Calcium Saturation Research Articles

In vivo calcium accumulation in presynaptic and postsynaptic dendrites of visual interneurons.

In this comparative in vivo study of dendritic calcium accumulation, we describe the time course and spatial integration properties of two classes of visual interneurons in the lobula plate of the blowfly. Calcium accumulation was measured during visual motion stimulation, ensuring synaptic activation of the neurons within their natural spatial and temporal operating range. The compared cell classes, centrifugal horizontal (CH) and horizontal system (HS) cells, are known to receive retinotopic input of similar direction selectivity, but to differ in morphology, biophysics, presence of dendrodendritic synapses, and computational task. 1) The time course of motion-induced calcium accumulation was highly invariant with respect to stimulus parameters such as pattern contrast and size. In HS cells, the rise of [Ca(2+)](i) can be described by a single exponential with a time constant of 5-6 s. The initial rise of [Ca(2+)](i) in CH cells was much faster (tau approximately 1 s). The decay time constant in both cell classes was estimated to be at least 3.5 times longer than the corresponding rise time constant. 2) The voltage-[Ca(2+)](i) relationship was best described by an expansive nonlinearity in HS cells and an approximately linear relationship in CH cells. 3) Both cell classes displayed a size-dependent saturation nonlinearity of the calcium accumulation. Although in CH cells calcium saturation was indistinguishable from saturation of the membrane potential, saturation of the two response parameters differed in HS cells. 4) There was spatial overlap of the calcium signal in response to nonoverlapping visual stimuli. Both the area and the amplitude of the overlap profile was larger in CH cells than in HS cells. Thus calcium accumulation in CH cells is spatially blurred to a greater extent than in HS cells. 5) The described differences between the two cell classes may reflect the following computational tasks of these neurons: CH cells relay retinotopic information within the lobula plate via dendritic synapses with pronounced spatial low-pass filtering. HS cells are output neurons of the lobula plate, in which the slow, local calcium accumulation may be suitable for local modulatory functions.

Differential thermogravimetric analysis of oxalate in hydrogen peroxide‐treated allophanic soils

Soil organic matter destruction by hydrogen peroxide (H2O2) treatment used in clay sampler, preparation of allophanic soils leads to oxalate formation which can be adsorbed on clay surfaces or precipitated as calcium oxalate (CaC2O4), when calcium (Ca) saturation is involved. Oxalate precipitation is detected through differential thermogravimetric (DTG) analysis. The DTG curves of Vilcun soil, a Chilean Andisol, potassium (K) or Ca ion homoionized show only the characteristic continuous weight loss of allophanic soils. After H2O2 treatment, the Ca homonized sample shows three more peaks attributed to CaC2O4 which remain even after iron oxide removal by the citrate‐dithionite‐bicarbonate treatment. However, they are not shown if water washings are applied after the H2O2 treatment.

Phase Equilibria and Superconducting Properties of BiSr2YCu2O7 (1212 Phase)

Phase equilibria of the quasi‐quaternary system BiO1.5–SrO‐YO1.5–CuO have been studied at a temperature of 950°C in air, with special regard to the 1212 phase. The 1212 phase reveals only very small changes in the cation ratio. Single‐phase samples exist for (Bi0.24–0.36Cu0.42‐0.55)–Sr2Y1.27Cu2Oy compositions. The bismuth‐rich composition of the 1212 phase is in thermodynamic equilibrium with a liquid and the 2212 phase, whereas the copper‐rich composition is in equilibrium with five other phases. The influence of combined calcium and lead doping also has been studied. Exceeding the calcium saturation of the 1212 phase increases the amount of 2212 as a secondary phase. Single‐phase 1212 samples do not show any superconductivity in either the as‐prepared or the post‐annealed state. The only compositions with bulk superconductivity are those with calcium and lead doping after annealing at a temperature of 980°C. The superconductivity is attributed to the 2212 phase crystallizing from the melt during slow cooling.

