Level of agreement between objectively determined body composition and perceived body image in 6- To 8-year-old South African children- To Body Composition-Isotope Technique study

To assess the level of agreement between body size self-perception and actual body size determined by body mass index (BMI) z-score and body fatness measured by the deuterium dilution method (DDM) in South African children aged 6-8 years. A cross-sectional sample of 202 children (83 boys and 119 girls) aged 6-8 years from the Body Composition-Isotope Technique study (BC-IT) was taken. Subjective measures of body image (silhouettes) were compared with the objective measures of BMI z-score and body fatness measured by the DDM. The World Health Organization BMI z-scores were used to classify the children as underweight, normal, overweight, or obese. DDM-measured fatness was classified based on the McCarthy centile curves set at 2nd, 85th and 95th in conjunction with fatness cut-off points of 25% in boys and 30% in girls. Data were analyzed using SPSS v26. Of 202 children, 32.2%, 55.1%, 8.8%, and 2.4% perceived their body size as underweight, normal, overweight, and obese, respectively. Based on BMI z-score, 18.8%, 72.8%, 6.9%, and 1.5% were classified as underweight, normal, overweight, and obese, respectively. Body fatness measurement showed that 2.5%, 48.0%, 21.8%, and 29.7% were underweight, normal weight, overweight, and obese, respectively

Nitrate assimilation in relation to total reduced N in bengal gram (Cicer arietinum)

On the basis of a preliminary experiment with 20-day-old Cicer seedlings, wherein the values obtained by integrating the in vivo nitrate reductase (NR) activity with the duration closely approximated the actual reduced N, a field experiment was conducted with cv BG 203 (indeterminate type) to ascertain the extent to which the nitrate assimilated via the enzyme NR contributed to the total reduced N. Soil-derived N accounted for 15.1, 8.3 and 7.2% of the total reduced N at pre-flowering (I), profuse flowering (II) and seed filling (III) stages respectively. Out of the total soil-derived N, 10.1, 59.3 and 30.6% was reduced during stages I, II and III respectively

Nitrogen economy of the main shoot of field-grown barley (Hordeum vulgare L.) I. Dry weight, duration, and nitrate content in different organs

The main shoot of field-grown Jyoti barley (Hordeum vulgare L.) grown at 40 kg ha-1 was separated into different organs at various stages of growth and development. Changes in fresh and dry weights and duration for which the parts remained metabolically active (green) were recorded. Weight duration (gram × day), a factor contributing to total NO-3 reduction of each organ, was calculated. The dry matter percentage increased in the successively formed laminae and sheaths. The weight duration of the different components viz. internodes, spike (excluding the grains), laminae, and sheaths, respectively were 40.2, 10.5, 21.8, and 17.8. Nitrate content (µmol g-1 dry wt.) was high in the initially formed organs and declined in the successively formed ones. In the laminae, there was a sharp fall after achieving maximal values except for the flag lamina where the changes in NO-3 content were marginal over a fairly long period. The ear components had low NO3- concentration. Total NO-3 content (µmol) in the main shoot showed peaks at 49, 84, and 118 d after sowing

Nitrogen economy of the main shoot of field grown barley (Hordeum vulgare L.) III. Content of reduced nitrogen in different organs

Nitrogen concentration pattern and total nitrogen content in the various organs of the main shoot of field grown Jyoti barley at 40 kg N ha-1 were determined. The laminae had a much higher N concentration (µmol g-1 dry wt.) than the other organs at a corresponding stage. The major amount of N accumulates in the main shoot by ear emergence. An observation of interest is the decline in the total N content of the laminae before anthesis. The results are discussed in relation to mobilization of N within the shoot and the contribution of the vegetative parts to the N in developing grains

Nitrogen economy of the main shoot of field-grown barley (Hordeum vulgare L.) II. In vivo nitrate reductase activity during growth

The method for assay of in vivo nitrate reductase (NR) activity was standardized for barley (Hordeum vulgare L.). NR activity was determined in the various organs of the main shoot of field-grown Jyoti barley at 40 kg N ha-1. Total nitrate reductase activity (TNRA) of each organ for the period it was metabolically active was calculated. The NR activity was highest in the laminae, followed by the sheaths, reproductive organs; and internodes. The NR activity was high in the first-formed laminae and it showed a decline in the ones formed subsequently. The values varied from 43.2 ± 4.33 to 7.2 ± 1.49 µmol NO-3 reduced g-1 dry wt. h-1. Maximum TNRA in the laminae, sheath, and internodes was at 49, 84, and 84-93 d after sowing, respectively. The TNRA of the main shoot as a whole showed three peaks, one around 49 d, a second around 63 d, and a third around 84 d after sowing. Correlation coefficient (r) between NR and NO3 concentration was highly significant in the laminae and sheath viz. 0.76 and 0.62, respectively. The results are discussed in relation to alteration in management practices to maximize nitrate assimilatory activity and the amount of reduced N harvested