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M. Das P. H. Zaidi M. Pal & U. K. Sengupta 《Journal of Agronomy and Crop Science》2002,188(4):219-224
An experiment was undertaken using open‐top chambers to study the effect of CO2 enrichment on crop growth and to assess the variation related to the time of CO2 exposure. In general, enriched CO2 conditions (600 ± 50 p.p.m.) in the chamber positively affected the growth and development of mungbean (Vigna radiata), a short‐duration (60–65 days) summer pulse crop. However, there was significant variability in the effect of the crop stage/time of CO2 exposure. It was observed that high CO2 exposure at an early growth stage [0–20 days after germination (DAG)] had a larger effect than that at a later growth stage (21–40 DAG). The experiment also provided a means of assessing the short‐ and long‐term effects of elevated CO2 on the carbon exchange rate at both stages of exposure. The study revealed that the sensitivity of plants to high CO2 was more pronounced with respect to net photosynthetic rate. The overall photosynthetic activity gave greater growth and development of plants under high CO2. 相似文献
45.
U. R. Pal B. A. Kalu J. C. Norman D. K. Adedzwa 《Journal of Agronomy and Crop Science》1988,160(2):132-140
Field experiments were conducted to investigate into the N and P fertilizer use in soybean/maize mixture during the wet seasons of 1985 and 1986 at Yandev Agricultural Experiment Station. Soybean/maize mixtures with 2/3 of the respective plant population of both crops in pure stands were raised at factorial combinations of four rates of N, 0, 40, 80, and 120 kg N/ha and four rates of P, 0, 13.2, 26.4 and 39.6 kg P/ha in a randomized complete block design with three replications.
The grain yield of maize cv. TZB (a pure line variety) in mixture and land equivalent ratio (LER) increased linearly up to 120 kg N/ha in 1985 as against significant increase in the grain yield of maize cv. 8322–3 (a hybrid variety) and LER up to 40 kg N/ha only in 1986 primarily due to greater fertilizer N recovery by the latter. Significant enhancement in LER was also recorded up to 26.4 kg P/ha in both years. The yield of soybean in mixture remained unaffected by N or P rates.
Total N uptake by shoots of soybean/maize mixture was significantly and linearly increased up to the application of 120 kg N/ha in 1985 as against significant increase in total N uptake by soybean/maize mixture only up to 40 kg N/ha in 1986 owing to the greater fertilizer N recovery by maize (69%) in the latter than the one (29.75—31.75%) in the former. Total N uptake by shoots of soybean/maize was also increased significantly due to the application of 26.4 kg P/ha.
Application of N and P also significantly enhanced P uptake by shoots of soybean/maize mixture and fertilizer P recovered by mixture was less (3.99—12.95%) in 1985 than the one (19.95—32.12%) in 1986. 相似文献
The grain yield of maize cv. TZB (a pure line variety) in mixture and land equivalent ratio (LER) increased linearly up to 120 kg N/ha in 1985 as against significant increase in the grain yield of maize cv. 8322–3 (a hybrid variety) and LER up to 40 kg N/ha only in 1986 primarily due to greater fertilizer N recovery by the latter. Significant enhancement in LER was also recorded up to 26.4 kg P/ha in both years. The yield of soybean in mixture remained unaffected by N or P rates.
Total N uptake by shoots of soybean/maize mixture was significantly and linearly increased up to the application of 120 kg N/ha in 1985 as against significant increase in total N uptake by soybean/maize mixture only up to 40 kg N/ha in 1986 owing to the greater fertilizer N recovery by maize (69%) in the latter than the one (29.75—31.75%) in the former. Total N uptake by shoots of soybean/maize was also increased significantly due to the application of 26.4 kg P/ha.
Application of N and P also significantly enhanced P uptake by shoots of soybean/maize mixture and fertilizer P recovered by mixture was less (3.99—12.95%) in 1985 than the one (19.95—32.12%) in 1986. 相似文献
46.
Allelopathic effects of aqueous extract of three weeds, Ageratum conyzoides L., Imperata cylindrica (L.) Beauv and Commelina benghalensis L. of Nigerian savanna were investigated on the germination and seedling vigour of soybean ( Glycine max [L.] Merr.) and maize ( Zea mays L.). Aqueous extracts of these weeds exhibited allelopathic phenomenon on seed germination and seedling vigour. Aqueous extracts of I. cylindrica and C. benghalensis at 1 % and 5 % concentration (w/v) had stimulatory effect on soybean germination as against inhibitory effect of 10 % aqueous extract of all weeds on the germination of both soybean and maize seeds. Seedling vigour-length of roots and shoots and fresh weight of seedlings were promoted by aqueous extract of A. conyzoides up to 5 % concentration in soybean whereas all concentrations of extract stimulated the seedling vigour of maize. Aqueous extract of I. cylindrica up to 5 % also caused stimulatory effect on the seedling vigour of both crops but such effects were lesser in magnitude than that observed in case of A. conyzoides. On the contrary, the aqueous extract of C. benghalensis at all concentrations resulted in deleterious effect on the seedling vigour of both soybean and maize. 相似文献
47.
