Molecular Responses to Cadmium in Roots of Pisum Sativum L.

Molecular responses to Cd were studied in roots of three pea genotypes (cv. Frisson, VIR4788, VIR7128) growing in a polluted substrate. Root and shoot fresh biomass was decreased by Cd pollution in all genotypes. Gene expression profiling after one weeks' exposure to Cd revealed that genes encoding stress-related proteins (heat-shock protein, pI206, chitinase, chalcone isomerase), a metallothionein, γ -glutamylcysteine synthetase and glutathione reductase were up-regulated in the pea genotypes. A glutathione synthetase gene was activated only in VIR4788 but a homoglutathione synthetase gene was unaffected by Cd, and concomitantly glutathione/homoglutathione accumulation in plant roots did not change with Cd stress. However, the overall concentration of thiol groups, which indicate the presence of phytochelatins and/or homophytochelatins, increased more than 2-fold.     

Effect of soil compaction on photosynthesis and carbon partitioning within a maize–soil system

Soil compaction is known to affect plant growth. However, most of the information regarding the effects of this factor on carbon partitioning has been obtained on young plants while little is known about the evolution of these effects with plant age. The objective of this work was to investigate how soil compaction affects carbon assimilation, photosynthate partitioning and morphology of maize plants during vegetative growth up to tassel initiation. A pressure was applied on moist soil to obtain a bulk density of 1.45 g cm⁻³ (compacted soil (CS) treatment) while the loose soil (LS) treatment (bulk density of 1.30 g cm⁻³) was obtained by gentle vibration of soil columns. Plants were grown in a growth chamber for 3–6 weeks and carbon partitioning in the plant–soil system was evaluated using ¹⁴C pulse-labelling techniques. Soil compaction greatly hampered root elongation and delayed leaf appearance rate, thereby decreasing plant height, shoot and root dry weights and leaf area. The increase in soil bulk density decreased carbon assimilation rate especially in early growth stages. The main effect of soil compaction on assimilate partitioning occurred on carbon exudation, which increased considerably to the detriment of root carbon. Furthermore, soil microbial biomass greatly increased in CS. Two hypotheses were formulated. The first was that increasing soil resistance to root penetration induced a sink limitation in roots and this increased carbon release into the soil and resulted in a root feedback that regulated carbon assimilation rate. The second hypothesis relies on soil–plant water relations since, due to compaction, the pore size distribution has to be considered. In a compacted soil, the peak of the pore size distribution curve is shifted towards the small pore size. The volume of small pores increases and the unsaturated conductivity decreases substantially, when compared to non-compacted soil. Due to small hydraulic conductivity, the inflow into the roots is well below optimum and the plant closes stomata thus reducing carbon assimilation rate. The effects of soil compaction persisted with plant age although the difference between the two treatments, in terms of percentage, decreased at advanced growth stages, especially in the case of root parameters.     

Translocation and recovery of 15N-labelled N derived from foliar uptake of 15NH3 by rice (Oryza sativa L.) cultivars

Foliar uptake of ¹⁵NH₃ applied at two growth stages (tillering and anthesis) and the subsequent ¹⁵N-labelled vegetative-N distribution in different plant components at maturity was investigated in three rice cultivars, IR-6, NIAB-6 and Bas-385. Rice plants absorbed 22–30% and 18–24% of the ¹⁵NH₃ applied at tillering and anthesis stages, respectively. Of the total ¹⁵NH₃ absorbed at tillering stage, IR-6 and Bas-385 showed higher recovery (71%) in different plant components at maturity as compared to NIAB-6 (48% recovery). At maturity, percent recovery of the ¹⁵NH₃ absorbed at anthesis stage was almost comparable in different cultivars, but it was lower (46–55%) than that absorbed at the tillering stage. Recovery of the absorbed ¹⁵NH₃-N in the soil was negligible and ranged from 0.3–1%. At maturity, the cultivars IR-6 and Bas-385 showed a higher loss (45–53%) of ¹⁵NH₃ absorbed at anthesis than at the tillering stage (29% loss), whereas for NIAB-6, the corresponding figures were comparable for the two growth stages (tillering, 51% loss; anthesis, 49% loss). Results indicated a variable potential of the tested rice cultivars for foliar uptake of atmospheric ¹⁵NH₃ and distribution of ¹⁵N-labelled vegetative-N in different plant components.     

