Studies on photodegradation of chlorimuron-ethyl in soil

Photolysis of chlorimuron-ethyl was studied on a soil surface under sunlight and UV light. Eight photoproducts were isolated and characterised by spectroscopic methods. Major photoproducts are formed by cleavage of the sulfonylurea bridge and minor products are formed via dechlorination, hydrolysis and cyclisation. The rates of photodegradation of chlorimuron-ethyl on different soils followed first-order rate kinetics, with half lives of 22·3 h, 9·4 h, 4·9 h (UV) and 20·7 days, 11·1 days and 11·1 days (sunlight) for alluvial, red and laterite soils, respectively. The differences in rates of photodegradation were dependent upon the soil pH. © 1997 SCI     

Variation in cardiac markers and electrocardiographic alterations in young calves naturally infected with bovine tropical theileriosis

The present study was designed to assess the deleterious effects of bovine tropical theileriosis on the cardiovascular system and the consequent myocardial involvement in young calves. Myocardial effects in parasitic diseases are often neglected. Hemolytic anemia, associated secondary hypoxia, and vasculitis are cardinal features of bovine theileriosis. In the present study, electrocardiogram (ECG) alongside serum cardiac troponin I (cTnI) and creatinine phosphokinase-myocardial band (CPK-MB) concentrations were analyzed in infected, treated, and control groups of young calves. Non-significant alterations were noticed in ECG. However, certain signs like sinus tachycardia, first-degree AV block, atrial premature complex, left atrial hypertrophy, and right atrial hypertrophy were found on consistent basis in infected calves. A significant increase in the serum concentration levels of cTnI and CPK-MB was noticed in infected calves followed by significant fall in both these biomarkers post treatment. cTnI and CPK-MB can definitely be used as myocardial markers in theileriosis-affected animals.     

Host density dependence and environmental factors affecting laurel wilt disease incidence

Host size, density, and distribution, in addition to climate, can affect the likelihood a pathogen will invade and saturate landscapes. Laurel wilt, caused by the vector-borne pathogen Raffaelea lauricola, has devastated populations of native Lauraceae in the south-eastern USA, and continues to spread. We surveyed 87 plots in six coastal islands in South Carolina, Georgia, and north Florida, and one inland site (Archbold Biological Station) in south Florida for laurel wilt-affected and unaffected individual plants belonging to the genus Persea. The coastal island sites were surveyed once in 2008 or 2009, and the inland site was surveyed eight times from 2011 to 2013. Disease incidence per plot ranged from 0% to 96%, with mean disease incidence 42% across all sites. Disease incidence was positively correlated with trunk diameter and with density of hosts with trunk diameter >5 cm, but negatively correlated with the degree of clustering, which was highest for small trees. A recursive partitioning model indicated that higher disease incidence was associated with moderate temperatures, wider trunk diameter, lower relative humidity, and lower wind speeds. Disease progress over time at Archbold followed a Gompertz curve, plateauing at 3% in 2 years. The dispersal kernel for disease incidence from a focus followed a negative exponential distribution. The number of plots with diseased trees at Archbold was similar for redbay (P. borbonia) and swampbay (P. palustris) but was lower for silkbay (P. humilis). Understanding how host density, size, and diversity interact with environmental effects will help guide future risk prediction efforts.     

Correction: Dissecting the plant genome: through new generation molecular markers

Genetic Resources and Crop Evolution -     

Optimal allocation of water from a single purpose reservoir to an irrigation project with pre-determined multiple cropping patterns

A model for optimal allocation of water from a single-purpose reservoir to an irrigation project with pre-determined multiple cropping patterns was developed. The model consisted of two modules: (I) the intra-seasonal allocation model (non-linear programming) which is used for allocation of water among different crops for a definite combination of state variables (inflow class, rainfall class, reservoir storage classes at the beginning and at the end of the season) for the non-dormant season to maximize total farm income; and (II) the seasonal allocation model (stochastic-dynamic programming) which is used for the convergent operating policy over seasons for optimal expected farm income over a year. The model was applied to Ardak reservoir dam (I.R. Iran) in an arid region. Low river inflow in the dormant season at the study area could not admit the reservoir class changes for specific combinations of state variables, and therefore resulted in a non-usable result. Imposing a fictitious positive relative net benefit for all possible combinations of reservoir class changes eliminated this problem. It was also shown that rainfall did not play a marked role in the study area, which is an arid region, and its stochastic nature can be removed from the model.     

Enzymatic surface modification of polyacrylonitrile and its copolymers: Effects of polymer surface area and protein adsorption

Polyacrylonitrile (PAN) is a widely used polymer in the textile industry. PAN contains cyano groups on the surface due to which it possess low hydrophilicity and limits its application. Thus, there is a need to modify the functional groups on the surface of PAN for its industrial demand to improve moisture uptake, dyeability with ionic dyes, without affecting mechanical properties. A number of strategies such as chemical treatment, plasma treatment, enzymatic treatment etc. have been applied for the surface modification of polymer but enzymatic treatment are advantageous over plasma treatment and chemical treatment. In enzymatic treatment, reaction is limited to polymer surface only, and provides milder condition with less damage to polymer. In present study, it was found that enzyme system of Amycolatopsis sp.IITR215 was effective enzyme system for modification of surface nitrile groups of polyacrylonitrile. PAN powder was treated with the cell free extract of Amycolatopsis sp.IITR215 and it was found that the nitrile metabolizing enzymes of this strain were efficiently able to transform -CN to -COOH groups present on the surfaces of PAN powder. The formation of carboxyl group was quantified by ammonia released and dye binding assay. Further, confirmation of carboxyl group on polymer was done by FTIR and XPS. This study indicates that, specific adsorption of enzyme probably plays an important role in the enzymatic surface modification of polymer.     

