Drill Seeding and 5-ALA Synergistically Maintain the Photosynthetic System and Ion Balance of Rice Seedlings to Alleviate Salt Stress

Drill Seeding and 5-ALA Synergistically Maintain the Photosynthetic System and Ion Balance of Rice Seedlings to Alleviate Salt Stress | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Drill Seeding and 5-ALA Synergistically Maintain the Photosynthetic System and Ion Balance of Rice Seedlings to Alleviate Salt Stress Shaobiao Duan, Liming Zhao, Renren Jiang, Rui Deng, Hang Zhou, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7695261/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Apr, 2026 Read the published version in BMC Plant Biology → Version 1 posted 16 You are reading this latest preprint version Abstract Background Seedling raising of rice ( Oryza sativa L.) is a critical step in rice cultivation, and salt stress significantly impedes the growth of rice seedlings, while 5-aminolevulinic acid (5-ALA) plays a vital role in plant responses to various abiotic stresses. This experiment combines agronomic practices with chemical regulation to investigate the effects of drill sowing and 5-ALA on the photosynthetic system and ionic homeostasis of rice seedlings under salt stress. Results The results demonstrated that salt stress led to substantial accumulation of Na⁺ and Cl⁻ in rice seedling leaves, which disrupted the photosynthetic system and significantly inhibited seedling growth. Exogenous application of 5-ALA increased the content of chloroplast synthesis precursors, promoted the synthesis of photosynthetic pigments, reduced the accumulation of Na⁺ and Cl⁻, enhanced the levels of K⁺ and Ca²⁺, improved antioxidant enzyme activity, and mitigated oxidative damage. Consequently, it improved gas exchange parameters and chlorophyll fluorescence characteristics, and thus increased carbohydrate accumulation. Under drill sowing conditions, the application of 5-ALA resulted in higher levels of chloroplast synthesis precursors and carbohydrate accumulation compared to broadcast sowing. Under salt stress, this provided more energy substrates for chlorophyll synthesis and photosynthetic system repair, thereby enhancing peroxidation scavenging capacity, maintaining the stability of the photosynthetic system and ionic homeostasis, and resulting in stronger salt tolerance than broadcast sowing. Conclusion In conclusion, the combination of drill sowing and foliar application of 5-ALA synergistically maintained the photosynthetic system and ionic balance in rice seedlings under salt stress, improving their salt tolerance. This study provides a theoretical basis for optimizing sowing methods and chemical regulation in rice seedling cultivation in saline-alkali soils. Rice Sowing methods 5-ALA Salt stress Photosynthetic system lon homeostasis Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 21 Apr, 2026 Read the published version in BMC Plant Biology → Version 1 posted Editorial decision: Revision requested 27 Oct, 2025 Reviews received at journal 25 Oct, 2025 Reviews received at journal 23 Oct, 2025 Reviews received at journal 21 Oct, 2025 Reviews received at journal 16 Oct, 2025 Reviewers agreed at journal 16 Oct, 2025 Reviews received at journal 14 Oct, 2025 Reviewers agreed at journal 14 Oct, 2025 Reviewers agreed at journal 13 Oct, 2025 Reviewers agreed at journal 13 Oct, 2025 Reviewers agreed at journal 13 Oct, 2025 Reviewers invited by journal 13 Oct, 2025 Editor invited by journal 26 Sep, 2025 Editor assigned by journal 25 Sep, 2025 Submission checks completed at journal 25 Sep, 2025 First submitted to journal 23 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7695261","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":533868671,"identity":"f3c5c7c8-f58a-45fc-a233-9347266f511d","order_by":0,"name":"Shaobiao Duan","email":"","orcid":"","institution":"Guangdong Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Shaobiao","middleName":"","lastName":"Duan","suffix":""},{"id":533868672,"identity":"3baeabf2-1dab-4b12-b5a6-02f5634069b4","order_by":1,"name":"Liming 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Stress","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-plant-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pbio","sideBox":"Learn more about [BMC Plant Biology](http://bmcplantbiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pbio/default.aspx","title":"BMC Plant Biology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Rice, Sowing methods, 5-ALA, Salt stress, Photosynthetic system, lon homeostasis","lastPublishedDoi":"10.21203/rs.3.rs-7695261/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7695261/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eSeedling raising of rice (\u003cem\u003eOryza sativa\u003c/em\u003e L.) is a critical step in rice cultivation, and salt stress significantly impedes the growth of rice seedlings, while 5-aminolevulinic acid (5-ALA) plays a vital role in plant responses to various abiotic stresses. This experiment combines agronomic practices with chemical regulation to investigate the effects of drill sowing and 5-ALA on the photosynthetic system and ionic homeostasis of rice seedlings under salt stress.