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Relationship of pH to Ion Uptake Imbalance by Varieties of Wheat ( Triticum vulgare ) 1
Author(s) -
Dodge C. S.,
Hiatt A. J.
Publication year - 1972
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1972.00021962006400040020x
Subject(s) - hordeum vulgare , nutrient , chemistry , absorption (acoustics) , poaceae , agronomy , ion , biology , physics , organic chemistry , acoustics
Varietal differences in plant‐induced pH changes have been considered a possible factor in Al tolerance. The objective of this study was to determine the magnitude of plant‐induced pH changes by wheat ( Triticum aestivum L.) and barley ( Hordeum vulgare L.) and to determine the cause of observed varietal differences. Varieties of wheat or barley differed considerably in their effect on the pH Level of complete nutrient solutions. Ion uptake and H + transfer between plants of three varieties of wheat and KNO 3 ‐Ca(NO 3 ) 2 solutions were measured to determine the reason for varietal differences in plant‐induced pH shifts. Changes in nutrient solution pH were attributable to differences in anion and cation absorption. Consequently, varietal differences in effect on solution pH levels were accounted for by varietal differences in anionminus‐cation uptake (A‐C) values. Nutrient solutions from which anions had been absorbed in excess of cations were highly buffered. This buffering capacity was lost when the solutions were acidified and aerated, suggesting that HCO ‐ 3 exchanged for the excess anions. Plant‐induced changes in nutrient solution pH varied with the form of N in the solution. When NO 3 ‐ was the only form of N present, pH levels consistently increased from the initial level. However, solution pH decreased when NH 4 + was present in quantities as low as 0.5% of the total N.