Decrease In Ca Concentration Research Articles

Relationship between microstructures and contents of Ca/P in near-eutectic Al–Si piston alloys

The relationship between microstructures and contents of Ca/P in near-eutectic Al–Si piston alloy (ZL109) was investigated by optical microscopy and electron probe microanalyzer (EPMA). Ca was found to have an obvious influence on the microstructures of ZL109 alloys. It is difficult to present phosphorus refinement effect when the Ca content in the ZL109 alloy exceeds 100 ppm. In order to obtain a good phosphorus refinement effect, the content of Ca impurity in the alloy should be under 50 ppm. It has also been shown that Ca can modify eutectic Si and enhance the formation of α-Al dendrites and fibrous eutectic Si in the alloy. Controlling the content of Ca impurity by the addition of C 2Cl 6 to the melt resulted in the appearance of phosphorus refinement effect. With the decrease of Ca content from 100 ppm to 12 ppm, the average primary silicon particle size is reduced to 16.2 μm from 31.7 μm.

Cadmium, zinc and the uptake of calcium by two crabs, Carcinus maenas and Eriocheir sinensis

The uptake of dissolved cadmium and zinc by crustaceans can usually be explained by the passive process of facilitated diffusion involving a transport protein in the membranes of permeable surfaces. Cadmium ions will also enter via uptake routes for calcium, given the similar size of the two free ions. This study has investigated the interaction of cadmium (and comparatively zinc) and calcium uptake in two crabs that show different permeability responses to changes in salinity, with consequently different effects on the uptake of cadmium and zinc with salinity change. Ca uptake rates in Carcinus maenas decreased in reduced salinity (33–15) with the decreased Ca concentration of the medium and increased if the Ca concentration was increased at salinity 20. It is concluded that Ca uptake over the salinity range 33–15 is via apical Ca channels in gill ionocytes, passively down an electrochemical gradient. The Ca uptake rate of Eriocheir sinensis showed no significant decrease over the salinity range 33–10 (probably because of the small differences in an already low Ca uptake rate in this crab against a background of inter-individual variability), but decreased significantly at salinity 5. Added calcium increased the Ca uptake rate of E. sinensis at salinities 15 and 5, supporting the interpretation that Ca uptake in gills is typically passive via apical Ca channels. Cadmium (but not zinc) inhibited calcium uptake in both crabs at 15 salinity, indicating sharing of Ca channels by Cd, but not at salinity 5 ( E. sinensis only) when Ca may be taken up into gill ionocytes by another (active?) physiological process.

Evidence of adipocere in a burial pit from the foot and mouth epidemic of 1967 using gas chromatography–mass spectrometry

Gas-chromatography–mass spectrometry was used to characterise the fatty acids from soils and associated tissues excavated from a 1967 Foot and Mouth burial pit. Subcutaneous fats were mainly comprised of 55–75% palmitic acid, 17–22% stearic acid and 3–16% oleic acid as well as 5–7% myristic acid. The distribution of fatty acids confirmed that the tissues were decayed to adipocere. The loss of oleic acid to <3% in two of the decayed fats suggested advanced stages of adipocere. However, adipocere formation was limited in a third tissue sample recovered from greater depth. Inductively coupled plasma atomic emission spectrometry of the pore waters revealed a decrease in Ca concentration and concurrent increase in Na concentrations this suggested that insoluble calcium salt had formed through displacement of sodium. The use of fatty acid profiles from soils and soil interstitial pore waters provide complementary evidence of adipocere formation in foot and mouth burial pits.

Enhanced Modification Process of B.390 Casting Alloy by the Ca Content Control

Primary Si particle size has been refined as Ca content of the melts decreased and cooling rate increased. A control of Ca content by the addition of CuCl2 to the melt was the most efficient in the refinement of primary Si particles. The minimum size of primary Si particles in this study was 15.0um when a residual content of Ca element in the alloy was 5ppm. Primary Si particle size was refined as primary Si crystallization temperature increased, which was attributed to the decrease of Ca content in the melts.

Distribution of minerals in quinoa (Chenopodium quinoa Willd.) seeds.

The distribution of minerals in quinoa (Chenopodium quinoa Willd.) seed was examined using energy dispersive X-ray microanalysis (EDX) in combination with scanning electron microscopy (SEM). Phosphorus, K, and Mg coincided in localization in embryonic tissue. Since phytin globoids have been known to localize in protein bodies in embryonic cells of quinoa seed, it is thought that P is attributed to phytic acid and that K and Mg form to phytate. Calcium and K were present in the pericarp, where the cell wall is thickly developed, suggesting that these minerals are associated with pectin. Sulfur occurred in embryonic tissues, which would be derived from sulfur amino acid residues of storage proteins concentrated in the tissues. Abrasion of quinoa seeds resulted particularly in decrease in Ca content.

