ISSN:
1573-5036
Keywords:
14CO2 atmosphere
;
Cobalt
;
Complexation
;
Maize
;
Manganese
;
Rhizosphere
;
Wheat
;
Zinc
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Water-soluble14C-labelled organic material, released into soil from roots of wheat and maize plants, was recovered with a mild percolation technique, without disturbing the root-soil interface. Extraction yields were relatively high for the14C materials (up to 11% of residual soil14C for 6 weeks maize) illustrating the water soluble character of the freshly added material. The complexation potential of the soil extracts was evaluated by adding57Co,65Zn and54Mn to the extract and determining their distribution among the organic fractions by a gel filtration technique. The results show that within four weeks a micro-environment is created around a plant root, characterized by an accumulation of root-derived organic materials. In parallel with this time dependent accumulation, a gradual shift from ionic metal to higher molecular weight forms occurred. The three metals were increasingly complexed throughout the growth period. Extracts from a fallow soil complexed minor amounts of the added tracer (6.4%; 1.9% and 0.2% for57Co,65Zn and54Mn respectively) while cropped soil extracts after 6 weeks complexed 61%; 16% and 6% of respectively Co, Zn and Mn in the case of maize, and 31%, 15% and 1% in the case of wheat. Although the effects are most pronounced in the case of Co and maize, evidence is given for similar effects with wheat and the other metals. The results indicate that the physicochemical status of transition metals in the rhizosphere is entirely different from that in the bulk soil.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02374999
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