Understanding physical clogging in drip irrigation: in situ,in-lab and numerical approaches

Dripper clogging is a major drawback of microirrigation systems that must be addressed to improve their efficiency and durability. Particle-induced clogging is first studied in situ. The experiments consist in observing in real conditions the behavior of a series of drippers fitted on an agricultural plot in the south of France. The plot is supplied from a canal with Durance River water. The latter is loaded with sediments that gradually clog drippers and filters. Water analysis reveal that physicochemical clogging prevails over biological clogging. This characterization helps in setting in-lab experiment protocol. Indeed, besides field observation of clogging, laboratory analyses of both the irrigation water and the clogging material are performed with reactive and inert clay: smectite and an illite–calcite mix. A surprising tendency is observed: Salt concentration in smectite seeded water decreases the clogging, whereas it increases agglomerate size. Computational fluid dynamic simulations are carried out to investigate the impact of particles on flow behavior. Results demonstrate that clay particles interacting with the flow govern the complex structure of the fluid velocity fields inside the dripper labyrinth channel.     

Effects of nanosilicon dioxide application on in vitro proliferation of apple rootstock

Although silicon (Si) is the second most abundant element of the earth's crust and in soils, it is not listed among the essential elements for plants. However, the beneficial role of Si in stimulating the growth and development of many plant species has been recognized. This study investigated the effects of in vitro application of nanosilicon oxide on growth and proliferation of apple rootstock MM₁₀₆ in tissue culture. The experiment included five levels nanosilicon oxide (0, 25, 50, 100, and 200 mg/L) added to Murashige and Skoog medium. The results showed that using nanosilicon increased in fresh and dry weights, length and number of branches, and chlorophyll in explants with the highest increase being at 100 mg/L. Growth suppression occurred at 200 mg/L. This investigation showed that 100 mg/L silicon oxide can be added to Murashige and Skoog medium for fast growth and proliferation of MM₁₀₆ apple rootstock explants.     

Effects of commonly used disinfectants on bacterial load,hatchability and survival of Bluefin Sea bream (Sparidentex hasta) eggs

The efficacy of four chemical reagents, iodophor, formalin, hydrogen peroxide and bronopol as fish egg surface disinfectants were evaluated in bluefin sea bream (Sparidentex hasta). Fertilized eggs were counted and subjected to a static bath dip treatment in different concentrations of the above chemicals for 4 min before being incubated at 20 ± 0.5°C for 40 h. Treatment efficacy of the different disinfectants was evaluated by assessing the bactericidal activity, egg hatch percentage and survival of larvae up to 3 days post hatch. Results showed that iodophor at medium concentrations (75 and 100 ppm) was the best of all tested disinfectants in bacterial killing ability (12% reduction in the bacterial counts), egg hatching per cent (99.8% and 99.6% respectively) and larval survival up to 3 days post hatch (50.8% and 54.8% respectively). Formalin was the second best disinfectant at levels of 100 and 150 ppm. Hydrogen peroxide gave good results compared with the control while, bronopol showed discouraging results. In conclusion, iodophor appeared to be suitable for bluefin sea bream eggs disinfection with a 4 min exposure to 75–100 ppm when applied 14–16 h after egg fertilization.     

Factors associated with gastrointestinal parasite infection in dogs in Rio de Janeiro, Brazil

Factors associated with parasitism by helminths and protozoans in 500 dogs presented to three veterinary clinics in the municipality of Rio de Janeiro from November 2003 to September 2004 were evaluated. Dogs were submitted to physical examination and owners were interviewed about the animal's management. One fecal sample from each dog was examined by centrifugal flotation and sedimentation methods followed by the safranin–methylene blue staining technique. Positive results for gastrointestinal parasites were detected in 46.4% of the examined samples. Infection with protozoans (29.6%) was more frequent than with helminths (23.2%). Cryptosporidium sp. (26.2%) and Ancylostoma sp. (15.2%) were the most frequent parasites. Logistic regression analysis showed that age (p < 0.001), access to soil (p < 0.001), hygiene of the environment (p = 0.001), illness (p = 0.007), owner's level of education (p < 0.006) and veterinary clinic (p = 0.043) were associated with gastrointestinal parasite infections in dogs. Treatment and control are especially important for puppies. Adult dogs should be submitted to fecal examination before treatment, placing special emphasis on those that present one or more factors associated with infection.     

Response Surface Methodology for Modeling Bisphenol A Removal Using Ultrafiltration Membrane System

In this work, the effects of various operating parameters (pressure, pH, BPA concentration, and filtration time) toward bisphenol A (BPA) removal via ultrafiltration (UF) membrane system were investigated using response surface methodology (RSM). Historical data design of RSM was used to obtain the interaction between variables and response as well as optimizing the process. The analysis of variance (ANOVA) showed that the third-order polynomial model was significant in which pH and filtration time were identified as significant terms that influence BPA removal. The 3D response surface plots revealed the two-factor interaction between independent and dependent variables. The optimization process of the model predicted optimum conditions of 99.61% BPA removal at 1 bar, pH 6.7, 10 μg/L BPA concentration, and 10-min filtration time. The predicted optimum conditions for BPA removal were consistent with the obtained experimental values, indicating reliable application of historical data design RSM for modeling BPA removal in UF membrane system.     

Do pre-sowing treatments affect seed germination in <Emphasis Type="Italic">Albizia richardiana</Emphasis> and <Emphasis Type="Italic">Lagerstroemia speciosa</Emphasis>?