Calcium and phosphorus concentrations and the calcium/phosphorus ratio in trabecular bone from the femoral neck of healthy humans as determined by neutron activation analysis

The Ca and P concentrations as well as the Ca/P ratio were estimated in intact trabecular bone samples from the femoral neck of healthy humans, 34 women and 44 men, aged from 15 to 55 years, using instrumental neutron activation analysis. The mean values (M±SD) for the investigated parameters (on a dry-weight basis) were: 12.1±3.0%, 5.94±1.71%, 2.07±0.25 and 10.9±2.5%, 5.30±1.23%, 2.07±0.22 for females and males, respectively. A statistically significant ( p⩽0.05) decrease of Ca concentration with age was found only for males while the P concentration and the Ca/P ratio were not affected by age. No statistically significant sex-related differences were observed in any of the parameters. The mean values for Ca, P and the Ca/P ratio lay close to the median of the very wide range of published data. The individual variation for the Ca/P ratio in trabecular bone from the healthy human femoral neck was lower than those for Ca and P separately. This suggests that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and may be more reliable for the diagnosis of bone disorders.

Effect of pH and Calcium Concentration on Some Textural and Functional Properties of Mozzarella Cheese

The effects of Ca concentration and pH on the composition, microstructural, and functional properties of Mozzarella cheese were studied. Cheeses were made using a starter culture (control) or by direct acidification of the milk with lactic acid or lactic acid and glucono-δ-lactone. In each of three trials, four cheeses were produced: a control, CL, and three directly-acidified cheeses, DA1, DA2, and DA3. The cheeses were stored at 4°C for 70 d. The Ca content and pH were varied by altering the pH at setting, pitching, and plasticization. The mean pH at 1 d and the Ca content (mg/g of protein) of the various cheeses were: CL, 5.42 and 27.7; DA1, 5.96 and 21.8; DA2, 5.93 and 29.6; DA3, 5.58 and 28.7. For cheeses with a high pH (i.e., ∼5.9), reducing the Ca content from 29.6 to 21.8mg/g of protein resulted in a significant decrease in the protein level and increases in the moisture content and mean level of nonexpressible serum (g/g of protein). Reducing the Ca concentration also resulted in a more swollen, hydrated para-casein matrix at 1 d. The decrease in Ca content in the high-pH cheeses coincided with increases in the mean stretchability and flowability of the melted cheese over the 70-d storage period. The fluidity of the melted cheese also increased when the Ca content was reduced, as reflected by a lower elastic shear modulus and a higher value for the phase angle, δ, of the melted cheese, especially after storage for <12 d. The melt time, flowability, and stretchability of the low-Ca, high-pH DA1 cheese at 1 d were similar to those for the CL cheese after storage for ≥12 d. In contrast, the mean values for flowability and stretchability of the high-pH, high-Ca DA2 cheese over the 70-d period were significantly lower than those of the CL cheese. Reducing the pH of high-Ca cheese (27.7 to 29.6mg/g of protein) from ∼5.95 to 5.58 resulted in higher flowability, stretchability, and fluidity of the melted cheese. For cheeses with similar pH and Ca concentration, the method of acidification had little effect on composition, microstructure, flowability, stretchability, and fluidity of the melted cheese.

Effects of application of nitrogen fertilizer on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in perennial ryegrass/white clover pastures in south‐western Victoria, Australia

Effects of timing and rate of N fertilizer application on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in herbage from perennial ryegrass/white clover pastures were studied at two sites in south‐western Victoria, Australia. Nitrogen fertilizer (0, 15, 25, 30, 45 and 60 kg ha–1) was applied as urea in mid‐April, early May, mid‐May, early June and mid‐June 1996 to pastures grazed by dairy cows. At Site 1, N fertilizer resulted in a linear increase in P, K, S, Mg and Cl concentrations in herbage and a linear decrease in Ca concentration. For all times of application, concentrations of P, K, Ca, Mg and Cl in herbage increased by 0·0048, 0·08, −0·010, 0·0013 and 0·053 g kg–1 dry matter (DM) per kg N applied respectively. For S concentration, maximum responses occurred in mid‐May (0·012 g kg–1 DM per kg N applied). At Site 2, N fertilizer resulted in a linear increase in P, S and Na concentrations in herbage, a linear decrease in Ca concentration and a curvilinear increase in K and Cl concentration. The maximum responses for P, S and K concentrations in herbage occurred for the N application in mid‐June and were 0·015, 0·008 and 0·47 g kg–1 DM per kg N applied respectively. For Cl concentration, the maximum response occurred for the N application in early June and was 0·225 g kg–1 DM per kg N applied. Overall, applications of N fertilizer up to 60 kg ha–1 did not alter herbage mineral concentration to levels that might affect pasture growth or animal health.

