On the phosphorus budget of a perennial herbSolidago altissima population

The same methods were used to study the phosphorus budget of aSolidago altissima population on the flood plain of the Tone River as were used for the nitrogen budget studies. The standing crop of phosphorus and the phosphorus flow through the population were determined seasonally and annually. The annual absorption of phosphorus was 2.25 g/m²/year, which is the same as the annual return to the environment. Turnover rates of phosphorus were calculated. Whether expressed seasonally or annually, turnover rates of phosphorus were larger than those of nitrogen. Phosphorus utility, net dry matter productivity of a unit amount of phosphorus absorbed, in this population was 1,060. This was in the range reported on other perennial herb communities. Phosphorus cycling in the population was quantified. Total phosphorus input to organs and the amount of phosphorus recycled in the living plants were 3.67 g/m²/year and 1.42 g/m²/year, respectively. The proportion of recycling to the total movement of phosphorus in the plant was 39%, which was lower than that of nitrogen. Comparing the phosphorus and nitrogen budgets in the population, it was concluded that larger recycling of an element results in a smaller turnover rate of the element in the population.     

Intestinal release and uptake of phenolic antioxidant diferulic acids.

Diferulic acids are potent antioxidants and are abundant structural components of plant cell walls, especially in cereal brans. As such, they are part of many human and animal diets and may contribute to the beneficial effect of cereal brans on health. However, these phenolics are ester-linked to cell wall polysaccharides and cannot be absorbed in this form. This study provides the first evidence that diferulic acids can be absorbed via the gastrointestinal tract. The 5-5-, 8-O-4-, and 8-5-diferulic acids were identified in the plasma of rats after oral dosing with a mixture of the three acids in oil. Our study also reveals that human and rat colonic microflora contain esterase activity able to release 5-5-, 8-O-4-, and 8-5-diferulic acids from model compounds and dietary cereal brans, hence providing a mechanism for release of dietary diferulates prior to absorption of the free acids. In addition, cell-free extracts from human and rat small intestine mucosa exhibited esterase activity towards diferulate esters. Hence, we have shown that esterified diferulates can be released from cereal brans by intestinal enzymes, and that free diferulic acids can be absorbed and enter the circulatory system. Our results suggest that the phenolic antioxidant diferulic acids are bioavailable.     

The Absorption and Utilization of Phosphate by Young Barley Plants: IV. THE INITIAL STAGES OF PHOSPHATE METABOLISM IN ROOTS

Organic phosphorus compounds have been extracted from the rootsof intact plants which have absorbed radioactive phosphate.The distribution of phosphorus between different organic fractionsof the root during a 24-hour absorption period is markedly influencedby the concentration of phosphorus supplied. Less than 1 minute after entry a significant proportion of theabsorbed phosphorus is found to be in organic compounds. Incorporationinto nucleotides is particularly rapid, whereas incorporationinto hexose phosphates occurs more slowly. The pattern of esterificationis influenced by the phosphate status of the plants. 2: 4-dinitrophenol (10^–4M.) reduces the uptake of phosphorusand also the extent of esterification, the latter effect beingdue solely to reduced incorporation into the nucleotide fraction. Although extensive esterification of phosphate occurs in roots,it appears to be transported to the shoot as inorganic phosphateaccompanied by only a small amount of a single organic compound.     

The determination of phosphorus in Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectrometry.

This study describes a method for the determination of phosphorus in lyophilized Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of polysaccharide is directly related to the concentration of phosphorus as measured in the laboratory. Phosphorus is present in the polyribosyl-ribitol phosphate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. The repeating unit of PRP is 3-B-D ribose[1-1]ribitol-5-phosphate. Phosphorus in the final container is measured in microg per dose. The amount of PRP is calculated from this and reported in microg per dose. The Haemophilus influenzae type b conjugate vaccine was analyzed for phosphorus content within the range of 1.34 to 2.02 microg phosphorus per ml. The relative difference of phosphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2.2 to 10.6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1.93+/-0.13 microg P/ml). The phosphorus determination of NIST SRM 3139 phosphorus spectrometric solution differed by 3.0% from the certified phosphorus value (10.00 mg P/ml).     

