Rice exudation patterns changed in response to P deficiency. Higher exudation rates were associated with lower biomass production. Total carboxylate exudation rates mostly decreased under P-limiting conditions.
AbstractWithin the rhizosphere, root exudates are believed to play an important role in plant phosphorus (P) acquisition. This could be particularly beneficial in upland rice production where P is often limited. However, knowledge gaps remain on how P deficiency shapes quality and quantity of root exudation in upland rice genotypes. We therefore investigated growth, plant P uptake, and root exudation patterns of two rice genotypes differing in P efficiency in semi-hydroponics at two P levels (low P\uffe2\uff80\uff89=\uffe2\uff80\uff891\uffc2\uffa0\uffc2\uffb5M, adequate P\uffe2\uff80\uff89=\uffe2\uff80\uff89100\uffc2\uffa0\uffc2\uffb5M). Root exudates were collected hydroponically 28 and 40\uffc2\uffa0days after germination to analyze total carbon (C), carbohydrates, amino acids, phenolic compounds spectrophotometrically and carboxylates using a targeted LC\uffe2\uff80\uff93MS approach. Despite their reported role in P solubilization, we observed that carboxylate exudation rates per unit root surface area were not increased under P deficiency. In contrast, exudation rates of total C, carbohydrates, amino acids and phenolics were mostly enhanced in response to low P supply. Overall, higher exudation rates were associated with lower biomass production in the P-inefficient genotype Nerica4, whereas the larger root system with lower C investment (per unit root surface area) in root exudates of the P-efficient DJ123 allowed for better plant growth under P deficiency. Our results reveal new insights into genotype-specific resource allocation in rice under P-limiting conditions that warrant follow-up research including more genotypes.
", "keywords": ["Genotype", "Hydroponics", "carbohydrates ; phenolics ; amino acids ; carboxylates ; phosphorus", "Plant Exudates", "Rhizosphere", "Original Article", "Oryza", "Phosphorus", "Biomass", "Amino Acids", "Plant Roots", "Carbon"], "contacts": [{"organization": "Henning Schwalm, Christiana Staudinger, Mohammad-Reza Hajirezaei, Eva Mundschenk, Alireza Golestanifard, Maire Holz, Matthias Wissuwa, Eva Oburger,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1007/s00425-024-04556-2"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Planta", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s00425-024-04556-2", "name": "item", "description": "10.1007/s00425-024-04556-2", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s00425-024-04556-2"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-10-23T00:00:00Z"}}, {"id": "10.1111/j.1461-0248.2010.01570.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:18:48Z", "type": "Journal Article", "created": "2010-12-22", "title": "Enhanced Root Exudation Induces Microbial Feedbacks To N Cycling In A Pine Forest Under Long-Term Co2 Fumigation", "description": "Ecology Letters (2011) 14: 187\uffe2\uff80\uff93194
AbstractThe degree to which rising atmospheric CO2 will be offset by carbon (C) sequestration in forests depends in part on the capacity of trees and soil microbes to make physiological adjustments that can alleviate resource limitation. Here, we show for the first time that mature trees exposed to CO2 enrichment increase the release of soluble C from roots to soil, and that such increases are coupled to the accelerated turnover of nitrogen (N) pools in the rhizosphere. Over the course of 3\uffe2\uff80\uff83years, we measured in situ rates of root exudation from 420 intact loblolly pine (Pinus taeda L.) roots. Trees fumigated with elevated CO2 (200 p.p.m.v. over background) increased exudation rates (\uffce\uffbcg\uffe2\uff80\uff83C\uffe2\uff80\uff83cm\uffe2\uff88\uff921\uffe2\uff80\uff83root\uffe2\uff80\uff83h\uffe2\uff88\uff921) by 55% during the primary growing season, leading to a 50% annual increase in dissolved organic inputs to fumigated forest soils. These increases in root\uffe2\uff80\uff90derived C were positively correlated with microbial release of extracellular enzymes involved in breakdown of organic N (R2\uffe2\uff80\uff83=\uffe2\uff80\uff830.66; P\uffe2\uff80\uff83=\uffe2\uff80\uff830.006) in the rhizosphere, indicating that exudation stimulated microbial activity and accelerated the rate of soil organic matter (SOM) turnover. In support of this conclusion, trees exposed to both elevated CO2 and N fertilization did not increase exudation rates and had reduced enzyme activities in the rhizosphere. Collectively, our results provide field\uffe2\uff80\uff90based empirical support suggesting that sustained growth responses of forests to elevated CO2 in low fertility soils are maintained by enhanced rates of microbial activity and N cycling fuelled by inputs of root\uffe2\uff80\uff90derived C. To the extent that increases in exudation also stimulate SOM decomposition, such changes may prevent soil C accumulation in forest ecosystems.