Dietary Ca inhibits waterborne Cd uptake in Cd-exposed rainbow trout, Oncorhynchusmykiss

The effects of chronic exposure to waterborne Cd and elevated dietary Ca, alone and in combination, were examined in juvenile rainbow trout, Oncorhynchus mykiss. Fish were chronically exposed to 0.05 (control) or 2.56 μg/l Cd [as Cd(NO 3) 2·4H 2O] and were fed 2% body mass/day of control (29.6 mg Ca/g) or Ca-supplemented trout food (52.8 mg Ca/g as CaCl 2·2H 2O). Cd accumulated mainly in gill, liver, and kidney. Waterborne Cd inhibited unidirectional Ca uptake from water into the gill and induced hypocalcemia in the plasma on day 40. Waterborne Cd also induced an elevated Ca concentration on day 20 in the gill tissue of trout fed the Ca-supplemented diet and a decreased Ca concentration on day 35 in the gills of trout fed the control diet. Dietary Ca protected against Cd accumulation in gill, liver, and kidney, but did not protect against the inhibition of Ca uptake into the gill or plasma hypocalcemia. When fed Ca-supplemented diet and exposed to waterborne Cd, fish showed 35% mortality, compared to 0–2% in control fish and in the Cd-exposed fish with normal Ca in the diet. Growth, on the other hand, was not affected by any treatment.

Calcium declines in northeastern Ontario lakes

Thousands of lakes in northeastern Ontario, Canada, have been acidified by sulphur deposition associated with emissions from the Sudbury area metal smelters. However, water quality improvements including increased pH and reduced sulphate concentrations have followed large reductions in Sudbury emissions that were implemented, beginning in the 1970s. Substantial decreases in Ca concentrations accompanied these other changes in lakewater chemistry. Monitoring of 38 lakes 20–128 km from Sudbury showed declines in Ca concentrations, averaging 2.7 µeq·L–1·year–1, over the period 1981–1999. Declines were particularly apparent during the 1990s, averaging 3.8 µeq·L–1·year–1. Paleolimnological reconstructions of the long-term Ca patterns in six lakes suggest that general lakewater Ca declines occurred through much of the 20th century. Comparison of recent measured Ca concentrations in 16 lakes with diatom-inferred pre-industrial Ca concentrations indicates that overall decreases in Ca have been large, averaging 74.6 µeq·L–1 or 46%. Long-term Ca patterns may reflect a combination of factors including climatic changes, forest harvesting activities, and leaching by acid deposition, the effects of which we can not separate. Calcium declines have biological implications that will need to be considered in the development of appropriate targets as these lakes continue to recover from acidification.

The effect of zinc supply on cadmium-induced changes in the tibia of rats

It has been determined that zinc supplementation (240 μg Zn/ml) during (for 12 weeks) or after (for 2 weeks) cadmium exposure (50 μg Cd/ml for 12 weeks) can prevent the accumulation and toxic action of Cd in the tibia of rats. The exposure to Cd led to disturbances in bone metabolism reflected by changes in the chemical composition of bone and decreased bone mineral density (osteomalacian changes). The Zn supply in conditions of Cd intoxication completely prevented the Cd-induced increase in percentage of water content and decrease in tibia ash weight, ash weight/dry weight, non-org. comp./org. comp., Zn content and concentration. Moreover, Zn partly protected from the decrease in Ca concentration and content, percentage of non-organic components content, Ca/wet weight, Ca/ash weight and Ca/dry weight. Zn administered after Cd exposure partly, but not completely, protected from Cd-induced decrease in percentage of non-organic components content, Ca/wet weight as well as Ca content and concentration. This protective effect on bone was most evident when Zn was administered during Cd exposure. But Zn, independently of the manner of its administration, did not prevent Cd accumulation in the tibia. Our results suggest that Zn supply in conditions of simultaneous exposure can prevent Cd-induced bone loss to some extent, and used after Cd treatment can give therapeutic benefits.

