Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress

Drought stress is one of the key environmental factors restricting the germination of alfalfa seeds (<i>Medicago sativa</i> L.). Nanopriming is an innovative seed-priming technology able to meet economic, agronomic, and environmental needs in agriculture. However, the use of conventional...

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Main Authors: Xinyue Wang, Mengting Ge, Xueqing He
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/8/1236
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author Xinyue Wang
Mengting Ge
Xueqing He
author_facet Xinyue Wang
Mengting Ge
Xueqing He
author_sort Xinyue Wang
collection DOAJ
description Drought stress is one of the key environmental factors restricting the germination of alfalfa seeds (<i>Medicago sativa</i> L.). Nanopriming is an innovative seed-priming technology able to meet economic, agronomic, and environmental needs in agriculture. However, the use of conventional nanomaterials is hampered by high costs, environmental risks, and biotoxicity. In this study, we synthesized iron oxide nanoparticles (Fe<sub>3</sub>O<sub>4</sub>NPs) using seasonal <i>Ginkgo biloba</i> leaf extracts (collected from August to November) obtained via an enzymatic ultrasonic-assisted method. The synthesized Fe<sub>3</sub>O<sub>4</sub>NPs were characterized using SEM, EDS, DLS, FTIR, UV-Vis, and XRD. To investigate the effects of Fe<sub>3</sub>O<sub>4</sub>NP priming on alfalfa seed germination under drought stress, germination and pot experiments were conducted with five Fe<sub>3</sub>O<sub>4</sub>NP priming concentrations (unprimed, 0, 20, 40, and 60 mg/L) and three PEG-6000 concentrations (0%, 10%, and 15%) to simulate normal, moderate, and severe drought conditions. The results showed that leaf extracts collected in November exhibited the highest flavonoid content (12.8 mg/g), successfully yielding bioactive-capped spherical Fe<sub>3</sub>O<sub>4</sub>NPs with a particle size of 369.5 ± 100.6 nm. Germination experiments revealed that under severe drought stress (15% PEG-6000), the 40 mg/L Fe<sub>3</sub>O<sub>4</sub>NP treatment most effectively enhanced seed vigor, increasing the germination rate, vigor index, and α-amylase activity by 22.1%, 189.4%, and 35.5% (<i>p</i> < 0.05), respectively, compared to controls. Under moderate drought stress (10% PEG-6000), the 20 mg/L Fe<sub>3</sub>O<sub>4</sub>NP treatment optimally improved germination traits, increasing the germination rate by 25.5% and seedling elongation by 115.6%. The pot experiments demonstrated morphological adaptations in alfalfa seedlings: under moderate drought stress, the 40 mg/L Fe<sub>3</sub>O<sub>4</sub>NPs significantly increased lateral root numbers, while under severe drought stress, the 60 mg/L Fe<sub>3</sub>O<sub>4</sub>NPs increased the root surface area by 20.5% and preserved the roots’ structural integrity compared to controls. These findings highlight that Fe<sub>3</sub>O<sub>4</sub>NPs synthesized via Ginkgo leaf extracts and enzymatic ultrasonic methods exhibit promising agricultural potential. The optimal Fe<sub>3</sub>O<sub>4</sub>NP priming concentrations enhanced seed vigor, germination traits, and drought resistance by modulating root morphology, with concentration-specific efficacy under varying drought intensities.
