{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T12:36:48Z","timestamp":1787315808007,"version":"build-2736575974"},"reference-count":33,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,27]],"date-time":"2025-12-27T00:00:00Z","timestamp":1766793600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Scientific Foundation","award":["81573524"],"award-info":[{"award-number":["81573524"]}]},{"name":"the earmarked fund for China Agriculture Research System","award":["CARS-21"],"award-info":[{"award-number":["CARS-21"]}]},{"name":"High-level Key Discipline Construction Project of National Administration of Traditional Chinese Medicine\u2014Clinical Traditional Chinese Medicine","award":["zyyzdxk-2023107"],"award-info":[{"award-number":["zyyzdxk-2023107"]}]},{"name":"National Administration of Traditional Chinese Medicine\u2019s National Inheritance Workshop Construction Project for Veteran Traditional Chinese Pharmacists","award":["2204-595292501"],"award-info":[{"award-number":["2204-595292501"]}]},{"name":"Fujian Provincial Science and Technology Plan Guiding Project","award":["2025Y0027"],"award-info":[{"award-number":["2025Y0027"]}]},{"name":"Startup Fund for Introduced Talent of Fujian University of Traditional Chinese Medicine","award":["X2024010-Talent"],"award-info":[{"award-number":["X2024010-Talent"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Glycyrrhiza uralensis is a highly valued medicinal species worldwide. However, a paradox arises in its cultivation in that high nitrogen fertilization boosts yield at the expense of root quality, a problem linked to nitrogen\u2019s regulation of tricarboxylic acid (TCA) cycle-driven respiration. It remains unclear how different nitrogen forms coordinate respiratory and primary metabolism. We examined the regulatory mechanisms of nitrate (NO3\u2212) versus ammonium (NH4+) on these processes in cultivated G. uralensis by supplying seedlings with varying concentrations of K15NO3 or (15NH4)2SO4 in a modified Hoagland solution (HNS). Using non-invasive micro-test technology (NMT) and 15N tracing, we found that G. uralensis employs distinct nitrogen acquisition strategies: sustaining uptake at optimal NH4+ and low-to-moderate NO3\u2212, while declining uptake under high NO3\u2212. These strategies drove form-specific differences in the activity of key nitrogen assimilation enzymes, nitrate reductase and nitrite reductase (NR\/NiR), as well as glutamine synthetase and glutamate synthase (GS\/GOGAT), and subsequent glutamate and glutamine accumulation. Ammonium nutrition enhanced primary ammonia assimilation and gamma-aminobutyric acid (GABA) metabolism, leading to greater glutamate and endogenous GABA levels. In contrast, nitrate nutrition preferentially stimulated the TCA cycle, resulting in higher accumulation of \u03b1-ketoglutarate (KGA) and succinate. The concomitant increase in GABA catabolism supported this nitrogen-responsive respiratory metabolism, acting as a compensatory mechanism to maintain KGA homeostasis. Our findings inform nitrogen form strategies for G. uralensis cultivation.<\/jats:p>","DOI":"10.3390\/ijms27010317","type":"journal-article","created":{"date-parts":[[2025,12,29]],"date-time":"2025-12-29T05:28:19Z","timestamp":1766986099000},"page":"317","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Integration of Non-Invasive Micro-Test Technology and 15N Tracing Reveals the Impact of Nitrogen Forms at Different Concentrations on Respiratory and Primary Metabolism in Glycyrrhiza uralensis"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6180-1600","authenticated-orcid":false,"given":"Ying","family":"Chen","sequence":"first","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"},{"name":"Faculty of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yisu","family":"Cao","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuan","family":"Jiang","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanjun","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhengru","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanfan","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6698-4773","authenticated-orcid":false,"given":"Zhirong","family":"Sun","sequence":"additional","affiliation":[{"name":"School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1874","DOI":"10.1111\/pbi.13868","article-title":"Multi-omics profiling reveals comprehensive microbe-plant-metabolite regulation patterns for medicinal plant Glycyrrhiza uralensis Fisch","volume":"20","author":"Zhong","year":"2022","journal-title":"Plant Biotechnol. 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