Advances in understanding plant root uptake of phosphorus

2021 ◽  
pp. 321-372
Author(s):  
Jiayin Pang ◽  
◽  
Zhihui Wen ◽  
Daniel Kidd ◽  
Megan H. Ryan ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Management Practices ◽  
Plant Root ◽  
Large Area ◽  
P Deficiency ◽  
Soil P ◽  
P Acquisition ◽  
Trade Offs ◽  
The Face ◽  
Fertiliser Use

At a global scale, phosphorus (P) deficiency comprises a large area of cropland, while P has also been used in excess of crop requirements in many other regions. Improved crop P-acquisition efficiency would allow lower target critical soil P values and provide savings in P-fertiliser use. At the same time, it would reduce P lost through erosion, leaching and/or soil sorption. This chapter summarises the progress in research on root traits associated with P acquisition, including root morphology, architecture, biochemistry, colonisation by arbuscular mycorrhizal fungi, and fine root endophytes, and the trade-offs among all these traits. Farming-management practices to improve P acquisition under current intensive agricultural systems are also discussed. The chapter summarises breeding progress in improving P-acquisition efficiency. In the face of soil P deficiency or legacy P globally, the chapter suggests future directions to improve P acquisition in five key areas.

Plant mechanisms to optimise access to soil phosphorus

2009 ◽  
Vol 60 (2) ◽  
pp. 124 ◽  
Author(s):  
Alan E. Richardson ◽  
Peter J. Hocking ◽  
Richard J. Simpson ◽  
Timothy S. George
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Specific Root Length ◽  
Soluble Form ◽  
P Availability ◽  
Agricultural Systems ◽  
Root Characteristics ◽  
P Deficiency ◽  
Soil P ◽  
Total P

Phosphorus (P) is an important nutrient required for plant growth and its management in soil is critical to ensure sustainable and profitable agriculture that has minimal impact on the environment. Although soils may contain a large amount of total P, only a small proportion is immediately available to plants. Australian soils often have low availability of P for plant growth and P-based fertilisers are, therefore, commonly used to correct P deficiency and to maintain productivity. For many soils, the sustained use of P fertiliser has resulted in an accumulation of total P, a proportion of which is in forms that are poorly available to most plants. The efficiency with which different P fertilisers are used in agricultural systems depends on their capacity to supply P in a soluble form that is available for plant uptake (i.e. as orthophosphate anions). In addition to fertiliser source, the availability of P in soil is influenced to a large extent by physico-chemical and biological properties of the soil. Plant access to soil P is further affected by root characteristics (e.g. rate of growth, specific root length, and density and length of root hairs) and biochemical processes that occur at the soil–root interface. The ability of roots to effectively explore soil, the release of exudates (e.g. organic anions and phosphatases) from roots that influence soil P availability, and the association of roots with soil microorganisms such as mycorrhizal fungi are particularly important. These processes occur as a natural response of plants to P deficiency and, through better understanding, may provide opportunities for improving plant access to soil and fertiliser P in conventional and organic agricultural systems.

scholarly journals Trade-Offs in Phosphorus Acquisition Strategies of Five Common Tree Species in a Tropical Forest of Puerto Rico

2021 ◽  
Vol 4 ◽  
Author(s):  
Daniela Yaffar ◽  
Camille E. Defrenne ◽  
Kristine G. Cabugao ◽  
Stephanie N. Kivlin ◽  
Joanne Childs ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Tree Species ◽  
Fine Root ◽  
Root Traits ◽  
Root Trait ◽  
Soil P ◽  
P Acquisition ◽  
Trade Offs ◽  
Acquisition Strategies ◽  
Common Tree

Tree species that are successful in tropical lowlands have different acquisition strategies to overcome soil phosphorus (P) limitations. Some of these strategies belowground include adjustments in fine-root traits, such as morphology, architecture, association with arbuscular mycorrhizal fungi, and phosphatase activity. Trade-offs among P-acquisition strategies are expected because of their respective carbon cost. However, empirical evidence remains scarce which hinders our understanding of soil P-acquisition processes in tropical forests. Here, we measured seven fine-root functional traits related to P acquisition of five common tree species in three sites of the Luquillo Experimental Forest in Puerto Rico. We then described species-specific P-acquisition strategies and explored the changes in fine-root trait expression from 6 months before to 6 months after two consecutive hurricanes, Irma and María, passed over the island. We found that variations in root trait expression were driven mainly by the large interspecific differences across the three selected sites. In addition, we revealed a trade-off between highly colonized fine roots with high phosphatase activity and fine roots that have a high degree of branching. Furthermore, the former strategy was adopted by pioneer species (Spathodea campanulata and Cecropia schreberiana), whereas the latter was adopted by non-pioneer species (mostly Dacryodes excelsa and Prestoea montana). Additionally, we found that root trait expression did not change comparing 6 months before and after the hurricanes, with the exception of root phosphatase activity. Altogether, our results suggest a combination of structural and physiological root traits for soil P acquisition in P-poor tropical soils by common tropical tree species, and show stability on most of the root trait expression after hurricane disturbances.

