scholarly journals The External Location of Phosphatase Activity in Phosphorus-Deficient Spirodela Oligorrhiza

1972 ◽  
Vol 25 (4) ◽  
pp. 707 ◽  
Author(s):  
RL Bieleski ◽  
PN Johnson
Keyword(s):  
Phosphatase Activity ◽  
External Medium ◽  
Phosphorus Deficiency ◽  
Fold Increase ◽  
Particle Fraction ◽  
Specific Staining ◽  
P Deficiency ◽  
Intact Plants ◽  
Spirodela Oligorrhiza

Phosphorus deficiency (P deficiency) caused a 10-20�fold increase in phos-phatase activity of S. oligorrhiza homogenates. Specific staining showed that phosphatase in control plants was located primarily in and around the vascular strands, and in P�deficient plants it was located in the epidermis of the root and undersurface of the frond. Dissection experiments showed that roots of P�deficient plants contained a disproportionately high phosphatase activity. When plant and root homogenates were fractionated, phosphatase activity was recovered in the supernatant rather than in any cell particle fraction. However, intact plants released very little phosphatase to the external medium.

Phosphate Uptake by Spirodela and Lemna during Early Phosphorus Deficiency

1987 ◽  
Vol 14 (5) ◽  
pp. 561
Author(s):  
I.R McPharlin ◽  
R.L Bieleski
Keyword(s):  
Phosphorus Deficiency ◽  
Fold Increase ◽  
P Fractions ◽  
P Deficiency ◽  
First Order ◽  
Phosphate Ion ◽  
P Concentration ◽  
Uptake Rates ◽  
Spirodela Oligorrhiza

Growth, internal P concentration and Pi uptake was investigated in sterile cultures of Spirodela oligorrhiza (Kurz) Hegelm. and Lemna major L. plants during early P-deficiency. Within 12 h of transfer to a P-deficient medium, Pi uptake rates by P-deficient (- P) plants were enhanced 30-120% compared with P adequate (+ P) controls at 1-1000 �M external [Pi]. The enhancement in Pi uptake rates with P-deficiency normally preceded, and was more pronounced than, other effects of P-deficiency such as reduced growth, reduced internal [P] and appearance of visual symptoms. Enhanced Pi uptake rates in - P compared with +P plants resupplied with Pi was more closely correlated with a fall in the internal [Pi] (r = -0.93 to -0.98) than with a fall in the concentration of three other P fractions (i.e. ester P, lipid P, and residual P). The role of tissue [Pi] in Spirodela and Lemna plants as a possible determinant of Pi uptake rates is discussed. Kinetic analysis showed that enhanced Pi uptake in -P compared with + P plants resupplied with Pi was the result of a 2-4-fold increase in V*max of two first- order systems and not by an increased affinity (i.e. reduced K*m) of the carrier for the phosphate ion.

scholarly journals Roles of Phosphate Solubilizing Microorganisms from Managing Soil Phosphorus Deficiency to Mediating Biogeochemical P Cycle

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 158
Author(s):  
Jiang Tian ◽  
Fei Ge ◽  
Dayi Zhang ◽  
Songqiang Deng ◽  
Xingwang Liu
Keyword(s):  
Phosphorus Deficiency ◽  
Soil Phosphorus ◽  
Biological Molecules ◽  
P Deficiency ◽  
Soil P ◽  
Soil Systems ◽  
Intensively Managed ◽  
Phosphate Solubilizing ◽  
P Fertilizers ◽  
P Cycle

Phosphorus (P) is a vital element in biological molecules, and one of the main limiting elements for biomass production as plant-available P represents only a small fraction of total soil P. Increasing global food demand and modern agricultural consumption of P fertilizers could lead to excessive inputs of inorganic P in intensively managed croplands, consequently rising P losses and ongoing eutrophication of surface waters. Despite phosphate solubilizing microorganisms (PSMs) are widely accepted as eco-friendly P fertilizers for increasing agricultural productivity, a comprehensive and deeper understanding of the role of PSMs in P geochemical processes for managing P deficiency has received inadequate attention. In this review, we summarize the basic P forms and their geochemical and biological cycles in soil systems, how PSMs mediate soil P biogeochemical cycles, and the metabolic and enzymatic mechanisms behind these processes. We also highlight the important roles of PSMs in the biogeochemical P cycle and provide perspectives on several environmental issues to prioritize in future PSM applications.

