Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nickel (Ni) availability in soil varies as a function of pH. Plants require Ni in small quantities for normal development, especially in legumes due its role in nitrogen (N) metabolism. This study investigated the effect of soil base saturation, and Ni amendments on Ni uptake, N accumulation in the leaves and grains, as well as to evaluate organic acids changes in soybean. In addition, two N assimilation enzymes were assayed: nitrate reductase (NR) and Ni-dependent urease. Soybean plants inoculated with Bradyrhizobium japonicum were cultivated in soil-filled pots under two base-cation saturation (BCS) ratios (50 and 70%) and five Ni rates - 0.0; 0.1; 0.5; 1.0; and 10.0 mg dm(-3) Ni. At flowering (R1 developmental stage), plants for each condition were evaluated for organic acids (oxalic, malonic, succinic, malic, tartaric, fumaric, oxaloacetic, citric and lactic) levels as well as the activities of urease and NR. At the end of the growth period (R7 developmental stage - grain maturity), grain N and Ni accumulations were determined. The available soil-Ni in rhizosphere extracted by DTPA increased with Ni rates, notably in BCS50. The highest concentrations of organic acid and N occurred in BCS70 and 0.5 mg dm(-3) of Ni. There were no significant differences for urease activity taken on plants grown at BSC50 for Ni rates, except for the control treatment, while plants cultivated at soil BCS70 increased the urease activity up to 0.5 mg dm(-3) of Ni. In addition, the highest values for urease activities were reached from the 0.5 mg dm(-3) of Ni rate for both BCS treatments. The NR activity was not affected by any treatment indicating good biological nitrogen fixation (BNF) for all plants. The reddish color of the nodules increased with Ni rates in both BCS50 and 70, also confirms the good BNF due to Ni availability. The optimal development of soybean occurs in BCS70, but requires an extra Ni supply for the production of organic acids and for increased N-shoot and grain accumulation.
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PMID:Nickel Availability in Soil as Influenced by Liming and Its Role in Soybean Nitrogen Metabolism. 2766 Jun 33

The Yamuna is one of the most polluted rivers in India and the land adjacent to river flowing through Delhi city is widely irrigated with its water for growing various food crops. Present study was undertaken to assess the heavy metal load in Yamuna water and surrounding soils of the river bank and its impact on soil enzyme activities. Long term impact of irrigation by Yamuna water on the activities of various soil enzymes namely dehydrogenase (DHA), urease (UA), fluroscein diacetate (FDA), aryl sulphatase (ASA), nitrate reductase (NRA), microbial biomass carbon (MBC) and potentially mineralizable nitrogen (PMN) were assessed. The sensitivity of soil enzymes to heavy metals were observed as DHA>UA>ASA>NRS. Total organic carbon, easily oxidisable soil organic carbon, available phosphorus and available potassium in different sites varied significantly. Total heavy metal contents in soils showed a decreasing order: Fe>Mn>Zn>Cr>Ni>Cu>Pb>Co>As>Cd and the DTPA extractable heavy metal contents followed the order: Mn>Cu>Pb>Zn >Fe>Ni>Cd>Cr>Co>As. Potential ecological risk factors (Er) were under low risk and comprehensive potential ecological risk indices (Ri) were found to be under low, moderate and high risk categories. Copper (Cu) is the main pollutant contributing considerable load to Ri. From (Ri) principal component analysis and cluster analysis, it is evident that the Okhla site (S8) is most contaminated. The water from Yamuna river needs to be cautiously used for growing various food crops on land adjacent to the river as its long-term usage might cross the permissible limits of heavy metals in the soil.
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PMID:River water irrigation with heavy metal load influences soil biological activities and risk factors. 3272 Dec 79