Showing papers on "Phosphorus published in 1982"

Changes in Inorganic and Organic Soil Phosphorus Fractions Induced by Cultivation Practices and by Laboratory Incubations

Abstract: Changes in inorganic and organic phosphorus (P) fractions resulting from 65 years of cropping in a wheat-wheat-fallow rotation were studied using a sequential extraction technique. Total P content of the cultivated soil was 29% lower than that of the adjacent permanent pasture; the major loss of P (74% of total P lost) was organic P and residual P. Of the total P lost, 22% was from the extractable organic P forms, whereas 52% originated from stable P.Incubation studies were used to study seasonal P transformations during simulated fallow with and without residue incorporation and P fertilization. Nine monthly additions of cellulose (765 µg C · g−1 soil) with and without P (9 µg · g−1 soil) significantly altered levels of total extractable organic P and inorganic P in incubated soils. Evidence is provided for microbial activity playing a major role in redistributing P into different forms in the soil

Phytates in Legumes and Cereals

Abstract: Publisher Summary This chapter discusses that the knowledge of phytic acid had its beginning in the discovery by Hartig, who isolated small particles or grains (which were not starch grains) from the seeds of various plants. Phytic acid has been generally regarded as the primary storage form of both phosphate and inositol in almost all seeds. The amount of phytic acid varies from 0.50% to 1.89% in cereals (except polished rice), from 0.40% to 2.06% in legumes, from 2.00% to 5.20% in oil seeds except soybeans and peanuts (grouped under legumes), and from 0.40% to 7.50% in protein products. Many foods and seeds contain myo-inositol hexaphosphate as an important source of phosphorus, and accurate methods for its determination are needed. Phytase (meso-inositol hexaphosphate phosphohydrolase, EC 3.1.3.8) is widely distributed in plants, animals, and fungi. In mature cereal grains, legumes, and oil seeds, the major portion of the total phosphorus is present in the form of phytic acid (phytate). Experiments with animals have suggested that phytic acid in plant foods complexes with dietary essential minerals such as calcium, zinc, iron, and magnesium and makes them biologically unavailable for absorption. The correlation of phytate with the cooking quality of peas was first suggested by Mattson. Phytic acid, myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate serves as the main phosphorus store in mature seeds and grains. In cereals and legumes, phytic acid content ranges from 0.14% to 2.05%, which accounts for 18 to 88% of the total phosphorus.

The utilization of inorganic and organic phosphorous compounds as nutrients by eukaryotic microalgae: a multidisciplinary perspective: part 1

Abstract: This comprehensive literature review of the phosphorus nutrition and metabolism of eukaryotic microalgae deals sequentially with (1) extracellular P-compounds available for algal utilization and growth; (2) orthophosphate uptake mechanisms, kinetics, and influence from environmental variables; (3) phosphatase-mediated utilization of organic phosphates involving multiple enzymes, induction and cellular location of repressible and irrepressible phosphatases, and their role in growth physiological processes; (4) intracellular phosphate metabolism covering diversity of phosphometabolites. ATP-linked energy regulation, polyphosphate pools and storage roles, phospholipids and phospholipases; (5) steady-state and transient-state models relating phosphate utilization to growth; (6) ecological aspects covering manifestations of phosphorus limitation, interspecific competition for phosphonutrients among microorganisms, and current views on phosphorus cycling and turnover in aquatic ecosystems. Although concentrating on the microalgae, the review often points out sounder conclusions drawn from bacteria and fungi, and includes specific macroalgae in considering certain subtopics where such algae were better investigated and provided a good basis for comparison with the microalgae.

The marine phosphorus cycle

Abstract: Phosphorus introduced to the ocean must ultimately be removed if a steady state is to be maintained over geologic time. Aeolian input is insignificant, and there is evidently no hydrothermal contribution. Rivers dominate P-input to the ocean. The fluvial P-flux is poorly quantified due to the interactions of two factors: (1) man's influence on river-nutrient fluxes; and (2) inherent complexities in understanding the biological and inorganic associations of P in estuarine and coastal waters. Our best estimate of the natural or pre-man P-input flux is about 10 x 10/sup -9/ moles - P/cm/sup 2/-ocean surface/year. Of the identified flux of phosphorus to the sediments, about 90 percent is in the form of biogenic debris or its regeneration products. The burial of phosphatic fish debris is negligible. P-removal by direct reaction of phosphate in seawater with sea-floor basalts during mid-ocean ridge hydrothermal circulation is insignificant. P-removal by processes such as sorption on clay surfaces or formation of authigenic Fe and Al phosphate phases is presently unquantified and remains a serious uncertainty in the phosphorus cycle. The identified sources and sinks approximately balance, yielding a residence time for P in the oceans of about 10/sup 5/ yrs.

