Modelling phosphorus uptake in microalgae

2018 ◽  
Vol 46 (2) ◽  
pp. 483-490 ◽  
Author(s):  
Dipali Singh ◽  
Ladislav Nedbal ◽  
Oliver Ebenhöh
Keyword(s):  
Circular Economy ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Phosphate Uptake ◽  
Phosphorus Uptake ◽  
Agricultural Runoff ◽  
P Uptake ◽  
Modern Agriculture ◽  
P Recovery ◽  
And Storage

Phosphorus (P) is an essential non-renewable nutrient that frequently limits plant growth. It is the foundation of modern agriculture and, to a large extent, demand for P is met from phosphate rock deposits which are limited and becoming increasingly scarce. Adding an extra stroke to this already desolate picture is the fact that a high percentage of P, through agricultural runoff and waste, makes its way into rivers and oceans leading to eutrophication and collapse of ecosystems. Therefore, there is a critical need to practise P recovery from waste and establish a circular economy applicable to P resources. The potential of microalgae to uptake large quantities of P and use of this P enriched algal biomass as biofertiliser has been regarded as a promising way to redirect P from wastewater to the field. This also makes the study of molecular mechanisms underlying P uptake and storage in microalgae of great interest. In the present paper, we review phosphate models, which express the growth rate as a function of intra- and extracellular phosphorus content for better understanding of phosphate uptake and dynamics of phosphate pools.

Transcription factor/DNA interactions visualized by electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 450-451
Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown
Keyword(s):  
Transcription Factor ◽  
Dna Sequences ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Dna Backbone ◽  
Two Parameters ◽  
High Level

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.

Periphytic microbial response to environmental phosphate bioavailability – relevance to P management in paddy fields

2021 ◽  
Author(s):  
Jianchao Zhang ◽  
Jing Su ◽  
Chao Ma ◽  
Xiangyu Hu ◽  
Henry H Teng
Keyword(s):  
Management Strategies ◽  
Phosphorus Uptake ◽  
Paddy Fields ◽  
P Availability ◽  
Biochemical Processes ◽  
Extracellular Metabolite ◽  
Microbial Response ◽  
P Utilization ◽  
Water Ecosystems ◽  
And Storage

Periphyton occurs widely in shallow-water ecosystems such as paddy fields and plays critical parts in regulating local phosphorus cycling. As such, understanding the mechanisms of the biofilm’s response to environmental P variability may lead to better perceptions of P utilization and retention in rice farms. Present study aims at exploring the biological and biochemical processes underlying periphyton’s P buffering capability through examining changes in community structure, phosphorus uptake and storage, and molecular makeup of exometabolome at different levels of P availability. Under stressed (both excessive and scarce) phosphorus conditions, we found increased populations of the bacterial genus capable of transforming orthophosphate to polyphosphate, as well as mixotrophic algae who can survive through phagotrophy. These results were corroborated by observed polyphosphate buildup under low and high P treatment. Exometabolomic analyses further revealed that periphytic organisms may substitute S-containing lipids for phospholipids, use siderophores to dissolve iron (hydr)oxides to scavenge adsorbed P, and synthesize auxins to resist phosphorus starvation. These findings not only shed light on the mechanistic insights responsible for driving the periphytic P buffer but attest to the ecological roles of periphyton in aiding plants such as rice to overcome P limitations in natural environment. Importance The ability of periphyton to buffer environmental P in shallow aquatic ecosystems may be a natural lesson on P utilization and retention in paddy fields. This work revealed the routes and tools through which periphytic organisms adapt to and regulate ambient P fluctuation. The mechanistic understanding further implicates that the biofilm may serve rice plants to alleviate P stress. Additional results from extracellular metabolite analyses suggest the dissolved periphytic exometabolome can be a valuable nutrient source for soil microbes and plants to reduce biosynthetic costs. These discoveries have the potential to improve our understanding of biogeochemical cycling of phosphorus in general and to refine P management strategies for rice farm in particular.

