ISSN:
1573-5036
Keywords:
Agar-pH indicator technique
;
Cation-anion balance
;
H ion efflux
;
HCO3
;
ion efflux
;
Nitrate nutrition
;
Nitrate reductase
;
Root growth
;
Split root system
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Changes in pH around the roots of young rape plants (Brassica napus cv. emerald) were studied using a nutrient film technique that allowed part or whole of the root system to be subjected to specific nutrient treatments. The rapidity and direction of pH change was assessed by imbedding absorbing roots in a thin film of agar containing bromocresol purple. When nitrate-fed plants were deprived of all sources of nitrogen at 15 or 17 days old, the release of H ions from the roots was immediate and uniformly distributed over the root length. When nitrate was witheld from half of the root system of nitrate-fed plants, the roots deprived of nitrate immediately started to produce H ions even though the nitrate-fed half of the root system continued to supply the whole of the plant with nitrate. However, the rate of H ion production in plants partly supplied with NO3 was less than in plants completely deprived of NO3. It is suggested that malate produced in the shoots, following nitrate reduction, may be redistributed to the roots deprived of nitrate. There, HCO3 produced by the decarboxylation of the malate masks some of the expected H ion efflux.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02275477
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