Development of a phosphatase activity assay using excised plant roots

Soil Research ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 193 ◽  
Author(s):  
Jaya Das ◽  
Nicholas Comerford ◽  
David Wright ◽  
Jim Marois ◽  
Cheryl Mackowiak
Keyword(s):  
Phosphatase Activity ◽  
Plant Species ◽  
Organic Phosphorus ◽  
Plant Stress ◽  
Develop Model ◽  
P Availability ◽  
Organic P ◽  
Inorganic P ◽  
Abiotic Degradation ◽  
Microbial Systems

Root phosphatase mediated mineralisation of organic phosphorus (P) can affect P availability in agricultural and forest landscapes. Phosphatases hydrolyse organic P into inorganic P that can be taken up by plants. We developed a method to determine mineralisable organic P by phosphatases exuded by excised live roots/microbial systems. We used excised greenhouse- and field-grown roots with para-nitrophenylphosphate, glucose-1-phosphate and phytic acid as sources of organic P. Experimental variables were analysed including linearity of the reaction, presence of inorganic P, organic P exuded from roots, possible abiotic degradation of organic P, and background inorganic/organic P. Organic P mineralisation by root–phosphatase complexes was found to be linear through 6 h. Phosphorus contaminants into the system were found to be within 10% of mineralised organic P. We used this technique to answer questions about organic P bioavailability, including effect of organic P sources, plant species, plant variety, plant stress and root conditions. Overall, this method was sensitive to organic P source and plant stress of greenhouse and field-grown roots, plant species and root physiological conditions. Unlike other methods used to determine phosphatase activity, this method is not limited by lengthy preparation to develop model plants, nor is there any restriction on the choice of organic P or plant species. Our results suggest that this is an attractive method for determining organic P mineralisation specificity among and within plant species, and it can be easily integrated into routine laboratory analyses.

scholarly journals Phosphatase activity and organic phosphorus turnover on a high Arctic glacier

2009 ◽  
Vol 6 (1) ◽  
pp. 2697-2721 ◽  
Author(s):  
M. Stibal ◽  
A. M. Anesio ◽  
C. J. D. Blues ◽  
M. Tranter
Keyword(s):  
Phosphatase Activity ◽  
Organic Phosphorus ◽  
High Arctic ◽  
Organic P ◽  
Glacier Surface ◽  
Nutrient Pools ◽  
Inorganic P ◽  
Low Concentrations ◽  
Arctic Glacier

Abstract. Arctic glacier surfaces harbor abundant microbial communities consisting mainly of heterotrophic and photoautotrophic bacteria. The microbes must cope with very low concentrations of nutrients and with the fact that both the dissolved and debris-bound nutrient pools are dominated by organic phases. Here we provide evidence that phosphorus (P) is deficient and limiting in the supraglacial environment on a Svalbard glacier, we show how the microbial community responds to the P stress and we quantify the contribution of the microbes to the cycling of the dominant organic P in the supraglacial environment. Incubation of cryoconite debris revealed significant phosphatase activity in the samples (19–67 nmol MUP g−1 h−1), which was controlled by the concentration of inorganic P during incubations and had its optimum at around 30°C. The phosphatase activity rates measured at near-in situ temperature and substrate concentration imply that the available dissolved organic P can be turned over by microbes within ~3–11 h on the glacier surface. By contrast, the amount of potentially bioavailable debris-bound organic P is sufficient for a whole ablation season. However, it is apparent that some of this potentially bioavailable debris-bound P is not accessible to the microbes.

scholarly journals Role of Organic Anions and Phosphatase Enzymes in Phosphorus Acquisition in the Rhizospheres of Legumes and Grasses Grown in a Low Phosphorus Pasture Soil

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1185 ◽  
Author(s):  
Driss Touhami ◽  
Richard W. McDowell ◽  
Leo M. Condron
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Plant Species ◽  
Alkaline Phosphatase Activity ◽  
White Clover ◽  
Organic Anions ◽  
Organic P ◽  
Inorganic P ◽  
Pasture Soil ◽  
Rhizosphere Processes

