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.

To the item of biochemical processes at reservation and storage of milk

2018 ◽  
pp. 22-25
Author(s):  
A.D. Koval’ ◽  
◽  
A.V. Mironova ◽  
V.A. Pushkarev ◽  
K.E. Shevchenko ◽  
...  
Keyword(s):  
Biochemical Processes ◽  
And Storage

scholarly journals Potential for Mycorrhizae-Assisted Phytoremediation of Phosphorus for Improved Water Quality

2020 ◽  
Vol 18 (1) ◽  
pp. 7
Author(s):  
Jessica A. Rubin ◽  
Josef H. Görres
Keyword(s):  
Water Quality ◽  
Animal Health ◽  
Phosphorus Uptake ◽  
Agricultural Practices ◽  
Fold Increase ◽  
Landscape Patterns ◽  
Cyanobacterial Blooms ◽  
Terrestrial Plants ◽  
Source Reduction ◽  
Water Ecosystems

During this 6th Great Extinction, freshwater quality is imperiled by upland terrestrial practices. Phosphorus, a macronutrient critical for life, can be a concerning contaminant when excessively present in waterways due to its stimulation of algal and cyanobacterial blooms, with consequences for ecosystem functioning, water use, and human and animal health. Landscape patterns from residential, industrial and agricultural practices release phosphorus at alarming rates and concentrations threaten watershed communities. In an effort to reconcile the anthropogenic effects of phosphorus pollution, several strategies are available to land managers. These include source reduction, contamination event prevention and interception. A total of 80% of terrestrial plants host mycorrhizae which facilitate increased phosphorus uptake and thus removal from soil and water. This symbiotic relationship between fungi and plants facilitates a several-fold increase in phosphorus uptake. It is surprising how little this relationship has been encouraged to mitigate phosphorus for water quality improvement. This paper explores how facilitating this symbiosis in different landscape and land-use contexts can help reduce the application of fertility amendments, prevent non-point source leaching and erosion, and intercept remineralized phosphorus before it enters surface water ecosystems. This literature survey offers promising insights into how mycorrhizae can aid ecological restoration to reconcile humans’ damage to Earth’s freshwater. We also identify areas where research is needed.

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 Management of Postharvest Diseases of Vegetables in a Tropical and Sub-tropical Environment of the Kingdom of Eswatini

2020 ◽  
pp. 1-13
Author(s):  
Diana M. Earnshaw ◽  
Michael T. Masarirambi ◽  
Bonginkhosi E. Dlamini ◽  
Kwanele A. Nxumalo
Keyword(s):  
Management Strategies ◽  
Pathogenic Fungi ◽  
Essential Amino Acids ◽  
Point Of View ◽  
Postharvest Diseases ◽  
Household Level ◽  
Post Harvest ◽  
Side Dish ◽  
Opportunistic Pathogenic ◽  
And Storage

Vegetables are important in human diets as a side dish eaten either cooked or raw as in salads. They are important for their nutritional contribution as major sources of minerals, vitamins, nine essential amino acids, beneficial phytochemicals, fibre and interesting colour from an aesthetic point of view. Despite the immerse health benefits offered by vegetables there are challenges encountered in their post-harvest handling and storage up to consumption. Challenges include post-harvest losses due to diseases. Some losses occur even at household level when vegetables are not stored appropriately when stored under the sink where humidity can be high leading to an environment which promotes diseases. Diseases in the post-harvest chain are caused by bacteria and opportunistic pathogenic fungi. Post-harvest losses of vegetables are not only a threat to nutritional security but a threat to food security as well. The aim of this research study was to document major post-harvest diseases of vegetables found in the Kingdom of Eswatini and to suggest appropriate management strategies or ways of alleviating them.

scholarly journals Seasonal Variations and Thinning Effects on Soil Phosphorus Fractions in Larix principis-rupprechtii Mayr. Plantations

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Huixia Tian ◽  
Xiaoqin Cheng ◽  
Hairong Han ◽  
Hongyuan Jing ◽  
Xujun Liu ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Management Practice ◽  
Management Strategies ◽  
Chemical Properties ◽  
P Availability ◽  
P Fractions ◽  
Soil P ◽  
Thinning Intensity ◽  
Soil P Fractions ◽  
P Bioavailability