A comparative analysis of nutrients and other factors influencing estuarine phytoplankton production

Abstract: We reviewed data concerning phytoplankton production, chlorophyll a, and associated physical and chemical variables from 63 different estuarine systems. Data were analyzed statistically to test hypotheses regarding algal productivity and factors regulating temporal patterns. Prior to statistical analysis, estuarine systems were classified into four groups based on criteria of physical circulation and geomorphology. Analysis of grouped data indicated that algal production and biomass were consistently high in warm periods of the year in a broad spectrum of estuaries and that ratios of available nitrogen to phosphorus were low during periods of high production, except in highly eutrophic systems. In general, phytoplankton production and biomass exhibited weak correlations with a variety of physical and chemical state variables, perhaps indicating the significance of rate processes as opposed to standing stocks in regulating these important features of estuarine systems. A six-year time series of measurements of algal production and chlorophyll a at stations in middle Chesapeake Bay exhibited considerable year-to-year variability, with a three-fold range in peak values. Summertime maxima were strongly related to annual loadings of both nitrogen (N) and phosphorus (P) but annual production appeared to be sustained primarily on recycled nitrogen and phosphorus. To generalize from these findings, N and P loading rates were estimated for 14 different estuarine systems, and a significant positive relationship was obtained between phytoplankton production and nitrogen (but not phosphorus) inputs.

The nitrogen and phosphorus dependence of algal biomass in lakes: An empirical and theoretical analysis1

Abstract: An analysis of mean growing season concentrations of chlorophyll, total phosphorus (TP), and total nitrogen (TN) in 228 north latitude lakes confirms previous observations that chlorophyll yield is dependent both on the phosphorus concentration and on the TN:TP ratio. Of two modified chlorophyll models which depend explicitly on both nitrogen and phosphorus developed and tested, one, a multiple regression model, appears to greatly reduce the error of chlorophyll prediction in lakes. A theoretical framework is presented which provides an explanation for the observed effects of N:P ratios.

The acquisition of phosphorus byLupinus albus L.

Abstract: It has been demonstrated by an agar film technique thatL. albus can cause the breakdown of colloids of iron/silicate, iron/phosphate, aluminium/silicate and aluminium phosphate and destabilise suspensions of manganese dioxide, calcium mono-hydrogen phosphate and ferric hydroxide. Dissolution of these compounds was most marked in areas adjacent to proteoid roots (dense clusters of secondary laterals of limited growth which develop on lateral roots) and parts of the tap root. Soil associated with these regions of the root system contained more reductants and chelating agents than the bulk soil. Soil from around the roots ofL. albus exhibited much greater reducing and chelating activity than that associated with the roots of rape and buckwheat.

Phytic Acid Determination in Soybeans

Abstract: Several established methods of phytic acid determination in soybeans were evaluated. Iron analysis methods, which rely on a 4:6 molar ratio of Fe:P, were eliminated because this ratio was not dependable. Three assay methods relying on phosphorus analysis were then compared. The anion-exchange method was considered most accurate but not convenient for routine analysis. Analysis of the ferric phytate precipitate and a new method, analysis of the supernatant before and after ferric chloride precipitation, were judged against the anion-exchange method under different extraction conditions. Based upon good agreement with anion-exchange column results and acceptable reproducibility, the best methods were (1) precipitate analysis of phosphorus after extraction with 3% TCA + 10% sodium sulfate, or (2) the supernatant difference method after extraction with 1.2% HCl.