Computing SI and CCPP using spreadsheet programs

Spreadsheets can automate any chemical equilibrium calculation that can be performed by hand.Lotus 1‐2‐3® worksheets for calculating the calcite saturation index (SI) and calcium carbonate precipitation potential of a water sample are described. A simplified worksheet illustrates the principles of the method, and a more complex worksheet suitable for modeling most potable water sources is briefly described. Both worksheets include ion pairing and adjustments of equilibrium constants for temperature and ionic strength. For several test cases with a wide range of temperature, alkalinity, pH, and calcium concentration, the worksheet SI values differed <1 percent from those computed by WATEQX. For water quality modeling, spreadsheets have several advantages compared with large equilibrium codes: flexible input and output, ease of maintaining the thermodynamic database, and relatively small memory and mass‐storage requirements. Modeling of archived chemical data is possible through the combination of database management and computational capabilities of many commercially available programs. The worksheets can be obtained from the authors.

Simultaneous Determination of Oxalate, Glycolate, Citrate, and Sulfate from Dried Urine Filter Paper Spots in a Pediatric Population

Measurement of oxalate in urine is important for the diagnosis of primary hyperoxaluria (McKusick 259900) and the secondary forms produced by excessive intake or abnormal intestinal absorption of oxalate (1). Determination of glycolic acid is essential for the diagnosis of primary hyperoxaluria type 1. Finally, to estimate the risk of stone formation in calcium oxalate urolithiasis and nephrocalcinosis, simultaneous determination not only of calcium but also of citrate (a potent inhibitor of calcium oxalate and calcium phosphate crystallization) and other constituents (electrolytes, phosphate and sulfate) is required to calculate urinary calcium saturation (2). Ion-chromatography HPLC (3)(4) and specific enzymatic assays (5)(6) are available only in specialized laboratories. In addition, preservation and storage of liquid samples may influence the stability of oxalate and glycolate (7). Use of urinary filter spots is a practical alternative for the collection and safe transport of samples to be analyzed for many metabolic disorders. To evaluate the age-related changes of oxalate, glycolate, citrate, and sulfate in a pediatric population, we developed an automated ion-chromatography system for the simultaneous measurement of these anions in urine and established their reference values for liquid urine samples as well as for dried urine on filter paper. We studied 20 individuals from each age group ( 16 years), all without renal or metabolic disease, all on a routine food intake at the time of study. The urines were preserved with 6 mol/L HCl at pH 1–2 to prevent nonenzymatic conversion of ascorbate to oxalate. Filter paper strips (3 × 5 …

Study of Calcium Oxalate Crystalluria on Renal and Vesical Urines in Stone Formers and Normal Subjects

Objective: The aim of this study is to compare vesical and renal calcium oxalate crystalluria in an attempt to correlate crystal formation with chemical composition and calcium oxalate saturation of renal urine. Material and Methods: Urine specimens were directly collected from the bladder and the kidney, of 11 stone formers and 11 control subjects under general anesthesia. The type of crystals present in urine as well as their size, number by cubic millimeter and state of aggregation were determined. In addition, calcium, magnesium, sodium, chloride, phosphate, citrate, oxalate, pyrophosphate and uric acid were measured in order to evaluate the calcium saturation status (EQUIL V program). Results: Calcium oxalate crystals were detected in 3 stone formers (27%) and 2 control subjects (18%) in vesical urine and in 4 stone formers (36%) and 3 control subjects (27%) in renal urine. Only 2 stone formers presented with simultaneous renal and vesical crystalluria. Subjects of the two groups with and without renal crystalluria were compared in terms of chemical composition and calcium oxalate saturation of renal urine. Crystalluric subjects (n = 7) had significantly higher uricosuria (p = 0.02), calciuria (p = 0.04), magnesiuria (p = 0.04) and calcium oxalate molar product (p = 0.05) than noncrystalluric (n = 15); calcium oxalate saturation was similar (p = 0.5). Conclusions: Beyond theorical considerations on lithogenesis, our observations and in particular the apparent discrepancy between renal and vesical crystalluria pose the problem of the clinical interest of the evaluation of calcium oxalate crystalluria based on freshly voided urine in the assessing the lithogenic risk or in the follow-up of patients who are particularly prone to stone recurrence.