Thinning is a common management practice in forest ecosystems. However, understanding whether thinning treatment will change the availability of phosphorus (P) in soils, and the effect of thinning on the seasonal dynamics of soil P fractions, are still limited. The objective of the present study was to assess seasonal variations in soil P fractions under different forest thinning management strategies in a Larch (Larix spp.) plantation in northern China. To accomplish this, we examined soil P fractions, soil physical–chemical properties, and litter biomass under control (CK), light (LT), moderate (MT) and high thinning (HT) treatments. Data were collected during the growing season of 2017. We found that most P fractions varied seasonally at different soil depths, with the highest values occurring in the summer and autumn. When compared to CK, MT enhanced the inorganic P (Pi) concentration extracted by resin strip (R-Pi). Labile organic P (Labile Po), moderately labile P and total P (TP) also increased in both MT and HT treatments irrespective of season. In contrast, less-labile Pi and Po fractions were lower in LT than in CK, especially when examining deeper soil layers. Our results suggest that LT leads to a strong ability to utilize Po and less-labile Pi. Moreover, the effect of thinning did not tend to increase with thinning intensity, P availability was maximized at the MT. Ultimately, we show that MT can improve soil P bioavailability and is recommended in Larix principis-rupprechtii Mayr. plantations of North China. Our results emphasize that the effect of thinning management on soil microenvironment is an important basis for evaluating soil nutrients such as soil P bioavailability.

scholarly journals Imprint of Climate Change on Pan-Arctic Marine Vegetation

2020 ◽  
Vol 7 ◽  
Author(s):  
Dorte Krause-Jensen ◽  
Philippe Archambault ◽  
Jorge Assis ◽  
Inka Bartsch ◽  
Kai Bischof ◽  
...  
Keyword(s):  
Time Series ◽  
Management Strategies ◽  
Open Water ◽  
The Arctic ◽  
Distribution Area ◽  
Arctic Ecosystems ◽  
Migration Rates ◽  
Lack Of Information ◽  
Distribution Limits ◽  
And Storage

The Arctic climate is changing rapidly. The warming and resultant longer open water periods suggest a potential for expansion of marine vegetation along the vast Arctic coastline. We compiled and reviewed the scattered time series on Arctic marine vegetation and explored trends for macroalgae and eelgrass (Zostera marina). We identified a total of 38 sites, distributed between Arctic coastal regions in Alaska, Canada, Greenland, Iceland, Norway/Svalbard, and Russia, having time series extending into the 21st Century. The majority of these exhibited increase in abundance, productivity or species richness, and/or expansion of geographical distribution limits, several time series showed no significant trend. Only four time series displayed a negative trend, largely due to urchin grazing or increased turbidity. Overall, the observations support with medium confidence (i.e., 5–8 in 10 chance of being correct, adopting the IPCC confidence scale) the prediction that macrophytes are expanding in the Arctic. Species distribution modeling was challenged by limited observations and lack of information on substrate, but suggested a current (2000–2017) potential pan-Arctic macroalgal distribution area of 820.000 km2 (145.000 km2 intertidal, 675.000 km2 subtidal), representing an increase of about 30% for subtidal- and 6% for intertidal macroalgae since 1940–1950, and associated polar migration rates averaging 18–23 km decade–1. Adjusting the potential macroalgal distribution area by the fraction of shores represented by cliffs halves the estimate (412,634 km2). Warming and reduced sea ice cover along the Arctic coastlines are expected to stimulate further expansion of marine vegetation from boreal latitudes. The changes likely affect the functioning of coastal Arctic ecosystems because of the vegetation’s roles as habitat, and for carbon and nutrient cycling and storage. We encourage a pan-Arctic science- and management agenda to incorporate marine vegetation into a coherent understanding of Arctic changes by quantifying distribution and status beyond the scattered studies now available to develop sustainable management strategies for these important ecosystems.

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.

