Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PHOSPHORUS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1983

Dietary interaction of phosphorus with sodium from either chloride or bicarbonate affects laying hen performance.

Experimental diets consisting of two levels of total phosphorus (.30 and .75%) and three different treatments of supplemental sodium (.35% NaCl, 1.40% NaCl, and .35% NaCl plus 1.50% NaHCO3) were fed in a 2 X 3 factorial arrangement to laying hens for 16 weeks. The latter two treatments of sodium were designed to supply the same level of sodium (.55%) from different chemical forms. Hens fed .30% phosphorus laid significantly (P less than .01) less eggs than those fed .75% phosphorus. A highly significant (P less than .01) interaction was found between phosphorus and sodium treatments. The high level of sodium from either chloride or bicarbonate decreased egg production at the lower level of phosphorus and increased it when the higher level of phosphorus was fed. Sodium bicarbonate affected egg production more strongly than sodium chloride did. There were no significant treatment effects on egg weight and egg shell weight. Addition of sodium bicarbonate to the low phosphorus diet significantly (P less than .05) decreased feed consumption of the hen. Supplemental sodium bicarbonate with either level of dietary phosphorus significantly (P less than .05) increased percent nitrogen retention of the hen, but excessive sodium chloride did not.

Animals↗
PubMed1983

The influence of dietary phosphorus level on laying hen performance, egg shell quality, and various blood parameters.

The influence of dietary phosphorus on hen performance and egg shell quality was investigated. Total dietary phosphorus levels of .17, .23, .30, .40, .50, .70, 1.50, and 2.30% were fed to four body weight groups of 23-week-old White Leghorn hens. Hens consuming the diets containing .17, .23, and .30% phosphorus, all from plant origin, consumed significantly (P less than or equal to .05) less feed, which resulted in poorer performance than hens fed diets supplemented with inorganic phosphorus. Addition of supplemental inorganic phosphorus at levels of .10 to .40% resulted in the best overall hen performance. Plasma phosphorus was directly related to dietary phosphorus level. Egg shell quality as measured by specific gravity was inversely related to dietary phosphorus levels above .50%.

Animals↗
PubMed1984

Plasma phosphorus at 0, 6, and 21 hours postoviposition in hens laying in the morning or afternoon.

Two experiments were conducted using White Leghorn hens. Blood samples were collected immediately following oviposition (0 hr) or 6 or 21 hr postoviposition from hens laying in the morning or afternoon. Plasma phosphorus was determined at each time period. In Experiment 1, plasma phosphorus at oviposition was essentially the same for hens laying in the morning or afternoon (3.95 and 4.10 mg/dl, respectively). At 6 hr postoviposition plasma phosphorus was lower than that observed at 0 hr (3.22 and 3.15 mg/dl, respectively). When comparing plasma phosphorus levels at 21 hr postoviposition of hens laying in the morning or afternoon a higher (P less than or equal to .05) phosphorus level was observed for hens that laid in the morning (5.90 vs. 4.91, respectively). In Experiment 2, plasma phosphorus levels at 0 and 6 hr postoviposition were 3.32 vs. 3.18 and 2.81 vs. 2.74 mg/dl for hens laying in the morning and afternoon, respectively. At 21 hr postoviposition, phosphorus values of 5.30 vs. 3.65 mg/dl were reported for hens laying in the morning and afternoon, respectively. Data also indicated that on the day a hen does not lay an egg, plasma phosphorus does not rise. An hypothesis is offered to explain the difference in egg shell quality between eggs laid in the morning or afternoon.

Animals↗
PubMed1988

Bioavailability of phosphorus from various phosphates based on body weight and toe ash measurements.

