Study on the Alleviative Effect of Diethyl Aminoethyl Hexanoate (DA-6) on Pepper Seed Germination under Salt Stress

Abstract

Diethyl aminoethyl hexanoate (DA-6) is a broad-spectrum high-energy plant growth regulator with multiple functions similar to auxin, gibberellin, and cytokinin. Research on crops such as corn, rice, peanuts, flowers, and vegetables has shown that it can increase the activity of plant peroxidase (POD) and nitrate reductase, promote plant cell division and elongation, and facilitate seed germination and seedling growth. This experiment used the seeds of the chili variety “Changxian Tianxia” as research materials. The experiment was conducted by designing DA-6 soaking experiments with different concentration gradients to determine physiological indicators of pepper growth, screen a suitable DA-6 concentration for pepper seed germination, and study the alleviating effect of DA-6 on pepper seed growth under salt stress. The aim is to provide a scientific basis for high-yield cultivation of chili in saline alkali soil. In the seed germination experiment, five DA-6 concentration treatment groups were set up, namely 0, 0.1 mmol/L, 0.5 mmol/L, 1 mmol/L, and 5 mmol/L. Three biological replicates were set up for each treatment group to screen for the most suitable DA-6 concentration for pepper seed germination. The germination and growth effects of pepper seeds under salt stress were then studied using this concentration. The growth physiological indicators were measured to investigate the alleviating effect of aminobutyric acid on pepper seed germination under salt stress. The experimental results showed that the appropriate concentration of aminobutyric acid ester (DA-6) promoted the germination of pepper seeds under salt stress. Under the treatment of soaking seeds in DA-6 at a concentration of 1 mmol/L, the activities of catalase (CAT) and POD increased by 8.6% and 14.6%, respectively, while inhibiting the accumulation of MDA (reducing it by 11.4%), improving the antioxidant effect of plant cell membranes, and enhancing the salt tolerance of pepper seeds. This experiment shows that soaking pepper seeds in 1 mmol/L DA-6 can effectively improve the antioxidant capacity of pepper seeds under salt stress environment, enhance seed germination rate and growth effect, and alleviate the damage caused by salt stress to pepper seedling growth to a certain extent.

Keywords

Pepper / Salt stress / Seed germination / Diethyl aminoethyl hexanoate (DA-6)

Statement of the Use of Generative AI and AI-Assisted Technologies in the Writing Process

During the preparation of this manuscript, the author(s) used baidu translation software 2.21 AI tools. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the article.

Acknowledgements

The authors thank Jie Liu (Huaibei Normal University, Department of School of life), Jiyuan Wang (Huaibei Normal university, Department of School of Life), Yupeng Fang (Huaibei Normal university, Department of School of Life) and Yanliang Guo (Huaibei Normal University, Department of School of Life), who were involved in the experiment.

Author Contribution

C.L. was responsible for experimental design and manuscript writing, M.F., J.L. and H.L. implemented the experimental content, and corrected and revised the paper.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The author confirms that all data generated or analysed during this study are included in this published article.

Funding

This work was supported by the Open Project of National Engineering Research Center of Tree breeding and Ecological restoration (LMYZKY2023001), supported by 2024 National College Student Innovation and Entrepreneurship Training Program Project (202410373052), 2023 Anhui Province College Students Innovation and Entrepreneurship Training Program (S202310373010S), supported by 2019 Huaibei Normal University’s newly introduced doctoral teachers’ research startup fund (03106059), and supported by 2023 Anhui Province Watermelon and Melon Biological Breeding Engineering Center Open Project Fund (AHXTKF2023003), and Natural Science Research Project of Colleges and Universities in Anhui Province (2024AH051665).

