Polygenetic Soils of the North-Central Part of the Gangetic Plains: A Micromorphological Approach

Micromorphology indicates that soils of the central part of the Gangetic Plains are polygenetic. They occur on surfaces originating at 13 500, 8000, 2500, >500 and <500 BP (QGH5 to QGH1, respectively). The QGH5 soils on upland interfluves show degraded illuvial clay pedofeatures of an early humid phase (13 500–11 000 BP) and thick (150–200 μm) microlaminated clay pedofeatures of a later humid phase (6500–4000 BP). The earlier clay pedofeatures were degraded by bleaching, loss of preferred orientation, development of a coarse speckled appearance and fragmentation, whereas those of the later phase are thick, smooth and strongly birefringent microlaminated clay pedofeatures. The illuviation was more extensive during the later phase, as indicated by enrichment of groundmass as discrete pedofeatures of clay intercalations. Pedogenic carbonate was formed during the intervening dry phase from the early Holocene to 6500 BP. It forms irregularly shaped nodules of micrite and diffuse needles with inclusions of soil constituents. The subsequent change to wetter conditions caused dissolution–reprecipitation, which resulted in partial to complete removal of carbonate from soils over large areas.     

Inhibitory effect(s) of polymeric black tea polyphenol fractions on the formation of [(3)H]-B(a)P-derived DNA adducts

Five polymeric black tea polyphenol fractions (PBP-1-5) were isolated from a popular brand of black tea. The effect of these PBPs and epigallocatechin gallate (EGCG), a major green tea polyphenol, was studied on the formation of [(3)H]-B(a)P-derived DNA adducts in vitro, employing rat liver microsomes. PBP-1-3 inhibited microsome-catalyzed [(3)H]-B(a)P-derived DNA adduct formation in vitro in a dose-dependent manner. This inhibition was further enhanced on preincubation of microsomes with each of the PBPs. PBP-4 was not effective per se and required preincubation with microsomes to exhibit its inhibitory effect, whereas PBP-5 remained ineffective with or without preincubation with microsomes. Further investigations revealed that the observed decrease in [(3)H]-B(a)P-DNA adduct formation was due to inhibition of isozymes of CYP450s by PBPs. Overall, results suggest that polymeric black tea polyphenol fractions retain one of the chemopreventive effects exhibited by the monomeric green tea polyphenol EGCG in vitro.     

PH—Postharvest Technology: Physical Properties of Okra Seed

The physical properties of okra seed were evaluated as a function of moisture content (m.c.). The average length, breadth and thickness of the seed varied from 5·92 to 7·30, 4·71 to 5·40 and 4·59 to 5·36 mm, respectively, as the moisture content increased from 8·16 to 87·57% d.b. The roundness and sphericity increased from 77·76 to 79·35% and 74·48 to 76·52%, respectively, with increase in moisture content from 8·16 to 19·56% d.b. and then decreased to 72·39 and 70·63%, respectively, with further increase of moisture content. In the moisture range of 8·16–87·57%, the seed volume increased from 0·067 to 0·124 cm³, 1000 seed weight, W₁₀₀₀ from 65·78 to 129·75 g and the angle of repose from 27·60 to 39·47°. The bulk density, true density and porosity decreased from 0·592 to 0·558 g cm⁻³, 1·107 to 0·986 g cm⁻³ and 46·34 to 43·20%, respectively, in the moisture range from 8·16 to 87·57% d.b. The static coefficient of friction increased on four structural surfaces namely, aluminium (0·390–0·484), bakelite (0·345–0·480), galvanised iron (0·368–0·493) and mild steel (0·389–0·480) as the moisture content increased from 8·16 to 87·57% d.b.     

Effects of environmental and biological variables on the toxicity of mercuric chloride

This study evaluated the effects of environmental and biological variables on the toxicity (LC₅₀) of mercuric chloride on the fish Notopterus notopterus. The results reveal that the change in temperature, dissolved oxygen, pH and fish size in experiments is highly significant both at 1 and 5% levels except in size, where it is insignificant at 1% level.     