Phospholipase C Isoforms δ1and δ3from Human Fibroblasts

Phospholipase C isoforms δ1and δ3(PLCδ1and δ3) were expressed inEscherichia coliusing the cDNA sequences from human fibroblasts. The enzymes were also expressed with the sequence Met-Gly-His6-Ser-Gly-Leu-Phe-Lys-Arg, a hexahistidine sequence followed by a Kex2 protease cleavage site, denoted as “-H6K2,” attached to their amino termini. PLCδ1, PLCδ1-H6K2, PLCδ3, and PLCδ3-H6K2 all expressed in highly active form. The H6K2-bearing isoforms were each purified to homogeneity in a single step, with yields of 90–100%, using agarose–iminodiacetic acid–Ni columns and imidazole buffer as eluting agent. Yields in terms of activity increased as the temperature of expression was decreased. Expression at 16°C for 72 h yielded 33 mg of pure PLCδ1-H6K2 and 13 mg of pure PLCδ3-H6K2 per liter of culture. Removal of H6K2 from both isoforms with Kex2 protease resulted in little or no loss of activity. Expression of PLC isoforms bearing -H6K2 at the amino terminus resulted in about 12 times more activity than expression of the isoforms lacking -H6K2. PLCδ3is much less stable than PLCδ1. Successful purification and storage of PLCδ3depends on a suitable stabilizing medium. Both isoforms require 0.3 μmcalcium ion for half-maximum activity. The specific activities of the isoforms expressed with and without -H6K2 are the same, as are their calcium saturation curves.

Improvement of heavy metal biosorption by mycelial dead biomasses (Rhizopus arrhizus, Mucor mieheiandPenicillium chrysogenum): pH control and cationic activation

Fungal mycelial by-products from fermentation industries present a considerable affinity for soluble metal ions (e.g. Zn, Cd, Ni, Pb, Cr, Ag) and could be used in biosorption processes for purification of contaminated effluents. In this work the influence of pH on sorption parameters is characterized by measuring the isotherms of five heavy metals (Ni, Zn, Cd, Ag and Pb) with Rhizopus arrhizus biomass under pH-controlled conditions. The maximum sorption capacity for lead was observed at pH 7.0 (200 mg g-1), while silver uptake was weakly affected. The stability of metal-biosorbent complexes is regularly enhanced by pH neutralization, except for lead. A transition in sorption mechanism was observed above pH 6.0. In addition, comparison of various industrial fungal biomasses (R. arrhizus, Mucor miehei and Penicillium chrysogenum) indicated important variations in zinc-binding and buffering properties (0.24, 0.08 and 0.05 mmol g-1, respectively). Without control, the equilibrium pH (5.8, 3.9 and 4.0) is shown to be related to the initial calcium content of the biosorbent. pH neutralization during metal adsorption increases zinc sorption in all fungi (0.57, 0.52 and 0.33 mmol g-1) but an improvement was also obtained (0.34, 0.33 and 0.10 mmol g-1) by calcium saturation of the biomass before heavy metal accumulation. Breakthrough curves of fixed bed biosorbent columns demonstrated the capacity of the biosorbent process to purify zinc and lead solutions in continuous-flow systems, and confirmed the necessity for cationic activation of the biosorbent before contact with the heavy-metal solution.

Increased urinary saturation and kidney calcium content in genetic hypercalciuric rats

We have established a colony of genetic hypercalciuric (IH) rats as a model of idiopathic hypercalciuria in humans. To test the hypothesis that hypercalciuria can cause crystallization in kidneys through increased supersaturation, in the absence of confounding effects of diet and whatever complex inhibitor disorders underlay stone disease, we fed males and females of the 21st generation of IH rats 13 g per day of a low calcium (LCD, 0.02% Ca), followed by a normal calcium (NCD, 0.6% Ca) and then a high calcium (HCD, 1.2% Ca) diet, each for seven days. During the last 24 hours of each period complete urine collections were obtained and analyzed for all substances known to affect urinary calcium oxalate (CaOx) and brushite (CaHPO4) supersaturation. Relative supersaturation with respect to the solid phases of CaOx and CaHPO4 were then calculated. Compared to same gender controls (Ctl) urine calcium excretion was higher in the female IH rats on all diets and in the male IH rats on NCD and HCD. The female and male IH rats on NCD and HCD were supersaturated with respect to CaOx; however, the male and female Ctl were supersaturated with respect CaOx only on HCD. The female IH rats on NCD and HCD and the male IH rats on NCD were supersaturated with respect to CaHPO4; however, neither the male nor female Ctl rats were supersaturated with respect to CaHPO4 on any diet. On NCD and HCD urine supersaturation with respect to CaHPO4 by females exceeded that of males.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume changes in high‐affinity calcium binding of the sarcoplasmic reticulum calcium‐transport enzyme