scholarly journals THE UNLABELED ANTIBODY ENZYME METHOD OF IMMUNOCYTOCHEMISTRY QUANTITATIVE COMPARISON OF SENSITIVITIES WITH AND WITHOUT PEROXIDASE-ANTIPEROXIDASE COMPLEX

1974 ◽  
Vol 22 (8) ◽  
pp. 782-801 ◽  
Author(s):  
JOHN P. PETRALI ◽  
DENNIS M. HINTON ◽  
GWEN C. MORIARTY ◽  
LUDWIG A. STERNBERGER
Keyword(s):  
Secretory Granules ◽  
Enzyme Reaction ◽  
Fold Increase ◽  
Immunocytochemical Staining ◽  
Intermediate Lobe ◽  
Reaction Products ◽  
Electron Microscopic ◽  
Specific Staining ◽  
Enzyme Method ◽  
Unlabeled Antibody

Araldite sections of rat pituitary intermediate lobe were used with anti-17-39 adrenocorticotropin in the unlabeled antibody enzyme method to compare electron microscopic immunocytochemical staining by peroxidase-antiperoxidase complex (PAP) with antiserum or purified antibody to peroxidase followed by peroxidase (PO). Quantitation of normalized optical densities of secretory granules offered high significance comparison (P < 0.0001) of experimental with control values and of experimental values with each other. Use of purified antibody (prepared by a new density gradient method) yielded four times higher sensitivity than antiserum to PO, while a 6.5-fold increase would have been expected from the degree of contamination of anti-PO in the serum by nonanti-PO immunoglobulin. Use of PAP was four to five times more sensitive than purified anti-PO and 20 times more sensitive than antiserum to PO. The increased sensitivity of PAP is explained by the high over-all binding affinity of PO for anti-PO in the cyclic PAP molecule, thus preventing the losses of PO that occur during washing when anti-PO and PO have been applied in sequence. Identification of the characteristic, cyclic PAP molecules affords confirmation of specific staining at high resolution. In the sequential application of anti-PO and PO, no PAP molecules are formed, thus making distinction of specific from nonspecific deposition of enzyme reaction products ambiguous. With the use of anti-17-39 ACTH and the intermediate lobe, the unlabeled antibody enzyme method was 16,000-100,000 times more sensitive than radioimmunoassay.

Modelling nutrient uptake: a possible indicator of phosphorus deficiency

Soil Research ◽  
1997 ◽  
Vol 35 (2) ◽  
pp. 313 ◽  
Author(s):  
D. S. Mendham ◽  
P. J. Smethurst ◽  
P. W. Moody ◽  
R. L. Aitken
Keyword(s):  
Nutrient Uptake ◽  
Phosphorus Deficiency ◽  
Soil Phosphorus ◽  
Soil Nutrient ◽  
Growth Period ◽  
Dry Weight ◽  
Root Surface ◽  
P Uptake ◽  
P Deficiency ◽  
Highly Correlated

An understanding of the processes controlling soil nutrient supply and plant uptake has led to process-based models that can predict nutrient uptake and the concentration gradient that develops at the root surface. By using this information, it may be possible to develop an indicator of soil phosphorus status based on the predicted uptake and/or concentration of phosphorus (P) at the root surface. To identify the potential for such a test, the relationships between model output and observed plant growth were examined using data from a published experiment. The experiment was initially designed to investigate the relationship between common indices of soil-available P and the growth of maize (Zea mays) in 26 surface soils from Queensland. There was a high correlation between observed and predicted P uptake, and between relative dry matter yield and predicted P uptake. The predicted concentration of P at the root surface was also highly correlated with P uptake and dry weight increase. It is hypothesised that the short growth period (25 days) was responsible for the high correlation between P uptake and measured soil solution P. The hypothesis that a predicted concentration of P at the root surface or predicted P uptake may be valuable indicators of P deficiency in the longer term still remains to be tested.