Semi-finished meat products were demonstrated to be heavily contaminated with microbes already at the moment of production. The main source of microorganisms was meat surface. Psychrotolerant organisms represented the main factors involved in the rise of organoleptical signs of decay. For the evaluation of the level of hygiene and sanitation, quality of the raw materials used and conditions of storage, the maximal limit values were proposed for 10 species or groups of the microorganisms under study. Pathogenic microorganisms were not detected by the multiplication method in any of the samples. 相似文献
48.
Water transmission characteristics under saturated and unsaturated conditions were studied in a sandy loam soil with (F1) and without (F0) long-term farmyard manure (FYM) treatments, in relation to sodium adsorption ratios (SAR) and electrolyte concentrations of water. The effect of FYM and ratios of Ca2+ : Mg2+ in water at a given SAR on sodication of the soil was also studied.Saturated hydraulic conductivity (k) and weighted mean diffusivity () were slightly higher for F1 than for F0, whereas sodication indices like Gapon constant (KG), Krishnamoorthy-Davis-Overstreet constant (KKDO) and Vanselow constant (KV) were slightly smaller. The k and decreased with an increase of SAR and decrease of electrolyte concentration, the effect of SAR being more pronounced. There was proportionately a sharper decrease in the k and values at SAR 10 with total electrolyte concentrations of 10–40 meq 1?1. However, with a total electrolyte concentration of 80 meq 1?1, there was a smaller drop at SAR 10.A small difference in the build-up of exchangeable sodium percentage (ESP) in F1 and F0 treatments at a given SAR suggests that, apart from slightly improving water transmission parameters, the use of FYM also reduces the sodication hazard in a soil irrigated with sodic waters. An increase in the Ca2+ : Mg2+ ratio from 25:75 to 75:25 slightly decreased the values of KG, KKDO and KV, thus indicating somewhat more preference for Ca2+ to Mg2+ at a given SAR, which was more so in F1 soil. This fact could also be expressed in terms of a slight shift of thermodynamic exchange constant (K) and standard free energy change of the exchange reaction (ΔG0r). The presence of some unidentified Na+ releasing minerals in the soils studied was observed and correction for exchangeable Na+ determination applied. 相似文献
49.
The anatomic villous surface area and the functional diffusive area (measured by the absorption of 64 mM thiourea) of the jejunum and ileum was estimated in fed and 3-d-fasted chickens. In the jejunum, fasting caused a 50% reduction of the anatomic villous surface area but only a 32% reduction in the functional diffusive area. The jejunal permeability to thiourea was unaltered. The ileal anatomic villous surface area was unaffected by fasting but the ileal functional diffusive area was decreased significantly by 26%, concomitant with a significant reduction of 34% in the permeability to thiourea. The passive absorption of thiourea cannot be used as a simple index of the functional diffusive surface area for dietary-induced changes in the small intestine of the domestic fowl. 相似文献
50.
Gupta S Khanna VK Maurya A Bawankule DU Shukla RK Pal A Srivastava SK 《Fitoterapia》2012,83(6):1092-1099
This study was undertaken to ascertain the antipsychotic properties of Rauwolfia tetraphylla L. leaves and to isolate and characterize the antipsychotic constituents. Among the MeOH extract and some alkaloidal fractions at different pHs, the alkaloidal CHCl(3) fraction at pH-9 (2C) showed the highest antipsychotic activity against dopaminergic (DA-D(2)) and serotonergic (5-HT(2A)) receptors in-vitro and amphetamine induced hyperactive mouse model in-vivo. The activity guided isolation of CHCl(3) fraction (2C) afforded six indole alkaloids: 10-methoxytetrahydroalstonine (1), isoreserpiline (2), an isomeric mixture of 11-demethoxyreserpiline (3) and 10-demethoxyreserpiline (4), α-yohimbine (5) and reserpiline (6). Given orally, alkaloids 3-6 showed significant antipsychotic activity in a dose dependent manner. None of the extract, alkaloidal fractions or alkaloids showed any extra pyramidal symptoms at the tested doses. It was also observed that MeOH extract was behaving similar to other clinically used novel atypical antipsychotics in having 5-HT(2A) occupancy greater than the DA-D(2) receptor at the tested doses. Further toxicity and safety evaluation studies of MeOH extracts of R. tetraphylla leaves at different doses (10, 100, 300 and 2000 mg/kg) on female Swiss albino mice showed that MeOH extract is non toxic. The isolated alkaloids, 3-6 could serve as a promising lead structure for drug development of treating psychotic conditions in human. 相似文献