Interaction of rubidium or sodium with potassium in absorption by intact sugar beet plants

This study concerns the selective absorption of K and Rb or of K and Na by intact sugar beet (Beta vulgaris) plants from modified conventional nutrient solutions over an extended period of plant growth. Long term results agreed with those of short term experiments by other investigators using excised root systems and simple salt solutions. Potassium and Rb were mutually competitive in their absorption. High selectivity of K relative to Na absorption was observed. Sodium was excluded during the early growth period of sugar beets.     

Sodium absorption by intact sugar beet plants

Sodium absorption by intact sugar beet plants (Beta vulgaris) was found to be mediated by at least two distinct mechanisms when uptake was studied over a wide range of Na and K concentrations. The first mechanism operates at low Na concentrations (<1 milliequivalent per liter); presence of K completely blocks this mechanism for Na. The second mechanism operates at high Na concentrations (>1 milliequivalent per liter), transporting Na as well as K; but apparently this mechanism is not active for Na absorption in young sugar beet plants up to the 10-leaf stage.     

Interactions of rubidium, sodium, and potassium on the nutrition of sugar beet plants

The effect of Rb on the growth and the development of sugar beet plants (Beta vulgaris, var. MS NB1 × NB4) depends on the Rb concentration, the K supply, and the relative abundance of Na. Rubidium added either to a low or high K solution with or without added Na increased leaf blade size greatly, possibly through an effect on phytohormones or through a “partitioning effect” on the distribution of carbohydrates, with top growth favored over storage roots.     

Sodium Absorption and Distribution in Forage Grasses of Different Potassium Status

The absorption and distribution of sodium were examined in threegrasses grown in flowing solution culture with different suppliesof potassium. There were marked differences between the speciesin the rate of absorption by their roots, timothy absorbingat a much slower rate than either ryegrass or cocksfoot. Inall species, the rate of Na absorption was greatest when therewas a maintained supply of K and/or when the K contents of theplants were high. Transport of Na from roots to shoots of timothywas restricted; it was less restricted in the other speciesand large proportions of the Na moved from roots to shoots whenK was not supplied to the plants. Sodium transported from theroots accumulated in old leaves and not in the younger leaves.When K was no longer supplied, the growth of ryegrass was maintainedin the plants previously grown with Na plus K; Na supplied insteadof K, however, did not maintain growth. Cocksfoot grown withNa grew less well than when grown without Na when plants wereno longer supplied with K; the growth of timothy was unaffectedby Na. Dactylis glomerata L., Lolium perenne L., Phleum pratense L., cocksfoot, ryegrass, timothy, absorption of ions, distribution of ions, potassium, sodium     

Effects of rubidium, potassium and gibberellic acid on plant growth

Growth retardation, measured as internode shortening, was observedin bean and tomato plants when grown in culture solutions towhich Rb had been added. The Rb effect was more pronounced inthe presence of low (0.5 meq/liter) K than high (8 meq/liter)K. Gibberellic acid, added to the solutions, ameliorated thegrowth retardation due to Rb. Epinastic symptoms similar tothose observed with auxin treatment also appeared on the tomatoplants treated with Rb. (Received October 2, 1968; )     

Effect of sodium in the nutrient medium on the incidence of potassium-deficiency symptoms in tomato plants

Summary Tomato plants (Lycopersicon esculentum cv. Amberley Cross) were grown in sand culture and were fed with four concentrations of potassium nitrate in combination with two levels of sodium nitrate. After six weeks the plants were scored for the presence and absence of a symptom of potassium deficiency, namely, marginal chlorosis and/or necrosis in the young, fully-expanded leaves. These leaves were also analysed for K and Na. Marginal chlorosis and/or necrosis occurred in plants given a nutrient solution containing 0.5 meq K/I or less and supplied with either of the sodium nitrate levels. However, the symptoms occurred more frequently in plants receiving the lower level of sodium nitrate. The laminae on plants receiving the lower concentration of sodium nitrate had a 50 per cent incidence of chlorisis and/or necrosis when the tissue potassium content was 0.74 per cent of the dry wt, while those laminae on plants receiving the higher level did not show a 50 per cent incidence until their potassium fell to 0.64 per cent of the dry wt.     