EFFECTS OF A MULTISTRAIN BIOFERTILIZER AND PHOSPHORUS RATES ON NUTRITION AND GRAIN YIELD OF PADDY RICE ON A SANDY SOIL IN SOUTHERN VIETNAM

Field experiments during two successive rainy seasons were conducted in southern Vietnam to evaluate the effects of a commercial inoculant biofertilizer (‘BioGro’) and fused magnesium phosphate (FMP) fertilizer on yield and nitrogen (N) and phosphorus (P) nutrition of rice. Inoculation with BioGro containing a pseudomonad, two bacilli and a soil yeast significantly increased grain yield in the second season and straw yield in both seasons by 3–5%. The FMP fertilizer significantly increased grain yield from 1.72–2.33 t ha^?1 to 2.99–3.58 t ha^?1 along with total N and P accumulation at all rates in both cropping seasons. In the first season the difference in grain yield between BioGro treated and untreated plots was marginal but in the second season BioGro out-yielded the control at all the rates of added P. Overall, BioGro application did not compensate for low P fertilizer application to the same extent previously demonstrated for low N fertilizer applications.     

Phonon Density of States and Specific Heat of Forsterite, Mg2SiO4

The phonon density of states of the geophysically important mineral forsterite has been calculated with a rigid-ion model, which gives good agreement with an experimental measurement by inelastic neutron scattering. The density of states has been used to calculate the specific heat as a function of temperature, the results of which are in excellent agreement with calorimetrically measured values. The rigid-ion model takes account of the interatomic interactions and normal modes of vibration on a detailed microscopic basis, and is therefore more realistic than the Debye and other empirical models used previously.     

Bed planted rice–wheat rotation at differential soil moisture regimes on soil hydro-physical properties, root growth, nitrogen uptake, and system productivity

Along with most widely practiced resources conserving technology zero-tillage wheat after rice, adoption of permanent beds for rice–wheat rotation is also gaining popularity. Since relatively a new approach particularly for dry-seeded rice and permanent beds for wheat, very little information is known about permanent beds on soil properties, nutrient (N) use efficiency, and system productivity. A field experiment was carried out in a Typic Haplustept soil of New Delhi, India to study the effect of permanent beds on soil hydro-physical properties, root growth, nitrogen uptake, and system productivity of irrigated rice–wheat rotation. Results revealed that direct-seeded rice followed by wheat on permanent beds irrigated at different soil water tensions (field capacity, 20 and 40 kPa) reflected a significant variation in soil hydro-physical properties, reduced total nitrogen uptake, contribution by different plant parts, and N use efficiency compared to wheat after flooded transplanted rice system. Rice root weight density at flowering was also significantly low at 0–15 cm depth but higher at 15–60 cm depth in dry-seeded rice on beds. System productivity of rice–wheat rotation was 25–33% lower in permanent beds compared to flooded transplanted system. For wider acceptability of permanent beds as a promising resource conserving technology, system productivity needs to be improved.     

Inoculant plant growth-promoting microorganisms enhance utilisation of urea-N and grain yield of paddy rice in southern Vietnam

Field experiments were conducted during successive rainy seasons in 2006 in the Chau Thanh district of southern Vietnam to evaluate the effects of an inoculant plant growth promoter product called “BioGro” and N fertiliser rates on yield and N and P nutrition of rice. The results indicated that inoculation with BioGro, containing a pseudomonad, two bacilli and a soil yeast, significantly increased grain and straw yields and total N uptake in both seasons, as well as grain quality in terms of percentage N. Nitrogen fertilisation increased grain and straw yields as well as total N and P uptakes significantly in both cropping seasons. The estimated grain yield response to added N was quadratic in nature with and without added BioGro. In the first crop, BioGro out-yielded the control up to 90 kg urea N ha^?1 whilst in the second season the beneficial effect of BioGro was observed up to 120 kg urea N ha^?1, indicating either an interaction of the inoculant with higher yielding seasonal conditions or a cumulative effect of BioGro application. In the first season, the estimated N rate for maximum grain yield was 103 kg N ha^?1 with BioGro while it was 143 kg N ha^?1 without BioGro. The maximum estimated grain yields were 3.21 and 3.18 t ha^?1 with and without BioGro, respectively. This information indicates that BioGro was able to save 40 kg N ha^?1 with an additional rice yield of 30 kg ha^?1 in the season. In the second rainy season, the estimated N rates for maximum grain yields were 94 and 97 kg N ha^?1 with and without BioGro, respectively. The estimated maximum grain yields were 3.49 and 3.25 t ha^?1 with and without BioGro, respectively. The two seasons’ combined results indicate that application of BioGro improved the efficiency of N use by rice significantly, saving 43 kg N ha^?1 with an additional rice yield of 270 kg ha^?1 in two consecutive seasons at the experimental site. The extra efficiency was shown by the fact that the same yield of rice was obtained with about 40 and 60 kg less fertiliser-N that the maximum yields with urea alone in the two successive harvests on the same plots.