Suitability of Using Rubidium‐86 as a Tracer for Potassium in Studying Potassium Uptake by Barley Plants

Marschner, H.; Schimansky, Ch.

doi:10.1002/jpln.19711280206

Cited by 30 publications

(8 citation statements)

References 24 publications

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“…K"^ was preferred against Rb"*" in low-K"*" roots of all three species, while Rb"^ was the preferred ion in high-K"^ roots of oat and spring wheat. The same has been demonstrated for different varieties of barley by Marschner and Schimansky (1971) and by Pettersson (1978). Lack of significant discrimination between K"*" and Rb"^ (as in our high-K"^ roots of cucumber) has been reported several times, e.^.…”

Section: K^(^^rb)/k'^ Selectivity In the Roots And The Shootssupporting

confidence: 70%

Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat

Jensen

Kylin

1980

Physiologia Plantarum

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Spring wheat (Triticum aestivum L. cv. Svenno), oat (Avena sativa L. cv. Brighton) and glasshouse cucumber (Cucumis sativus L. cv. Bestseller Fl) were cultured for a week after germination on complete nutrient solutions of three different dilutions (1, 25 and 50% of the full strength medium). K-'(*''Rb) and "'Ca were present during the whole culture period. Relative humidity (RH) was 50% except during the last day, when half the material was transferred to 90% RH. Efflux of labelled ions was then followed during eight hours on unlabelled solutions of the same composition as before, and at both 50% and 90% RH in the atmosphere. -Uptake of K"^(*''Rb) during growth tended to be saturated in the 25% medium. Contrariwise, the level of Ca^"^ in the roots increased continuously with strength of the medium. At low concentrations cucumber roots were higher in Ca^"^ than roots of oat or wheat, whereas all three species showed similar levels of Ca^"^ in 50% medium. -At the lowest ionic strength, smooth efflux curves were obtained that could be resolved according to the three-compartment theory. At higher ionic strength, irregularities were observed, and more for Ca'' ' than for K*; but for practical purposes compartment analysis with the same time constants could be applied as for the lowest concentration. -Discrimination between K"^ and Rb"^ differed between the roots, but not much between the shoots of different species. The roots of oat and wheat took up Rb"^ preferentially over K "^ in the 25% and 50% media; whereas K"*" was preferred over Rb^'^or little discrimination made in 1 % medium and for cucumber. The shoots generally showed less discrimination than the roots. The main variability in discrimination between K"^ and Rb"^ thus appears to be localized in the tonoplasts of the roots cells. -Low RH around the shoots increased efflux of K'^(**'Rb) from the cytoplasm and vacuoles of the root cells as compared to the efflux at high RH. DNP (2,4-dinitrophenol) in the medium had the same effect as high RH around the shoots. The signal system that must exist between shoots and roots is discussed as a response to "drought" conditions. In relation to investigations of others, it is assumed that the effect of DNP may indicate that part of the chain between roots and shoots consists of metabolically influenced sites, whose output is influenced by the rate of water transport.

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Section: K^(^^rb)/k'^ Selectivity In the Roots And The Shootssupporting

confidence: 70%

Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat

Jensen

Kylin

1980

Physiologia Plantarum

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“…In a variation of isotope methods, stable rubidium (Rb) was used as a tracer for K. Details of this method are described by Haak (1977), Kuhlmann et al (1985) and Kuhlmann (1988). The differences between K and Rb in the metabolism of plants (Alten and Gottwick, 1933;Marschner and Schimansky, 1971), as well as differences in their absorption by the soil (Baligar and Barber, 1978;Fried et al, 1959;Marckwordt and Niederbudde, 1964), had no effect on the determination of K uptake from the subsoil by this method (Kuhlmann, 1988).…”

