Differential Cation &amp; Anion Absorption as Affected by Climate

Williams, D. E.; Vlamis, J.

doi:10.1104/pp.37.2.198

Cited by 16 publications

(3 citation statements)

References 7 publications

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“…Ammonification is less temperature-sensitive than nitrification so that the relative availability of NH4' versus N03 increases in cold soils (6,20). In addition, roots absorb NH4' more readily than N03 at low temperatures (2,8,15,19,24). These previous studies, however, examined temperature effects upon NH4' and NO3 absorption only at substrate concentrations (0.5-1.1 mm) which usually saturate influx.…”

Section: Introductionmentioning

confidence: 94%

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties

Bloom¹,

Chapin²

1981

Plant Physiol.

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A flowing nutrient culture system permitted relatively rapid determination of the steady-state net nitrogen influx by an intact barley (Hardewm vugare L. cv Kombar and Oll) plant. Ion-selective electrodes monitored the depletion of ammonium and nitrate from a nutrient solution after a single pass through a root cuvette. Influx at concentrations as low as 4 micromolar was measured. Standard errors for a sample size of three plants were typically less than 10% of the mean.When grown under identical conditions, a variety of barley bred for cold soils had higher nitrogen influx rates at low concentrations and low temperatures than one bred for warm soils, whereas the one bred for warm soils had higher influx rates at high concentrations and high temperatures. Ammonium was more readily absorbed than nitrate by both varieties at all concentrations and temperatures tested. Ammonium and nitrate influx in both varieties were equally inhibited by low temperatures.In most plants, low temperatures generally increase reliance upon NH4' as a mineral nitrogen source (12). Ammonification is less temperature-sensitive than nitrification so that the relative availability of NH4' versus N03 increases in cold soils (6,20). In addition, roots absorb NH4' more readily than N03 at low temperatures (2,8,15,19,24). These previous studies, however, examined temperature effects upon NH4' and NO3 absorption only at substrate concentrations (0.5-1.1 mm) which usually saturate influx. The present work used new methods to monitor, in cold-and warm-adapted barley (Hordeum vulgare L.) varieties, the influence oflow temperatures upon the balance between NH4' and N03 absorption at limiting substrate concentrations. MATERIALS AND METHODSNutrient flow system. The flow system for steady-state net NH4' and NO03 influx measurements is depicted in Figure 1 JAC m Where Q is net influx rate; J is flow rate; AC is concentration difference; and m is root dry weight.A constant flow rate through the cuvette and the electrodes was maintained with piston metering pumps (Fluid Metering). The flow rate through the cuvette was varied between 1.7 and 6.0 ml min-' with the first metering pump (Fig. 1) to keep the depletion of the nutrient solution between 5 and 15%; the flow rate to the electrodes was held at 1.0 ml min-' with the second metering pump. To prevent air bubbles from becoming trapped under the electrodes' sensing tips, the solution flowing to the electrodes was degassed (Fig. 1). First, a peristaltic pump (Technicon) periodically injected air into the solution stream, thereby creating large air bubbles which served to absorb small bubbles. The solution stream was then heated to 45 C. Subsequently, the air was collected in the upper chamber of a bubble trap and drawn off by a second channel of the peristaltic pump (9). Ammonium in the solution was converted to ammonia for detection with an ammonia electrode by adding 10 N NaOH to the solution in a 1 to 20 proportion with a third channel of the peristaltic pump. A slotted rubber stopper with an a...

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Section: Introductionmentioning

confidence: 94%

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties

Bloom¹,

Chapin²

1981

Plant Physiol.

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“…This difference was attributed to lower nitrate uptake at the lower temperatures, the lower uptake being possibly linked to the lower activity of the enzymic nitrate-reducing system. Williams & Vlamis (1962) noted that, in nutrient solution, nitrate absorption was affected more by lower temperature than that of other ions. Almost no nitrate absorption occurred at 13 "C while absorption of phosphate, sulphate, potassium, calcium, magnesium and ammonium continued.…”

Section: ;mentioning

confidence: 99%

Ammonium and Nitrate Nutrition of Plants

Haynes¹,

Goh²

1978

Biological Reviews

521

265

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“…The concentration of N 0 3-N in the root tended to be elevated with root-zone heat, probably as a result of more nitrifying bacteria activity at the higher temperature. However, a 10-fold increase in N 0 3 uptake by barley from solution cultures with temperature increasing from 10° to 13°C to 20° to 23° was reported by Williams and Vlamis (26). The increase then was due at least partially to increased uptake or transport to the shoot as root-zone temperature increased.…”

Section: Resultsmentioning

confidence: 81%

Effects of Root-zone Heating on Elemental Composition of Calceolaria

White

Biernbaum

1984

J. Amer. Soc. Hort. Sci.

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Root-zone heating increased the tissue concentration and total uptake of N, P, K, Ca, Mg, S, Cl, Fe, MnZn, and Cu; decreased the tissue concentration but not total uptake of Na and Zn, and had no effect on the tissue concentration of B. The element with the greatest increase in concentration in the shoot was water-soluble NO3-N. The ratio of cations to anions did not change significantly with changes in root-zone temperature. The concentration and balance of cations did not change significantly with changes in percentage of NH4-N at ambient root-zone temperatures.

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Differential Cation & Anion Absorption as Affected by Climate

Abstract: Barley plants grown at different seasons of the year exhibit marked differences in yield as well as in Mn uptake (12). In order to study Mn and B interactions, barley

Cited by 16 publications

References 7 publications

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties

Ammonium and Nitrate Nutrition of Plants

Effects of Root-zone Heating on Elemental Composition of Calceolaria

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