The impact of biomass harvesting on phosphorus uptake by wetland plants

2001 ◽  
Vol 44 (11-12) ◽  
pp. 61-67 ◽  
Author(s):  
S-Y. Kim ◽  
P.M. Geary
Keyword(s):  
Plant Biomass ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Plant Parts ◽  
Biomass Harvesting ◽  
Below Ground ◽  
The Impact ◽  
Total P ◽  
Better Than ◽  
P Removal

Two species of macrophytes, Baumea articulata and Schoenoplectus mucronatus, were examined for their capacity to remove phosphorus under nutrient-rich conditions. Forty large bucket systems with the two different species growing in two types of substrate received artificial wastewaters for nine months, simulating a constructed wetland (CW) under high loading conditions. Half of the plants growing in the topsoil and gravel substrates were periodically harvested whereas the other half remained intact. Plant tissue and substrate samples were regularly analysed to determine their phosphorus concentrations. With respect to phosphorus uptake and removal, the Schoenoplectus in the topsoil medium performed better than the Baumea. Biomass harvesting enhanced P uptake in the Schoenoplectus, however the effect was not significant enough to make an improvement on the overall P removal, due to the slow recovery of plants and regrowth of biomass after harvesting. From P partitioning, it was found that the topsoil medium was the major P pool, storing most of total P present in the system. Plant parts contributed only minor storage with approximately half of that P stored below ground in the plant roots. The overall net effect of harvesting plant biomass was to only remove less than 5% of total phosphorus present in the system.

scholarly journals Effect of Intercropping and Fertility Levels on the Nitrogen, Phosphorus and Potash Content and Uptake by Summer Pearlmillet (Pennisetum glaucum L.) under South Gujarat Condition

2021 ◽  
Vol 9 (3) ◽  
pp. 174-179
Author(s):  
K. R. Patel ◽  
Keyword(s):  
Pearl Millet ◽  
Phosphorus Content ◽  
Pennisetum Glaucum ◽  
P Uptake ◽  
Green Gram ◽  
Treatment Combination ◽  
K Uptake ◽  
Nitrogen And Phosphorus ◽  
College Of Agriculture ◽  
Nitrogen Phosphorus

A field experiment was conducted at College Agronomy Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari during summer, 2019 and 2020 comprising four intercropping treatments i.e. pearlmillet sole, pearlmillet+greengram, pearlmillet+cowpea, pearlmillet+clusterbean and three fertility levels viz., 75 % RDF, 100 % RDF and 125 % RDF. Among the different intercropping system examined, sole pearl millet (I1) accumulated significantly less content of N and P in pearl millet grain and straw as compared to intercropping with pulses treatments. Pearl millet + green gram (I2) recorded significantly higher N and P uptake by pearl millet straw than other intercropping systems. The sole pearl millet (I1) was at par with pearl millet intercropped with green gram (I2) had significantly higher K content and uptake in pearl millet grain and straw. In case of fertility levels, nitrogen and phosphorus content and uptake in pearl millet grain and straw were recorded significantly higher by application of 100 % RDF. Significantly higher N, P and K uptake by pearl millet grain and straw in pooled results were produced by treatment combination of pearl millet + green gram (I2) intercropping along with 75 % RDF (F1).

scholarly journals Water and phosphorus uptake by upland rice root systems unraveled under multiple scenarios: linking a 3D soil-root model and data

2020 ◽  
Author(s):  
Trung Hieu Mai ◽  
Pieterjan De Bauw ◽  
Andrea Schnepf ◽  
Roel Merckx ◽  
Erik Smolders ◽  
...  
Keyword(s):  
Upland Rice ◽  
Phosphorus Uptake ◽  
Root Systems ◽  
Multiscale Model ◽  
P Uptake ◽  
Water Dynamics ◽  
Small Scale ◽  
P Availability ◽  
P Deficiency ◽  
Plant P Uptake