Rainwater Composition at a Regional Representative Site of a Semi-Arid Region of India

Rainwater samples (N = 51) were collected at Rampur, an areafree from anthropogenic activity during the monsoon of 1997 and1998. The concentration of ions follows a general pattern as Ca> NH₄ > Mg > SO₄ > Cl > F >Na > NO₃ > K > HCOO >CH₃ COO. The pH of precipitation ranges between 5.9 and 7.4. The levels of Ca and Mg at this site are higher than otherremote sites, probably dominated by particles of soil origin.Good correlation between Ca, NO₃, SO₄, HCOO and CH₃COO indicate that a fraction of NO₃, SO₄, HCOOand CH₃COO may be derived from soil or associated with Ca and Mg after neutralization. The order of neutralization factorCa (2.19) > NH₄ (1.26) = Mg (1.26) indicates that majorneutralization occurred by Ca. Factor analysis suggested thatCa, Mg, Na, K, NO₃, SO₄, HCOO and CH₃COO arecontributed by soil. NH₃ is known to exist as(NH₄)₂SO₄, NH₄NO₃ and NH₄Cl. Theymay be formed in the atmospheric water droplets by scavenging ofaerosols and reaction of gaseous species.     

Microbial contribution to extractable N and P after air-drying of dry tropical soils

The microbial contribution to extractable N and P after the air-drying of eight Indian dry tropical Ultisols was quantified. Air-drying of the soils decreased microbial biomass C by 25–53% but increased extractable N and P by 14–34% and 24–121%, respectively. This increase in the extractable N and P was accounted for, to some extent, by microbial biomass killed due to air-drying. Microbial biomass contributes 17–36% and 19–82% to the extractable N and P, respectively, possibly due to air-drying of the soils. I conclude that due to contamination of microbial biomass with the available nutrients in air-dried soils, measurements of extractable nutrients should be made on field-moist soils. Received: 22 October 1996     

Delineating Genotype × Environment interactions towards durable resistance in mungbean against Cercospora leaf spot (Cercospora canescens) using GGE biplot

Cercospora leaf spot (Cercospora canescens) is a major fungal disease which impedes mungbean production worldwide. Presence of wider host range with existence of pathogenic variability creates intricacy towards host-pathogen dynamics. Moreover, environmental factors having crucial role in augmenting severity of this disease further complicate disease management. An attempt has been made for unfolding genotype x environment interactions towards identifying and validating durable resistant genotypes against cercospora leaf spot in multi-environment testing. Preliminary screening with 246 genotypes under artificial epiphytotic condition was conducted to extract out a subset of 22 mungbean genotypes for further evaluation in field testing across six environments consecutively for two years. GGE biplot analysis detected significant environmental influence towards genotypic response and confirmed the presence of non-crossover interaction with incoherent genotypic response, thus advocating the urgency for multi-location testing. GGE biplot aptly identified “LGG 460” and “COGG 912” as “ideal” and “desirable” genotypes, respectively having durable resistance and genetic homeostasis and thus suggested for their utilization in future resistance breeding programme in mungbean against cercospora leaf spot.     

Identification and characterization of SSRs in <Emphasis Type="Italic">Clarias batrachus</Emphasis> and their application in population study

Magur Clarias batrachus is an indigenous catfish, commonly found in India, Nepal, Bhutan and Bangladesh. Presently, the populations of magur have declined rapidly in their natural habitat mainly due to overexploitation and habitat degradation. Understanding the population genetic structure of the species has significance in improvement of stocks and in conservation of the species. In the present study, simple sequence repeat (SSR) markers were used to differentiate the populations of magur, collected from three geographic locations. For this, a total of 31,814 SSRs were mined from the de novo assembled pooled of whole genome sequence data of C. batrachus. A bioinformatics pipeline with stringent criteria was applied to analyze the data which resulted in selection of 30,142 microsatellite loci falling in the intergenic region. Out of the 25 loci selected for primer development, 16 loci were successfully amplified and 9 loci were found to be polymorphic in this species. The average observed as well as expected heterozygosity in the loci across different stocks varied from 0.652 to 0.688 and 0.864 to 0.873, respectively. These three populations were further segregated into two clusters based on the NJ genetic distance. The Lucknow population formed one cluster, while the Bhubaneswar and Kolkata populations constituted another cluster. A comparable finding was also deduced from the STRUCTURE analyses. The results revealed significant variation among the populations of C. batrachus under study.     

