The effects of organic and inorganic phosphorus concentration on the acid phosphatase activity of ectomycorrhizal fungi

1988 ◽  
Vol 66 (4) ◽  
pp. 750-756 ◽  
Author(s):  
Carolyn J. Kroehler ◽  
Robert K. Antibus ◽  
Arthur E. Linkins

Kinetic constants (Km and Vmax) were determined for surface and extracellular soluble acid phosphatases produced by two ectomycorrhizal fungi (Cenococcum geophilum Fr. and Entoloma sericeum (Bull, ex Merat) Quel.) grown in axenic culture at 2 or 50 μM KH2PO4 or sodium inositol hexaphosphate. Results for cultures supplied inorganic phosphorus were similar to those supplied organic phosphorus: surface Vmax estimates were significantly greater for 2 than for 50 μM grown isolates. The presence of constitutive extracellular soluble phosphatase activity resulted in the appearance of inorganic phosphate in media initially supplied with organic phosphorus, suggesting substrate hydrolysis in excess of phosphate uptake. No consistent relationship was found between apparent Km estimates and phosphorus treatments. The two species had surface phosphatase Vmax values differing by as much as two orders of magnitude. The magnitude of the response to phosphorus treatment differed among isolates. The response of phosphatases to changes in phosphorus at concentrations comparable with soil solution phosphorus supports the hypothesis that levels of available soil phosphorus may control ectomycorrhizal phosphatase production or activation.

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
Buhlebelive Mndzebele ◽  
Bhekumthetho Ncube ◽  
Melake Fessehazion ◽  
Tafadzwanashe Mabhaudhi ◽  
Stephen Amoo ◽  
...  

Low available soil phosphorus (P) is associated with its immobility, which renders it unavailable for plant uptake. In addition, farmers normally apply inorganic fertilisers to legumes to activate soil-bound phosphorus using root exudates. Sufficient soil mineral nutrition is key to sustainable crop production, and hence food and nutritional security. The aim of this study was to quantify the acid and alkaline phosphatase activity as an indicator of P supply and availability under varying levels of nitrogen, phosphorus and potassium (NPK) fertilization and different cropping systems. An intercropping (cowpea and amaranth) and fertiliser (control, 25%, 50%, and 100% of the recommended NPK levels) field trial was laid out in a 2 × 4 factorial treatment structure in a completely randomized design (CRD) with four replications. There was higher acid and alkaline phosphatase activity in the rhizosphere of cowpea and amaranth grown as sole crops compared to those from intercropping. The cowpea and amaranth plants grown without fertiliser or 25% NPK had the highest rhizospheric phosphatase activity, while 100% NPK application exhibited the least. The markedly higher phosphatase activity from the low fertiliser application treatments indicates the possible stimulation of microbial activity to supplement P demands for the crops. The study revealed that the application of lower rates inorganic fertilisers in a legume intercrop stimulates the activity of the phosphatase enzymes, which can subsequently liberate soil-bound phosphorus. Plant tissue phosphorus concentration of cowpea and amaranth plants increased proportionately to the increase in fertiliser application up to 50% of the recommended NPK level. The land equivalent ratio (LER) was greater than 1, indicating that it is more beneficial to intercrop cowpea and amaranth as opposed to growing them as sole crops. Overall, the application of NPK fertilizer to amounts of up to 50%, based on the results of this study, appear to be better than 100% in terms of biomass accumulation and phosphate activity.


1986 ◽  
Vol 64 (11) ◽  
pp. 2383-2387 ◽  
Author(s):  
Robert K. Antibus ◽  
Carolyn J. Kroehler ◽  
Arthur E. Linkins

Isolates of the ectomycorrhizal fungi Cenococcum geophilum, Hebeloma pusillum, and Entoloma sericeum were grown in axenic culture to study the effects of assay pH, temperature, and substrate concentration on the activity of surface acid phosphatases. In addition, isolates were grown at 12 and 20 °C to determine whether the Arrhenius activation energies of surface phosphatases were affected by temperature acclimation. Four of the six isolates examined demonstrated distinct pH optima at pH 5.0; one isolate showed optimal activity at pH 4.5. None of the fungi examined produced significant surface alkaline phosphatase activity. Arrhenius activation energy values were not affected by lowering the growth temperature, suggesting that a phenotypic change in surface acid phosphatases did not occur with acclimation. Vmax and Km values for the hydrolysis of p-nitrophenyl phosphate were found to differ significantly among the isolates examined. Our findings support previous research by confirming the existence of interspecific and intraspecific differences in acid phosphatase activity, but they demonstrate the importance of considering assay pH and substrate concentration when making such comparisons.


Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1858 ◽  
Author(s):  
Xiaolong Cheng ◽  
Yanan Huang ◽  
Xunchi Pu ◽  
Ruidong An ◽  
Wendian Huang ◽  
...  