UV radiation and low calcium as mutual stressors for Daphnia

The cladocerans Daphnia magna and D. tenebrosa were exposed to daily 6‐h ultraviolet (UV) radiation along a gradient of ambient Ca in the medium (0.5, 1.0, 5.0, and 10 mg Ca L−1) at nearly constant conductivity. Integrated irradiance over 300–400 nm was 35.95 W m−2, corresponding to maximum outdoor intensities during midsummer. D. magna was most susceptible to UV radiation, but the UV susceptibility for both species increased significantly with decreased Ca content. Ca uptake (45Ca) was apparently not influenced by short‐term (3 h) UV exposure; thus, although lipid peroxidation and membrane damage are likely mechanisms for impaired ionic uptake, the overall role of low Ca may be reduced stress tolerance. While general conclusions on other species and taxa are premature, the data indicate that water hardness could be a major determinant to UV susceptibility among Ca‐demanding zooplankton species like Daphnia.

The effect of boron on calcium uptake and growth in micropropagated potato plantlets

Boron (B) requirements differ widely among plant species and the concentration range between toxicity and deficiency is less for B than for any other nutrient. Excess B can adversely affect calcium (Ca) uptake and plant growth. Potato cvs Bintje and Norland plantlets were micropropagated on Murashige & Skoog (MS) nutrient medium, supplemented with 3 (MS control level) or 9 mM Ca, and a range of H3BO3 levels (0.025 to 0.300 mM B). Medium B levels of 0.100 and 0.300 mM decreased Ca content in leaves and shoots of cv. Norland, but not Bintje. Medium B level of 0.025 mM, which is 25% of the control MS level, enhanced Ca uptake in cv. Norland and did not compromise normal plantlet growth in either cultivar. This lower H3BO3 level (0.025 mM B), and a B-free gelling agent such as Gelrite, could be used for micropropagation of potato and possibly other species susceptible to Ca defifiency disorders.

Coexisting monazite and allanite in peraluminous granitoids of the Tribeč Mountains, Western Carpathians

Monazite, a typical light rare-earth element (LREE) mineral of S-type granitoids in the Western Carpathians, was found in the peraluminous biotite granodiorite-tonalite in the Tribec Mountains commonly containing polymineralic inclusions. These inclusions are dominated by anhedral allanite, although allanite also occurs rarely as discrete grains not enclosed by monazite. The monazite studied here is relatively homogeneous and characterized by high Th contents with proportions of huttonite (ThSiO4) and brabantite [CaTh(PO4)2] up to 14.6 and 9.3%, respectively. The discrete allanite grains are highly aluminous with a composition consistent with the peraluminous type of host rock. However, allanite included in monazite is extremely variable in LREE, Al, Fe, and Mg contents. This variation is interpreted to result from entrapment of allanite (+ melt) in monazite before local equilibrium was attained. The change from allanite to monazite as the stable LREE-rich phase is related to an overall decrease in Ca concentration caused by the onset of plagioclase crystallization. The early precipitation of allanite was possible because of the high LREE concentrations in the melt. The crystallization temperature of allanite must have been higher than monazite saturation (>856–845 °C and 798–790 °C for two analyzed samples). The Zr saturation temperature based on zircon solubility and REE thermometry based on monazite solubility reflect an increase in temperature from the edge to the center of the pluton, which coincides with an increase in the huttonite content in monazite. The primary LREE assemblage is accompanied by small grains of late huttonite(?) replacing monazite and brabantite replacing allanite.