Carbon metabolism in developing spears of two asparagus (Asparagus officinalis) cultivars with contrasting yield

2001 ◽  
Vol 28 (10) ◽  
pp. 1013 ◽  
Author(s):  
Jianmin Guo ◽  
William A. Jermyn ◽  
Matthew H. Turnbull
Keyword(s):  
Enzyme Activities ◽  
Elongation Rate ◽  
Carbon Accumulation ◽  
Asparagus Officinalis ◽  
Elongation Zone ◽  
Carbohydrate Accumulation ◽  
Biochemical Processes ◽  
Neutral Invertase ◽  
The Difference ◽  
And Storage

To assess the relative importance of sucrose-cleaving enzymes in the regulation of carbon accumulation in developing asparagus spears (growing shoots), we investigated spear elongation, carbohydrate accumulation and enzyme activities of acid invertase (AI), neutral invertase (NI) and sucrose synthase (SS) in two asparagus (Asparagus officinalis L.) cultivars with contrasting yield. The greater elongation rate measured in the high-yielding cultivar ASP-69 was associated with a significantly higher hexose accumulation (P < 0.05) in spear tissue in comparison with the low-yielding cultivar ASP-03. However, sucrose content was similar in the two cultivars, suggesting a more efficient machinery for transport and catalysis of carbohydrate in spears of ASP-69. Biochemical evidence indicated that the greater elongation rate in ASP-69 was associated with a significantly higher AI activity (P < 0.05) in the elongation zone, whereas SS activity was not significantly different between the two cultivars. There was little NI activity detected in either cultivar. These results strongly suggest that it is AI, and not SS or NI, that is an important determinant of the difference in sucrose metabolism between the two asparagus cultivars in metabolising imported sucrose in the elongation region, which in turn plays a part in regulating the import of sucrose into spear tissue. The profile of sucrose-cleaving enzyme activities along spear sections indicated that SS was the dominant enzyme in both the tip and base of spears, whereas AI was the dominant enzyme in the elongation zone. Apart from sucrose-cleaving enzymes, the associated biochemical processes for structure and component synthesis in spear tissues also contributed to the regulation of carbohydrate accumulation. It is most likely that carbohydrate metabolism in the developing spears is a whole spear property influenced by sucrose degradation (AI and SS activity) and its utilisation in building spear structure and storage materials. The overall data substantiate the conclusion that changes in the activity of sucrose-cleaving enzymes are correlated with sink functions in developing spears.

NITROGEN ENHANCEMENT OF SURFACE APPLIED FERTILIZER PHOSPHORUS UPTAKE BY FORAGE SPECIES

1974 ◽  
Vol 54 (1) ◽  
pp. 89-104 ◽  
Author(s):  
R. W. SHEARD
Keyword(s):  
Phosphorus Uptake ◽  
Phleum Pratense ◽  
Grass Species ◽  
Similar Data ◽  
Forage Grasses ◽  
Efficient Utilization ◽  
N Application ◽  
P Utilization ◽  
Medicago Sativa L ◽  
Phleum Pratense L

Nitrogen, supplied as NH4NO3 to timothy (Phleum pratense L.) and bromegrass (Bromus inermis L.) or as N derived from alfalfa (Medicago sativa L.) growing in association with timothy, enhanced the utilization of surface applications of pelleted, 32P-labelled calcium phosphate. The proportion of the P in timothy derived from a single application of 60 kg P/ha increased from a range of 16% to 21% without N to a range of 38% to 43% with an application of 60 kg N/ha before spring growth and repeated after the first and second harvests. At the first two harvests, growing timothy in association with alfalfa further increased the proportion. The increase was greater at the second harvest and at the lower rates of N, amounting to an increase of one-third at applications of 15 and 30 kg N/ha. The proportion of P in the first harvest of bromegrass which was derived from a surface application was increased 17% to 26% as the rate of P was increased from 40 to 120 kg P/ha; however, N fertilizer as NH4NO3 increased fertilizer P utilization from 17% to 32% as the rate of N was increased from zero to 120 kg N/ha at the 40 kg P/ha rate, and from 26% to 57% with increasing N at the 120 kg P/ha rate. Similar data were obtained when the rates of N application were repeated for the second and third harvests. A relationship, developed between the N concentration in the grass species and the percent utilization of fertilizer P, would suggest that enhancement in utilization of P was, in part, the result of an increase in the assimilated N in the plant. The experiments illustrate that it is imperative to provide adequate N for efficient utilization of surface-applied P by perennial forage grasses.

Sign in / Sign up

Export Citation Format

Share Document