Responses to low phosphorus in high and low foliar anthocyanin coleus (Solenostemon scutellarioides) and maize (Zea mays)

2012 ◽  
Vol 39 (3) ◽  
pp. 255 ◽  
Author(s):  
Amelia Henry ◽  
Surinder Chopra ◽  
David G. Clark ◽  
Jonathan P. Lynch
Keyword(s):  
Chlorophyll A ◽  
Anthocyanin Biosynthesis ◽  
Phosphorus Deficiency ◽  
Growth Conditions ◽  
P Deficiency ◽  
Light Harvesting Complex ◽  
Stress Effects ◽  
Low Phosphorus ◽  
Constitutive Production ◽  
Anthocyanin Production

Foliar anthocyanin production is frequently induced by phosphorus deficiency, but the adaptive significance of increased anthocyanin production under P stress, if any, remains unknown. In this study we hypothesised that if anthocyanin expression is an adaptive response to mitigate the stress effects of P deficiency, genotypes with constitutive anthocyanin expression would have greater tolerance to P stress than low anthocyanin-producing genotypes. Four studies were conducted in greenhouse, outdoor chamber and field conditions to compare genetically similar maize and coleus plants with contrasting anthocyanin accumulation (i.e. ‘red-leafed’ vs ‘green-leafed’). In low-P treatments, anthocyanin production did not consistently result in greater photosynthesis or biomass. In coleus, red-leafed phenotypes showed lower chlorophyll a/b ratios suggesting photoprotection by anthocyanins against degradation of light harvesting complex proteins. However, the opposite trend was observed in maize, where red-leafed phenotypes showed greater chlorophyll a/b ratios and lower qP (oxidation state of PSII). Based on results from the various treatments and growth conditions of this study, it could not be concluded that high foliar anthocyanin production confers a general functional advantage under low-P stress. More research comparing inducible vs constitutive production may help elucidate the role of anthocyanin biosynthesis in P deficiency responses.

scholarly journals Effects of P deficiency on assimilation and transport of nitrate and phosphate in intact plants of castor bean (Ricinus communisL.)

1997 ◽  
Vol 48 (1) ◽  
pp. 75-91 ◽  
Author(s):  
W. Dieter Jeschke ◽  
Ernest A. Kirkby ◽  
Andreas D. Peuke ◽  
John S. Pate ◽  
Wolfram Hartung
Keyword(s):  
Castor Bean ◽  
P Deficiency ◽  
Intact Plants

Acid phosphatase activity of intact roots and phosphorus nutrition in plants. 1. Assay conditions and phosphatase activity

1980 ◽  
Vol 31 (3) ◽  
pp. 429 ◽  
Author(s):  
KD McLachlan
Keyword(s):  
Reaction Time ◽  
Phosphatase Activity ◽  
Microbial Contamination ◽  
Plant Root ◽  
Phosphorus Deficiency ◽  
Reaction Times ◽  
Subterranean Clover ◽  
Phosphorus Nutrition ◽  
Nitrophenyl Phosphate ◽  
Low Phosphorus

This veries sets out to investigate the possibility of developing root phosphatase activity as an indicator of plant efficiency in obtaining phosphorus from low phosphorus situations. This paper examines the effect of substrate pH, temperature, reaction time, microbial contamination and phosphorus nutrition on the expression of phosphatase activity of plant roots. Rye, wheat, buckwheat and subterranean clover plants have been used. Phosphatase (E.C. 3.1.3.4.1) activity measured by p-nitrophenyl phosphate (PNPP) assay was essentially the activity of the plant root. Increased acidity in the substrate, on its own, did not hydrolyse PNPP nor did microbial contamination significantly affect the plant value. Temperature and reaction time were positively related to the assay value, least variation in assay values occurring with substrate temperatures of 20�C and reaction times of 60-120 min. Optimum pH for phosphatase activity lay in the range pH 5-6. Deficient plants had greater activities than sufficient ones. There was no evidence of alkaline phosphatase activity with phosphorus deficiency. In wheat, the phosphatase activity increased within the first 4 days of plants being deprived of phosphorus and reached its peak in 8 days. Some of the phosphatase was soluble, but most was associated with the root itself. There was evidence that it could be strongly adsorbed on cellulose nitrate filters.

Effect of Phosphorus Deficiency on Phosphatase Activity of Cell Walls from Roots of Subterranean Clover

1984 ◽  
Vol 35 (4) ◽  
pp. 466-480 ◽  
Author(s):  
M. N. H. DRACUP ◽  
E. G. BARRETT-LENNARD ◽  
H. GREENWAY ◽  
A. D. ROBSON
Keyword(s):  
Phosphatase Activity ◽  
Cell Walls ◽  
Phosphorus Deficiency ◽  
Subterranean Clover
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