scholarly journals The effects of soil phosphorus and zinc availability on plant responses to mycorrhizal fungi: a physiological and molecular assessment

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thi Diem Nguyen ◽  
Timothy R. Cavagnaro ◽  
Stephanie J. Watts-Williams
Keyword(s):  
Mycorrhizal Fungi ◽  
Plant Biomass ◽  
Zn Deficiency ◽  
P Availability ◽  
P Deficiency ◽  
Soil P ◽  
Positive Effects ◽  
Mycorrhizal Colonisation ◽  
Mycorrhizal Plants ◽  
Soil Zn

Abstract The positive effects of arbuscular mycorrhizal fungi (AMF) have been demonstrated for plant biomass, and zinc (Zn) and phosphorus (P) uptake, under soil nutrient deficiency. Additionally, a number of Zn and P transporter genes are affected by mycorrhizal colonisation or implicated in the mycorrhizal pathway of uptake. However, a comprehensive study of plant physiology and gene expression simultaneously, remains to be undertaken. Medicago truncatula was grown at different soil P and Zn availabilities, with or without inoculation of Rhizophagus irregularis. Measures of biomass, shoot elemental concentrations, mycorrhizal colonisation, and expression of Zn transporter (ZIP) and phosphate transporter (PT) genes in the roots, were taken. Mycorrhizal plants had a greater tolerance of both P and Zn soil deficiency; there was also evidence of AMF protecting plants against excessive Zn accumulation at high soil Zn. The expression of all PT genes was interactive with both P availability and mycorrhizal colonisation. MtZIP5 expression was induced both by AMF and soil Zn deficiency, while MtZIP2 was down-regulated in mycorrhizal plants, and up-regulated with increasing soil Zn concentration. These findings provide the first comprehensive physiological and molecular picture of plant-mycorrhizal fungal symbiosis with regard to soil P and Zn availability. Mycorrhizal fungi conferred tolerance to soil Zn and P deficiency and this could be linked to the induction of the ZIP transporter gene MtZIP5, and the PT gene MtPT4.

scholarly journals VA MYCORRHIZAL INFLUENCE ON GROWTH AND MINERAL UPTAKE OF POTATO

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1161e-1161
Author(s):  
D.A.J. McArthur ◽  
N.R. Knowles
Keyword(s):  
Mycorrhizal Fungi ◽  
Soil Phosphorus ◽  
Growth Period ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Morphological Development ◽  
Similar Response ◽  
Dry Matter Accumulation ◽  
P Deficiency ◽  
Soil P

The growth response of potato to infection by vesicular-arbuscular mycorrhizal fungi (VAM) (Glomus dimorphicum, G. intraradices, and G. mosseae), at increasing levels of soil phosphorus (P), was related to VAM-altered mineral status of the plant. In addition, the morphological development of the VAM was characterized using light and scanning electron microscopy.Four weeks after inoculation, arbuscules and coiled hyphae were the predominate fungal structures within the roots, however, vesicle development increased steadily over the remainder of the 12 week growth period. As expected, the percent infection of roots by VAM decreased with increasing soil-P level. Leaf area, relative growth rate (RGR), lateral branching and root dry weight were increased by VAM, although the relative-response diminished with increasing soil-P level. A similar response to VAM-infection was evident for the concentration of and total shoot N, P and K. Examination of the shoot N status indicated that VAM influenced the rates at which the plant was partitioning N into various N pools. But again, differences between non-VAM and VAM plants tended to decrease with increasing soil-P level. These results indicate that VAM modification of dry matter accumulation and nutrient uptake is mostly a consequence of the alleviation of P-deficiency of the plant and the improved growth of roots, allowing increased mineral absorption.

scholarly journals Utilization of soil residual phosphorus and internal reuse of phosphorus by crops

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11704
Author(s):  
Mei Yang ◽  
Huimin Yang
Keyword(s):  
Management Practices ◽  
Agricultural Practices ◽  
P Availability ◽  
Agricultural Systems ◽  
P Deficiency ◽  
Residual P ◽  
Soil P ◽  
Stubble Retention ◽  
Phosphate Solubilizing ◽  
Leaf P