The effect which hydrostatic pressure exerts on the hydrolysis of dinitrophenyl phosphate and nitrophenyl phosphate by the sarcoplasmic reticulum calcium-transport enzyme was determined. Activation volumes for substrate hydrolysis at saturating and non-saturating concentrations of calcium were determined and used to evaluate volume increments for initial calcium binding. A reaction scheme in which two unidirectional substrate-driven reactions transfer high-affinity into low-affinity calcium-binding sites was applied to determine binding-volume increments. It has been inferred from the pressure dependence of the volume-generating function, defined as the difference between the reciprocal reaction rates of the saturated and the unsaturated enzyme, that calcium binding proceeds in two steps. The two associated binding constants are endowed with large binding-volume increments of opposite signs (+84 to +207 ml/mol and -3 to -136 ml/mol). Under different experimental conditions, with respect to the temperature, degree of calcium saturation and absence or presence of Me2SO, they add up to the same integral volume increment of 73 +/- 3.5 ml/mol for the entry of two calcium ions into the reaction cycle. In aqueous media, the two binding constants contribute about equally to binding and to the observed binding-volume increment. The presence of Me2SO strongly favours the first binding step. The size of the integral volume increment is in line with that determined for the interaction of calcium with calmodulin [Kupke, D.W. & Dorrier, T.E. (1986) Biochem. Biophys. Res. Commun. 38, 199-204].

Changes in Depth of Lime Zones of Haplustolls in Northeastern Nebraska

Observations in 1989 of Moody soils (fine-silty, mixed, mesic Udic Haplustoll) in northeastern Nebraska suggested that lime zones usually noted in these soils no longer exist at depths recorded in earlier studies. Because of these observations it was hypothesized that lime zones no longer existed at characteristic depths in Moody or associated Nora soils. Exact locations of sites of 1959 studies were determined from established landmarks. Transects were established across the landscape units of the earlier sites; soils were sampled and described to a depth of 95 in. (240 cm). Horizons of lime accumulation were not present at the depth sampled in any of the Moody pedons. Lime zones were present in the Nora soils (fine-silty, mixed, mesic Udic Haplustoll) but at greater depths than were noted in the earlier studies. Calcium saturation paralleled this change. Other aspects of the soils were much the same in 1989 as in 1959.

The effect of Acacia albida on tin-mine spoil and their possible use in reclamation

From a number of studies in Africa, Acacia albida has been shown to have some extremely beneficial effects on the soil lying within the confines of its canopy shadow. On the Jos Plateau of Nigeria, Acacia albida is a natural colonizer of spoil mounds created as a result of opencast tin mining. Observation of the ground vegetation growing in the vicinity of a number of isolated Acacia albida indicated that the ground vegetation growing below the canopy was taller, more lush and a darker green than that growing outside the influence of the canopy, thus suggesting that the beneficial effect of Acacia albida on soils reported from elsewhere in Africa was operating at these sites. Analyses of soil samples collected from sites beneath and outside the canopy of a single tree confirmed this tentative hypothesis. Organic carbon, total nitrogen, pH, percentage base saturation and exchangeable calcium, magnesium, sodium and potassium were all significantly higher in soils from beneath the canopy than in those from outside. The soil beneath the tree also had a better-developed and stronger structure and a more active population of soil fauna. Having established that the Acacia albida did indeed have a beneficial effect on the spoil soils, the study was extended to compare the effect of Acacia albida on the spoil soil with that of the eucalypt plantations established on areas of reclaimed mine land. The sites under Acacia albida were found to have significantly higher levels of exchangeable calcium, pH and base saturation than those under the eucalypts. This difference is of some importance, since it has recently been shown that the eucalypt plantations are causing a gradual degradation of the soils rather than the amelioration hoped for by the unit that established the plantation policy in the 1960s. Having established that Acacia albida has a more beneficial effect on the spoil soils than the eucalypts, consideration is given to the possibility of using the native Acacia albida as an alternative to the exotic eucalypts. It is concluded, however, that a more detailed study is required into the effect that Acacia albida has on the spoil soils before any firm recommendation can be made, particularly as the eucalypts have much greater economic value than Acacia.