The Yarlung Zangbo River basin ecosystem is fragile. The distribution and transportation of phosphorus is of great significance for aquatic environmental protection and ecological security. The sequential extraction method and molybdenum antimony anti-spectrophotometry were used to measure the concentrations of different forms of phosphorus in the surface sediments from 15 sampling sites along the middle reaches of the Yarlung Zangbo River and its tributaries. The results show that the total phosphorus concentration in the surface sediments is 194.0~540.7 mg/kg, which is mainly composed of inorganic phosphorus. The concentrations of various phosphorus forms ranked as calcium-bound phosphorus (355.6 ± 86.0 mg/kg) > soluble phosphorus (15.9 ± 10.0 mg/kg) > iron-bound phosphorus (12.4 ± 12.3 mg/kg) > organic phosphorus (9.6 ± 6.1 mg/kg) > occluded phosphorus (9.2 ± 3.8 mg/kg) > aluminum-bound phosphorus (5.4 ± 2.3 mg/kg). On the whole, phosphorus concentration is greater in wet season than dry season. Regarding the spatial distribution characteristics, there are great disparities in the different forms of phosphorus in the middle reaches of the Yarlung Zangbo River. Comprehensive analysis shows that phosphorus of this area is mainly self-generated, and concentration of bioavailable phosphorus is small, demonstrating there will not be a large release. We also drew a “specific triangle” of the different forms of phosphorus concentrations in the research area and defined the “α” angle to determine the nutrient status of the overlying water quickly and effectively. Finally, phosphorus flux of the mainstream was estimated. This research may provide information on the phosphorus of Plateau Rivers.


1938 ◽  
Vol 28 (2) ◽  
pp. 234-246 ◽  
Author(s):  
L. A. Dean

1. Extractions of soils with sodium hydroxide, followed by an acid, have been used in an attempt to fractionate the soil phosphorus.2. Colorimetric methods for the estimation of the organic and inorganic phosphorus in alkali soil extracts have been suggested.3. The amount of soil phosphorus soluble in sodium hydroxide is affected by the active soil calcium. It is suggested that sodium-saturated soils be used when studying the alkali-soluble phosphorus.4. The acid-soluble phosphorus remaining in soil after extraction with sodium hydroxide was determined. This fraction appears by analogy to be similar to the apatites.5. The largest fraction of the total soil phosphorus was not dissolved by the sodium hydroxide and acid extractions. This fraction was not increased by the long-continued use of phosphatic fertilizers at Rothamsted and Woburn.6. Relatively large amounts of organic phosphorus were found in soils and the amounts were closely related to the carbon contents.


Soil Research ◽  
1992 ◽  
Vol 30 (3) ◽  
pp. 383 ◽  
Author(s):  
KW Perrott ◽  
SU Sarathchandra ◽  
BW Dow

A two year investigation of soil phosphorus and the soil organic cycle was carried out on a typical hill country site in the North Island, New Zealand. This included investigation of changes in soil phosphorus, as well as seasonal and fertilizer (superphosphate) effects on soil microbial phosphorus and sulfur, sodium bicarbonate extractable phosphorus and calcium chloride extractable sulfur. No net utilization of soil organic phosphorus occurred when application of phosphate fertilizer was withheld. On the contrary, accumulation of organic phosphorus was found in both fertilized and unfertilized plots. Immobilization of inorganic phosphorus into organic forms appeared to be a significant factor in fertilizer phosphorus requirements at this site. It was also a significant cause of the decline in the soil phosphorus status when no fertilizer was applied. Despite declining pasture production, there were no effects of withholding superphosphate on the soil biological cycle as measured by soil microbial phosphorus and sulfur, total organic phosphorus and sodium bicarbonate extractable organic phosphorus. However, seasonal variations occurred indicating storage and release of phosphorus by the soil organic matter and microbial biomass. Release of phosphorus occurred during periods of rapid pasture growth and could account for phosphorus uptake by the pasture at those times.


1984 ◽  
Vol 35 (6) ◽  
pp. 777 ◽  
Author(s):  
KD McLachlan

Wheat plants grown at two levels of phosphorus supply were subjected to drought or given adequate water. Acid phosphatase activities in the youngest fully expanded leaves, and inorganic and total phosphorus concentrations in the plant tops were determined at four stages of crop development. Phosphatase activity increased with plant age, with phosphorus deficiency and with drought. Inorganic phosphorus concentration decreased with plant age and phosphorus deficiency. Drought markedly decreased the inorganic phosphorus concentration in phosphorus sufficient plants but had little effect on the concentration in deficient plants. Total phosphorus concentration increased as the plants aged and was greatest where the plants were phosphorus sufficient and adequately watered. Drought markedly reduced the total phosphorus concentration in phosphorus sufficient plants, but had little effect on the total phosphorus concentration in deficient plants. Leaf acid phosphatase activity was related inversely to the inorganic phosphorus concentration in the plant tops. Changes in activity with aging, phosphorus supply and moisture stress were associated with changes in the inorganic phosphorus concentration. An argument is developed which indicates that a single 'critical value' separating sufficient from deficient plants, either for phosphatase activity, inorganic or total phosphorus concentration, is not practicable. Different values will be required for different stages of maturity. Complications introduced by drought and aging, through their effect on phosphorus concentration and enzyme activity, were overcome by developing phosphatase zymograms. Two bands were specifically associated with phosphorus deficient plants irrespective of plant age or moisture stress. The technique offers further opportunity for studies in phosphorus metabolism and shou!d provide a useful means of diagnosing phosphorus deficiency in field groRn plants.