Improving quality of sugarcane-growing soils by organic amendments under subtropical climatic conditions of India

A field trial was conducted on an inceptisol to assess the effect of different bio-manures on sugarcane yield, cane quality, and changes in soil physico-chemical and microbial properties in plant–ratoon system. Seven treatments, viz. control, vermicompost, farmyard manure (FYM), biogas slurry, sulphitation pressmud cake (SPMC), green manuring with intercropped Sesbania, and recommended dose of NPK (150:60:60 kg ha⁻¹), were randomized within a block and replicated three times. Improvement in bulk density and infiltration rates was recorded after the addition of various bio-manures. The highest organic C was recorded in the vermicompost (0.54%) and pressmud (0.50%) treatments. The highest increase in soil microbial biomass C (185.5%) and soil microbial biomass N (220.2%) over its initial value was recorded with the addition of FYM. Dry matter production in plant, as well as ratoon crop, was significantly higher by bio-manure application over the control. Plant N uptake was highest in the pressmud treatment (227.7 kg ha⁻¹), whereas P and K uptake were highest (41.4 and 226.50 kg ha⁻¹) in vermicompost treatment. The highest number of millable canes (95.6 and 101.0 thousand ha⁻¹) in plant and ratoon crop were obtained with the addition of pressmud. The highest yield (76.7 t ha⁻¹) was recorded in planted cane with vermicompost application, whereas ratoon yield was highest (78.16 t ha⁻¹) with pressmud application. In both planted and ratoon crop, organic amendments produced yields statistically similar to those with recommended NPK (76.1 and 78.1 t ha⁻¹ for plant and ratoon cane).     

Sesbania aculeata leaf meal as replacer of de‐oiled rice bran in aquaculture feed: Growth,IGF‐1 expression,metabolic and biochemical responses in Cyprinus carpio (Linnaeus 1758)

A feeding trial was conducted to evaluate the effect of inclusion of Sesbania leaf meal in the diet of Cyprinus carpio as a replacer of de‐oiled rice bran (DORB). Bacillus subtilis was used to ferment the Sesbania leaf meal (SLM) to produce FSLM (fermented sesbania leaf meal). Fishes were fed with five isonitrogenous (30% CP) and isocaloric diets for 60 days and treatments were viz., C (30% DORB, 0% SLM), R15 (15% DORB, 15% SLM), R30 (0% DORB, 30% SLM), F15 (15% DORB, 15%FSLM) and F30 (0% DORB, 30% FSLM) by replacing DORB with SLM. A similar growth performance with control was observed in 15% FSLM group while there was a growth reduction in all the raw leaf meal fed groups. Similarly, the expression of insulin‐like growth factor‐1 (IGF‐1) was significantly (p < .05) higher in control and 15% FSLM fed groups. Growth and metabolic enzymes such as protease, amylase, ALT and AST activities were significantly higher in the fermented leaf meal fed groups compared to their non‐fermented counterparts. Antioxidant enzymes, serum transaminase enzymes (SGOT, SGPT) and total bilirubin (TBR) were found to be increased by enhanced level of RSLM, however, reduced by inclusion of FSLM. However, 30% inclusion level of FSLM even after fermentation showed detrimental effect on growth and metabolic response at cellular and molecular level. Thus, the results concluded that fermented Sesbania leaf meal (FSLM) using B. subtilis could replace 50% DORB (15% FSLM group) in the diet of C. carpio without affecting the growth and other physiological responses.