ISSN:
1573-5036
Keywords:
Freeze-cutting technique
;
In situ phosphate depletion profile
;
Maize
;
Radioautography
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary A radioautographic method is described which allows the determination of phosphate concentration profiles around a root in situ,i.e. under conditions of radial diffusional flow. The device consisted of a soil column containing a distinct layer labelled with33P which was kept separated from the rest of the content of a (modified) Kich-Brauckmann vessel. The primary root of a maize plant was directed into the special soil core whereas the other roots were allowed to develop into the unlabelled portion of the pot. Two or five days after the roots had penetrated the labelled soil sections the soil blocks were immediately frozen in liquid nitrogen and, ommitting any further embedding procedures, sliced perpendicular to the growth direction of the root by means of a stone cutting saw. From the frozen soil slices radioautograms were prepared and densitometrically analysed for phosphate content within and outside the root. The P-depletion zones around the root as well as areas of P-accumulation within the root coincided well with anatomical and morphological root parameters as determined with maize plants grown under similar conditions thus mutually corroborating the findings. Interestingly, the P-depletion zone around the primary root did not exceed the area of the root hair cylinder. Although soil composition and the extent of water supply to the pot somewhat limit the applicability of the presented technique, it should be appropriate for the investigation of a variety of agricultural soils. Since laterals did not interfere with the analysis this method should also allow long-term studies to be performed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02383231
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