", "keywords": ["0106 biological sciences", "Nitrogen", "Plant Exudates", "Pinus taeda", "04 agricultural and veterinary sciences", "15. Life on land", "Carbon Dioxide", "01 natural sciences", "Plant Roots", "Carbon", "Trees", "Soil", "13. Climate action", "Rhizosphere", "North Carolina", "0401 agriculture", " forestry", " and fisheries", "Soil Microbiology"]}, "links": [{"href": "https://doi.org/10.1111/j.1461-0248.2010.01570.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Ecology%20Letters", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1461-0248.2010.01570.x", "name": "item", "description": "10.1111/j.1461-0248.2010.01570.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1461-0248.2010.01570.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-12-22T00:00:00Z"}}, {"id": "10.1093/treephys/tpu116", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:18:16Z", "type": "Journal Article", "created": "2015-01-24", "title": "Dinitrogen Fixation By Legume Shade Trees And Direct Transfer Of Fixed N To Associated Cacao In A Tropical Agroforestry System", "description": "Natural abundance of (15)N (\u03b4\u2009(15)N) was determined in bulk soil, rhizospheric soil and vegetation in an organically managed cacao (Theobroma cacao L.) plantation with Inga edulis Mart. legume trees (inga) as the principal shade for studying the nitrogen (N) cycle in the system. Cacao without contact with legumes in an adjacent plantation was used as the reference for N2 fixation and direct N transfer calculations. Bulk and rhizospheric soils contained 72 and 20%, respectively, of whole- system N. No vegetation effect on \u03b4\u2009(15)N in rhizospheric soil was detected, probably due to the high native soil N pool. Fine roots of the cacaos associated with inga contained \u223c35% of N fixed from the atmosphere (Nf) out of the total N. Leaves of all species had significantly higher \u03b4\u2009(15)N than fine roots. Twenty percent of system Nf was found in cacao suggesting direct N transfer from inga via a common mycelial network of mycorrhizal fungi or recycling of N-rich root exudates of inga. Inga had accumulated 98\u2005kg [Nf] ha(-1) during the 14-year history of the plantation. The conservative estimate of current N2 fixation rate was 41\u2005kg [Nf] ha(-1)\u2005year(-1) based on inga biomass only and 50\u2005kg [Nf] ha(-1)\u2005year(-1) based on inga and associated trees.", "keywords": ["2. Zero hunger", "Cacao", "Tropical Climate", "Nitrogen Isotopes", "Nitrogen", "Plant Exudates", "Fabaceae", "04 agricultural and veterinary sciences", "Forests", "15. Life on land", "Plant Roots", "Trees", "Plant Leaves", "Soil", "Mycorrhizae", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "Biomass", "Soil Microbiology"]}, "links": [{"href": "https://doi.org/10.1093/treephys/tpu116"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Tree%20Physiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/treephys/tpu116", "name": "item", "description": "10.1093/treephys/tpu116", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/treephys/tpu116"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2015-01-24T00:00:00Z"}}, {"id": "10.1111/gcb.12161", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:18:32Z", "type": "Journal Article", "created": "2013-02-06", "title": "Enhanced Root Exudation Stimulates Soil Nitrogen Transformations In A Subalpine Coniferous Forest Under Experimental Warming", "description": "AbstractDespite the perceived importance of exudation to forest ecosystem function, few studies have attempted to examine the effects of elevated temperature and nutrition availability on the rates of root exudation and associated microbial processes. In this study, we performed an experiment in whichin situexudates were collected fromPicea asperataseedlings that were transplanted in disturbed soils exposed to two levels of temperature (ambient temperature and infrared heater warming) and two nitrogen levels (unfertilized and 25\uffc2\uffa0g N\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0a\uffe2\uff88\uff921). Here, we show that the trees exposed to an elevated temperature increased their exudation rates I (\uffce\uffbcg\uffc2\uffa0C\uffc2\uffa0g\uffe2\uff88\uff921root biomass\uffc2\uffa0h\uffe2\uff88\uff921), II (\uffce\uffbcg\uffc2\uffa0C\uffc2\uffa0cm\uffe2\uff88\uff921\uffc2\uffa0root length\uffc2\uffa0h\uffe2\uff88\uff921) and III (\uffce\uffbcg\uffc2\uffa0C\uffc2\uffa0cm\uffe2\uff88\uff922\uffc2\uffa0root area\uffc2\uffa0h\uffe2\uff88\uff921) in the unfertilized plots. The altered morphological and physiological traits of the roots exposed to experimental warming could be responsible for this variation in root exudation. Moreover, these increases in root\uffe2\uff80\uff90derived C were positively correlated with the microbial release of extracellular enzymes involved in the breakdown of organic N (R2\uffc2\uffa0=\uffc2\uffa00.790;P\uffc2\uffa0=\uffc2\uffa00.038), which was coupled with stimulated microbial activity and accelerated N transformations in the unfertilized soils. In contrast, the trees exposed to both experimental warming and N fertilization did not show increased exudation rates or soil enzyme activity, indicating that the stimulatory effects of experimental warming on root exudation depend on soil fertility. Collectively, our results provide preliminary evidence that an increase in the release of root exudates into the soil may be an important physiological adjustment by which the sustained growth responses of plants to experimental warming may be maintained via enhanced soil microbial activity and soil N transformation. Accordingly, the underlying mechanisms by which plant root\uffe2\uff80\uff90microbe interactions influence soil organic matter decomposition and N cycling should be incorporated into climate\uffe2\uff80\uff90carbon cycle models to determine reliable estimates of long\uffe2\uff80\uff90term C storage in forests.