Acidity properties in swedish forest soils—regional patterns and implications for forest liming

The chemical status within a subset of Swedish forest soils representing Spodosols and acid Entisols and Inceptisols at mesic sites is reported. Three regions which differ in climate and deposition, southwestern (SW), southeastern (SE) and northern (N) Sweden are compared. Most of the soils are located on acid siliceous bedrock. The three regions differ in the percentage of sample plots where the value of a given variable exceeds the mean calculated for the whole country. The order of decreasing frequency in the 0 and B horizons is N>SE>SW for base saturation, calcium saturation and magnesium saturation, and N>SW>SE for potassium saturation. For aluminium saturation the order is SW=SE>N in the 0 horizon and SE>SW>N in the B horizon. The regional difference is especially pronounced with respect to the calcium saturation in the B horizon. The percentage figure is 13, 37 and 45 in SW, SE and N respectively. 33 and 38% of the sample‐plots in SE and N respectively have a calcium saturation <1 % of CEC, the corresponding figure for SW being 73 %. Different liming criteria and the possible need for forest liming are discussed.

Tensile characteristics of collenchyma cell walls at different calcium contents

Collenchyma fibres from celery (Apium graveolens L.) were extracted with detergent and phenol‐acetic acid‐water to leave the intact cell walls, free from active enzymes. Under a small, constant stress the cell wall fibres showed elastic and plastic extension and viscoelastic deformation, but viscous flow was observed only at high stresses close to the breaking stress. After complete removal of calcium ions with cyclohex‐anediamine tetraacetic acid (CDTA) and incubation for 18 h, comparable levels of these extensibility components were observed at much lower stresses. However, partial removal of calcium ions with citrate did not increase the plastic, elastic or viscoelastic components even when the residual calcium was reduced to 3.5% of the exchange capacity. The breaking stress of the fibres was rather more sensitive to calcium removal, being reduced by 50% at 7% calcium saturation. CDTA‐extracted fibres broke by cell separation at very low stress. These characteristics did not appear compatible with removal of calcium ions, or their displacement by protons, as a mechanism for auxin‐induced growth in this material: however such mechanisms are not excluded in other tissues or under other conditions. Strong chelating agents which remove enough calcium to weaken cell walls should be avoided in experiments on other mechanisms of auxin‐induced growth.

Increasing the efficiency of utilization of soil and fertilizer phosphorus in the subtropical and tropical agricultural systems C

As a rule, soils of the subtropical and tropical regions, in which rainfall is not limiting, are acidic, and low in phosphorus, and, to a less extent, in other macro and micronutrients as well, such a sulfur, boron and zinc. The establishment of a permanent agricultural prac. tice therefore, demands relatively high usage of liming and phosphatic fertilization, to begin with. Several approaches, not mutually exclusive, could be used in order to increase the efficiency of utilization of soil and fertilizer phosphorus so that, goal of diminishing costs of production is reached. The use of liming materials bringing up pH to 6.0-6.5 causes the conversion of iron and aluminum phosphates to more available calcium phosphates; on the other hand, by raising calcium saturation in the exchange complex, it improves the development and operation if the root system which allows c or a higher utilization of all soil nutrients, including phosphorus, and helps of stand water deficits which may occur. The role of mycorrhizal fungi should be considered as a way of increasing soil and fertilizer P utilization, as well as the limitations thereof. Screening of and breeding for varieties with higher efficiency of uptake and utilization of soil and fertilizer phosphorus leads to a reduction in cost of inputs and to higher benefit/cost ratios. Corrective fertilization using ground rock phosphate helps to saturate the fixation power of the soil thereby reducing, as a consequence, the need for phosphorus in the maintenance fertilization. Maintenance fertilization, in which soluble phos-phatic sources are used, could be improved by several means whose performance has been proved: limimg, granula tion, placement, use of magnesium salts. Last, cost of phosphate fertilization could be further reduced, without impairing yields, through impairing yields, through changes in technology designed to obtain products better adapted to local conditions and to the availability or raw materials and energy sources.

Calcium control of the intestinal microvillus cytoskeleton: its implications for the regulation of microfilament organizations.