Ion Absorption and Retention by Chlorella pyrenoidosa. III. Selective Accumulation of Rubidium, Potassium and Sodium

The selective preference of Chlorella pyrenoidosa for alkali metal cations was found to have the order Rb > K > > > Na. It was demonstrated that a cation of higher preference can replace in the cell cations of lower preference by an ion interchange process.

The replacement of Na from the cell by K or Rb occurred against high external Na concentrations up to 450 meq/1 Na.

It is suggested that the structural selectivity of the Chlorella cell may be amplified by a chromatographic type repetitive selection process, driven by metabolically dependent unsymmetric shape changes of cellular membranes.

     

Decrease in nitrate uptake and increase in proton release in zinc deficient cotton,sunflower and buckwheat plants

The effect of varied Zn supply on the pH of the nutrient solution and uptake of cations and anions was studied in cotton (Gossypium hirsutum L.), sunflower (Helianthus annuus L.) and buckwheat (Fagopyrum esculentum Moench) plants grown under controlled environmental conditions in nutrient solutions with nitrate as source of nitrogen. With the appearance of visual Zn deficiency symtoms, the pH of the nutrient solutions decreased from 6 to about 5 whereas the pH increased to about 7 when the plants were adequately supplied with Zn. In Zn deficient plants the pH decrease was associated with a shift in the cation-anion uptake ratio in favour of cation uptake. Of the major ions, uptake of Ca²⁺ and K⁺ was either not affected or only slightly lowered whereas NO₃ ^- uptake was drastically decreased in Zn deficient plants. Although the Zn nutritional status of plants hardly affected the NO₃ ^- concentrations in the plants, the leakage of NO₃ ^- from roots of Zn deficient plants into a diluted CaCl₂ solution was nearly 10 times higher than that of plants adequately supplied with Zn. In contrast to Zn deficiency, Mn deficiency in cotton plants neither affected NO₃ ^- uptake nor the pH of the nutrient solution.The results indicate that, probably as a consequence of the role of Zn in plasma membrane integrity and nitrogen metabolism, when Zn is deficient in dicotyledonous species net uptake of NO₃ ^- is particularly depressed which in turn results in an increase in cation-anion uptake ratio and a corresponding decrease in external pH. The ecological relevance of this rhizosphere acidification is discussed.     

Uptake and Physiological Effects of Cadmium in Sugar Beet (Beta vulgaris) Related to Mineral Provision

Sugar beet seedlings (Beta vulgaris L. cv. Monohill) were grownfor 14 d on a nutrient solution based on the nutrient proportionsin healthy plants. Nutrients were supplied either once at relativelyhigh concentrations, or in small amounts with a daily incrementalincrease of 0?15 or 0?20 in accordance with an exponential growthrate. Cadmium (0, 0?6, 2?3, 50 or 20?0 µmol) was introducedeither by a single addition or in daily increments of 0?15 or0?20. Cadmium uptake, expressed as a percentage of total Cd²⁺supplied, decreased with increasing total C^d2+ content and withdecreasing availability of nutrients. With a daily supply ofcadmium, net uptake, transport and content per unit of dry weightin roots and shoots were related to the total Cd²⁺ supplied.Cadmium caused growth retardation, increased root/whole-plantratio, and decreased root-tip respiration and photosynthesis.At high initial nutrient concentrations, Cd²⁺ decreased thecontents of sucrose, glucose, fructose, and starch per unitof dry weight. The opposite was found if nutrients were addeddaily. In the latter case, the dry weight/fresh weight ratioalso increased. The effects of cadmium were related to [Cd²⁺]in proportion both to the root absorption area and to the nutrientconcentration. Key words: Sugar beet, mineral provision, cadmium uptake, sugar formation, growth     

Effect of Sodium Application on Growth of Amaranthus tricolor L.

