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991.
Sorption behavior of triazole fungicides in Indian soils and its correlation with soil properties 总被引:6,自引:0,他引:6
Singh N 《Journal of agricultural and food chemistry》2002,50(22):6434-6439
Adsorption-desorption of triazole fungicides, hexaconazole [2-(2,4-dichlorophenyl)-1-(1H-1,2,4,-triazol-1-yl) hexan-2-ol], triadimefon [1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl) butan-2-one], and penconazole[1-(2,4-dichloro-beta-propyl phenethyl)-1H-1,2,4-triazole] was studied in five Indian soils using batch method. The adsorption isotherms fitted very well to the Freundlich equation. Adsorption of various triazole fungicides increased in this order: triadimefon > hexaconazole > penconazole. The product of the Freundlich adsorption constants, K(f)(1/n), showed good correlation with the soil organic carbon (OC) content, suggesting that soil OC is the main controlling factor for triazoles adsorption. Clay and silt content of the soil also affected the adsorption constants. Adsorption of hexaconazole and triadimefon was nearly reversible in two low OC soils (soil 3, soil 5) where 90-100% of the sorbed fungicides was released in a single washing step. Otherwise, desorption of triazole fungicides showed hysteresis, and 30-60% of the triazole fungicides were retained by the soil after single washing. IR spectra showed that H-bonds and charge-transfer bonds between humic acid and fungicides probably operated as mechanisms of adsorption. 相似文献
992.
Sorption, persistence and transport of herbicides in soils depend on the relative saturation of soils with cations from various soil amendments. Current research was conducted to study the effect of preequilibration of a Candler fine sand (Hyperthermic uncoated typic Quartzipsamments; 0–30 cm depth) with AlCl3, CaCl2, CuCl2, FeCl3, or KCl salt solutions on sorption in bromacil, simazine, norflurazon, and diuron herbicides commonly used in Florida citrus groves. Preequilibration of the soil with either FeCl3, or AlCl3 significantly decreased the sorption and therefore increased internal leaching potential, of all four herbicides as compared to their sorption in untreated soil. This decrease in sorption was much greater for bromacil and simazine (24 to 35%) than for norflurazon and diuron (7 to 8%). The desorption of bromacil and diuron in 1M NH4OAc was also significantly lower in soils preequilibrated with FeCl3 or AlCl3 than the untreated soil. However, the reverse was true in the case of simazine and norflurazon. Preequilibration of the soil with CuCl2, KCl, and CaCl2 resulted in a significant decrease in sorption of norflurazon, diuron, and simazine but did not affect bromacil sorption. Accordingly, the species of adsorbed cation had varying effects on the sorption/desorption of each of the herbicides and varied their leaching potential. 相似文献
993.
S. Singh R. Prasad B. V. Singh S. K. Goyal S. N. Sharma 《Biology and Fertility of Soils》1990,9(3):235-238
Summary A field trial was set up to examine the effect of green manuring, blue-green algae, and neem-cake-coated urea on a rice crop. Summer green manuring using Sesbania aculeata increased the crop yield. Inoculation of blue-green algae increased the rice grain yield when 60 kg N ha-1 was applied as prilled urea, but the increase in grain yield was greater when 60 kg N ha-1 was applied as neem-cake-coated urea. The results of the present study show that applications of green manure, neem-cake-coated urea, and blue-green algae are complementary and that the three treatments can be used together in the rice ecosystem. The green manure and the fertilizer treatments had no effect on the algal flora of the soil. 相似文献
994.
Singh TK Young ND Drake M Cadwallader KR 《Journal of agricultural and food chemistry》2005,53(4):1185-1189
995.