Two experiments involving 1,152 turkeys were conducted to determine the relative bioavailability of phosphorus of eight phosphates from commercial and experimental sources. The basal diet, composed of 52% dehulled soybean meal and 41% ground yellow corn, contained 1.48% calcium and .44% total phosphorus. Phosphorus from the eight sources was added to the basal diet at levels of .09, .18, or .27% to form 24 diets with a constant calcium content. Each diet was fed to one pen of eight males and eight females from 1 to 4 wk of age in the first experiment and to two pens (one of each sex) of 16 poults/pen from 0 to 4 wk of age in the second experiment. Measurements of percentage ash of the middle toe pooled from all poults within a pen and of average body weight at 4 wk of age provided similar relative phosphorus availability values. With the phosphorus in monocalcium phosphate as the standard set at 100%, phosphorus from two sources of dicalcium phosphate and one source of defluorinated phosphate were found not significantly different in bioavailability (95, 105, and 103%, respectively). Phosphorus in curacao phosphate was only 55% available and in the three experimental defluorinated phosphates, phosphorus was 81, 70, and 87% available. Significant differences in bioavailability between two samples greater than 13 and 18% were found when using toe ash and body weight measurement, respectively.

Animals↗
PubMed1998

[The mechanism of hemorrhage following phosphorus burns and the effect of calcium gluconate].

OBJECTIVE: To investigate the mechanism of hemorrhagic tendency after phosphorus poisoning. METHODS: 45% phosphoric acid and 20 mg/cm2 phosphorus were used to produce burn injury in rabbits. The total content of phosphorus remaining on the wound and 7-day mortality were similar in both groups. RESULTS: The results showed that plasma free calcium contents were significantly lower in both phosphorus groups than healthy and thermal burn controls (0.80 vs 1.40 mol/l, P < 0.01). The free calcium content of platelet was lowered to 116-140 nmol/l, which was significantly lower than that of healthy control (285 nmol/l) and thermal injury group (480-504 nmol/l). Concomitantly, the platelet aggregation rate was lowered to 1.29% and 10.78% in phosphoric acid group and phosphorus group, respectively, while it was 67.01% in healthy control and 82.1%-84.9% in thermal injury group; the difference was statistically significant. CONCLUSION: Calcium therapy brought back intracellular and extracellular free calcium contents to normal in phosphorus burn group. Also platelet aggregation rate approached normal level after calcium therapy. The results suggest that the bleeding tendency after phosphorus burn is due to combination of phosphorus with intracellular and extracellular calcium of platelets, thus inhibiting aggregation of platelets.

Animals↗
PubMed2005

Developing an independent, generic, phosphorus modelling component for use with grid-oriented, physically based distributed catchment models.

Grid-oriented, physically based catchment models calculate fields of various hydrological variables relevant to phosphorus detachment and transport. These include (i) for surface transport: overland flow depth and flow in the coordinate directions, sediment load, and sediment concentration and (ii) for subsurface transport: soil moisture and hydraulic head at various depths in the soil. These variables can be considered as decoupled from any chemical phosphorus model since phosphorus concentrations, either as dissolved or particulate, do not influence the model calculations of the hydrological fields. Thus the phosphorus concentration calculations can be carried out independently from and after the hydrological calculations. This makes it possible to produce a separate phosphorus modelling component which takes as input the hydrological fields produced by the catchment model and which calculates, at each simulation time step, the phosphorus concentrations in the flows. This paper summarises the equations and structure of such a Grid Oriented Phosphorus Component (GOPC) developed by the authors for simulating phosphorus concentrations and loads using the outputs of a fully distributed physical based hydrological model. The GOPC performance is illustrated by an example of a simplified hypothetical catchment subjected to some ideal conditions.

Fertilizers↗
PubMed2005

[Effects of free-air CO2 enrichment (FACE) on phosphorus nutrition of Oryza sativa at its different growth stages].

Using free-air CO2 enrichment (FACE) platform and under different nitrogen supply level, this paper studied the phosphorus nutrition of Oryza sativa at its different growth stages. The CO2 concentration of FACE platform was 200 micromol.mol(-1) more than that in ambient air, and the nitrogen supply levels were 150 kg.hm(-2), 250 kg.hm(-2) and 280 kg.hm(-2). The results showed that during rice growth period, FACE significantly increased the phosphorus content of rice plant and its phosphorus uptake by 3.9%-20.6% and 28.9%-71.4%, respectively. Before heading, FACE had little effect on the phosphorous accumulation in leaf or stake, but after heading, made the proportion of phosphorus accumulation in reproductive organ decreased by 9.8%-26.3% and that in vegetative organ increased by 2.2%-23.9% at 0.01 or 0.05 significant level. Under FACE treatment, the phosphorus use efficiency for biomass production (PUEp) at different growth stages, the phosphorus use efficiency for grain output (PUEg), and the phosphorus harvest index (PHI) were decreased by 3.7%-16.6%, 6.5% -15.5%, 5.4%-9.0%, respectively. Nitrogen supply level and its interaction with FACE had less effect on the phosphorus-nutrition of rice at its different growth stages.