AbstractBackground and aimsUpland rice is often grown where water and phosphorus (P) are limited and these two factors interact on P bioavailability. To better understand this interaction, mechanistic models representing small-scale nutrient gradients and water dynamics in the rhizosphere of full-grown root systems are needed.MethodsRice was grown in large columns using a P-deficient soil at three different P supplies in the topsoil (deficient, suboptimal, non-limiting) in combination with two water regimes (field capacity versus drying periods). Root architectural parameters and P uptake were determined. Using a multiscale model of water and nutrient uptake, in-silico experiments were conducted by mimicking similar P and water treatments. First, 3D root systems were reconstructed by calibrating an architecure model with observed phenological root data, such as nodal root number, lateral types, interbranch distance, root diameters, and root biomass allocation along depth. Secondly, the multiscale model was informed with these 3D root architectures and the actual transpiration rates. Finally, water and P uptake were simulated.Key resultsThe plant P uptake increased over threefold by increasing P and water supply, and drying periods reduced P uptake at high but not at low P supply. Root architecture was significantly affected by the treatments. Without calibration, simulation results adequately predicted P uptake, including the different effects of drying periods on P uptake at different P levels. However, P uptake was underestimated under P deficiency, a process likely related to an underestimated affinity of P uptake transporters in the roots. Both types of laterals (i.e. S- and L-type) are shown to be highly important for both water and P uptake, and the relative contribution of each type depend on both soil P availability and water dynamics. Key drivers in P uptake are growing root tips and the distribution of laterals.ConclusionsThis model-data integration demonstrates how multiple co-occurring single root phene responses to environmental stressors contribute to the development of a more efficient root system. Further model improvements such as the use of Michaelis constants from buffered systems and the inclusion of mycorrhizal infections and exudates are proposed.

scholarly journals Simultaneous phosphorus uptake and denitrification by EBPR-r biofilm under aerobic conditions: effect of dissolved oxygen

2015 ◽  
Vol 72 (7) ◽  
pp. 1147-1154 ◽  
Author(s):  
Pan Yu Wong ◽  
Maneesha P. Ginige ◽  
Anna H. Kaksonen ◽  
Ralf Cord-Ruwisch ◽  
David C. Sutton ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Aerobic Denitrification ◽  
Biological Phosphorus Removal ◽  
Denitrification Activity ◽  
Biofilm Process ◽  
Oxygen Intrusion ◽  
Biofilm Structure ◽  
Biological Phosphorus

A biofilm process, termed enhanced biological phosphorus removal and recovery (EBPR-r), was recently developed as a post-denitrification approach to facilitate phosphorus (P) recovery from wastewater. Although simultaneous P uptake and denitrification was achieved despite substantial intrusion of dissolved oxygen (DO >6 mg/L), to what extent DO affects the process was unclear. Hence, in this study a series of batch experiments was conducted to assess the activity of the biofilm under various DO concentrations. The biofilm was first allowed to store acetate (as internal storage) under anaerobic conditions, and was then subjected to various conditions for P uptake (DO: 0–8 mg/L; nitrate: 10 mg-N/L; phosphate: 8 mg-P/L). The results suggest that even at a saturating DO concentration (8 mg/L), the biofilm could take up P and denitrify efficiently (0.70 mmol e−/g total solids*h). However, such aerobic denitrification activity was reduced when the biofilm structure was physically disturbed, suggesting that this phenomenon was a consequence of the presence of oxygen gradient across the biofilm. We conclude that when a biofilm system is used, EBPR-r can be effectively operated as a post-denitrification process, even when oxygen intrusion occurs.

THE INFLUENCE OF VARIETY, SOIL TEMPERATURE, AND PHOSPHORUS FERTILIZER ON YIELD AND PHOSPHORUS UPTAKE BY ALFALFA

1963 ◽  
Vol 43 (3) ◽  
pp. 355-360 ◽  
Author(s):  
M. Levesque ◽  
J. W. Ketcheson
Keyword(s):  
Soil Temperature ◽  
Dry Matter ◽  
Phosphorus Content ◽  
Soil Phosphorus ◽  
Phosphorus Uptake ◽  
Growth Period ◽  
Yield Potential ◽  
Phosphorus Fertilization ◽  
Maximum Value ◽  
Phosphorus Application

Du Puits and Ladak varieties of alfalfa were grown for 10 weeks in the greenhouse on soil-sand media controlled at temperatures of 10°, 18°, and 26 °C. P32-tagged superphosphate was applied at rates of 10 and 80 p.p.m. phosphorus, respectively. Dry matter yields and phosphorus content of the tissue was determined at the end of the growth period. Increasing soil temperature from 10° to 26 °C. caused corresponding increases in total phosphorus uptake as a result of an increase in dry matter yields as well as an increase in the percentage of phosphorus in the plant tissue. Ladak exhibited the higher yield potential although Du Puits was less affected by low soil temperature conditions and appeared capable of making better use of soil phosphorus. With the higher phosphorus application, the root-top ratio for Du Puits was greater than that for Ladak, and the maximum value for this ratio occurred at 18 °C. for each variety. P32 activity measured in the tissue indicated that soil temperature was critical in terms of phosphorus fertilization in the 4- and 6-week stages of growth.