In this paper, seed morphology and effects of pre-sowing treatments were studied. Matured seeds of the species were collected from healthy trees in the National Botanical Garden, Bangladesh, and treated with five pre-sowing treatments. The average length, breadth and thickness were found to be 0.56±0.03 cm, 0.44±0.009 cm and 0.26±0.008 cm in Albizia richardiana King and Prain, and 1.32±0.02 cm, 0.55±0.04 cm and 0.11±0.002 cm in Lagerstroemia speciosa L., respectively. Germination was carried out in polybags with a mixture of topsoil, coconut husk compost, coarse sand and fine sand in a ratio of 3:4:1:1. Results revealed that the germination rates of seeds in different pre-sowing treatments were significantly increased compared to those in cold-water treatment in both species. The highest germination rate was found to be 96% in hot-water treatment followed by 87%, 83% and 49% in treatments with scarification, H₂SO₄ and control in A. richardiana, respectively. However, the highest germination rate (79%) was found in H₂SO₄ treatment followed by 64%, 62% and 25% in treatments with hot water, scarification and control in L. speciosa, respectively. The lowest germination (35% in A. richardiana and 20% in L. speciosa) was found in cold-water treatment in both cases. Analysis of variance (ANOVA) showed the significant difference among the treatments for both species. It is concluded that hot-water treatment is recommended for seed germination of both species in rural Bangladesh.     

New withanolides from Mandragora officinarum: First report of withanolides from the Genus Mandragora

Two new withanolides named mandragorolide A (1) and mandragorolide B (2) were isolated from the MeOH extract of the whole plant of Mandragora officinarum of Jordanian origin, along with five known withanolides namely larnaxolide A (3), withanolide B (4), datura lactone 2 (5), withanicandrin (6) and salpichrolide C (7). Compound 3 has been reported only once before, from the leaves of Larnax glabra. This is the first report of withanolides of different biogenetic types from the genus Mandragora. Isolation of known fatty compounds, coumarins, sterols and tropane alkaloids was also achieved in this study.     

Taurine is more effective than melatonin on cytochrome P450 2E1 and some oxidative stress markers in streptozotocin-induced diabetic rats

Melatonin and taurine have alleviative effects in streptozotocin (STZ)-induced diabetic rats. Male Wistar rats were divided into nondiabetic, diabetic, diabetic melatonin supplemented and diabetic taurine supplemented groups. At the end of the study, both blood and liver were collected for determination of some oxidative stress parameters, and hepatic cytochrome P450 2E1 (CYP2E1) enzyme activity and gene expression. An increased CYP2E1 activity and expression level with a concomitant significant change in oxidative stress parameters were found in STZ-induced diabetic rats. Taurine or melatonin supplementation to the diabetic rats alleviated these experimental parameters with a more significant effect for taurine than that of melatonin. Suppression of β-hydroxybutyrate (β-HB) production by taurine can be one of the mechanisms of a reduction in CYP2E1. Taurine was effective more than melatonin in reducing CYP2E1 activity and expression; therefore antioxidants might prove beneficial in type 1 diabetes associated with manifestations of liver injury.     

Limited genotype- and ploidy-related variation in the nutritive value of perennial ryegrass (Lolium perenne L.)

Abstract

Water-soluble carbohydrates and fibre fractions are important traits that influence forage utilization by the ruminant. Little is known about the quality variation among perennial ryegrass genotypes within the same maturity group or between near-isogenic diploids and tetraploids. The current study was carried out in the form of two experiments on two successive years (2006–2007) in three sites in Northern Germany. The main aim was to investigate the variation in nutritive value that could be attributed to differences in maturity among 20 intermediate heading perennial ryegrass genotypes or to differences in ploidy between near-isogenic diploids and tetraploids. Results of the first experiment revealed significant variation among the 20 tested genotypes in the investigated quality parameters that were consistent with the discovered variation in the maturity of the genotypes determined in terms of their Mean Stage by Count (MSC). In the second experiment, few but consistent significant differences were detected between near-isogenic diploids and tetraploids. The tetraploid derivatives had always significantly higher water-soluble carbohydrate content and lower neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) than their near-isogenic diploid parents.     

Changes in Growth,Yield, Photosynthetic Pigments,Biochemical Substances,Oxidative Damage,and Antioxidant Activities Induced by Treatment with Different pH of Artificial acid rain in Pumpkin (Cucurbita Moschata)

Acid rain is one of the major environmental problems that causes plant morphological and physiological disorders. But there are few studies about the impact of acid rain on vegetable crops. This work aimed to study the various effects of simulated acid rain (SAR) at different levels of pH (5.0, 4.5, 4.0, 3.5 or 3.0) on growth, yield, pigment content, protein, carbohydrate, water content in leaves, minerals (NPK), oxidative damage and the activity of various antioxidants in pumpkin. The results show that the plant growth, yield, chlorophyll, carotenoids, protein, carbohydrates, leaf water content, NPK in the leaves of the pumpkin crop decreased significantly with increasing levels of acidity of SAR as compared to the untreated set. H₂O₂ and MDA are increased by SAR treatment which depends on the level of pH value of SAR. The highest value of hydrogen peroxide and malondialdehyde was recorded at pH 3.0 and lower at pH 5.0 of SAR treatment on the pumpkin crop. In contrast, superoxide dismutase, catalase, nitrate reductase and proline contents were accumulated at pH 3.0 and degraded at pH 5.0 of SAR treatment on pumpkin as compared to control. In conclusion, our findings suggest that pumpkin produces more reactive oxygen species (ROS) scavenging SAR stress through the production of enzyme and non-enzyme antioxidant compounds at 3.0 pH. Meanwhile, growth inhibition as well as the photosynthesis of pumpkin and the magnitude of oxidative damage increased as acidity increased (pH 3.0 of SAR).