Rhizosphere processes play a critical role in phosphorus (P) acquisition by plants and microbes, especially under P-limited conditions. Here, we investigated the impacts of nutrient addition and plant species on plant growth, rhizosphere processes, and soil P dynamics. In a glasshouse experiment, blue lupin (Lupinus angustifolius), white clover (Trifolium repens L.), perennial ryegrass (Lolium perenne L.), and wheat (Triticum aestivum L.) were grown in a low-P pasture soil for 8 weeks with and without the single and combined addition of P (33 mg kg−1) and nitrogen (200 mg kg−1). Phosphorus addition increased plant biomass and total P content across plant species, as well as microbial biomass P in white clover and ryegrass. Alkaline phosphatase activity was higher for blue lupin. Legumes showed higher concentrations of organic anions compared to grasses. After P addition, the concentrations of organic anions increased by 11-,10-, 5-, and 2-fold in the rhizospheres of blue lupin, white clover, wheat, and ryegrass, respectively. Despite the differences in their chemical availability (as assessed by P fractionation), moderately labile inorganic P and stable organic P were the most depleted fractions by the four plant species. Inorganic P fractions were depleted similarly between the four plant species, while blue lupin exhibited a strong depletion of stable organic P. Our findings suggest that organic anions were not related to the acquisition of inorganic P for legumes and grasses. At the same time, alkaline phosphatase activity was associated with the mobilization of stable organic P for blue lupin.

scholarly journals Phosphatase activity and organic phosphorus turnover on a high Arctic glacier

2009 ◽  
Vol 6 (5) ◽  
pp. 913-922 ◽  
Author(s):  
M. Stibal ◽  
A. M. Anesio ◽  
C. J. D. Blues ◽  
M. Tranter
Keyword(s):  
Phosphatase Activity ◽  
Organic Phosphorus ◽  
High Arctic ◽  
Organic P ◽  
Glacier Surface ◽  
Nutrient Pools ◽  
Inorganic P ◽  
Low Concentrations ◽  
Arctic Glacier

Abstract. Arctic glacier surfaces harbour abundant microbial communities consisting mainly of heterotrophic and photoautotrophic bacteria. The microbes must cope with low concentrations of nutrients and with the fact that both the dissolved and debris-bound nutrient pools are dominated by organic phases. Here we provide evidence that phosphorus (P) is deficient in the supraglacial environment on a Svalbard glacier, we quantify the enzymatic activity of phosphatases in the system and we estimate the contribution of the microbes to the cycling of the dominant organic P in the supraglacial environment. Incubation of cryoconite debris revealed significant phosphatase activity in the samples (19–67 nmol MUP g−1 h−1). It was inhibited by inorganic P during incubations and had its optimum at around 30°C. The phosphatase activity measured at near-in situ temperature and substrate concentration suggests that the available dissolved organic P can be turned over by microbes within ~3–11 h on the glacier surface. By contrast, the amount of potentially bioavailable debris-bound organic P is sufficient for a whole ablation season. However, it is apparent that some of this potentially bioavailable debris-bound P is not accessible to the microbes.

Nitrogen and Phosphorus Availability and the Role of Fire in Heathlands at Wilsons Promontory

1994 ◽  
Vol 42 (3) ◽  
pp. 269 ◽  
Author(s):  
MA Adams ◽  
J Iser ◽  
AD Keleher ◽  
DC Cheal
Keyword(s):  
Phosphatase Activity ◽  
C:N Ratio ◽  
Soil Nutrient ◽  
Fire Frequency ◽  
P Availability ◽  
Native Plant ◽  
Nitrogen And Phosphorus ◽  
Nutrient Pools ◽  
Inorganic P ◽  
Eucalypt Forests