Carbon Dioxide↗
PubMed2006

[Adaptive changes in activity of tonoplast H(+)-ATPase from the roots of tomato seedlings under phosphorus starvation].

We studied the growth state of tomato seedlings and the adaptive changes in activity of tonoplast H(+)-ATPase on different days (5 d, 7 d, 9 d, 11 d, 13 d) sampling from the roots of tomato seedlings under phosphorus starvation. The results indicated that the average height of the seedlings decreased under phosphorus starvation, while the main roots of the seedlings were significantly longer than those of the control. The phosphorus uptake rates of tomato seedlings under phosphorus starvation significantly increased and were much higher than those of controls and reached maximum values under the starvation for 7 days. The tonoplast H(+)-ATPase activity in the roots of tomato seedlings increased under phosphorus starvation and reached maximum values under the starvation for 7 days, while the activity of the control changed little. Kinetic analysis of tonoplast H(+)-ATPase showed that phosphorus starvation significantly lowered the K(m) value, but had no significant effect on the V(max) value of the enzyme. The results showed that phosphorus starvation increased the affinity of the enzyme to its substrate. In addition, phosphorus starvation did not alter the optimum pH (7.5) of the ATPase activity.

Adaptation, Physiological↗
PubMedDate not supplied

Chemical characterization and bioavailability of phosphorus in water-insoluble fractions of three mono-ammonium phosphate fertilizers.

Elemental impurities in mono-ammonium phosphate (MAP) fertilizers, such as Fe, Al, Ca, Mg, and F, result in compounds other than NH4H2PO4. The phosphorus availability of the impurity compounds was determined in 3 commercial MAP fertilizers produced from North Carolina, Florida, and Idaho phosphate rocks. Soluble compounds, including NH4H2PO4, were washed out of the fertilizers, and the water-insoluble fraction was collected. The North Carolina, Florida, and Idaho MAP fertilizers contained 13, 16, and 17% water-insoluble fractions, respectively. Availability of phosphorus in each MAP fertilizer and water-insoluble fraction was determined in a greenhouse pot study using sorghum-sudangrass (Sorghum bicolor) as the test crop. There were no differences in dry matter weights or phosphorus uptake between reagent grade MAP and each MAP fertilizer. Lower dry matter weights and phosphorus uptake were produced from the water-insoluble North Carolina, Florida, and Idaho fractions (NC greater than FL greater than ID). Chemical analysis and characterization with optical microscopy, infrared spectroscopy, and X-ray diffractometry indicated 77.3, 73.8, and 73.6% NH4H2PO4 in the North Carolina, Florida, and Idaho MAP fertilizers, respectively. MgAl(NH4)2H(PO4)2F2, AlNH4HPO4F2, and FeNH4(HPO4)2 were identified as water-insoluble phosphorus compounds. There was a significant negative correlation between the percent phosphorus present as MgAl(NH4)2H(PO4)2F2 and the phosphorus availability. Increased crystallinity of the various water-insoluble compounds also contributed to reduced phosphorus availability.

Biological Availability↗
PubMed1983

Improved dietary treatment with low protein and phosphorus restriction in uremic rats.

The independent effect of low-protein or low-phosphorus diets in chronic renal failure were studied. The following four isocaloric diets, which contained various amounts of protein (24%, 6%) and phosphorus (0.5%, 0.12%) were fed to chronically uremic rats: high protein and no phosphorus restriction (HPrNP), high protein and phosphorus restriction (HPrRP), low protein and no phosphorus restriction (LPrNP), and low protein and phosphorus restriction (LPrRP). Adult male rats were made chronically uremic by electrocoagulation of one kidney and contralateral nephrectomy. Two grades of renal damage were produced, one of which was mild and the other severe. The mean number of days of survival in the severely uremic animals was 7.5 +/- (SEM) 2.5 with the HPrNP diet, 17.6 +/- 2.4 with the HPrRP diet, 20.3 +/- 2.3 with the LPrNP diet, and over 41.8 +/- 2.5 with the LPrRP diet during a 50-day period of observation. The BUN, serum creatinine (SCr), calcium (SCa), phosphorus (SP), urea and creatinine clearances (Curea, CCr), and plasma PTH levels before and 3 weeks after the diets were compared in the surviving rats with mild and severe uremia. There were marked reductions in the BUN and SP concentrations with the low-protein diets, whereas the SCa increased with all diets. Curea remained practically unchanged with the low-protein diets, whereas CCr decreased with all diets. Plasma PTH levels varied with each diet, but those rats with elevated PTH levels before dietary therapy experienced a fall in plasma PTH after the low-phosphorus diets were administered, with or without protein restriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Decreasing the complications of renal osteodystrophy secondary to high phosphorus levels by using an innovative self-monitoring educational program.