Sodium application of 0.5 meq./liter to water-cultured Amaranthustricolor L. cv. Tricolor plants brought about a three-fold increasein dry matter production compared with those of plants deprivedof sodium. This increase was due to sodium itself and not toa supplementary effect of sodium on potassium shortage nor tothe accompanying anion. In sodium-sufficient plants, the totalnitrogen and potassium contents were lower and calcium, chlorophylland betacyanin contents were higher than in the deficient plants. (Received June 18, 1985; Accepted November 18, 1985)     

Salinity-calcium interactions on growth and ionic concentration of Citrus plants

Two-year-old Navel orange scions (Citrus sinensis (L.) Osbeck) budded to either Cleopatra mandarin (C. reticulata) and Troyer citrange (C. sinensis × P. trifoliata) rootstocks were used in this experiment. Cleopatra manda in rootstock was considered more tolerant to salinity than Troyer citrange, and this property was attributed to a greater capacity to exclude chloride ions.Plants were grown under glasshouse conditions and supplied with nutrient solution containing either no or 45 mM NaCl. Calcium concentration was increased from 3 to 30 mM. Sodium, potassium, calcium and chloride concentrations in plant organs were analyzed after 90 days of treatment.Supplemental Ca was found to mitigate the adverse effects of salinity on plant growth, defoliation or leaf injury.Chemical analysis indicated that in plants grafted on Troyer citrange Ca restricted uptake and subsequent translocation of Na to the leaves and increased K concentration in both roots and leaves. However, in Cleopatra mandarin-grafted plants increasing Ca levels seemed to reduce transport of Na from roots to leaves, and Na accumulation in roots was associated with reduced concentration of K in this rootstock.Organ chloride analysis showed that Cl accumulation in leaves of plants grafted on both rootstocks was reduced when external Ca concentration increased, whereas Cl concentration in roots remained constant or increased. The data of distribution of Cl in plants showed that a high external Ca level increased Cl accumulation in the basal stem and roots, and reduced the transport of Cl from roots to leaves.     

Effect of replacing nutrient potassium by sodium on uptake and distribution of sodium in tomato plants

Summary Tomato plants (Lycopersicon esculentum cv. Amberley Cross) were grown in a series of nutrient solutions in which 0, 60, 90, 95, 98 and 99 per cent of the K was replaced by Na. The plants selectively absorbed K relative to Na from the nutrient solutions and transported K to the shoots in preference to Na. In the nutrient solution having the highest K/Na ration most of the Na taken up by the plants accumulated in the roots, but as the K was progressively replaced by Na an increasing proportion of the total Na absorbed was transported to the leaves. Sodium was present at up to 2.4 per cent of the dry wt of whole, fully-expanded leaves without there being any apparent visual signs of damage or reduction in the rate of growth of the plants. On closer examination it was found that most of the Na transported to the leaves was excluded from the laminar tissue and accumulated in the adjacent petioles. The ability of the roots and petioles to retain large amounts of Na depended on an adequate supply of K to the plants.     

Heterogeneous distribution of phosphorus and potassium in soil influences wheat growth and nutrient uptake