Phosphorus retranslocation in Hordeum vulgare during early tillering

Summary In Hordeum vulgare, phosphorus retranslocation was studied after it had been supplied to the roots for three days (experiment 1), and after foliar application (experiments 3–8). Phosphorus uptake by leaves of different ages was also measured 16 and 60 minutes after ³²P addition to the medium (experiment 2).In experiment 1, treatments at 0.6 and 31 p.p.m. of phosphorus were applied when the first leaf had completed its rapid growth. The plants were then grown for three days in media labelled with ³²P, and for a subsequent 10 days in non-labelled solutions. Retranslocation was measured by changes in total phosphorus and in ³²P.Both root feeding, and foliar application of ³²P, demonstrated three phases during leaf development: import (recently initiated leaf), export (mature leaf) and an intermediate phase with both export and import (leaf half developed).There was large transport of foliar applied ³²P, from mature leaves to roots, and some of this ³²P was re-exported to the shoots, including the mature leaves. Root feeding of ³²P over short periods strongly suggested that phosphorus uptake by the shoots occurred via the xylem, even at low phosphorus.In experiment 1, there were distinct treatment differences in relative growth rates, growth of young organs and roots, and in phosphorus concentrations of all but the very young leaves. Mature leaves showed a large net phosphorus export at low phosphorus, but a large net import at high phosphorus. This was not due to treatment differences in export, because total export from the mature leaves was even somewhat smaller at low than at high phosphorus. The treatment differences, with net export at low but net import at high phosphorus, were thus due to the higher import in the mature leaves at high phosphorus. Total export remained at a high level throughout the experiment at high phosphorus, while it declined with time at low phosphorus.For phosphorus absorbed during early growth, both the export from the mature leaves, and the intake by the developing leaves, was independent of phosphorus treatment; i.e. for each individual organ the quantities of phosphorus involved were the same in the two phosphorus treatments. Thus, the higher phosphorus contents of developing organs at high phosphorus were obtained from phosphorus supplied to the roots during later growth, and not from phosphorus supplied during early growth of the whole plant.The data are consistent with the notion that phosphorus export is controlled in the source. It is suggested that at high phosphorus this control is due to a saturation of the sites transporting phosphorus into the phloem. At low phosphorus, on the other hand, release from individual leaf cells might have been the dominating factor.     

不同杉木无性系磷素特性的比较

通过土培试验,进行磷素胁迫条件下不同杉木(Cunninghamia lanceolata)无性系磷素特性的比较研究。结果表明:在磷胁迫条件下不同杉木无性系的干物质积累、磷素吸收效率和磷素利用效率均存在显著差异。随着磷胁迫的加剧,不同杉木无性系的干物质积累量和磷素吸收效率下降,而磷素利用效率增强。总体而言,8、9、24、37号无性系的干物质积累量受胁迫影响最小,23号无性系受胁迫影响最大。其中8号无性系的磷素吸收和利用效率均较高,24、37号无性系的磷素吸收效率较高,而9号无性系的磷素利用效率较高,23号无性系的磷素吸收和利用效率均较低。 在磷胁迫条件下,杉木无性系可通过提高磷素吸收效率和利用效率途径来提高杉木对环境磷素的利用。     

The Effect of Bicarbonate on P32 Uptake by Tomato and Runner Bean

The effect of bicarbonate on the absorption and translocationof P³² by tomato and runner bean has been investigated. Whilebicarbonate stimulated phosphorus uptake from potassium phosphatesolutions it inhibited it from Hoagland solution. Translocationof absorbed phosphorus was inhibited in the single salt solutionbut stimulated in Hoagland solution. Bicarbonate caused morephosphorus to be concentrated in the stems and less in the leavesin Hoagland solution and the reverse was true in the single-saltsolution. It is concluded that the effect of bicarbonate onphosphorus in causing iron chlorosis in some plants is indirect.     

Different behaviour of crop species in phosphate absorption

Summary Isotopic-dilution technique was used to study the differential phosphate absorption abilities of several field crops. The response of crops was found to be inversely related to the ratio of phosphorus absorbed from the soil to that absorbed from the fertilizer. The ‘A’ values ranged from 2.03 ppm for mustard to 21.77 ppm for soybeans. A highly significant correlation (r=0.77**) was found between per cent yields and the ‘A’ values.     