Morphological Variability of Prosopis cineraria (L.) Druce, from the Cholistan Desert, Pakistan

Sixty-two accessions of Prosopis cineraria, collected from different areas of the Cholistan desert and from the vicinity of Islamia University, Bahawalpur during June, 2002 were evaluated for agro-morphological diversity. Data collected revealed considerable variation for pod length, pod thickness, number of seeds per pod, pod weight, 100-seed weight, seed size, number of pinnules, length of pinnae, length of the pinnulae, and breadth of the pinnulae. Accessions GD-1 and GD-2, collected from Gadhen Wala Toba, KWT-1, KWT-3, KWT-4, KWT-6, from Khokhran Wala Toba, TWT-2, TWT-7, TWT-8, from Taraway Wala Toba, CSW-2, CSW-7, CSW-8, from Chah Sulleh Wala, and IUB-5, IUB-9, from Islamia University, Bahawalpur, showed very high variation. Overall, accessions KWT-6 from Khokhran Wala Toba, and TWT-7, from Taraway Wala Toba, (both from Cholistan desert), appeared as best genotypes based on their morphological variation detected in this study.     

Multilocus variable number tandem repeat analysis (MLVA)-typing of Brucella abortus isolates of India reveals limited genetic diversity

Tropical Animal Health and Production - Multilocus variable number tandem repeat analysis (MLVA) technique has wide applications in studying phylogenies and short-term epidemiology of pathogens....     

Effects of Potassium Sulfate on Adaptability of Sugarcane Cultivars to Salt Stress under Hydroponic Conditions

The effect of potassium sulfate (K₂SO₄) on adaptability of sugarcane to sodium chloride (NaCl) stress was investigated under hydroponic conditions. Two sugarcane cultivars, differing in salinity tolerance, were grown in half strength Johnson's solution at 80 mM NaCl with 0, 2.5 and 5.0 mM potassium (K) as K₂SO₄. Salinity disturbed above and below-ground dry matter production in both sugarcane cultivars. However, salt sensitive cultivar showed more reduction in shoot dry matter and higher root:shoot ratio compare to the salt tolerant cultivar under. Application of K significantly (p < 0.05) improved dry matter production in both sugarcane cultivars. The concentration of Na was markedly increased with increasing salinity; however, the application of K reduced its uptake, accumulation and distribution in plant tissues. Salinity induced reduction in K concentration, K-uptake, K utilization efficiency (KUE) and K:Na ratio in both sugarcane cultivars was significantly improved with the addition of K to the saline growth medium.     

Determination of thiamphenicol in bovine plasma by liquid chromatography

A liquid chromatographic method is described for the measurement of thiamphenicol in bovine plasma. The plasma (1 mL) is extracted with ethyl acetate. After the solvent is evaporated under a stream of nitrogen, the residue is reconstituted in methanol-water and analyzed by reverse-phase liquid chromatography with UV detection at 224 nm. The intra-day recoveries for bovine plasma spiked with 5 and 50 micrograms/mL of thiamphenicol were 102 and 101%, respectively, with coefficients of variation of 2.40 and 0.28%, respectively. The interday recoveries for the 5 and 50 micrograms/mL samples were 103 and 101%, respectively, with coefficients of variation of 3.40 and 0.94%, respectively. The sensitivity of the method allows quantitation to at least the 100 ng/mL level.     

Performance assessment of irrigation water management in old lands of the Nile delta of Egypt