Section: Introductionmentioning

confidence: 99%

Importance of the subsoil for the K nutrition of crops

Kuhlmann¹

1990

Plant Soil

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A K/Rb isotope dilution method was used to determine the uptake of K from undisturbed subsoils. Rb was applied to the topsoil (0-30 cm) to trace the K taken up from the topsoil by crops. The K/Rb ratio in the crops increases when roots contact the Rb-free subsoil. This change in the K/Rb ratio enables the calculation of the uptake of K from the subsoil.Results of 34 field experiments on loess-parabrown soils in N. Germany showed that the subsoil (>30 cm) supplied, on average, 34% of the total K uptake by spring wheat (range 9-70%).The range between the experimental sites is considered in relation to the contents of K in the top and subsoils (as extracted by 0.025 N CaC12 solution), the proportion of the total root length in the subsoils, and competition for K between roots in the top and subsoil.

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“…Before starting the experiments, the labeling of K* by ''^K and ^Rb was compared because labeling of K"* bŷ^R b is not suitable in all cases (Maas and Leggett 1968, Marschner and Schimansky 1971, West and Pitman 1967. The percentage distribution of KC^K) and K(^^Rb) in detached ears was similar at 4 and 8 h of uptake (Tab.…”

Section: Resultsmentioning

confidence: 99%

Long distance transport of potassium in cereals during grain filling in detached ears

Haeder¹,

Beringer²

1984

Physiologia Plantarum

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1984, Long distance transport of potassium in cereals during grain filling in detached ears. -Phy.siol. Plant. 62: 433-438,Ears of wheat plants {Triticum aestivum L, cv. Kolibri), which were given different and uniform K-^-nutrition in two experiments, were cut at 2, 4 and 6 weeks after anthesis at 15 cm below the ear. These detached ears were fed 30 mM (experiment 1) or 15, 30, 60 or 90 mM ^^Rb-K^malate (experiment 2) and 146 mM [i*C]-sucrose. After a pulse period of 6 and 4 h, respectively, the ears were transferred to identical non-labeled solutions for additional 0, 4, 8 or 20 h. About 50% of the K+ and sucrose supplied was absorbed by detached ears. This rate declined with plant age and decreasing transpiration. Within the 6 and 4 h uptake period less than 7% of the absorbed K-^, but 20% of the sucrose taken up were incorporated into the grain. During the chase period labeled K* in the grain increased to 15% and "^C even to 50% of total tracer uptake. Incorporation of labeled K+ into the grain was not affected by the previous K+ nutrition of the plant and was proportional to the K-^ concentration in the uptake solution. Transition of K^ from xylem into phloem during its acropetal transport is assumed. No evidence was found that the grain itself could control its uptake of K+, Additional key words -K(**Rb) uptake, [''•Cj-sucrose translocation, Triticum aestivum. H.-E. Haeder and H. Beringer (reprint requests). Agricultural Research Station BUntehof,

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Suitability of Using Rubidium‐86 as a Tracer for Potassium in Studying Potassium Uptake by Barley Plants

Cited by 30 publications

References 24 publications

Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat

Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat

Importance of the subsoil for the K nutrition of crops

Long distance transport of potassium in cereals during grain filling in detached ears

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Suitability of Using Rubidium‐86 as a Tracer for Potassium in Studying Potassium Uptake by Barley Plants

Cited by 30 publications

References 24 publications

Effects of ionic strength and relative humidity on the efflux of K+ (86Rb) and Ca2+ (45Ca) from roots of intact seedlings of cucumber, oat and wheat

Effects of ionic strength and relative humidity on the efflux of K+ (86Rb) and Ca2+ (45Ca) from roots of intact seedlings of cucumber, oat and wheat

Importance of the subsoil for the K nutrition of crops

Long distance transport of potassium in cereals during grain filling in detached ears

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Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat

Effects of ionic strength and relative humidity on the efflux of K⁺ (⁸⁶Rb) and Ca²⁺ (⁴⁵Ca) from roots of intact seedlings of cucumber, oat and wheat