Highly efficient uptake of phosphorus in epiphytic bromeliads

Background and Aims

Vascular epiphytes which can be abundant in tree crowns of tropical forests have to cope with low and highly intermittent water and nutrient supply from rainwater, throughfall and stem flow. Phosphorus rather than nitrogen has been suggested as the most limiting nutrient element, but, unlike nitrogen, this element has received little attention in physiological studies. This motivated the present report, in which phosphate uptake kinetics by leaves and roots, the subsequent distribution within plants and the metabolic fate of phosphate were studied as a step towards an improved understanding of physiological adaptations to the conditions of tree canopies.

Methods

Radioactively labelled [³²P]phosphate was used to study uptake kinetics and plant distribution of phosphorus absorbed from bromeliad tanks. The metabolism of low molecular phosphorus metabolites was analysed by thin-layer chromatography followed by autoradiography.

Key Results

Uptake of phosphate from tanks is an ATP-dependent process. The kinetics of phosphorus uptake suggest that epiphytes possess effective phosphate transporters. The K_m value of 1·05 µm determined for leaves of the bromeliad Aechmea fasciata is comparable with values obtained for the high affinity phosphate transporters in roots of terrestrial plants. In this species, young leaves are the main sink for phosphate absorbed from tank water. Within these leaves, phosphate is then allocated from the basal uptake zone into distal sections of the leaves. More than 80 % of the phosphate incorporated into leaves is not used in metabolism but stored as phytin.

Conclusions

Tank epiphytes are adapted to low and intermittent nutrient supply by different mechanisms. They possess an effective mechanism to take up phosphate, minimizing dilution and loss of phosphorus captured in the tank. Available phosphorus is taken up from the tank solution almost quantitatively, and the surplus not needed for current metabolism is accumulated in reserves, i.e. plants show luxury consumption. Young, developing leaves are preferentially supplied with this nutrient element. Taken together, these features allow epiphytes the efficient use of scarce and variable nutrient supplies.Key words: Epiphytic bromeliads, phosphorus uptake, forest canopies, luxury consumption, phytotelms, plant nutrition, Aechmea fasciata     

Extracellular secretion of Aspergillus phytase from Arabidopsis roots enables plants to obtain phosphorus from phytate

Phosphorus (P) deficiency in soil is a major constraint for agricultural production worldwide. Despite this, most soils contain significant amounts of total soil P that occurs in inorganic and organic fractions and accumulates with phosphorus fertilization. A major component of soil organic phosphorus occurs as phytate. We show that when grown in agar under sterile conditions, Arabidopsis thaliana plants are able to obtain phosphorus from a range of organic phosphorus substrates that would be expected to occur in soil, but have only limited ability to obtain phosphorus directly from phytate. In wild-type plants, phytase constituted less than 0.8% of the total acid phosphomonoesterase activity of root extracts and was not detectable as an extracellular enzyme. By comparison, the growth and phosphorus nutrition of Arabidopsis plants supplied with phytate was improved significantly when the phytase gene (phyA) from Aspergillus niger was introduced. The Aspergillus phytase was only effective when secreted as an extracellular enzyme by inclusion of the signal peptide sequence from the carrot extensin (ex) gene. A 20-fold increase in total root phytase activity in transgenic lines expressing ex::phyA resulted in improved phosphorus nutrition, such that the growth and phosphorus content of the plants was equivalent to control plants supplied with inorganic phosphate. These results show that extracellular phytase activity of plant roots is a significant factor in the utilization of phosphorus from phytate and indicate that opportunity exists for using gene technology to improve the ability of plants to utilize accumulated forms of soil organic phosphorus.     