Analyses of carbon, nitrogen and phosphorus in heathland soils at Wilsons Promontory and on Snake Island show that the effects of fire, including repeated fires, are confined to the surface 2 cm. The uppermost soil in long-unburnt heathlands is rich in these elements and usually has a smaller C:N ratio compared with the soil below. Indices of N and P availability (C:N ratios, concentrations of potentially mineralisable N and extractable inorganic P, phosphatase activity) are similar to those in highly productive eucalypt forests-a finding in conflict with past assessments of nutrient availability in heathlands. Phosphatase activity and concentrations of carbon, nitrogen and potentially mineralisable N were less in soils from repeatedly burnt heathlands than in soils from long unburnt heathlands whereas there was a greater concentration of extractable inorganic P in soils from repeatedly burnt heathlands. The balance between nitrogen input and loss is dependent on fire frequency and present-day management of heathland (and other native plant communities with low nutrient capitals) should recognise that over- or under-use of fire will significantly alter soil nutrient pools and availability and that these changes may alter community species composition and productivity.

Dynamics of phosphorus fractions in soils treated with dairy manure

Soil Research ◽  
2020 ◽  
Vol 58 (3) ◽  
pp. 289
Author(s):  
L. B. Braos ◽  
A. C. T. Bettiol ◽  
L. G. Di Santo ◽  
M. E. Ferreira ◽  
M. C. P. Cruz
Keyword(s):  
P Uptake ◽  
Dairy Manure ◽  
P Availability ◽  
Organic P ◽  
Triple Superphosphate ◽  
P Fractions ◽  
Inorganic P ◽  
Soil P ◽  
Plant P Uptake ◽  
Inorganic P Fractions

The evaluation of phosphorus (P) transformations in soil after application of manure or mineral P can improve soil management and optimise P use by plants. The objectives of the present study were to assess organic and inorganic P forms in two soils treated with dairy manure and triple superphosphate and to establish relationships between soil P fraction levels and P availability. Soil organic and inorganic P fractions were quantified using a pot experiment with two soils, a typical Hapludox and an arenic Hapludult, with three types of fertiliser treatments applied (no fertiliser application, application of dairy manure, and application of triple superphosphate, by adding 100 mg P dm–3 in the form of fertiliser in the two latter treatments) and four incubation times (15, 45, 90, and 180 days). Inorganic P was fractionated into aluminium-bound, iron-bound, occluded, and calcium-bound P. Organic P was extracted sequentially using sodium bicarbonate, hydrochloric acid, microbial biomass, sodium hydroxide, and residual organic P. After incubation, maize plants were cropped to quantify dry matter yield and absorbed P. Application of dairy manure resulted in a significant increase in most of the organic P fractions, and application of triple superphosphate led to a significant increase in inorganic P fractions. Both fertilisers raised labile organic P fractions in the two soils. The major sinks of P in Hapludox were occluded and fulvic acid-associated P. In contrast, the major sink of P in Hapludult was iron-bound P. The available P levels were stable after application of dairy manure, and decreased with time when fertilised with triple superphosphate. In the Hapludox, the organic P fractions had a significant positive correlation with P uptake by plants. The results suggest that organic P mineralisation plays a more significant role in plant P uptake in the Hapludox soil and inorganic P forms are the main contributors to plant P uptake in the Hapludult soil.

Phosphorus cycling in wheat-pasture rotations. III. Organic phosphorus turnover and phosphorus cycling

Soil Research ◽  
1988 ◽  
Vol 26 (2) ◽  
pp. 343 ◽  
Author(s):  
MJ Mclaughlin ◽  
AM Alston ◽  
JK Martin
Keyword(s):  
Organic Phosphorus ◽  
Soil Surface ◽  
P Uptake ◽  
Phosphorus Cycling ◽  
Plant Residue ◽  
Organic P ◽  
Inorganic P ◽  
Soil P ◽  
Wheat Pasture ◽  
P Cycle