This paper provides the methodology and results of a cross-scale diagnostic performance assessment program of the irrigation water management in the old lands of the Nile Delta of Egypt. The analysis was done at three levels; main canal level, branch canals level and on-farm level of the Meet Yazid command (82,740 ha) for the year 2008?C2009 to highlight areas for improvement. At the main canal level the annual average percentage of irrigation water returning to drains and groundwater was 53% of the total water supplied. Since Meet Yazid lies at tail end of the delta, and there is groundwater salinity, opportunities for reuse are increasingly limited moving north to Lake Burullus. This would indicate opportunities for real water savings. The results of monthly relative water supply of the main canal indicated mismatch between demand and supply especially during the winter months, and when supply is low farmers do reuse drainage or groundwater. Also, the assessment of the three branch canals showed non-uniformity of water distribution and mismatch between demand and supply even when comparing improved and non-improved canals. At the on-farm level in paddy fields, the amount of irrigation flows to drains and saline sinks varied from 0.46 to 0.71 of inflow. In spite of these values of non-uniformity and low depleted fraction, the relative evapotranspiration (ratio of actual to potential) evaporation was uniformly high, indicating most crops of most farmers were not water stressed, which is also confirmed by the high yield values. The average values of productivity per unit water depleted by ET_act were 1.04 and 1.05 kg/m³ for rice and wheat fields, respectively, with yields of rice and wheat at 8 and 6 t per ha respectively. On farm and tertiary improvements alone will not yield real water savings, as excess water in the main canal and drains will continue to flow out of the system. Rather the focus should first be on supplies to the main canal, accompanied by more precise on farm and water delivery practices at branch and tertiary levels, and ensuring that environmental flows are met. There is an added advantage of focusing on this tail end region of Egypt that this response would lessen vulnerability to reuse of polluted and saline water.     

Detection of Coxiella burnetii, the agent of Q fever, in oviducts and uterine flushing media and in genital tract tissues of the non pregnant goat

The aim of the present study was the detection and quantification of Coxiella burnetii DNA in the flushing media (oviducts and uterine horns) and genital tract tissues of non pregnant goats from 20 goats chosen at random from 86 goats originating from 56 different breeding herds in south-west France. The serological prevalence rate of C. burnetii in the study population was 70.3%.The DNA of C. burnetii was identified using conventional PCR in the flushing media from the oviducts and uterus in 8/20 goats (40%) and in genital tract tissues (oviduct, uterus and ovary) in 5/20 goats (25%). This study clearly shows for the first time that the media used to flush the oviducts or uterine horns, collected using the standard embryo harvesting technique in goats, are susceptible to infection with C. burnetii. The 16 conventional PCR-positive samples were also analyzed using real-time PCR. The bacterial load of the oviduct and uterine flushing media varied from 2.9 × 10⁴ to 7.5 × 10⁶ bacteria per flushing medium, while the bacterial load of the tissue samples varied from 1.0 × 10² to 1.5 × 10⁵ bacteria per mg of tissue. The infection of genital tract flushing media and tissues is a risk factor for the transmission of C. burnetii from donor to recipient during embryo transfer or to the embryo and fetus when gestation is pursued to term.     

Electrokinetic Remediation of Pentachlorophenol Contaminated Clay Soil

This paper presents a bench-scale experimental study performed to investigate the remediation of low permeable soil contaminated with pentachlorophenol (PCP) using the electrokinetic technique. A total of six electrokinetic tests were performed using kaolin soil spiked with 100 mg/kg of PCP. The first three tests were performed with an applied voltage gradient of 1 VDC/cm, where each test employed one of the three different flushing solutions: deionized water, electrolyte, or buffered electrolyte. The other three tests were performed using the same electrolyte solution, but each employed voltage gradient of 2 VDC/cm under constant and periodic application modes and constant voltage gradient with electrode liquid recirculation. The results of this study showed that PCP can be degraded in an electrokinetic system due to the direct electrochemical reduction process at the electrodes. The degradation of PCP ranged from 52% to about 78% depending on the conditions present. As the applied voltage gradient across the PCP-contaminated soil increased, the electroosmotic flow and PCP migration toward the cathode increased, resulting in higher PCP degradation by the direct reduction process. In the tests with electrolyte flushing solution, PCP degradation was about 58% and 65% under the applied voltage gradients of 1 and 2 VDC/cm, respectively. The mode of application of voltage potential across the PCP-contaminated soil showed noticeable effect on the system pH and electroosmotic flow and hence the PCP degradation. The highest PCP degradation (i.e., 78%) was in the test with constant 2 VDC/cm voltage gradient and recirculation application. Overall, this study demonstrated that electrokinetic technology has the potential to remediate PCP-contaminated clay soils by the direct reductive process. The electroosmatic flow as well as degree of PCP degradation during electrokinetics depend on the applied potential gradient and properties of the aqueous phase such as pH, ionic strength, and presence of carbonates.