We wanted continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) patients to become more cognitive of the complications of high-serum phosphorus levels (> 6.0 mg/dL). The phosphorus self-monitoring program was designed to encourage patients to be more responsible for preventing the complications of renal osteodystrophy. Patients' phosphorus levels were graphed monthly on a poster in the exam room. Additional posters discussed their responsibilities to control phosphorus and the complications associated with hyperphosphatemia. All patients received an informative letter regarding the inception of the program in March 1994 and also were assured total anonymity of their laboratory results. At monthly clinic appointments, they received additional written information on phosphorus and discussed their phosphorus levels. Our teaching method proved effective in our CAPD/CCPD population. In March 1994, 31% of our patients had a phosphorus level greater than 6.0 mg/dL versus 10% in September 1994. The ability of patients to see their monthly progress and the comparison with other patients encouraged much interest and questions regarding phosphorus control.

Adolescent↗
PubMed2001

Determination of trace phosphorus in high purity tantalum materials by inductively coupled plasma mass spectrometry subsequent to matrix separation with on-line anion exchange/coprecipitation.

An on-line matrix separation/inductively coupled plasma mass spectrometry (ICP-MS) method is proposed for the determination of trace amounts of phosphorus in high purity tantalum metal, tantalum (V) oxide, and tantalum pentaethoxide. In the present method, the matrix tantalum in the sample solution was adsorbed on the anion exchange resin, and phosphorus (phosphate ion) was eluted with the carrier solution of HF and HNO3 mixture. Then, the effluent solution was subsequently mixed with bismuth solution and aqueous ammonia solution to coprecipitate phosphate together with bismuth hydroxide. The precipitate formed was collected on the in-line membrane filter to wash out nitric acid with pure water, and then dissolved with hydrochloric acid. The obtained phosphorus sample solution was introduced directly into the nebulizer of ICP-MS for the determination of phosphorus. Phosphorus was determined at the molecular ion signal of 31P16O+ (m/z 47). The detection limit (3sigma) of phosphorus in the present method was 1.3 ng mL(-1) as the sample solution basis, and the relative standard deviation for 30 ng mL(-1) of phosphorus in the standard solution was 4.3% in the replicate measurements (n=11). The present method was applied to the analysis of high purity tantalum materials. The concentrations of phosphorus in tantalum samples were in fairly good agreement with those obtained by glow discharge mass spectrometry (GDMS).

Journal Article↗
PubMed2005

Phosphorus fractions and phosphate sorption characteristics in relation to the sediment compositions of shallow lakes in the middle and lower reaches of Yangtze River region, China.

Phosphorus is recognized as the most critical nutrient limiting lake productivity. The trophic status and development of lake systems are also influenced by the phosphorus content and fractions and phosphate sorption characteristics of the lake sediments. The phosphorus fractions and phosphate sorption characteristics of sediments in shallow lakes from the middle and lower reaches of Yangtze River region in China were investigated. The results show that the phosphorus contents in the sediments ranged from 217.8 to 1640 mg kg(-1); inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus bound to Al, Fe, Mn oxides, and hydroxides (Fe/Al-P), and calcium bound phosphorus (Ca-P) were the main fractions of IP. Phosphate sorption on the sediments mainly occurred within 2 h and then reached equilibrium in 10 h. The phosphate sorption rate was closely related to the concentration of fine particles. The phosphate sorption capacity ranged from 128.21 to 833.33 mg kg(-1), showing a significant correlation with the contents of Fe, Fe+Al, total organic carbon (TOC), cationic exchange capacity, total nitrogen, TP, Ca, IP, and the ratio of P/(Al+Fe), and it was higher in the sediments of eutrophic lakes than in mesotrophic lakes. Phosphate was mainly sorbed onto Fe and Al particles. The phosphate sorption efficiency ranged from 26.74 to 312.50 L kg(-1), and had a strong positive correlation with Fe content. For the eutrophic lake sediments, there were no significant relationships between the phosphate sorption efficiency and the selected physical and chemical parameters. But for the mesotrophic lake sediments, the phosphate sorption efficiency was found to be positively related to the contents of Al and Fe+Al.