The incorporation of 32P and 33P from 33P-labelled fertilizer and 33P-labelled pasture residues into organic and inorganic fractions of soil P was studied in a solonized brown soil (Calcixerollic xerochrept) cropped to wheat (Triticum aestivum). Most of the plant residue 33P was present as inorganic P at the time it was added to the soil, but only 7 days later almost 40% had been incorporated into organic P fractions of the soil. As the fertilizer was banded near the soil surface at sowing, little of the 32P from the 32P-labelled fertilizer was incorporated into organic forms, even after 95 days. From a knowledge of the P uptake by the plants and microorganisms, an integrated P cycle for this soil under wheat-pasture rotations was developed. We propose that fertilization of the pasture phase of the rotation stimulates the build-up of residual inorganic and organic P, while fertilization of the wheat phase predominantly stimulates the accumulation of inorganic forms of P in the soil.

Influence of long-term irrigation on the distribution and availability of soil phosphorus under permanent pasture

Soil Research ◽  
2006 ◽  
Vol 44 (2) ◽  
pp. 127 ◽  
Author(s):  
L. M. Condron ◽  
S. Sinaj ◽  
R. W. McDowell ◽  
J. Dudler-Guela ◽  
J. T. Scott ◽  
...  
Keyword(s):  
Soil Phosphorus ◽  
Soil Layer ◽  
P Availability ◽  
Organic P ◽  
Retention Capacity ◽  
Pasture Production ◽  
Inorganic P ◽  
Permanent Pasture ◽  
P Movement

This study examined the influence of irrigation on soil phosphorus (P) distribution and availability under permanent pasture in New Zealand. Soil samples (0–0.075, 0.075–0.15, 0.15–0.25 m) were taken from a long-term field experiment, which included a dryland and 2 irrigation treatments (irrigated at 10% and 20% soil moisture) that had received 25 kg P/ha annually as superphosphate for 52 years. Corresponding data for soil from an adjacent ‘wilderness’ site that had not been used for agriculture for 54 years were included for comparison. Analyses included total P, organic P, and inorganic P; isotopic exchange kinetics (IEK) was used to determine soil inorganic P pools of differing plant availability. Concentrations of total and inorganic P were greater in soil taken from the dryland treatment than the irrigated treatments at all depths. This was attributed to a combination of decreased pasture growth and P transfer in drainage and off-farm produce. Concentrations of organic P were greater in the irrigated treatments (e.g. 0–0.075 m: 672–709 mg P/kg) than in the dryland treatment (e.g. 0–0.075 m: 574 mg P/kg) as a consequence of increased pasture production and soil biological activity. Inorganic P availability (Cp and E1min) was also greater in the dryland treatment than the irrigated treatments. Furthermore, concentrations of inorganic P in the recalcitrant IEK pool (E>3m = E3m–1y + E>1y) in the 0–0.075 m soil from the dryland treatment (479 mg P/kg) were significantly greater than the 10% irrigated (346 mg P/kg) and 20% irrigated (159 mg P/kg) treatments, which was mainly attributed to physico-chemical reactions that decreased the exchangeability of accumulated inorganic P with time. Despite increased P retention capacity at depth (R/r1, 0.15–0.25 m: dryland 6.6, 10% irrigated 10.2, 20% irrigated 12.8), concentrations of total inorganic P in the 0.15–0.25 m soil layer were lower under irrigation (195–266 mg P/kg) than dryland (354 mg P/kg), which indicated that long-term flood irrigation increased P transfer by leaching. The findings of this study revealed that while irrigation improved the utilisation of applied fertiliser P it also resulted in increased P movement to depth in the soil profile.

scholarly journals ORGANIC PHOSPHORUS FRACTIONS IN SOIL FERTILIZED WITH CATTLE MANURE