Phosphorus (P) participates in various assimilatory and metabolic processes in plants. Agricultural systems are facing P deficiency in many areas worldwide, while global P demand is increasing. Pioneering efforts have made us better understand the more complete use of residual P in soils and the link connecting plant P resorption to soil P deficiency, which will help to address the challenging issue of P deficiency. We summarized the state of soil “residual P” and the mechanisms of utilizing this P pool, the possible effects of planting and tillage patterns, various fertilization management practices and phosphate-solubilizing microorganisms on the release of soil residual P and the link connecting leaf P resorption to soil P deficiency and the regulatory mechanisms of leaf P resorption. The utilization of soil residual P represents a great challenge and a good chance to manage P well in agricultural systems. In production practices, the combination of “optimal fertilization and agronomic measures” can be adopted to utilize residual P in soils. Some agricultural practices, such as reduced or no tillage, crop rotation, stubble retention and utilization of biofertilizers-phosphate-solubilizing microorganisms should greatly improve the conversion of various P forms in the soil due to changes in the balance of individual nutrients in the soil or due to improvements in the phosphatase profile and activity in the soil. Leaf P resorption makes the plant less dependent on soil P availability, which can promote the use efficiency of plant P and enhance the adaptability to P-deficient environments. This idea provides new options for helping to ameliorate the global P dilemma.

scholarly journals Gas Exchange and Mycorrhizal Development of Neem Trees in Response to Phosphorus Nutrition

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 860C-860
Author(s):  
L. Phavaphutanon ◽  
F.T. Davies ◽  
S.A. Duray
Keyword(s):  
Gas Exchange ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Tissue Concentration ◽  
Net Photosynthesis ◽  
P Deficiency ◽  
Soil P ◽  
Extraradical Hyphae ◽  
P Concentration ◽  
Leaf P

Cuttings of neem trees (Azadirachta indica) were grown for 65 days at four P levels: 0, 15, 30, and 60 mg P/kg soil. Half of the plants were inoculated with the vesicular–arbuscular mycorrhizal fungi (VAM) Glomus intraradices. VAM increased growth and net photosynthesis (A) at the lowest two soil P levels. Increased A was attributed to increased stomatal conductance (g) and greater leaf P concentration. Nonstomatal inhibition of A due to P deficiency also was observed in non-VAM plants at lower soil P levels. At higher soil P, VAM and non-VAM plants had comparable growth, A, g, and tissue concentration of P and other elements. VAM plants at 0 mg P/kg soil had similar growth and leaf P concentration when compared to non-VAM plants at 15 mg P/kg soil, yet had a 11% higher A, indicating a direct effect of VAM on gas exchange. As soil P increased, total VAM colonization and vesicle formation decreased, while the amount of extraradical hyphae increased. Arbuscule formation was highest at 0 and 15 mg P/kg soil. Apparently, arbuscules and extraradical hyphae play an important role in the enhanced growth and gas exchange of VAM plants at lower soil P levels.

scholarly journals COMPARATIVE CARBON BALANCE OF MYCORRHIZAL AND NONMYCORRHIZAL PEPPER PLANT

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 438c-438
Author(s):  
Fred T. Davies ◽  
Randal S. Stahl ◽  
Sharon A. Duray
Keyword(s):  
Mycorrhizal Fungi ◽  
Carbon Balance ◽  
Growth Efficiency ◽  
Crop Productivity ◽  
Pepper Plant ◽  
P Availability ◽  
Maintenance Respiration ◽  
P Deficiency ◽  
Soil P ◽  
Time Dynamics

Symbiotic mycorrhizal fungi increase the P uptake of agronomic, horticultural, and forestry crops. Little is known about the real-time dynamics of carbon balance (net gain of biomass resulting from photosynthesis less the respiratory costs) of plants colonized with mycorrhizae. Our objective was to determine the carbon balance of endomycorrhizal (VAM) chile pepper `San Luis' (Capsicum annuum L.) as a model system for predicting plant response to limited P availability under elevated CO2. The increase in atmospheric CO2 is expected to result in increased plant productivity and greater demand for soil P, however, the lack of available soil P may become the most important nutritional problem limiting crop productivity. Under current conditions, the limitation of soil-P availability is an enormous problem that affects 25% of the world's arable lands. We are quantifying the carbon costs paid by the mycorrhizal plant under varying levels of P deficiency over the life cycle of the plant. Preliminary results from this study under ambient CO2 conditions indicate that there is a lower maintenance respiration and higher growth efficiency with mycorrhizal pepper plants under low soil-P conditions.

scholarly journals Richness of Rhizosphere Organisms Affects Plant P Nutrition According to P Source and Mobility

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 157
Author(s):  
Jean Trap ◽  
Patricia Mahafaka Ranoarisoa ◽  
Usman Irshad ◽  
Claude Plassard
Keyword(s):  
Careful Consideration ◽  
Soil Conditions ◽  
Organic P ◽  
P Nutrition ◽  
Soil P ◽  
P Acquisition ◽  
Complex Interactions ◽  
Experimental Trials ◽  
The Relationship

Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness—plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition.

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