Journal Article↗
PubMed2002

Phosphorus in soils and field drainage water in the Thame catchment, UK.

Field drains were sampled at five farms in a catchment in south-central England. The farms were selected to include the main soil types present in the catchment, stagnogleys and pelosols. The phosphorus content of field drainage water was measured on several occasions from 1999 to 2000, under varying flow conditions. The components measured were soluble reactive phosphorus (SRP), total dissolved phosphorus (TDP) and total phosphorus (TP). SRP concentrations in drainage water were lower than in streams in the catchment which had no apparent point source. This indicated that many streams were receiving unidentified point sources of SRP. Measurements of P in field drainage water samples under high flow conditions showed concentrations of particulate phosphorus and SRP up to 1300 and 300 microg l(-1), respectively, these being associated with high suspended sediment concentrations. Comparison of field drain and soil phosphorus contents at the locations sampled did not provide evidence of an inter-relationship. The equilibrium phosphorus content (EPC0) of surface soil was generally higher than the SRP content of drainage water, at one farm by 1 order of magnitude. The variability in measurements suggested a larger-scale and more focussed survey would be required to characterise catchment-scale phosphorus losses from commercial farms by land use and soil type.

Journal Article↗
PubMed2002

Phosphorus chemical shift tensors of phosphido ligands in ruthenium carbonyl compounds: (31)P NMR spectroscopy of single-crystal and powder samples and ab initio calculations.

The phosphorus chemical shift (CS) tensors of several ruthenium carbonyl compounds containing a phosphido ligand, micro), bridging a Ru [bond] Ru bond were characterized by solid-state (31)P NMR spectroscopy. As well, an analogous osmium compound was examined. The structures of most of the clusters investigated have approximate local C(2v) symmetry about the phosphorus atom. Compared to the "isolated" PH(2)(-) anion, the phosphorus nucleus of a bridging phosphido ligand exhibits considerable deshielding. The phosphorus CS tensors of most of the compounds have spans ranging from 230 to 350 ppm and skews of approximately zero. Single-crystal NMR was used to investigate the orientation of the phosphorus CS tensors for two of the compounds, Ru(2)(CO)(6)(mu(2)-C [triple bond] C [bond] Ph)(mu(2)-PPh(2)) and Ru(3)(CO)(9)(mu(2)-H)(mu(2)-PPh(2)). The intermediate component of the phosphorus CS tensor, delta(22), lies along the local C(2) axis in both compounds. The least shielded component, delta(11), lies perpendicular to the Ru [bond] P [bond] Ru plane while the most shielded component, delta(33), lies perpendicular to the C [bond]P [bond] C plane. The orientation of the phosphorus CS tensor for a third compound, Ru(2)(CO)(6)(mu(2)-PPh(2))(2), was investigated by the dipolar-chemical shift NMR technique and was found to be analogous, suggesting it to be the same in all compounds. Ab initio calculations of phosphorus magnetic shielding tensors have been carried out and reproduce the orientations found experimentally. The orientation of the CS tensor has been rationalized using simple frontier MO theory. Splittings due to (99,101)Ru [bond] (31)P spin-spin coupling have been observed for several of the complexes. A rare example of (189)Os [bond] (31)P spin-spin splittings is observed in the (31)P MAS NMR spectrum of the osmium cluster, where (1)J((189)Os, (31)P) is 367 Hz. For this complex, the (189)Os nuclear quadrupolar coupling constant is on the order of several hundred megahertz.