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spelling doaj-art-0abe92bf15e24082a13aa883e71e9bb52025-08-20T03:13:58ZengMDPI AGPlants2223-77472025-04-01148123610.3390/plants14081236Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought StressXinyue Wang0Mengting Ge1Xueqing He2College of Grassland Agriculture, Northwest A&F University, Yangling 712100, ChinaCollege of Grassland Agriculture, Northwest A&F University, Yangling 712100, ChinaCollege of Grassland Agriculture, Northwest A&F University, Yangling 712100, ChinaDrought stress is one of the key environmental factors restricting the germination of alfalfa seeds (<i>Medicago sativa</i> L.). Nanopriming is an innovative seed-priming technology able to meet economic, agronomic, and environmental needs in agriculture. However, the use of conventional nanomaterials is hampered by high costs, environmental risks, and biotoxicity. In this study, we synthesized iron oxide nanoparticles (Fe<sub>3</sub>O<sub>4</sub>NPs) using seasonal <i>Ginkgo biloba</i> leaf extracts (collected from August to November) obtained via an enzymatic ultrasonic-assisted method. The synthesized Fe<sub>3</sub>O<sub>4</sub>NPs were characterized using SEM, EDS, DLS, FTIR, UV-Vis, and XRD. To investigate the effects of Fe<sub>3</sub>O<sub>4</sub>NP priming on alfalfa seed germination under drought stress, germination and pot experiments were conducted with five Fe<sub>3</sub>O<sub>4</sub>NP priming concentrations (unprimed, 0, 20, 40, and 60 mg/L) and three PEG-6000 concentrations (0%, 10%, and 15%) to simulate normal, moderate, and severe drought conditions. The results showed that leaf extracts collected in November exhibited the highest flavonoid content (12.8 mg/g), successfully yielding bioactive-capped spherical Fe<sub>3</sub>O<sub>4</sub>NPs with a particle size of 369.5 ± 100.6 nm. Germination experiments revealed that under severe drought stress (15% PEG-6000), the 40 mg/L Fe<sub>3</sub>O<sub>4</sub>NP treatment most effectively enhanced seed vigor, increasing the germination rate, vigor index, and α-amylase activity by 22.1%, 189.4%, and 35.5% (<i>p</i> < 0.05), respectively, compared to controls. Under moderate drought stress (10% PEG-6000), the 20 mg/L Fe<sub>3</sub>O<sub>4</sub>NP treatment optimally improved germination traits, increasing the germination rate by 25.5% and seedling elongation by 115.6%. The pot experiments demonstrated morphological adaptations in alfalfa seedlings: under moderate drought stress, the 40 mg/L Fe<sub>3</sub>O<sub>4</sub>NPs significantly increased lateral root numbers, while under severe drought stress, the 60 mg/L Fe<sub>3</sub>O<sub>4</sub>NPs increased the root surface area by 20.5% and preserved the roots’ structural integrity compared to controls. These findings highlight that Fe<sub>3</sub>O<sub>4</sub>NPs synthesized via Ginkgo leaf extracts and enzymatic ultrasonic methods exhibit promising agricultural potential. The optimal Fe<sub>3</sub>O<sub>4</sub>NP priming concentrations enhanced seed vigor, germination traits, and drought resistance by modulating root morphology, with concentration-specific efficacy under varying drought intensities.https://www.mdpi.com/2223-7747/14/8/1236alfalfadrought stressgreen synthesisseed primingseed germination
spellingShingle Xinyue Wang
Mengting Ge
Xueqing He
Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
Plants
alfalfa
drought stress
green synthesis
seed priming
seed germination
title Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
title_full Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
title_fullStr Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
title_full_unstemmed Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
title_short Effect of Green Synthesized Fe<sub>3</sub>O<sub>4</sub>NP Priming on Alfalfa Seed Germination Under Drought Stress
title_sort effect of green synthesized fe sub 3 sub o sub 4 sub np priming on alfalfa seed germination under drought stress
topic alfalfa
drought stress
green synthesis
seed priming
seed germination
url https://www.mdpi.com/2223-7747/14/8/1236
work_keys_str_mv AT xinyuewang effectofgreensynthesizedfesub3subosub4subnpprimingonalfalfaseedgerminationunderdroughtstress
AT mengtingge effectofgreensynthesizedfesub3subosub4subnpprimingonalfalfaseedgerminationunderdroughtstress
AT xueqinghe effectofgreensynthesizedfesub3subosub4subnpprimingonalfalfaseedgerminationunderdroughtstress