WATERSHED CLASSIFICATION BY DISCRIMINANT ANALYSES OF LAKEWATER-CHEMISTRY AND TERRESTRIAL CHARACTERISTICS

We used canonical discriminant analyses to improve an existing classification scheme by identifying those lakewater-chemistry and terrestrial variables that can jointly differentiate among a set of lakes in the Adirondack region of the northeastern USA. We then used predictive discriminant analysis to examine the ability of the models constructed in predicting class membership for lakes with unknown hydrogeological settings into known classes. We used two sets of data collected during summers of 1984-1987 and 1994. For both periods, two main underlying dimensions were identified reflecting watershed hydro- geology and lake dissolved organic carbon. The hydrogeological construct was defined by lakewater concentrations of Ca, Mg, Na, and Si. This construct provides a continuous index from several previously assigned class variables and can help in data reduction and elim- ination of multicolinearity in further multivariate studies of ecosystem processes in the study lakes. The importance of Ca in defining the hydrogeological construct decreased from 1984-1987 to 1994, due to differential decrease in Ca concentration in the lake classes. The periodic decrease in Ca concentration of many drainage lakes suggests that they con- tinue to lose buffering capacity to acidic deposition and that the current decreased emission and deposition of acidic S compounds may not be sufficient for chemical recovery of these lakes. The construct reflecting lakewater concentration of dissolved organic carbon was defined by lakewater Fe concentration and the lake-volume-weighted watershed areas cov- ered by wetlands and forest. Our methodology and results should provide useful information for studies conducted in the Adirondack watersheds and may be applicable to other regions with properties and environmental issues comparable to those in the Adirondack region.

APPLE YIELD AND QUALITY AS AFFECTED BY TRAINING AND SHADING

Fruit yield and quality were investigated on five-year-old apple trees (Malus domestica Borkh. cv. Cox's Orange Pippin) on M9 rootstocks growing in field lysimeters, as affected by training to Y-trellis or slender spindle at full light exposure or 60 % shading treatment in the fourth growing season after planting. In comparison with the spindles and shaded trees, Y-trellis and exposed ones bore more fruits and got higher fruit yield with heavier average fruit weight and larger fruit size. Contents of dry matter, total soluble solids, the solids/acid ratio, starch, glucose, fructose, sucrose, sorbitol and total non-structural carbohydrates were higher in fruits from Y-trellis and exposed trees than those from the spindles and shaded ones. In addition, shading treatment increased N, P, K and Mg contents and K/Ca ratio, especially in K and Mg, but tendenciously decreased Ca content of fruits. Incidences of physiological disorder and fungi diseases of fruits during five months' storage were lower from shaded trees and the spindles than those from exposed and Y-trellis trees.

Prenatal Cocaine, Alcohol, and Undernutrition Differentially Alter Mineral and Protein Content in Fetal Rats

Alcohol exposure and undernutrition during pregnancy have been associated with altered fetal body composition. Recent observations suggest that cocaine exposure during pregnancy may impair delivery of nutrients to the fetus and could thereby alter body growth and composition. Such effects are important because they can adversely influence physical and neural development. Consequently, we investigated the dose-dependent effects of cocaine on fetal body composition in an animal (rat) model and compared such effects with those caused by prenatal alcohol exposure and undernutrition. Pregnant Sprague–Dawley rats received either 20, 30, 40, or 50 mg/kg cocaine HCl (SC) twice daily from gestation days 7 through 19. Pair-fed (undernutrition) and untreated control groups and a group receiving 3.0 g/kg alcohol (PO) twice daily served as comparison groups ( n = 11 to 14/group). Females were sacrificed on gestation day 20. One male and one female fetus was removed from each dam. The fetuses were minced, dehydrated, defatted, and analyzed for content of protein and the minerals Zn, Ca, Fe, Mg, K, and Na. In terms of concentration per unit of fat-free dry solids, male fetuses in the cocaine groups showed significant decreases in protein compared to untreated controls (15 ± 3 to 20 ± 2 mg/g vs. 24 ± 4 mg/g, p = 0.01). There was a significant treatment effect for Ca ( p < 0.05), reflecting a trend for decreased Ca concentrations in the fetuses of the cocaine and undernutrition groups. Male fetuses in the alcohol group had significantly elevated Mg levels compared to male fetuses in the other groups (3.0 ± 0.8 vs. 1.0 ± 0.2 to 2.3 ± 0.7 mg/g, p < 0.05). There were some sex differences, with female fetuses having significantly lower concentrations of Mg, Fe, K, and higher protein concentrations than male fetuses. Although the effects were few and modest, these results suggest that prenatal cocaine, alcohol, and undernutrition can differentially alter fetal body weight and composition and, therefore, adversely influence fetal development.