PHOSPHORUS UPTAKE BY ALFALFA AS INFLUENCED BY PHOSPHATE SOURCE AND MOISTURE

1962 ◽  
Vol 42 (2) ◽  
pp. 254-265 ◽  
Author(s):  
J. D. Beaton ◽  
D. W. L. Read ◽  
W. C. Hinman
Keyword(s):  
Phosphorus Uptake ◽  
Significant Negative Correlation ◽  
P Uptake ◽  
Water Soluble ◽  
Ammonium Polyphosphate ◽  
Short Term ◽  
Treated Soil ◽  
Extractable P ◽  
Phosphate Source ◽  
Soil Fertilizer

The effect of phosphate source and soil moisture during the initial soil-fertilizer reaction period on subsequent phosphorus uptake by alfalfa was investigated in a growth chamber. Phosphate-treated soils with moisture adjusted to four different tensions were stored at approximately 18 °C. for 10 weeks. Following this storage interval phosphorus uptake by alfalfa was measured using a short-term technique.Phosphorus content and phosphorus uptake by both tops and roots increased significantly when water-soluble materials such as ammonium polyphosphate, monoammonium and monocalcium phosphate were applied. Less soluble sources, i.e., hydroxyapatite and anhydrous dicalcium phosphate, were much less effective. Calcium metaphosphate produced intermediate results.Moisture content of the soil during the reaction period did not greatly alter subsequent P uptake. The water-soluble sources of phosphorus were affected to the greatest degree.Uptake of P was significantly correlated with the amount of P extracted by NaHCO3 from the treated soils. The highest degree of correlation occurred with ammonium polyphosphate treated soil. A significant negative correlation occurred with calcium metaphosphate. With the exception of the 0.8 bar treatment, moisture tension had little influence on the correlation of P uptake with NaHCO3 extractable-P.

Phosphorus Uptake by Klebsiella Pneumoniae and Acinetobacter Calcoaceticus

1985 ◽  
Vol 17 (11-12) ◽  
pp. 113-118 ◽  
Author(s):  
R. M. Gersberg ◽  
D. W. Allen
Keyword(s):  
Klebsiella Pneumoniae ◽  
Municipal Wastewater ◽  
Phosphorus Uptake ◽  
High Capacity ◽  
Acinetobacter Calcoaceticus ◽  
P Uptake ◽  
Cell System ◽  
Biological Phosphorus Removal ◽  
Immobilized Cell ◽  
Suspended Growth

The objective of our study was to show that pure cultures of Klebsiella pneumoniae and Acinetobacter calcoaceticus could be Induced to accumulate large amounts of phosphorus (P), when P-starved cultures were enriched with phosphorus either in suspended growth or immobilized cell reactors. Suspended growth cultures of K. pneumoniae were more efficient than those of A. calcoaceticus, with specific uptake rates of 14.1 - 17.1 mg P1−1 hr−1 per O.D. unit, and 5.4 - 10.0 mg P1−1 hr −1 per O.D. unit, respectively. The absolute rate of P accumulation of 24.6 mg P1−1 hr−1 measured for a K. pneumoniae culture was among the highest ever reported in the literature. In an immobilized cell system, which facilitates the separation of the cells (for recycling) from the liquid phase, K. pneumoniae cells entrapped in agar gel beads, remained viable and showed rates of P uptake of 6.1 and 7.9 mg P1−1 hr−1. K. pneumoniae cultures also showed a high capacity for removing dissolved phosphate from municipal wastewater, with greater than 95% P removal in two hours. These studies suggest the important role such high-phosphate accumulating bacteria may play in wastewater treatment systems designed for enhanced biological phosphorus removal.

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