Heterogeneous distribution of mineral nutrients in soil profiles is a norm in agricultural lands, but its influence on nutrient uptake and crop growth is poorly documented. In this study, we examined the effects of varying phosphorus (P) and potassium (K) distribution on plant growth and nutrient uptake by wheat (Triticum aestivum L.) grown in a layered or split soil culture in glasshouse conditions. In the layered pot system the upper soil was supplied with P and either kept watered or allowed to dry or left P-deficient but watered, whereas the lower soil was watered and fertilised with K. Greater reductions in shoot growth, root length and dry weight in the upper soil layer occurred in −P/wet than in +P/dry upper soil treatment. Shoot P concentration and total P content were reduced by P deficiency but not by upper soil drying. Genotypic responses showed that K-efficient cv. Nyabing grew better and took up more P and K than K-inefficient cv. Gutha in well-watered condition, but the differences decreased when the upper soil layer was dry. In the split-root system, shoot dry weight and shoot P and K contents were similar when P and K were applied together in one compartment or separated into two compartments. In comparison, root growth was stimulated and plants took up more P and K in the treatment with the two nutrients supplied together compared with the treatment in which the two nutrients were separated. Roots proliferated in the compartment applied with either P or K at the expense of root growth in the adjoining compartment with neither P nor K. Heterogeneous nutrient distribution has a direct decreasing effect on root growth in deficient patches, and nutrient redistribution within the plant is unlikely to meet the demand of roots grown in such patches.     

The Influence of Accompanying Cations on the Foliar Uptake of Na, K, Rb and Cs

The influence Na, K, Rb or Cs may have when accompanying one of these elements applied foliarly to bean plants has bean studied under controlled environmental conditions. No competition was found in the speed of initial penetration from the outer leaf surface to the protoplasts of epidermal cells between any two of the cations considered separately. The magnitude of penetration of Na, Rb or Cs. Retention in the treated area showed competition among the elements, Na being held more strongly when accompanied by Cs, Rb or K in that order. Presence of another cation influenced retention differently. Transport of Na was faster than of either K, Rb or Cs when applied together. K and Rb were transported simultaneously at equal rates, and either more than Cs. Total quantities transported were influenced differently by the various cations present and in turn determined the total quantities taken up by the plants.     

Partitioning of Sugar between Growth and Nitrate Reduction in Cotton Roots

The level of endogenous sugars was inversely related to nitrate availability in young cotton (Gossypium hirsutum L.) plants, with high nitrate causing a greater decline in sugar content of roots than of shoots. High nitrate (low sugar) plants also displayed relatively more shoot growth and less root growth than low nitrate (high sugar) plants. These data are consistent with the theory that roots are poor competitors for sugar, and that sugar supply is a major factor limiting root growth in vivo.

The effects of endogenous sugar level on root growth and on nitrate reductase activity in the root were different. When root sugar level was experimentally controlled by varying nitrate concentration in the nutrient solution, root growth was less sensitive than nitrate reductase activity to sugar deficiency. Also, in sterile root tips cultured on media containing a wide range of sucrose concentrations, growth rate was considerably less sensitive to endogenous sugar deficiency than was nitrate assimilation rate. Similarly, in plants which were detopped or girdled, nitrate reductase activity in the roots declined more rapidly than did root sugars, especially glucose and fructose. These results suggest that when sugar is deficient, cotton roots preferentially use it for growth at the expense of nitrate reduction.

     

Sodium, an Obligate Growth Requirement for Predominant Rumen Bacteria

Sodium is an obligate growth requirement for most currently recognized predominant species of rumen bacteria. The isoosmotic deletion of Na(+) from a nutritionally adequate defined medium completely eliminated growth of most species. Growth yields and rates were both a function of Na(+) concentration for Na(+)-requiring species, and Na(+) could not be replaced by Rb(+), Li(+), or Cs(+) when these ions were substituted for Na(+) at a concentration equivalent to an Na(+) concentration that supported abundant growth. Li(+), Cs(+), or Rb(+) was toxic at an Na(+)-replacing concentration (15 mM) but not at a K(+)-replacing concentration (0.65 mM). K(+) was also an obligate growth requirement for rumen bacteria in media containing Na(+) and K(+) as major monovalent cations, but K(+) could be replaced, for most species, by Rb(+). The quantities of Na(+) that support rapid and abundant growth of Na(+)-requiring rumen bacteria show that these organisms are slight halophiles. A growth requirement for Na(+) appears more frequent among nonmarine bacteria than has been previously believed.     