Simultaneous removal of phosphorus and nitrogen in sequencing batch reactor

In this research, investigations were made on material transfer mechanisms and optimum operation mode for sequencing batch reactor system removing phosphorus and nitrogen simultaneously. Phosphorus release characteristics were expressed in the Monod equation, in which the reaction rate was replaced with specific phosphorus release (SPR) rate. The rate of SPR was increased during the first 80 days, but increased sharply to reach 0.003 hr^-1 afterwards. Phosphorus removal efficiencies were about 60% in the first 80 days, 75% after 80 days, and above 95% after 120 days. After 120 days, phosphorus concentration in effluent was below 0.5 mgl^-1 when 8 mgl^-1 was in the influent and the released phosphorus after 3-hour-anaerobic period was 60 mgl^-1. In the proposed optimum operation strategy (2-hour anaerobic react, 3-hour aerobic react, 4-hour anoxic react, and 3-hour settle and draw), phosphorus reappeared if the oxidized nitrogen was completely denitrified. In order to prevent this undesirable phosphorus release, anoxic period should be reduced to the extent of which the minimal concentration of the oxidized nitrogen existed. Phosphorus removal efficiency was stable under shock load as 5 times high as normal phosphorus concentration.Abbreviations dP/dt Phosphorus release rate (mgl^-1 hr^-1) - K Phosphorus release yield constant (mg P mg TOC^-1) - dS/dt Substrate utilization rate (mgl^-1 hr^-1) - X Mixed liquor suspended solid (MLSS, mgl^-1) - S Soluble TOC (mgl^-1) - k-q_max (Y_max)^-1 Maximum substrate utilization rate - Y Yield coefficient (mg mg^-1) - K_s Saturation constant (mgl^-1) - P_max kK-Maximum phosphorus release rate (hr^-1) - P_rel Total released phosphorus (mgl^-1) - P_o Phosphorus in influent (mgl^-1) - P_e phosphorus in effluent (mgl^-1) - t Anaerobic period (hr)     

三种植物对土壤磷吸收和富集能力的比较北大核心CSCD

筛选磷富集植物是磷矿废弃地土壤与植被修复的关键。该文以向日葵(Helianthus annuus)、苏丹草(Sorghum sudanense)、南瓜(Cucurbita moschata)为研究对象,采用盆栽试验,设置5个磷浓度(0、100、300、500和700 mg·kg–1),分别在3个不同生长时段(4周、7周、10周)内采样,对这3种植物的磷吸收和富集能力进行了比较。结果表明:(1)在相同生长时间内,向日葵、苏丹草、南瓜的地上部磷含量均随磷处理浓度的升高而增大,最大值分别为9.67 g·kg–1、4.86 g·kg–1、6.32 g·kg–1;相同浓度下,向日葵地上部磷含量随着生长时间的延长呈上升趋势,苏丹草则呈下降趋势,南瓜无显著变化;(2)3种植物的地上部磷累积量均在磷处理浓度为700 mg·kg–1时,生长10周后达到最大值,分别为217.83 mg·plant–1、93.92 mg·plant–1、135.82 mg·plant–1;(3)各浓度处理下,向日葵、苏丹草的地上部磷富集系数和转移系数均大于1.00,南瓜的地上部磷富集系数和转移系数波动较大;向日葵的富集系数和转移系数最大值分别达11.39和4.09。综合比较可知,3种植物磷吸收和富集能力的大小顺序为:向日葵>南瓜>苏丹草。向日葵各项富磷特征基本符合磷富集植物的筛选标准,可作为磷矿废弃地土壤与植被修复的备选物种。     

The Effect of Applying a Nutrient in Leaf Sprays on the Absorption of the Same Nutrient by the Roots

Ammonium nitrate solution applied to the leaves of sugar-beetincreased plant dry weight and uptake of nitrogen by the roots.Uptake of phosphorus by the roots of swedes, but not sugar-beet,grown with high phosphorus supply to the roots, was decreasedby applying sodium phosphate solution to the leaves; uptakefrom a lower phosphorus supply to the roots was unaffected.Phosphorus applied to the leaves had no effect on dry weight.Potassium uptake by the roots of sugar-beet plants grown withhigh potassium supply to the roots was unaffected by paintingthe leaves with a potassium chloride solution, that of plantswith an intermediate potassium supply was increased, and plantsgrown with a low supply to the roots absorbed almost all theavailable potassium so painting could not much increase uptakeby the roots. Application of potassium to the leaves increaseddry weight of plants with low or medium potassium supply tothe roots and did not affect that of plants with a high potassiumsupply. The top: root ratio for phosphorus content in mg. per plantwas greater for phosphorus absorbed via leaves than for phosphorusabsorbed via roots. Increasing the phosphorus supply to theroots increased this ratio for phosphorus absorbed either vialeaves or roots. Potassium absorbed by leaves was slightly more efficient inincreasing dry weight than potassium absorbed at the same timeby the root. A similar comparison was not possible for nitrogenor phosphorus. The results of these and previous experiments indicate thatall the nitrogen and potassium and over 80 per cent. of thephosphorus applied to leaves was absorbed. The small amountof phosphorus remaining unabsorbed on the surface of the leafwas unaffected by phosphorus supply to the root.     