Size-dependent phosphorus uptake kinetics and cell quota in phytoplankton1

Abstract: The allometric equation, y = aXb, described the interspecific variation of phosphate uptake kinetics and cell quota with phytoplankton cell size and showed that smaller cells are superior in uptake rate to large. Species-specific measurements, made by track autoradiography in phosphorus deficient cultures of communities from a phosphorus-limited lake, revealed that eight different species did not differ significantly in the Michaelis-Menten half-saturation constant, Km. However, both saturated uptake rates (Vmax) and the initial slope of the uptake curve (Vmax:Km) decreased per unit biomass with increasing cell size. Biomass-specific cell phosphorus quotas also decreased with increasing cell volume, but less rapidly than did Vmax or Vmax: Km. Comparable data from the literature showed that marine species were superior in phosphorus uptake to freshwater species of similar size, but allometric variation of kinetics appeared to exist within both groups. Together with a variable internal stores model of phosphorus-limited growth, the allometric relationships of uptake kinetics and quotas predicted competition to favor smaller cells, with a differential in growth rate diminishing as competitive intensity increased.

Phosphorus fractions of a climosequence of soils in New zealand tussock grassland

Abstract: The different forms of phosphorus in alkaline extracts of eight New Zealand topsoils, which are members of a climosequence, were characterized by 31 P-nuclear magnetic resonance (NMR). A further two topsoils were used in an experiment to demonstrate that the NMR technique detected all of the P in the extracts. This direct method of estimating organic P in soil extracts enabled the different types and the relative amounts of P compounds to be estimated. Inorganic orthophosphate and orthophosphate monoesters were the major P components of the extracts from all soils, while all but the two driest soils also contained orthophosphate diesters. Only the high country and alpine soils, developed in a moist cool environment, contained phosphonates, a recently-discovered form of soil P of probable microbial origin. Across the climosequence of soils, the amount of orthophosphate diesters in the extracts was strongly and positively correlated with annual precipitation. This organic P fraction, together with phosphonates, could provide through mineralization a ready supply of “available” P in these mainly undisturbed tussock grassland ecosystems.

Different patterns of phosphorus release from lake sediments in laboratory experiments

Abstract: The phosphorus release from surface sediments of eight lakes, mainly shallow lakes in agricultural areas, was studied in laboratory batch experiments with additions of acetate and/ or nitrate. The lake sediments could be separated into three categories. Some sediments did not release phosphorus under any conditions. The second category showed a high phosphorus release rate when acetate was added, in order to stimulate bacterial activity and oxygen consumption. The addition of nitrate, only, stabilized the redox conditions and prevented phosphorus release. This pattern followed the classical theories of Einsele and Mortimer. The third sediment category released phosphorus up to some level which remained constant throughout the experiment, and was independent of acetate and/or nitrate additions.

Growth and Phosphate Transport in Barley and Tomato Plants During the Development of, and Recovery from, Phosphate-stress

Abstract: Barley and tomato plants were cultured in nutrient solutions including 0-15 mol m 3 H2P04. The phosphate supply was discontinued and the subsequent effects on growth, internal phosphorus concentrations, phosphate absorption and translocation were measured at frequent intervals. Growth rates were at first unchanged and the internal phosphorus concentration decreased. During this phase the rate of phosphate transport by the roots sometimes increased significantly. Growth slowed more in shoots than in roots during a second phase of stress development and visual symptoms of deficiency appeared in tomato but not in barley. During this phase, enhancement of phosphate uptake capacity reached a maximum in both species. The subsequent decline in uptake capacity was associated with visible symptoms of deficiency developing in barley and intensifying in tomato. When stressed plants were returned to a solution containing 0-15 mol m"3 H2P04 rapid absorption continued for several days after the internal phosphorus concentration had returned to the level of the controls. Phosphate toxicity may have been the cause of leaf lesions and necrosis during the 'recovery' phase. Stomatal conductance in tomato was decreased at an early stage of stress development. Foliar-applied phosphate was absorbed more rapidly by P-stressed barley leaves than by their controls and much larger amounts were translocated from the leaves to the roots.