Potential therapeutic applications of some antinutritional plant secondary metabolites 总被引:8,自引:0,他引:8
Plant-based formulations have been used since ancient times as remedial measures against various human and animal ailments. Over the past 20 years interest in traditional medicines has increased considerably in many parts of the world. Whereas modifications in lifestyles, including diet, have had a profound effect on the increased risks of various diseases, there is considerable scientific evidence, both epidemiological and experimental, regarding vegetables and fruits as key features of diets associated with reduced risks of diseases such as cancers and infections. This has led to the use of a number of phytometabolites as anticarcinogenic and cardioprotective agents, promoting a dramatic increase in their consumption as dietary supplements. There are changing perceptions regarding the therapeutic potential of various plant secondary metabolites (PSMs), some of which have also been known to possess certain antinutritional qualities. The knowledge gained at the cellular and molecular levels, and biological activities of PSMs including tannin-polyphenols, saponins, mimosine, flavonoids, terpenoids, and phytates, would be useful in planning for future epidemiological studies and human cancer prevention trials, especially when a large pure dosage is not the option to deliver the active compounds to many tissues. It is well observed that alteration of cell cycle regulatory gene expression is frequently found in tumor tissues or cancer cell lines, and studies have suggested that the herbal-based or plant-originated cell cycle regulators might represent a new set of potential targets for anticancer drugs. The recent upsurge of interest in this area of research and advances made therein indicate that the impact of a number of diseases affecting humans and animals may be lessened, if not prevented, by simple dietary intake of PSMs with putative therapeutic properties. 相似文献
996.
Seema Prajapati Suphla Bajpai Digvijay Singh Rajesh Luthra Madan M. Gupta Sushil Kumar 《Genetic Resources and Crop Evolution》2002,49(2):183-188
The capsule husks of a set of 115 Indian land races of opium poppy Papaver somniferum L. obtained over two cropping seasons were screened for the percent contents of papaverine, reticuline, narcotine, thebaine, codeinone, codeine,morphine and oripavine. Among the accessions screened 36, 7 and 1 didnot accumulate papaverine, papaverine and narcotine and codeine and morphine, respectively. The alkaloid profiles and correlations between alkaloids in all the four classes of accessions showed thatin the Indian genetic resources of P.somniferum (a) morphine is synthesized from codeine rather than oripavine, (b) net alkaloid contents are low under narcotine deficiency, and (c)accumulation of morphine and codeine was limited upstream of codeine and morphine. The accessions identified to be harboring genetic blocks in the phenenthrine and benzylisoquinolinebiosynthetic pathways will be useful for understanding the genetic control of secondary metabolism in opium poppy. 相似文献
997.
Rajinder Singh Antil Martin H. Gerzabek Georg Haberhauer Gerfried Eder 《植物养料与土壤学杂志》2005,168(2):212-218
The present study evaluated the effect of fertilizer amendments (organic manure and mineral fertilizers), management practices (fallow and untilled vs. cropped and tilled) on changes of N in bulk soil and N associated with different particle‐size fractions. The long‐term field experiment was conducted since 1962 in Gumpenstein, Austria, on a Dystric Cambisol. The N content of the topsoils changed distinctively during 28 and 38 yr of treatments under both fallow and cropped management practices. Highest increase in total N content was found in animal‐manure (liquid)‐treated plots. The remaining ranking was: animal manure (solid) > cattle slurry > half cattle slurry + straw = PK = NPK. Quite short N‐half‐life values of around 2 yr were found for the cattle‐slurry application, while animal manure exhibited longer N‐half‐lives of around 8 yr. Crop removal of N and mineralization losses in cropped plots obviously were higher than N losses from the bare soil plots lacking a plant cover to keep N in the system. This was confirmed by a consistent shift in the natural 15N abundances. Comparing the mean N contribution of particle‐size fractions to the total N amounts revealed the following ranking after 28 and 38 yr of different treatments: silt > clay > fine sand > coarse sand, with small exceptions. Particle‐size separates showed more significant responses to changes in the N dynamics of the system due to the various treatments than the bulk soil and can be regarded as the better indicators in this respect. 相似文献
998.
