Phosphorus Deficiency of Lake Ontario Plankton

1987 ◽  
Vol 44 (12) ◽  
pp. 2069-2076 ◽  
Author(s):  
D. R. S. Lean ◽  
A. A. Abbott ◽  
F. R. Pick
Keyword(s):  
Heterotrophic Bacteria ◽  
Phosphorus Deficiency ◽  
Sufficient Conditions ◽  
Carbon Assimilation ◽  
Lake Ontario ◽  
Turnover Time ◽  
Phosphate Deficiency ◽  
Large Lakes ◽  
P Deficiency ◽  
Biomass Turnover

The phosphate deficiency index (PDI), the ratio of photosynthetic carbon assimilation at optimal light to the maximum uptake velocity for phosphate, showed that P deficiency occurred in the near-shore plankton of Lake Ontario during spring thermal bar conditions and in the midlake plankton immediately after stratification. This condition persisted until October, when deep mixing of the water column occurred. Carbon and phosphate assimilation were by similar size classes, and as the ratio of two rate processes, PDI was independent of both temperature and biomass. Turnover time and alkaline phosphatase activity (APA) correlated with PDI. Short-term photosynthetic depression with phosphate enrichment occurred in only 7 of 23 experiments and may either reflect P-sufficient conditions or high protein to carbohydrate ratios due to physical events common to large lakes. PDI, protein to carbohydrate ratios, and photosynthetic depression respond principally to algal activity. Although turnover time and APA reflect the activity of smaller microorganisms, primarily heterotrophic bacteria, all indices were consistent.

scholarly journals Transcriptome and metabolome analysis provide insights into root and root released organic anion responses to phosphorus deficiency in oat

2018 ◽  
Author(s):  
Yanliang Wang ◽  
Erik Lysøe ◽  
Tegan Armarego-Marriott ◽  
Alexander Erban ◽  
Lisa Paruch ◽  
...  
Keyword(s):  
Inositol Phosphate ◽  
Phosphorus Deficiency ◽  
Organic Anion ◽  
Sufficient Conditions ◽  
Organic Anions ◽  
Soil Conditions ◽  
Metabolome Analysis ◽  
P Deficiency ◽  
Hydroponic Experiment ◽  
Nutritional Compounds

AbstractRoot and root-released organic anions play important roles in uptake of phosphorus (P), an essential macronutrient for food production. Oat, ranking sixth in the world’s cereal production, contains valuable nutritional compounds and can withstand poor soil conditions. The aim of this research was to investigate root transcriptional and metabolic responses of oat grown under P-deficient and P-sufficient conditions. We conducted a hydroponic experiment and measured root morphology, organic anions exudation, and analysed changes in the transcriptome and metabolome, to understand oat root adaptation to P deficiency. We found that oat roots showed enhanced citrate and malate exudation after four weeks of P-deficiency. After 10 days of P-deficiency, we identified 9371 differentially expressed transcripts with a two-fold or greater change (p < 0.05): forty-eight sequences predicted to be involved in organic anion biosynthesis and efflux were consistently up-regulated; twenty-four up-regulated transcripts in oat were also found up-regulated upon P starvation in rice and wheat under similar conditions. Phosphorylated metabolites (i.e. glucose-6-phosphate, myo-inositol-phosphate) reduced dramatically, while citrate and malate, some sugars and amino acids increased slightly in P-deficient oat roots. Our data provide new insights into the root responses to P deficiency and root-released organic anions in oat.HighlightWe found oat- a monocot food crop, showed high exudation rate of citrate under phosphorus deficiency; root transcriptome and metabolome were then investigated to understand oat adaptation to P deficiency.

Phosphorus Deficiency Diagnostics in the Eutrophic Rímov Reservoir

1993 ◽  
Vol 28 (6) ◽  
pp. 75-84 ◽  
Author(s):  
J. Nedoma ◽  
P. Porcalová ◽  
J. Komárková ◽  
V. Vyhnálek
Keyword(s):  
Primary Production ◽  
Phosphorus Deficiency ◽  
Soluble Reactive Phosphorus ◽  
Turnover Time ◽  
Clear Water ◽  
P Deficiency ◽  
Elemental Stoichiometry ◽  
Římov Reservoir ◽  
Reactive Phosphorus ◽  
Index Ratio

In order to assess the occurrence and the degree of phosphorus deficiency, the upper layer (0-2 m) of the eutrophic Římov Reservoir (Czechoslovakia) was sampled from March to October 1990 in one- to three-week intervals. Soluble reactive phosphorus and maximum possible orthophosphate (by Rigler's radiobioassay) concentrations, seston elemental stoichiometry (C/P; N/P), orthophosphate turnover time, and phosphorus deficiency index (= ratio of the primary production to the Vmax of the PO4 uptake) were estimated. Early in spring, during the spring clear-water period, and in the autumn, no indications of P-deficiency were found. Strong P-deficiency was detected in summer (June - September), moderate to strong deficiency also during the spring phytoplankton maximum. The concentration of SRP &lt; 5 µg.1−1 indicates phosphorus deficiency in the Říimov reservoir.