The microvillus core-filament bundle from intestinal epithelial cells is a highly ordered structure containing actin and four major associated proteins. Two of these, villin and calmodulin, bind calcium ions (Kd approximately 10(-6) M) in the physiologically important range. Because ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid is present throughout the purification and the isolated cores contain levels of calcium substoichiometric to calmodulin, the protein is bound in the structure without calcium saturation. 10-[3-(4-Methyl-1-piperazinyl)propyl]-2-trifluoromethylphenothiazine, a calmodulin-specific drug, removes the protein from the cores without visibly affecting their ultrastructure. Calmodulin-depleted cores rebind exogenously supplied brain calmodulin. Although the core filaments are stable when the calcium level is less than 10(-7) M, they dissassemble when it is greater than 10(-6) M. This appears to be due to the calcium-sensitive allosteric transition of villin from an F-actin bundling protein to an F-actin severing protein. The actions of the two calcium-binding proteins, villin and calmodulin, are discussed in terms of the calcium sensitivity of the filament bundle. We suggest that villin may act as a calcium-sensitive factor regulating microfilament assembly and disassembly and that calmodulin serves as a buffer modulating the free calcium concentration. This hypothesis may explain some aspects of the physiological process of calcium uptake in the intestine and of the effects of calcium fluxes on the submembranous organization of microfilaments in other cells and tissues.

日本ナシ果実の硬化障害に関する研究 (第2報)

This paper deals with the effects of application of CaO2 and CaO and soil moisture regimes, pF 1.3, 2.2 and 2.6, on the incidence of ‘Yuzuhada’ disorder. The effects were examined during the period from 1973 to 1977, using potted eight-year-old Nijisseiki pear trees that so far had developed the symptoms of ‘Yuzuhada’ disorder more or less every year. Besides the pot tests, multivariate analysis was applied to the data obtained by chemical analysis of soils, fruits, and leaves to detect major contributing factors. This information is necessary for devising an effective control measure of the ‘Yuzuhada’ disorder. The results obtained are summarized as follows:1. In the treatment of pF 2.2, the incidence of ‘Yuzuhada’ disorder was decreased markedly by CaO2 and CaO applications even in the first year after the application and thereafter decreased further to as low as 13 percent in the fourth year. Fruits of these treatments had grown fully and showed considerably high marketable quality with slight symptoms of the disorder. Under both pF 2.6 and 1.3, however, CaO2 application increased the percentage of ‘Yuzuhada’ fruit up to 60 percent, and CaO up to 80 percent, though the calcium applications decreased it to less than 50 percent in the first year only.2. When expressed as percentages of dry weight basis or as total quantity per fruit, N, P, and K contents of fruits of pF 1.3 treatment were lower than those of pF 2.2 and 2.6, and Ca and Mg contents of pF 1.3 treatment were lower than those of pF 2.2. K and Ca contents of fruits were lower, while N content was higher, under pF 2.6 than under pF 2.2 and 1.3.3. P, K, and Ca contents of leaves expressed on a dry weight basis were lower under pF 1.3, and K and Ca contents were lower under pF 2.6 than under pF 2.2. Exchangeable Ca and Mg contents of soils were decreased in the pF 1.3 treatment, while exchangeable K and Ca were decreased in the pF 2.6 treatment. Besides, total calcium content of the soil was lower under pF 1.3 and 2.6 than under pF 2.2. These facts imply that the fixation and leaching of basic elements occurred in the soil by drying and moistening treatments, respectively.4. Fructose and sucrose contents in the fruit were increased, while glucose and sorbitol contents were decreased, by the calcium applications under pF 2.2. Under pF 1.3 and 2.6, however, neither fructose nor sucrose was increased and glucose or sorbitol was not decreased by calcium application. On the other hand, titratable acidity of fruit juice was somewhat increased under pF 2.6 and conversely decreased under pF 1.3.5. Respiration rate and ethylene production in the fruit were more increased under pF 1.3 and 2.6 than under pF 2.2. In other words, fruit maturity was markedly progressed by both drying and moistening of pot soils.6. Principal component analysis was applied to the data obtained by chemical analysis of soil and plant materials. Ca contents of both fruit and leaves significantly contributed to the first principal component, while various factors, such as the content of exchangeable Ca and Mg, percentage calcium saturation, and pH values of soils, contributed to the second principal component. Additionally, amounts of CO2, ethylene, and starch production also seemed to be significant factors pertaining to the incidence of ‘Yuzuhada’ disorder. The results of multiple regression analysis showed a tendency similar to those obtained by principal component analysis. It is suggested that factors which significantly contribute to the first and second components may influence the incidence of ‘Yuzuhada’ disorder developed on the Nijisseiki pear tree.