Interaction of light and mineral nutrient supply in the growth of impatiens parviflora

Abstract: Summary (1) Plants of Impatiens parviflora were grown on a boulder-clay woodland soil at four levels of irradiance with and without addition of ammonium nitrate and calcium phosphate. (2) Addition of nitrogen and phosphorus fertilizer increased dry wt yield and relative growth rate at all four levels of irradiance, and there was a true interaction between the level of irradiance and nutrient supply. (3) At the three higher levels of irradiance the increased growth resulted from an increase in unit leaf rate and leaf weight ratio, but at the lowest level an increase in leaf weight ratio alone was found. (4) Evidence was obtained for lower rates of respiration in the leaves of plants grown with fertilizer at high irradiance. Mycorrhizas were absent from all fertilized plants, but were well developed in the unfertilized plants at high irradiance and absent from unfertilized plants at the lowest irradiance. (5) Plants grown at high irradiance with additional phosphate alone responded initially exactly like plants with additional nitrogen and phosphorus but grew poorly later; plants with additional ammonium nitrate alone showed no response initially, but grew about as fast as plants with additional nitrogen and phosphorus later on. (6) Plants grown one per small pot responded only to additional phosphate in the short term, but plants grown 10 per small pot responded only to additional nitrogen. (7) Emphasis is placed on the important effects of the differential mobilities of nitrate and phosphate ions in experiments on the limiting mineral nutrients in soils. (8) The results are discussed in relation to earlier work, and the penetration of deeper shade by herbs on soils of higher pH is tentatively related to a superior supply of nitrate.

Phosphorus release by submerged macrophytes: Significance to epiphyton and phytoplankton1,1

Abstract: Ahstrnct The contribution of nine species of macrophytes to the phosphorus nutrition of their epiphytes and the rates of P &ease by Myriophyllum spicntunz L. were measured in situ on fully labeled (“‘I?) plants. The cpiphytcs derived only 3.4-9.0% of their P from the supporting macrophyte, indicating that previously suggested macrophyte-epiphytc nutrient interactions are of relatively minor importance. Although high diurnal P release rates (X = 3.24 pg*g-’ * h-‘) were observed for the Myriophyllum-epiphyte complex, Myriophyllum accounted for only 9.9% (0.32 pg*g-’ ah ‘) of the total I? released: The Myriophyllum-deriveclyZZum-derived P was, however, released in a highly available soh~blc form (minimum estimate: 60.3%). During the growing season, MyriophyZZum thus appears to be principally important as a physical support for an active microbial community rather than as a P source to its epiphyton and surrounding waters.

UV‐sensitive complex phosphorus: Association with dissolved humic material and iron in a bog lake1

Abstract: The concentration of uv-sensitive complex phosphorus compounds in water from an acid bog lake was linearly related to the concentration of dissolved high molecular weight humic material (DHM) both seasonally and diurnally. The first-order rate of photoreduction (Fe/sup 3 +/ to Fe/sup 2 +/) of DHM..iron equaled the rate of release of orthophosphate (SRP) from these compounds. The rate of photoreduction of DHM..iron was the same as the rate of photoreduction of ferric citrate under similar conditions. Reduced DHM..iron was auto-oxidizable (Fe/sup 2 +/ to Fe/sup 3 +/); ferrous citrate was not. These data support the view that orthophosphate sorbed to ferric iron..DHM complexes may be released by a mechanism involving uv-induced photoreduction of ferric iron to the ferrous state.

Effects of naturally senescing aquatic macrophytes on nutrient chemistry and chlorophyll a of surrounding waters1

Abstract: Field experiments were performed to demonstrate the effects of senescing stands of Myriophyllum spicatum (Eurasian water milfoil) on water chemistry and chlorophyll a in a large soft-water Indiana reservoir. Replicate enclosures were used to isolate water columns over monospecific stands of M. spicatum until annual dieback began. Systems were sampled routinely for 119 days before, during, and after fall dieback. Decomposing macrophytes supplied significant inputs of nitrogen and phosphorus to surrounding waters. Nitrogen inputs were sharply pulsed and never accounted for >2.2% of annual allochthonous inputs. Phosphorus inputs from senescing plants equaled up to 18% of the annual (1978) total phosphorus loading for the reservoir. Annual dieback occurred in late summer and early autumn when conditions were suitable for phytoplankton response. Phytoplankton biomass (Chl a) showed significant increases in response to senescing macrophytes.