Journal Article↗
PubMed1999

Response of broiler chickens to microbial phytase supplementation as influenced by dietary phytic acid and non-phytate phosphorus contents. I. Effects on bird performance and toe ash.

1. Seven-day old male broilers (n=900) were fed on wheat-sorghum-soyabean meal-based diets containing 3 concentrations of phytic acid (10.4, 13.2 and 15.7 g/kg; equivalent to 2.9, 3.7 and 4.4 g/kg phytate phosphorus), 2 of non-phytate phosphorus (2.3 and 4.5 g/kg) and 3 of microbial phytase (Natuphos 5000 L; 0, 400 and 800 FTU/kg) in a 19-d trial. The dietary phytic acid contents were manipulated by the inclusion of rice pollard. 2. Each dietary treatment was fed to 5 pens (10 birds/pen) from 7 to 25 d of age. Records of body weight, food intake and mortality were maintained. On d 25, all surviving birds were killed and toe samples were obtained for toe ash measurements. 3. Increasing dietary phytic acid negatively influenced body weight gain, food intake and food/gain. These adverse effects were partially overcome by the addition of microbial phytase. 4. Supplemental phytase caused improvements in weight gain and food efficiency of broilers but the magnitude of the responses was greater in low non-phytate phosphorus diets, resulting in significant non-phytate phosphorus x phytase interactions. 5. Toe ash contents were improved by phytase addition but the response was greater at the highest concentration of phytic acid, resulting in a significant phytic acid x phytase interaction. Responses were also greater in low non-phytate phosphorus diets as indicated by significant non-phytate phosphorus x phytase interaction. 6. In general, there was very little difference in the responses to phytase additions at 400 and 800 FTU/kg. 7. The performance responses to added phytase in birds receiving adequate non-phytate phosphorus diets provide evidence for the influence of the enzyme on animal performance independent of its effect on phosphorus availability.

6-Phytase↗
PubMed1992

A leaf phosphorus assay for seedlings of Acacia mangium.

Concentrations of extractable and total phosphorus in leaves, stem, root and nodules of 12-week-old seedlings of two provenances of Acacia mangium Willd. were analyzed to identify the fraction of phosphorus and the plant part most suitable for predicting the phosphorus nutritional status of the seedlings.For both provenances, concentrations of extractable phosphorus were more sensitive to changes in soil phosphorus status and varied less among different plant parts than concentrations of total phosphorus. Concentrations of extractable phosphorus in the youngest fully expanded leaf (Leaf 3 from the apex) and the next two older leaves correlated closely with seedling dry mass and may be used to assess the phosphorus nutritional status of Acacia mangium seedlings.

Journal Article↗
PubMed1994

Phosphorus supply affects the photosynthetic capacity of loblolly pine grown in elevated carbon dioxide.

Effects of phosphorus supply and mycorrhizal status on the response of photosynthetic capacity to elevated CO(2) were investigated in loblolly pine (Pinus taeda L.) seedlings. Seedlings were grown in greenhouses maintained at either 35.5 or 71.0 Pa CO(2) in a full factorial experiment with or without mycorrhizal inoculum (Pisolithus tinctorius (Pers.) Coker & Couch) and with an adequate or a limiting supply of phosphorus. Assimilation versus internal CO(2) partial pressure (C(i)) curves were used to estimate maximum Rubisco activity (V(c,max)), electron transport mediated ribulose 1,5-bisphosphate regeneration capacity (J(max)), phosphate regeneration capacity (PiRC) and daytime respiration rates (R(d)). Nonmycorrhizal seedlings grown with limiting phosphorus had significantly reduced V(c,max) and PiRC compared to seedlings in other treatments. Elevated CO(2) increased photosynthetic capacity in nonmycorrhizal seedlings in the low phosphorus treatment by increasing PiRC, whereas it induced phosphorus limitation in mycorrhizal seedlings in the low phosphorus treatment and did not affect the photosynthetic capacity of seedlings in the high phosphorus treatment. Despite the variety of effects on photosynthetic capacity, seedlings in the elevated CO(2) treatments had higher net assimilation rates than seedlings in the ambient CO(2) treatments. We conclude that phosphorus supply affects photosynthetic capacity during long-term exposure to elevated CO(2) through effects on Rubisco activity and ribulose 1,5-bisphosphate regeneration rates.

Journal Article↗