2015 ◽  
Vol 39 (1) ◽  
pp. 140-150 ◽  
Author(s):  
Lucas Boscov Braos ◽  
Mara Cristina Pessôa da Cruz ◽  
Manoel Evaristo Ferreira ◽  
Fernando Kuhnen
Keyword(s):  
Exchange Resin ◽  
Organic Phosphorus ◽  
Tropical Soils ◽  
Inorganic Phosphorus ◽  
Cattle Manure ◽  
Available P ◽  
P Availability ◽  
Organic P ◽  
Soil Material ◽  
Sampling Times

Inorganic phosphorus (Pi) usually controls the P availability in tropical soils, but the contribution of organic P (Po) should not be neglected, mainly in systems with low P input or management systems that promote organic matter accumulation. The aims of this study were to evaluate the changes in the Po fractions over time in soil fertilized and not fertilized with cattle manure and to correlate Po forms with available P extracted by anion exchange resin. The experiment was carried out under field conditions, in a sandy-clay loam Haplustox. The experimental design was a 2 × 9 randomized complete block factorial design, in which the first factor was manure application (20 t ha-1) or absence, and the second the soil sampling times (3, 7, 14, 21, 28, 49, 70, 91, and 112 days) after manure incorporation. Labile, moderately labile and non-labile Po fractions were determined in the soil material of each sampling. Manure fertilization increased the Po levels in the moderately labile and non-labile fractions and the total organic P, but did not affect the Po fraction proportions in relation to total organic P. On average, 5.1 % of total Po was in the labile, 44.4 % in the moderately labile and 50.5 % in the non-labile fractions. Available P (resin P) was more affected by the manure soluble Pi rather than by the labile Po forms. The labile and non-labile Po fractions varied randomly with no defined trend in relation to the samplings; for this reason, the data did not fit any mathematical model.

Effects of aluminum and fluoride on phosphorus acquisition by Chlamydomonas reinhardtii

1995 ◽  
Vol 52 (2) ◽  
pp. 353-357 ◽  
Author(s):  
Elaine M. Joseph ◽  
François M. M. Morel ◽  
Neil M. Price
Keyword(s):  
Cell Surface ◽  
Chlamydomonas Reinhardtii ◽  
Phosphatase Activity ◽  
Low Ph ◽  
Alkaline Media ◽  
Organic P ◽  
Phosphorus Acquisition ◽  
Compensatory Response ◽  
Inorganic P ◽  
P Utilization

Al (10 μM) and F (50 μM) added singly or in combination have no effect on growth of Chlamydomonas reinhardtii in acid or alkaline media containing organic or inorganic P. Cell surface phosphatase activity, however, is increased in glucose-1-phosphate-amended cultures exposed to Al, but only at low pH. This result is an indirect effect caused by Al binding to the organic P, which inhibits organic P utilization and induces phosphatase synthesis in C. reinhardtii as a compensatory response. Phosphatase activity is inversely correlated with lake pH, suggesting that such a mechanism may operate in nature. Al thus appears to enhance phosphatase activity in acidified waters by impeding dissolved organic P catabolism.

scholarly journals Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon

2021 ◽  
Author(s):  
Karst J. Schaap ◽  
Lucia Fuchslueger ◽  
Marcel R. Hoosbeek ◽  
Florian Hofhansl ◽  
Nathielly Pires Martins ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Phosphatase Activity ◽  
Litter Decomposition ◽  
Soil Phosphorus ◽  
Litter Production ◽  
P Availability ◽  
Organic P ◽  
Phosphorus Cycle ◽  
P Fractions ◽  
Soil P

Abstract Purpose The tropical phosphorus cycle and its relation to soil phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on abiotic and biotic processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods We analyzed intra-annual variation of tropical soil phosphorus pools using a modified Hedley sequential fractionation scheme. In addition, we measured litterfall, the mobilization of P from litter and soil extracellular phosphatase enzyme activity and tested their relation to fluctuations in P- fractions. Results Our results showed clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition was positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion We conclude that input of P by litter decomposition and potential soil extracellular phosphatase activity are the two main factors related to seasonal soil P fluctuations, and therefore the P economy in P impoverished soils. Organic soil P followed a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.

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