2012 ◽  
Vol 518-523 ◽  
pp. 4801-4805
Author(s):  
Li Xin Chen ◽  
Wen Biao Duan

Variation in total phosphorus (TP), available phosphorus (AP), the forms of organic phosphorus (OP) and inorganic phosphorus (IP) in rhizosphere soil (RS) and non-rhizosphere soil (NRS) at different development stages in larch (Larix olgensis) plantations was quantitively studied through field investigation, chemical analysis and statistical test. The results indicated that: AP, O-P (occluded phosphate), TP, OP in RS exhibited a significantly or apparently decreased tendency over stand age, but IP, Ca-P (phosphate combined with calcium) and Fe-P (phosphate combined with Ferrum) in RS presented a significantly or apparently increased trend when stand age increased; Ca-P in NRS increased when stand age became larger; Fe-P in half-mature stand (HMS), AP and Fe-P in near mature stand (NMS), AP and Ca-P in mature stand (MS) in NRS was higher than in RS


1986 ◽  
Vol 26 (4) ◽  
pp. 445
Author(s):  
DK Muldoon

The elements nitrogen, phosphorus, potassium, sulfur and zinc were sequentially omitted from a 'complete' fertiliser applied to plots on an alkaline soil, and lucerne (Medicago sativa) was sown immediately afterwards. The dry matter production of lucerne was measured in repeated cuts over 2 years; its mineral composition was determined periodically. In a second experiment 4 rates of phosphorus were applied to a l -year-old stand of lucerne and dry matter production recorded for 1 year. Lucerne yields in the first year were reduced from 17-1 8 t/ha to less than 14 t/ha by omitting phosphorus. Yields universally decreased in the second year as the 50 kg/ha P applied at sowing was depleted through the removal of 40 kg/ha P in forage. Following this depletion a linear yield response up to 80 kg/ha P was found (experiment 2). Omitting phosphorus fertiliser reduced the plant phosphorus concentration from 0.23 to 0.21% when sampled 15 months after sowing. The plant phosphorus concentration decreased with time in all treatments. The available soil phosphorus level decreased from an initial 12 to 6-7 �g/g after 6 months and further to 2 �g/g after 30 months. Fertiliser phosphorus raised the soil phosphorus level but this also was depleted to 2-3 �g/g in 30 months. Omitting zinc reduced the plant zinc concentration. However, neither the omission of nitrogen, potassium, sulfur nor zinc from the fertiliser had any effect on lucerne yields.


1981 ◽  
Vol 59 (12) ◽  
pp. 2458-2465 ◽  
Author(s):  
R. K. Antibus ◽  
J. G. Croxdale ◽  
O. K. Miller ◽  
A. E. Linkins

Pure culture isolates were obtained from fungi fruiting in the vicinity of dwarf willows at Barrow and Cape Simpson, Alaska. Four of these isolates and one isolate from Maryland were tested for their ability to form ectomycorrhizae with cuttings of Salix rotundifolia under controlled environmental conditions. Isolates of Entoloma sericeum, Hebelomapusillum, and Cenococcum geophilum from Barrow and Cape Simpson, Alaska all formed typical ectomycorrhizae with S. rotundifolia, while an isolate of C. geophilum from a temperate ecosystem (Maryland) did not.All of the ectomycorrhizae synthesized with S. rotundifolia, plus uncolonized roots, demonstrated an ability to hydrolyze p-nitrophenyl phosphate at a pH of 4.7. The acid phosphatase activity of E. sericeum ectomycorrhizae was from 10 to 40 times as great as that demonstrated by other mycorrhizal and nonmycorrhizal roots on a surface area basis.


1939 ◽  
Vol 17b (7) ◽  
pp. 199-205 ◽  
Author(s):  
C. L. Wrenshall ◽  
W. J. Dyer

Dissolved organic phosphorus may be determined, even in highly coloured alkaline soil extracts, by the application of photoelectric colorimetry to the ceruleomolybdate colour reaction of phosphate ions. Total organic phosphorus may be extracted from soil with 4 N hydrochloric acid followed by treatment of the residue with 3 N ammonium hydroxide. Inorganic phosphorus is determined by direct colorimetry in the acid extract and in the acidified alkaline extract. Total phosphorus is determined similarly in each extract after ignition. The difference between total and inorganic phosphorus is equivalent to the organically combined phosphorus content of the soil sample.The soil organic phosphorus was found to be stable under these treatments. A considerable proportion of the organic phosphorus is extracted by acid, and the total soil phosphorus is almost completely extracted by the two treatments with 4 N hydrochloric acid and 3 N ammonium hydroxide.


Sign in / Sign up

Export Citation Format

Share Document