ISSN:
1573-1561
Keywords:
Saponins
;
alfalfa
;
soils
;
humic acid
;
allelopathy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Alfalfa seedlings (cv. Cimmaron) were aseptically grown in a glass test tube containing a nutrient salts solution and 14C-labeled sodium acetate into which filtered air was pumped. After five days of exposure to fluorescent light at 22°C, the alfalfa seedlings were removed, washed with cold water, and their saponins extracted. Mean yield of 14C-labeled saponins was 50.2 mg/2.2 g of seed, and mean activity of the 14C-labeled saponins was 5.1 × 104 dpm/mg. Thin-layer chromatography (TLC) of 14C-saponins indicated soyasaponin I, medicagenic acid-3,28 glucoside, and medicagenic acid 3-O-glucoside, plus several unidentified spots, whereas TLC of hydrolyzed saponins (aglycones) showed medicagenic acid, hederagenin, and soyasapogenol B. After 150 hr at 22°C, 17.0% of the 14C-labeled saponins added to a sterile clay loam soil were converted to 14CO2, whereas 54.5% of the saponins were converted to 14CO2 in the nonsterile soil. 14CO2 evolution from each of four nonsterile soils that were amended with 14C-labeled saponins was 57.4–69.9% after 14 days of incubation, and 2.4–24.0% of the added 14C-labeled saponin was recovered in the humic acid fractions from the soils. Only 1.0–2.1% of the 14C label was associated with microbial biomass, as estimated following chloroform fumigation of the soils. Use of 14C-labeled saponins should facilitate a better understanding of the fate of these compounds in soil.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1020886527371
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