Deep hypothermia and circulatory arrest: effect on cerebrospinal fluid electrolytes in newborn lambs.

Cerebrospinal fluid (CSF) Na, K, and acid-base changes were studied in 13 new-born lambs anesthetized with α-chloralose (60 mg/kg) or diethylether during 90 min of normothermic (37 °C) or hypothermic (20 °C) circulatory arrest. CSF K concentration increased linearly from 3.1 to 23.2 meq/liter during 90 min of normothermic circulatory arrest. During hypothermic circulatory arrest, animals anesthetized with α-chloralose exhibited an exponential increase in CSF K concentration from 3.1 to 13.6 meq/liter and animals anesthetized with diethylether had an exponential increase in CSF K concentration from 3.3 to 12.7 meq/liter. The rate of increase in CSF K concentration in hypothermic and normothermic animals between 60 and 90 min of circulatory arrest was the same. CSF Na concentration decreased slightly in both hypothermic and normothermic animals, with a greater decrease in the normothermic group.Although CSF pH and bicarbonate were significantly decreased during normothermia as well as hypothermia, both CSF pH and bicarbonate showed greater decreases during normothermia. Mean pH values after 90 min of circulatory arrest were 6.34, 6.87, and 6.77, respectively, in the normothermic, α-chloralose-hypothermic, and diethylether-hypothermic groups; corresponding values for bicarbonate were 7.7, 13.8, and 12.2 meq/liter.CSF pCO₂ increased linearly from 40.2 to 190.0 Torr during 90 min of normothermic circulatory arrest, from 28.6 to 92 Torr in the ether-hypothermic group, and from 28 to 81 Torr in the α-chloralose-hypothermic group.     

The Influence of Low Substrate Sodium Levels upon the Free Amino Acid Content of Cotton Leaves

The sodium nutrition of cotton (Gossypium hirsutum L.) was investigated. Plants were grown in purified nutrient solutions within a chamber designed to minimize sodium contamination. Three nutrient solutions were employed that contained in microequivalents/liter: (a) 0.17 Na, (b) 43.5 Na and (c) 0.75 Cs, 14.41 Li, and 1.17 Rb. All solutions had adequate potassium. Total free amino acids were increased by sodium. Leaves from plants grown in the high sodium solution contained significantly more free asparagine, arginine, and methionine than leaves from plants of the other treatments. The other alkali metals had little or no effect on concentrations of the free amino acids. An unknown was tentatively identified as argininosuccinic acid.     

Slash pine seedling response to potassium and calcium on imperfectly drained coastal plain soil

In a greenhouse study, increases in dry weight and N, P, K, Ca, and Mg content of seedlings from a preplanting application of 0.16 meq K/100 g of Caddo silt loam topsoil were markedly greater on soil containing 0.06 meq K, than on soil containing 0.09 meq K/100 g. Except for further increasing K and reducing Ca content of seedlings, applications of 0.32 and 0.48 meq K/100 g added little to growth or nutrient accumulation. Additions of 1 to 5 meq Ca/100 g either did not affect or slightly reduce dry weight and uptake of all nutrients except Ca. Potassium and calcium treatments did not interact to influence growth or nutrient uptake. Dry weight and accumulation of N, P, and K were all associated with the amount of K available; Ca accumulation was related only to available Ca.     

Cation movements in the high sodium erythrocyte of the cat

The uptake of ⁴²K and ²⁴Na by cat erythrocytes was investigated. Under steady-state conditions, the nontransient component of ⁴²K influx was found to be 0.18 ± 0.01 meq/liter RBC/hr and insensitive to ouabain (100 µM); the corresponding value for ²⁴Na was 17 ± meq/liter RBC/hr. A study was made of the effects of anions upon cation movements in these and other mammalian red cells. Iodide was found to inhibit markedly (>50%) Na inward movements in cat and dog but not in the other erythrocytes. An increase (15–30%) in K uptake in the presence of iodide was noted in all the mammalian cells studied.