Cation exchange capacity and base saturation of imperfectly drained surface coastal plain soils

Abstract Testing three imperfectly drained forest soils (Alfisols and Ultisol) by nine methods showed that cation exchange capacities were highly pH dependent. Adding lime increased CEC values obtained by buffered and unbuffered methods but decreased CEC values when total bases were added to total acidity or salt replaceable acidity. No method tested completely explained the change in CEC caused by liming. Fractionation of the whole soil CEC Indicated an appreciable masked charge caused by an apparent complexing of amorphous metal oxides with clay or organic matter. In both buffered and unbuffered solutions, calcium saturation usually gave higher CEC values than monovalent ion saturation.

Hydrolysis of Propazine by the Surface Acidity of Organic Matter

AbstractPropazine [2‐chloro‐4, 6‐bis (isopropylamino)‐s‐triazine] hydrolysis in acidic aqueous soil‐free systems was pH dependent, increasing with lower pH values. At a given pH, degradation followed first‐order kinetics. At 23.5C, the relationship was log t½ (days) = 0.59 pH −0.21. Adsorption of propazine by organic matter prepared from Michigan peat was also pH dependent, but both molecular and cationic adsorption occurred. An increased rate of degradation in the presence of organic matter was postulated as due to hydrolysis by ionized surface hydrogen. Increasing the calcium saturation resulted in decreased hydrolysis. Increasing the CaCl2 concentration of the propazine‐organic matter‐aqueous system had no effect on acid hydrolysis. In the salt‐amended systems, an increased hydrolysis, to be expected from the lower pH in the ambient solution, was apparently offset by a decreased hydrolysis due to the lowered amounts of ionized surface hydrogen.

Effect of Appilication of Phosphate and Lime on the Growth and Fruiting of Satsuma Mandarin Trees

In order to clarify the effect of application of various amounts of phosphate in combination with lime to the soil on the growth and fruiting of young Satsuma mandarin trees, field experiments were carried out for ten years from 1960 to 1970, in the orchard of diluvial clayey loam.1. The growth of new shoot and trunk, and the increase in leaf number were accelerated by the application of lime until 1962 when the tree sizes were comparatively small The effect of applied phosphate was found only in the plots without lime, that is, the development of trees was accelerated as the amount of applied phosphate was increased. These trends were observable in 1963, but significant differences have disappeared since 1964.2. Since 1963, a similar symptom that was caused by calcium deficiency was found on twigs and leaves of trees in the plots without application of lime, and defoliation and twig dieback occurred in 1964 and 1965. These trees gradually recovered since 1968.3. The number of flowers of P0 plot in 1964 was distinctly low, and this was recovered by an application of phosphate. Since 1965 no significant differences in yield among the various plots were found, although a slight low yield was found in P0 and P1 plots in 1964.4. During five years from 1964 to 1968, there were no substantial differences in fruit weight among the plots. A slight difference was found in 1969, but this might be due to a difference of the number of fruits per tree.No significant differences were also found in fruit color and rate of fruit rind among the individual plots. Total sugar content in fruit juice was slightly low in the plots of phosphate deficiency. It is notable that citric acid content was distinctly lowered by an application of lime. The amounts of applied phosphate did not affect the content of citric acid. Sugar acid ratio was substantially high in the plots treated with lime, which is resulted from lower values of acid content caused by lime application.5. There were not so much differences in phosphorus content of leaves among the plots which received various amounts of phosphate. However, the plots which received lime showed clearly higher values in calcium content of leaves than those which did not receive lime. Magnesium content was higher in the plots which did not receive lime, its content was decreased by increasing the amount of applied phosphate.6. The content of available phosphorus in the soil was increased in proportion to the amount of applied phosphate. The contents of available phosphorus at 30-cm depth were less than half of those at 10-cm depth. Exchangeable CaO, degree of calcium saturation and pH of the soil were very high in the areas which received lime. Those values in the plots which did not receive lime were increased by increasing the amounts of applied phosphate.