", "keywords": ["2. Zero hunger", "China", "Soil", "Plant Exudates", "0401 agriculture", " forestry", " and fisheries", "Biomass", "04 agricultural and veterinary sciences", "Models", " Theoretical", "Nitrogen Cycle", "Picea", "15. Life on land", "Global Warming", "Plant Roots"], "contacts": [{"organization": "Juan Xiao, Huajun Yin, Zhenfeng Xu, Xinyin Cheng, Yufei Li, Qing Liu,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1111/gcb.12161"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcb.12161", "name": "item", "description": "10.1111/gcb.12161", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcb.12161"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2013-04-18T00:00:00Z"}}, {"id": "PMC11499414", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:28:18Z", "type": "Journal Article", "created": "2024-10-23", "title": "Root exudation patterns of contrasting rice (Oryza sativa L.) lines in response to P limitation", "description": "Abstract Main conclusionRice exudation patterns changed in response to P deficiency. Higher exudation rates were associated with lower biomass production. Total carboxylate exudation rates mostly decreased under P-limiting conditions.
AbstractWithin the rhizosphere, root exudates are believed to play an important role in plant phosphorus (P) acquisition. This could be particularly beneficial in upland rice production where P is often limited. However, knowledge gaps remain on how P deficiency shapes quality and quantity of root exudation in upland rice genotypes. We therefore investigated growth, plant P uptake, and root exudation patterns of two rice genotypes differing in P efficiency in semi-hydroponics at two P levels (low P\uffe2\uff80\uff89=\uffe2\uff80\uff891\uffc2\uffa0\uffc2\uffb5M, adequate P\uffe2\uff80\uff89=\uffe2\uff80\uff89100\uffc2\uffa0\uffc2\uffb5M). Root exudates were collected hydroponically 28 and 40\uffc2\uffa0days after germination to analyze total carbon (C), carbohydrates, amino acids, phenolic compounds spectrophotometrically and carboxylates using a targeted LC\uffe2\uff80\uff93MS approach. Despite their reported role in P solubilization, we observed that carboxylate exudation rates per unit root surface area were not increased under P deficiency. In contrast, exudation rates of total C, carbohydrates, amino acids and phenolics were mostly enhanced in response to low P supply. Overall, higher exudation rates were associated with lower biomass production in the P-inefficient genotype Nerica4, whereas the larger root system with lower C investment (per unit root surface area) in root exudates of the P-efficient DJ123 allowed for better plant growth under P deficiency. Our results reveal new insights into genotype-specific resource allocation in rice under P-limiting conditions that warrant follow-up research including more genotypes.
", "keywords": ["Genotype", "Hydroponics", "carbohydrates ; phenolics ; amino acids ; carboxylates ; phosphorus", "Plant Exudates", "Rhizosphere", "Original Article", "Oryza", "Phosphorus", "Biomass", "Amino Acids", "Plant Roots", "Carbon"]}, "links": [{"href": "https://link.springer.com/content/pdf/10.1007/s00425-024-04556-2.pdf"}, {"href": "https://doi.org/PMC11499414"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Planta", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "PMC11499414", "name": "item", "description": "PMC11499414", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/PMC11499414"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-10-23T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Plant+Exudates&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Plant+Exudates&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Plant+Exudates&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Plant+Exudates&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-07-27T08:59:08.565903Z"}