control (CK). Mulching increased temperature and moisture in the upper 5 cm of soil, and shoots emerged 8 d earlier than in CK. Mulching also increased number of tillers, length of the growing period, spikelet and grain numbers per spike, and the duration from flowering to harvest. In the mulched treatments, photosynthesis rate and soluble sugar content were higher in the vegetative period, but soluble sugar content was lower in the grain filling period relative to CK. Grain yield following 20 d mulching was greatest (8207 kg ha⁻¹), and decreased gradually as the mulching period increased (7847 and 6702 kg ha⁻¹ for M2 and M3, respectively). Plastic film removed after 20 d maximizes yield and minimizes soil pollution.     

麦套春棉对棉花生育动态的影响

麦套春棉覆膜栽培．棉株性状次于单作春棉覆膜栽培。而优于单作春棉露地栽培；生育期晚于单作春棉覆膜栽培，而早于单作春棉露地栽培。因此。麦套春棉覆膜栽培能够超过单作春棉露地栽培的产量。麦棉共生期．降雨量少，小麦浇水次数多．麦套春棉覆膜栽培的棉株性状．与单作春棉覆膜栽培的相差较大。与单作春棉露地栽培的相差较小；降雨量多、小麦浇水次数少其差异则反之。麦棉共生期。作物层和耕层土壤热量不足．是影响棉苗生长发育诸因子中的首要因子。     

Chemistry of groundwater of Al-Ahsa Oasis eastern region Saudi Arabia and its predictive effects on soil properties

Saudi Arabia is an arid and the largest country in the middle east with a total land area of 2.253 x 10(6) km2. Recent urban and rural expansion has shown manifold increases in water use in various sectors. Water resources are limited and non-renewable coupled with unpredicted scanty rainfall. In order to meet the rising water needs, evaluation of water quality is important for allocation to various uses. A total of 101 well water samples were collected from Al-Ahsa Oasis. Water samples were analyzed for total salt concentration, pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, F and B contents. Soil Salinity Development (SSD), adjusted sodium adsorption ratio (adj.SAR), adjusted sodium adsorption ratio (adj. R(Na)) and Exchangeable Sodium Percentage (ESP) were calculated. The EC of groundwater ranged between 1.23 and 5.05 dS m(-1). Sodium was the most abundant cation followed by Ca, Mg and K in descending order. Chloride was the most abundant anion followed by SO4 and HCO3 in groundwater of Al-Ahsa Oasis. A significant correlation was found between Na and Cl (R2 = 0.936). Thermodynamics calculation revealed that an appreciable amount of Ca and Mg is associated with Cl and SO4 ions. The SAR and ESP values are within the permissible limits according to Ayers and Westcot, 1985. The NO3 concentration is within safe limits for drinking purpose according to WHO (1998) standards. The Saturation Indices (SI) indicated that groundwater is under-saturated (negative SI) with respect to certain minerals (for example: calcite, dolomite, gypsum, anhydrite, halite, pyrite, fluorite and aragonite) and oversaturated (positive SI) with respect to some other minerals (For example: Goethite, Siderite and hematite). The negative saturation index (SI) reveals that most of minerals are in un-saturated state and will dissolve more Ca and Mg into the soil solution after irrigation. A good relationship exists between Cl and other ions (Na, Ca and Mg) as well as between SO4 and Ca and Mg ion of groundwater. The salinity and sodicity hazards of groundwater of Al-Ahsa Oasis were classified as C3S1 and C4S2 i.e., high salinity with medium sodicity problems. The predicted soil salinity suggested application of 15-20% leaching requirements to keep soil salinity within permissible limits. Cultivation of slight to moderate salt and sodium tolerant crops is recommended for optimal agricultural production and efficient water use.     

Studies on samh seeds (Mesembryanthemum forsskalei Hochst) growing in Saudi Arabia, 1: Anatomy of Samh Seed

The seeds of Samh (Mesembryanthemum forsskalei) are Ostensibly Campylatropous as they seem externally anatropous but internally they have a curved embryo and both the seed body and the funicle exchange shapes. The embryo occupies a cylindrical seed body and is surrounded by a thin layer of endosperm; the major part of the endosperm occupies an ovoid bulge resembling a seed body.     