Tissues and organs as indicators of intestinal absorption of minerals and trace elements,evaluated in rats

Tissue and organ deposition and blood parameters were evaluated as indices of mineral and trace element absorption in rats. The absorption of elements was quantified in relation to nitrogen retention, i.e., considering the weight gain and new tissue synthesis. A rapeseed meal diet was supplied with three levels of calcium, two levels of zinc, and two levels of copper in a factorial design. In general, an increase in dietary mineral content increased the relative absorption, which in turn, increased the tissue deposition progressively. Striated muscle, however, did not respond to either an increased calcium or zinc supply. Furthermore, an increased calcium absorption caused a depression of the fractional phosphorus and magnesium content of femur bones. The copper content of the kidneys and the heart muscle was directly proportional to the amount of absorbed zinc and iron, respectively. The iron content of tissues was, in general, inversely proportional to zinc absorption and showed a tendency to be directly proportional to copper absorption. The zinc level in tissues was, in a similar way, inversely correlated to measured calcium absorption. In conclusion, interactions between elements do not only affect the intestinal element absorption, but also the distribution of already absorbed elements in tissues and organs.     

Root Proliferation,Proton Efflux,and Acid Phosphatase Activity in Common Bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis>) Under Phosphorus Shortage

The impact of phosphorus (P) availability on root proliferation, proton efflux, and acid phosphatase activities in roots and leaves was investigated in two lines of common bean (Phaseolus vulgaris): BAT 477 and CocoT. Phosphorus was supplied as KH₂PO₄ at 0 and 60 μmol per plant (0P and 60P, respectively). Under P shortage, the plant growth was more restricted in CocoT than in BAT 477, shoots being more affected than roots. The root area increased significantly at 0P in both lines. Up to 1 week following P shortage, the proton efflux increased in both lines despite a higher extent in BAT 477 as compared to CocoT. Root acid phosphatase activity was significantly higher under P limitation in the both lines, this trend being more pronounced in BAT 477 than in CocoT. This was also true for the leaf acid phosphatase. Regardless of the bean line, higher values were recorded for the old leaves as compared to the young ones for this parameter. Interestingly, a significant correlation between Pi content in old leaves and their acid phosphatase activity was found in P-lacking (0P) plants of the both bean lines, suggesting that acid phosphatase may contribute to increase the phosphorus use efficiency in bean through the P remobilization from the old leaves. As a whole, our results highlight the significance of the root H⁺ extrusion and the acid phosphatase activity rather than the root proliferation in the relative tolerance of BAT 477 to severe P deficiency.     

The Determination of Phosphorus in Haemophilus influenzae Type b Conjugate Vaccines by Inductively Coupled Plasma-Atomic Emission Spectrometry

This study describes a method for the determination of phosphorus in lyophilized Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of polysaccharide is directly related to the concentration of phosphorus as measured in the laboratory. Phosphorus is present in the polyribosyl-ribitol phosphate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. The repeating unit of PRP is 3-B-D ribose[1-1]ribitol-5-phosphate. Phosphorus in the final container is measured in μ g per dose. The amount of PRP is calculated from this and reported in μ g per dose. The Haemophilus influenzae type b conjugate vaccine was analyzed for phosphorus content within the range of 1·34 to 2·02 μg phosphorus per ml. The relative difference of phosphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2·2 to 10·6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1·93±0·13 μ g P/ml). The phosphorus determination of NIST SRM 3139 phosphorus spectrometric solution differed by 3·0% from the certified phosphorus value (10·00 mg P/ml).     