Dietary Phosphorus Requirement of Channel Catfish

Abstract: Two experiments were conducted to reevaluate the dietary phosphorus requirement of fingerling channel catfish. Basal diets containing either casein with supplemental inorganic phosphorus and 0.5% total calcium or egg albumin with supplemental inorganic phosphorus and 0.75% total calcium yielded similar requirement data. Eleven-week growth, feed efficiency, serum phosphorus, bone ash, bone calcium and bon phosphorus data indicate that 0.33% apparent available dietary phosphorus is adequate for maximum growth and bone mineralization. Based on these data and previous findings, we would suggest a value of 0.4% apparent available phosphorus be used in formulating catfish feeds. The apparent availability of phosphorus from soybean meal, as determined by the chromic oxide indicator method, was 29% for channel catfish.

An Empirical Model to Estimate the Relative Importance of Roots in Phosphorus Uptake by Aquatic Macrophytes

Abstract: A simple empirical model for predicting the relative contribution of roots in phosphorus uptake by submersed macrophytes is presented. The model requires only approximate dissolved reactive phosphorus (DRP) concentrations in the sediment pore water and overlying water as inputs and can explain 97% of the observed variance. It has the form: P = 99.8/1 + 2.66 (s/w)−0.83 where P is the relative contribution of the root in phosphorus uptake, s and w are the pore water and overlying water DRP concentrations, respectively. The nonspecificity of the model makes it readily applicable to environmental problems related to the role of macrophytes in phosphorus cycling and suggests a similar phosphorus uptake behavior for morphologically different species.Key words: macrophytes, phosphorus, empirical model

The enrichment of a mesotrophic lake by carbon, phosphorus and nitrogen from the cage aquaculture of rainbow trout, salmo gairdneri

Abstract: (1) The cage aquaculture of rainbow trout, Salmo gairdneri Richardson, enriched the mesotrophic Glebokie Lake with carbon, phosphorus and nitrogen. (2) Two generations were studied, from their introduction to the cages as 0 group trout in June until their removal as marketable trout in the Autumn of the following year. (3) An inter-generation budget of energy and bioelements (C, P, N) showed that, for every kilogram of marketable trout produced, the lake was enriched by 0.75 kg C, 0 023 kg P and 0.10 kg N (27-91, 0.84 and 3.58 g m-2 yr-1 respectively). This eutrophication is expected to cause the loss of the natural populations of Coregonidae. (4) The values of K1, K2 and U-1 showed that harvesting trout in Summer and Autumn does not make full use of the high utilization of food during those periods; it is suggested that harvesting should occur in October and November.

Mild phosphorus stress in barley and a related low-phosphorus-adapted barleygrass: Phosphorus fractions and phosphate absorption in relation to growth

Abstract: Barleygrass (Hordeum leporinum) from Australian low-P (phosphorus) soils and commercial barley (H vulgare) with high fertilizer requirements were grown in solution culture at 3 levels of P supply The high-P-adapted barley produced more biomass at all levels of P supply and was more responsive to added P in terms of rate of tillering, rate of leaf production, final leaf size, and therefore total shoot weight compared to barleygrass In both species root: shoot ratio decreased in response to improved tissue P status, even at P levels where total biomass did not respond to P supply Removal of endosperm reserves of barley reduced total biomass to a greater extent than it altered phosphate absorption rate, thus increasing tissue P status and making plants less responsive to added P Similarly, barleygrass had a slower growth rate but a comparable P absorption rate to that of barley Thus barleygrass also accumulated tissue P and was unresponsive to added P All phosphorus chemical fractions increased in response to improved tissue P status, but to differing extents (inorganic-P > nucleic acid-P > lipid-P > ester-P), suggesting that all P fractions (particularly inorganic P) serve, in part, a storage function Both barleygrass and barley without endosperm had higher concentrations of all P fractions (particularly inorganic P) than did unaltered barley, but this was due entirely to their higher P status (due to slow growth) rather than to any major difference in P metabolism between species We conclude that slow growth is more important than interspecific differences in P metabolism, P absorption, or efficiency of P utilization in explaining the success of barleygrass and other low-P-adapted species on infertile soils