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 Overexpression of OsPIN2 Regulates Root Growth and Formation in Response to Phosphate Deficiency in Rice

2019 ◽  
Vol 20 (20) ◽  
pp. 5144
Author(s):  
Huwei Sun ◽  
Xiaoli Guo ◽  
Fugui Xu ◽  
Daxia Wu ◽  
Xuhong Zhang ◽  
...  
Keyword(s):  
Root Growth ◽  
Growth And Development ◽  
Plant Root ◽  
Lateral Roots ◽  
Root Hairs ◽  
Phosphate Deficiency ◽  
P Deficiency ◽  
Auxin Distribution ◽  
Seminal Roots ◽  
Underlying Mechanisms

The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.

Effects of Lake Size on Phytoplankton Nutrient Status

1994 ◽  
Vol 51 (12) ◽  
pp. 2769-2783 ◽  
Author(s):  
S. J. Guildford ◽  
L. L. Hendzel ◽  
H. J. Kling ◽  
E. J. Fee ◽  
G. G. C. Robinson ◽  
...  
Keyword(s):  
Nutrient Status ◽  
Canadian Shield ◽  
Small Lakes ◽  
Large Lakes ◽  
P Deficiency ◽  
Water Renewal ◽  
Mixed Layers ◽  
Shield Lakes ◽  
Lake Size ◽  
Total P

Phytoplankton nutrient status measurements (C/P, C/N, C/chlorophyll, N/P, alkaline phosphatase activity, and N debt) were measured for 6 yr in seven remote Canadian Shield lakes. Lakes Nipigon and Superior were also studied for 2 yr. These lakes varied in surface area from 29 to 8.223 × 10 ha, they all stratified fully during the summer and had water renewal times > 5 yr. All lakes were severely P deficient; however, the large lakes (> 2000 ha) were consistently less P deficient than small lakes. A growth-rate indicator (photosynthesis normalized to particulate C) agreed with nutrient status indicators, in that small lakes had lower rates than large lakes. Total P was a good predictor of chlorophyll, but factors related to lake size (temperature and mixed depth) were equally good or better predictors of nutrient status. Decreasing mean water column light intensity could not explain the lower P deficiency of large lakes. The deeper, more energetic mixed layers in large lakes apparently cause P to be recycled more efficiently. Extrapolation of observations or experimental results from small to large lakes requires recognition that phytoplankton in large lakes are less nutrient deficient and may have higher growth rates.

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.

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.

Controls on phytoplankton physiology in Lake Ontario during the late summer: evidence from new fluorescence methods

2007 ◽  
Vol 64 (1) ◽  
pp. 58-73 ◽  
Author(s):  
Katharine L Pemberton ◽  
Ralph EH Smith ◽  
Greg M Silsbe ◽  
Todd Howell ◽  
Susan B Watson
Keyword(s):  
Anthropogenic Disturbance ◽  
Late Summer ◽  
Lake Ontario ◽  
Lower Surface ◽  
Nutrient Ratios ◽  
Surface Mixed Layer ◽  
P Deficiency ◽  
Photosynthetic Physiology ◽  
Physiological Variations

Fast repetition rate fluorescence (FRRF) and spectral fluorescence, together with measures of nutrients and pigments, were used to characterize the composition and photosynthetic physiology of Lake Ontario phytoplankton in late summer and relate them to environmental conditions. Two stations demonstrated effects from relatively heavy anthropogenic disturbance and showed that the response of phytoplankton physiology to different impacts is highly variable. Other stations were more similar in phytoplankton composition, and in situ fluorescence yields ([Formula: see text]) in the lower surface mixed layer suggested good physiological condition (0.45–0.50). Nutrient ratios and mean irradiance indicated a general state of light saturation and slight phosphorus (P) deficiency, but physiological variations among stations were unrelated to measures of P deficiency. Fluorescence yields often decreased when surface layer samples were held in the dark, consistent with an induction of chlororespiration and prior exposure to supersaturating levels of irradiance. Comparative estimates of photosynthesis by FRRF and 14C revealed disparities suggestive of substantial differences between in situ and incubation methods, while spectral fluorescence appeared to underestimate cyanobacterial abundance. FRRF parameters, particularly [Formula: see text], were effective in identifying higher-impact stations and showed promise as an efficient means of characterizing variations in phytoplankton condition that may underlie phenomena such as taste and odour production.

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.

Rat intestinal and renal calcium-binding proteins

1977 ◽  
Vol 55 (3) ◽  
pp. 595-600 ◽  
Author(s):  
J. E. Harrison ◽  
A. J. W. Hitchman ◽  
G. B. Gordon ◽  
S. A. Hasany
Keyword(s):  
Vitamin D ◽  
Direct Effect ◽  
Calcium Binding ◽  
Active Metabolite ◽  
Binding Capacity ◽  
Binding Protein ◽  
Phosphate Deficiency ◽  
Deficient Diet ◽  
P Deficiency ◽  
Intestinal Protein

The effect of vitamin D activity on the major renal Ca-binding protein has been compared with that on the intestinal Ca-binding protein. Using a method based on Ca-binding capacity, these proteins were measured in vitamin D deficient rats after vitamin D treatment for varying periods up to 5 days. Since P deficiency has been shown to stimulate synthesis of the active metabolite 1,25-dihydroxycholecalciferol, a similar experiment was done on rats fed a P-deficient diet for periods up to 21 days. The renal Ca-binding protein was unchanged by vitamin D treatment to vitamin D deficient rats and was only slightly increased (50%) by phosphate deficiency. By comparison, the intestinal protein was increased twofold by vitamin D treatment and fivefold by phosphate deficiency. Results indicate that vitamin D activity has no direct effect on the major renal Ca-binding protein.

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