Assessment of soil calcium status in red spruce forests in the northeastern United States

Long-term changes in concentrations of available Ca in soils of red spruce forests have been documented, but remaining questions about the magnitude and regional extent of these changes have precluded an assessment of the current and future status of soil Ca. To address this problem, soil samples were collected in 1992-93 from 12 sites in New York, Vermont, New Hampshire, and Maine to provide additional data necessary to synthesize all available research results on soil Ca in red spruce forests. Sites were chosen to encompass the range of environmental conditions experienced by red spruce. Concentrations of exchangeable Ca ranged from 2.13 to 21.6 cmolc kg 1 in the Oa horizon, and from 0.11 to 0.68 cmol c kg 1 in the upper 10 cm of the B horizon. These measurements expanded the range of exchangeable Ca reported in the literature for both horizons in northeastern red spruce forests. Exchangeable Ca was the largest Ca fraction in the forest floor at most sites (92% of acid-extractable Ca), but mineral Ca was the largest fraction at the three sites that also had the highest mineral-matter concentrations. The primary factor causing variability in Ca concentrations among sites was the mineralogy of parent material, but exchangeable concentrations in the B horizon of all sites were probably reduced by acidic deposition. Because the majority of Ca in the forest floor is in a readily leachable form, and Ca inputs to the forest floor from the mineral soil and atmospheric deposition have been decreasing in recent decades, the previously documented decreases in Ca concentrations in the forest floor over previous decades may extend into the future.

Short-term effects of Ca(OH) 2 additions on phytoplankton biomass: A comparison of laboratory and in situ experiments

To identify mechanisms by which Ca(OH) 2 additions reduce phytoplankton biomass in the short term (<20 d), we investigated changes in concentrations of chlorophyll a (chl a), total phosphorus (TP) and calcium (Ca), and pH and turbidity in four eutrophic hardwater lakes, two dugouts and limnocorrals. We also tested the potential effects of high pH and turbidity on biomass of three representative species of planktonic cyanobacteria, green algae and diatoms in the laboratory. When chl a concentrations were higher than 10 μg·l −1, Ca(OH) 2 additions with dosages ranging from 25 to 87 mg·l −1 decreased chl a concentrations by 80% in lakes. Chl a concentrations were also reduced by adding 50, 75 or 100 mg·l −1 Ca(OH) 2 to limnocorrals and 250 mg·l −1 Ca(OH) 2 to dugouts. Transitory high pH and turbidity did not reduce phytoplanton biomass in the laboratory. The pH in limnocorrals and dugouts increased to > 10, which may have affected phytoplankton biomass. After treatment, TP concentrations declined in limnocorrals and dugouts, but not always in lakes. In lakes and dugouts, Ca concentrations > 30 mg·l −1 or pH levels > 10 were related to < 10 μg·l −1 chl a. In lakes, pH was always < 10 due to the inherently high buffering capacity, and the reduced phytoplankton biomass coincided with decreased Ca concentrations; therefore, precipitation of phytoplankton cells likely caused the short-term reduction in chl a.

Effect of aluminium on yield and plant chemical concentrations of some temperate legumes

The aluminium (Al) tolerance of 34 temperate legume species (143 genotypes, including 57 from Trifolium repens) was determined in 60 experiments over a 3 year period in a low ionic strength (2.7 × 10-3M) solution culture. For each genotype, the relationship between solution Al3+ activity (μM) and relative yield was determined and the Al3+ activity associated with a 50% reduction in yield (AlRY50) calculated. In addition, plant chemical concentrations were determined in at least one genotype from most species. For white clover, AlRY50 over all genotypes had an approximately normal distribution with mean of 1.31 μM for the tops and 1.51 μM for the roots, and a standard deviation of about 0.4. This suggested that Al tolerance had a polygenic inheritance. For the other species tested, AlRY50 ranged from 0.15 to 4.53 μM in the tops and from 0.21 to 4.89 μM in the roots. In the tops and roots, 37% and 26% respectively of the genotypes had an AlRY50 less than 1 μM, including all species tested in the genera Melilotus and Medicago. Only 8% or 23% of the genotypes, based on the tops and roots respectively, had an AlRY50 greater than 2, including all genotypes in the species Lotus pedunculatus. Except for Lotus, there were no consistent differences between genera in plant chemical concentrations. In Lotus, concentrations of Ca, Zn, Mn and Cu in the tops and of all elements except B in the roots were lower than that of the other species. The AlRY50 of the species was not related to plant chemical concentrations in the absence of Al. Depending on the plant element, increasing solution Al concentrations had no significant effect on plant chemical concentrations for 56–94% of the species. When a significant effect did occur, increasing Al in solution generally decreased S and K concentrations and increased Mn, Zn, Cu Fe, B and Al concentrations in the tops and roots and decreased Ca concentrations in the tops. Plant P concentrations decreased in the tops but increased in the roots. Increasing Al in solution increase plant Al at the average rate of 44 μg g-1 μM-1 (range 20–87) in the tops and 333 μg μM-1 (range 162–616) in the roots.