חיפוש מתקדם
Plant and Soil
Imas, P., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
Bar-Yosef, B., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
Kafkafi, U., Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
Ganmore-Neumann, R., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
The exudation of certain organic anions and protons by roots which may affect solubility of metals and P and uptake by plants, is affected by nitrogen form and pH. The objective of this work was to study exudation of carboxylates and H+/OH- by tomato plants in response to NH4/NO3 ratio and pH in nutrient solution. Four NH4/(NH4+NO3) ratios (R= 0, 0.33, 0.67 and 1) and constant vs. variable solution pH treatments were investigated. The sum of the exudation rates of all carboxylates tended to decline with increasing R, particularly tri- and dicarboxylates. The molar fraction of the exuded tri- and dicarboxylates, averaged over all treatments and plant ages, increased in the order tartarate (~2%), malate (~6%), succinate (~15%), citrate (~26%) and fumarate (~46%). At R=1 the solution pH dropped from 5.2 to ~3 and at R=0 increased to ~8. The R corresponding to the pH stat of tomato plant was ~0.3. For the constant solution pH treatment, the effect of solution pH on carboxylate exudation rate was small as compared to the effect of R. The exudation of citrate and H+ efflux which were initiated when NO3 and NH4 uptake rates per plant exceeded certain threshold values, increased with plant age.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Release of carboxylic anions and protons by tomato roots in response to ammonium nitrate ratio and pH in nutrient solution
191
Imas, P., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
Bar-Yosef, B., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
Kafkafi, U., Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
Ganmore-Neumann, R., Agricultural Research Organization, Institute of Soils and Water, Bet-Dagan 50250, Israel
Release of carboxylic anions and protons by tomato roots in response to ammonium nitrate ratio and pH in nutrient solution
The exudation of certain organic anions and protons by roots which may affect solubility of metals and P and uptake by plants, is affected by nitrogen form and pH. The objective of this work was to study exudation of carboxylates and H+/OH- by tomato plants in response to NH4/NO3 ratio and pH in nutrient solution. Four NH4/(NH4+NO3) ratios (R= 0, 0.33, 0.67 and 1) and constant vs. variable solution pH treatments were investigated. The sum of the exudation rates of all carboxylates tended to decline with increasing R, particularly tri- and dicarboxylates. The molar fraction of the exuded tri- and dicarboxylates, averaged over all treatments and plant ages, increased in the order tartarate (~2%), malate (~6%), succinate (~15%), citrate (~26%) and fumarate (~46%). At R=1 the solution pH dropped from 5.2 to ~3 and at R=0 increased to ~8. The R corresponding to the pH stat of tomato plant was ~0.3. For the constant solution pH treatment, the effect of solution pH on carboxylate exudation rate was small as compared to the effect of R. The exudation of citrate and H+ efflux which were initiated when NO3 and NH4 uptake rates per plant exceeded certain threshold values, increased with plant age.
Scientific Publication
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