Spatial mapping of phosphorus influx in bean root systems using digital autoradiography

A novel technique was developed to spatially map the phosphorus net influx capacity in intact root systems. The method is based on digital autoradiography and permits the quantification of phosphorus influx at high spatial resolution (2 mm). Roots of 18-d-old common bean plants were exposed to (32)P-labelled orthophosphate, quickly frozen, excised, lyophilized, scanned, and exposed to a storage phosphor screen. Plots of (32)P content versus root length (distance from the root tip or from the base of the root) were obtained for three different root classes: basal, basal laterals, and taproot laterals. Radioactivity detected by filmless autoradiography correlated well (r(2)=0.99) with measurements made by scintillation counting. Basal roots absorbed 2.5 times and 1.9 times more phosphorus than the taproot lateral and basal lateral root classes, respectively, in the first 20 mm from the root apex. External phosphorus markedly affected influx: roots averaged 5, 16, and 34 pmol P min(-1) in the apical 20 mm when exposed to 1, 5, and 10 microM P solutions, respectively. The spatial pattern of phosphorus influx along the root axes of the different root classes was rather homogeneous when measured on a root surface area basis. Phosphorus influx in the older segments of basal roots (those next to the hypocotyl) did not differ from the newer segments close to the root apex. However, a heterogeneous pattern was detected for basal roots when measured on a length basis, indicating that both root class and diameter constitute main factors controlling the spatial pattern of net influx.     

THE RELATIONSHIP OF XYLEM MATURATION TO THE ABSORPTION AND TRANSLOCATION OF P32

Techniques were developed to supply radioactive phosphorus to specific regions of the roots of corn and to ascertain the extent of functional xylem. The data support the view that all regions of the root are effective in absorbing phosphorus but translocation of the absorbed phosphorus to the shoot was correlated with the presence of functional xylem in the region where phosphorus was supplied.     

湖南会同不同年龄杉木人工林土壤磷素特征

对湖南会同不同年龄(7年生、17年生、25年生)杉木人工林土壤全磷、有效磷、无机磷组分和有机磷进行了研究,结果表明:3种不同林龄杉木林土壤全磷和有效磷的含量分别在317.06—398.56 mg/kg和0.82—1.38 mg/kg之间,土壤全磷和速效磷含量均属低水平;杉木林土壤全磷含量从7年生幼龄林到25a近熟林出现先升高后降低的规律,并且17年生和25年生林分比7年生林分分别增加了19.68%、15.75%,土壤有效磷含量17年生和25年生林分比7年生林分提高了45.55%左右;土壤磷素活化系数均小于2.0%,这表明本研究区土壤全磷向速效磷转化较难,土壤中磷素的有效性较低,但该值随着林分年龄的增加而出现增大的现象;无机磷含量分别为:7年生169.50 mg/kg、17年生182.03 mg/kg、25年生175.94 mg/kg,从幼龄林到中龄林增高,中龄林以后降低;土壤中无机磷组分以O-P含量最高,其次是Fe-P,Ca-P,Al-P最少;杉木不同生长发育阶段对无机磷形态的吸收是有选择性的,幼龄林到中龄林阶段林木以吸收Al-P为主,近熟林阶段林木以吸收Fe-P和Ca-P为主;有机磷含量在全磷所占比例随林龄的变化来看,杉木生长过程中有部分的有机磷矿化为无机磷。土壤不同形态磷的相关性分析结果显示,土壤有效磷与有机磷相关系数为0.667,呈极显著相关性,是研究区杉木人工林土壤有效磷的主要来源。     

Translocation of soil-derived phosphorus in mycelial cord systems in relation to inoculum resource size

Abstract: Uptake of ³²P phosphorus from soil was investigated in mycelial cord systems of Phanerochaete velutina, Hypholoma fasciculare, Tricholomopsis platyphylla and Phallus impudicus which extended from 0.5, 2, 4 or 8 cm³ beech ( Fagus sylvatica ) inocula. Cord systems accumulated between 4.8 and 18.7% of phosphorus supplied to soil, according to species and size of inoculum. Phosphorus translocation to newly-colonized 2 cm³ beech baits, determined non-destructively, was characterized by an initial steady phase, of 2.5 to 32 nmol P day⁻¹ which lasted at least 12 days for all four species. After the initial steady phase, translocation rates declined. Initial mycelial extension and wood decay rates also varied with species and inoculum size. There was no clear relationship between phosphorus translocation rates, wood decay or the distribution of soil-derived phosphorus in cord system components. However, with increasing inoculum size, P. velutina systems allocated a significantly greater proportion of available phosphorus to newly-colonized baits. The degree to which distribution of soil-derived phosphorus in cord systems is related to nutrient conservation or metabolic demand in the fungi is discussed.