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe results demonstrated that salt stress led to substantial accumulation of Na⁺ and Cl⁻ in rice seedling leaves, which disrupted the photosynthetic system and significantly inhibited seedling growth. Exogenous application of 5-ALA increased the content of chloroplast synthesis precursors, promoted the synthesis of photosynthetic pigments, reduced the accumulation of Na⁺ and Cl⁻, enhanced the levels of K⁺ and Ca\u0026sup2;⁺, improved antioxidant enzyme activity, and mitigated oxidative damage. Consequently, it improved gas exchange parameters and chlorophyll fluorescence characteristics, and thus increased carbohydrate accumulation. Under drill sowing conditions, the application of 5-ALA resulted in higher levels of chloroplast synthesis precursors and carbohydrate accumulation compared to broadcast sowing. Under salt stress, this provided more energy substrates for chlorophyll synthesis and photosynthetic system repair, thereby enhancing peroxidation scavenging capacity, maintaining the stability of the photosynthetic system and ionic homeostasis, and resulting in stronger salt tolerance than broadcast sowing.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eIn conclusion, the combination of drill sowing and foliar application of 5-ALA synergistically maintained the photosynthetic system and ionic balance in rice seedlings under salt stress, improving their salt tolerance. This study provides a theoretical basis for optimizing sowing methods and chemical regulation in rice seedling cultivation in saline-alkali soils.\u003c/p\u003e","manuscriptTitle":"Drill Seeding and 5-ALA Synergistically Maintain the Photosynthetic System and Ion Balance of Rice Seedlings to Alleviate Salt Stress","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-27 12:07:53","doi":"10.21203/rs.3.rs-7695261/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-27T08:13:17+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-25T04:21:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-23T09:31:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-22T03:58:26+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-16T11:19:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"214239988168769808968965176884446580560","date":"2025-10-16T08:28:31+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-15T03:51:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"107078870816333983020647248518021314073","date":"2025-10-14T10:44:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"58002181368841925797306586621247807597","date":"2025-10-13T22:29:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"28535795869815228428203883415668587225","date":"2025-10-13T16:18:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"80143781934732151831085987127711429656","date":"2025-10-13T13:25:28+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-13T11:03:55+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-26T15:50:50+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-26T02:30:07+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-26T02:28:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Plant Biology","date":"2025-09-23T13:54:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-plant-biology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pbio","sideBox":"Learn more about [BMC Plant Biology](http://bmcplantbiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pbio/default.aspx","title":"BMC Plant Biology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9617d6a0-27e2-4993-bd05-9e201f8a20ff","owner":[],"postedDate":"October 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T16:02:41+00:00","versionOfRecord":{"articleIdentity":"rs-7695261","link":"https://doi.org/10.1186/s12870-026-08799-x","journal":{"identity":"bmc-plant-biology","isVorOnly":false,"title":"BMC Plant Biology"},"publishedOn":"2026-04-21 15:59:04","publishedOnDateReadable":"April 21st, 2026"},"versionCreatedAt":"2025-10-27 12:07:53","video":"","vorDoi":"10.1186/s12870-026-08799-x","vorDoiUrl":"https://doi.org/10.1186/s12870-026-08799-x","workflowStages":[]},"version":"v1","identity":"rs-7695261","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7695261","identity":"rs-7695261","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}