We studied the nutrient limitations of microbial respiration over time after the addition of glucose (G), glucose+nitrogen (G+N) or glucose+phosphorus (G+P) to a phosphorus-fixing tropical acrisol down to a depth of 80 cm, compared with those from compost. In the acrisol, the initial rate of respiration increase was higher when P was added together with glucose than when P was excluded. Without N, respiration reached a plateau faster and at a lower level than when N was added in excess. With glucose alone, the respiration kinetics followed the lower of the curves with G+N or G+P at any given time. Thus, nitrogen limited the maximum level of microbial respiration in the acrisol if ample carbon was available, but the initial respiration rate was limited by phosphorus. In contrast, for compost respiration was always lowest when N was not added. In conclusion, microbial respiration depended on the P-fixing properties of the soil, the time scale and the carbon availability. 相似文献
999.
Rozzi NL Singh RK Vierling RA Watkins BA 《Journal of agricultural and food chemistry》2002,50(9):2638-2643
Tomato seeds and skins acquired from the byproduct of a local tomato processing facility were studied for supercritical fluid extraction (SFE) of phytochemicals. The extracts were analyzed for lycopene, beta-carotene, alpha-carotene, alpha-tocopherol, gamma-tocopherol, and delta-tocopherol content using high-performance liquid chromatography-electrochemical detection and compared to a chemically extracted control. SFEs were carried out using CO(2) at seven temperatures (32-86 degrees C) and six pressures (13.78-48.26 MPa). The effect of CO(2) flow rate and volume also was investigated. The results indicated that the percentage of lycopene extracted increased with elevated temperature and pressure until a maximum recovery of 38.8% was reached at 86 degrees C and 34.47 MPa, after which the amount of lycopene extracted decreased. Conditions for the optimum extraction of lycopene from 3 g of raw material were determined to be 86 degrees C, 34.47 MPa, and 500 mL of CO(2) at a flow rate of 2.5 mL/min. These conditions resulted in the extraction of 61.0% of the lycopene (7.19 microg lycopene/g). 相似文献
1000.
A. Selvi N. V. Nair J. L. Noyer N. K. Singh N. Balasundaram K. C. Bansal K. R. Koundal T. Mohapatra 《Genetic Resources and Crop Evolution》2006,53(4):831-842
Amplified fragment length polymorphism (AFLP) markers were evaluated for determining the phylogenetic relationships, and the
diversity in the Saccharum complex using 30 clones belonging to S. officinarum, S. robustum, S. spontaneum, S. barberi, S. sinense and the related genus Erianthus. The phenetic tree of the species clones based on AFLP data was consistent with the known taxonomical relationships. AFLP
gave higher resolution of closely related species into discrete groups than that by RAPD and RFLP markers, reported earlier.
The levels of diversity within the various Saccharum species were also found to be higher than those obtained previously with the same set of clones using RAPD markers. The intraspecies
similarity in S. barberi and S. sinense was much higher than interspecies similarity suggesting a clear separation of the two, which are considered ‘horticultural
species’. The genetic similarity matrix derived from a single primer combination highly correlated (r = 0.980) with that obtained from all the 12 primer combination used in the study, thus highlighting the efficiency of a single
primer combination in delineating species relationships. All the primer combinations could identify markers that are specific
to each of the species and the genus Erianthus. Among the species, specific markers were highest in S. spontaneum followed by S. robustum, S. barberi, S. officinarum and S. sinense. Erianthus had a distinct profile with 30% of the total amplified fragments being specific to it. This offers great scope for identifying
intergeneric hybrids, which has been very difficult using morphological traits and RAPD markers. High degree of correspondence
between the results from the cluster analysis based on Jaccard's similarity index, Neighbour Joining tree based on Sokal and
Michener distance matrix and AFTD (Analyses Factorielle on Table of Distances) analysis clearly demonstrated that AFLP markers
would be an appropriate tool in providing better information about the relationships among the species, estimation of diversity,
and in revealing species and genus specific markers that could be directly applied in sugarcane breeding programmes. 相似文献