Variation in gluten quality parameters of spring wheat varieties of different origin grown in contrasting environments

The aim of this study was to investigate variation in protein content and gluten viscoelastic properties in wheat genotypes grown in two mega-environments of contrasting climates: the southeast of Norway and Minnesota, USA. Twelve spring wheat varieties, nine from Norway and three HRS from Minnesota, were grown in field experiments at different locations in Norway and Minnesota during 2009–2011. The results showed higher protein content but lower TW and TKW when plants were grown in Minnesota, while the gluten quality measured as Rmax showed large variation between locations in both mega-environments. On average, Rmax of the samples grown in Minnesota was higher than those grown in Norway, but some locations in Norway had similar Rmax values to locations in Minnesota. The data showed inconsistent relationship between the temperature during grain filling and Rmax. Our results suggest that the weakening effect of low temperatures on gluten reported in this study are caused by other environmental factors that relate to low temperatures. The variety Berserk showed higher stability in Rmax as it obtained higher values in the environments in Norway that gave very weak gluten for other varieties.     

Water-deficit and high temperature affected water use efficiency and arabinoxylan concentration in spring wheat

This study was conducted in a controlled environment to evaluate the combined effects of water-deficit (imposed at the stem elongation stage) and high temperature (imposed at the booting stage) on the water use efficiency (WUE) and arabinoxylan concentration of two spring wheat varieties (‘Superb’ and ‘AC Crystal’) commonly grown in Canada. The temperature treatments were 22/12 (day/night, T1) and 32/22 °C (T2). Overall, time to maturity under high temperature was 10 days shorter for ‘Superb’ than for ‘AC Crystal’, indicating that ‘Superb’ was more sensitive to high temperature stress. Leaf relative water content (RWC) and specific leaf area (SLA) were more sensitive to drought than to high temperature for both varieties. Drought and high temperature decreased (P < 0.05) biomass, water use and grain yield but increased WUE of ’Superb’ and ‘AC Crystal’. Without temperature stress, significant drought and variety effects were found on CID (carbon isotope discrimination) which was negatively correlated with WUE. All gas exchange parameters declined under drought and high temperature. High temperature increased the grain arabinoxylan concentration (especially the water-extractable arabinoxylans). The different arabinoxylan fractions were positively correlated with WUE suggesting that arabinoxylans can be increased by selecting for increased WUE.     

Responses of time of anthesis and maturity to sowing dates and infrared warming in spring wheat

Reliable prediction of the potential impacts of global warming on agriculture requires accurate data on crop responses to elevated temperatures. Controlled environments can precisely regulate temperature but may impose unrealistic radiation, photoperiod and humidity regimes. Infrared warming with automatic control of temperature rise has shown potential for warming field plots above ambient temperatures, while avoiding such biases. In a field experiment conducted at Maricopa, AZ, we assessed the utility of a temperature free-air controlled enhancement (T-FACE) approach by comparing phenology of wheat from a series of six sowing date treatments using T-FACE and an additional nine sowing dates that exposed crops to an exceptionally wide range of air temperatures (<0 °C to >40 °C). The T-FACE treatments were intended to achieve a warming of +1.5 °C during the daytime and +3.0 °C at night; the achieved warming averaged +1.3 °C during daytime and +2.8 °C at night. T-FACE and sowing date treatments had large effects on phenology. A regression-based analysis of simulations with the CSM-CROPSIM-CERES model showed that effects of T-FACE on phenology were similar to what would be expected from equivalent changes in air temperature. However, systematic deviations from the expected 1-to-1 relation suggested that assumed cardinal temperatures for phenology should be revised. Based on the single cultivar and location, it appeared that the base temperature for emergence to anthesis should be reduced from 0 °C to −5 °C, whereas the base temperature for grain filling should be increased from 0 °C to 4 °C and the optimal temperature, from 30 °C to 34 °C. Both T-FACE and extreme sowing date treatments proved valuable for improving understanding of high temperature effects on plant processes, as required for accurate prediction of crop responses to elevated temperatures under climate change.     

Light and electron microscopic study on a haemogregarine species infecting the viper cerastes Cerastes gasperitti from Saudi Arabia

A Haemogregarine sp. infecting the Viper Cerastes cerastes gasperitti (35%) from K.S.A. was recorded for the 1st time. Parasites were recorded exclusively in the red blood cells of the Vipers. Erythrocytic parasites measured 17.5 x 3 microm with a nucleus of 8.1 x 2.5 microm. Mature Schizonts of 30 x 2.5 microm and producing 18-30 merozoites by ectomerogony were reported in the endothelial cells of blood capillaries of different internal organs (liver, spleen and lung). The merozoites measured 13 x 3.5 microm and these were similar to the stages in the red blood cells. The motile stages of the parasite recorded in the present study showed all the general architectures of the Apicomplexa with some pecularities such as presence of micronemes and rhoptries at both sides of the nucleus and the occurance of large number of subpellicular microtubules (80-90) extending to the posterior end of the parasite.