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

[1] Salehi B, Zakaria ZA, Gyawali R, Ibrahim SA, Rajkovic J, Shinwari ZK, et al. Piper Species: A Comprehensive Review on Their Phytochemistry, Biological Activities and Applications. Molecules 2019, 24, 1364. DOI:10.3390/molecules24071364

[2] Ma J, Wang Y, Wang LY, Lin D, Yang Y. Transcriptomic analysis reveals the mechanism of the alleviation of salt stress by salicylic acid in pepper (Capsicum annuum L.). Mol. Biol. Rep. 2022, 50, 3593-3606. DOI:10.1007/s11033-022-08064-y

[3] Lu J, Guan P, Gu J, Yang X, Wang F, Qi M, et al. Exogenous DA-6 Improves the Low Night Temperature Tolerance of Tomato Through Regulating Cytokinin. Front. Plant Sci. 2021, 11, 599111. DOI:10.3389/fpls.2020.599111

[4] Hassan MJ, Qi H, Cheng B, Hussain S, Peng Y, Liu W, et al. Enhanced adaptability to limited water supply regulated by diethyl aminoethyl hexanoate (DA-6) associated with lipidomic reprogramming in two white clover genotypes. Front. Plant Sci. 2022, 13, 879331. DOI:10.3389/fpls.2022.879331

[5] Wang X, Zhang Y, Zhang J, Li X, Jiang Z, Dong S. Effects of DA-6 and MC on the growth, physiology, and yield characteristics of soybean. BMC Plant Biol. 2025, 25, 304. DOI:10.1186/s12870-025-06310-6

[6] Huang X, Rao G, Peng X, Xue Y, Hu H, Feng N, et al. Effect of plant growth regulators DA-6 and COS on drought tolerance of pineapple through bromelain and oxidative stress. BMC Plant Biol. 2023, 23, 180. DOI:10.1186/s12870-023-04200-3

[7] Zhang J, Li S, Cai Q, Wang Z, Cao J, Yu T, et al. Exogenous diethyl aminoethyl hexanoate ameliorates low temperature stress by improving nitrogen metabolism in maize seedlings. PLoS ONE 2020, 15, e0232294. DOI:10.1371/journal.pone.0232294

[8] Li XL, Su X, Liu YP, Yu MJ, Yang Q, Sun CL, et al. Effects of drought and salt stress on seed germination and seedling physiological index of Rumex patientia (polygonaceae). Pratacult. Sci. 2025, 43, 1-10. DOI: 10.11829/j.issn.1001-0629.2024-0547

[9] Liu J, Wu Y, Dong G, Zhu G, Zhou G. Progress of Research on the Physiology and Molecular Regulation of Sorghum Growth under Salt Stress by Gibberellin. Int. J. Mol. Sci. 2023, 24, 6777. DOI:10.3390/ijms24076777[GoogleScholar]

[10] Guo M, Wang XS, Guo HD, Bai SY, Khan A, Wang XM, et al. Tomato salt tolerance mechanisms and their potential applications for fighting salinity: A review. Front. Plant Sci. 2022, 13, 949541. DOI:10.3389/fpls.2022.949541

[11] Fu H, Yang Y. How Plants Tolerate Salt Stress. Curr. Issues Mol. Biol. 2023, 45, 5914-5934. DOI:10.3390/cimb45070374

[12] Ashraf M, Munns R. Evolution of approaches to increase the salt tolerance of crops. Crit. Rev. Plant Sci. 2022, 41, 128-160. DOI:10.1080/07352689.2022.2065136

[13] Ashraf M, Shahzad SM, Imtiaz M, Rizwan MS. Salinity effects on nitrogen metabolism in plants—Focusing on the activities of nitrogen metabolizing enzymes: A review. J. Plant Nutr. 2018, 41, 1065-1081. DOI:10.1080/01904167.2018.1431670

[14] Ashraf M, Foolad MR, Tuberosa R. Crop breeding for salt tolerance in the era of molecular markers and marker-assisted selection. Plant Breed. 2012, 132, 10-20. DOI:10.1111/pbr.12000

[15] Hua JS, Wang XJ, Chen LQ. The effect of soaking quinoa seeds in different concentrations of ammonium salt on germination. Tillage Cultiv. 2020, 40, 29-31. DOI:10.13605/j.cnki.52-1065/s.2020.01.009

[16] Wang D, Tian YL, Zhang HJ, Zhang QQ, Chen KR, Li Z. Effects of diethyl aminoethyl hexanoate on seed germination characteristics of white clover under chromium stress. Pratacult. Sci. 2021, 38, 1986-1997. DOI:10.11829/j.issn.1001-0629.2021-0227

[17] Yang Q. The Effect of DA-6 Treatment on the Vitality of Corn Seeds. Master’s Thesis, Shandong Agricultural University, Tai’an, China, 2018.

[18] Cao YQ, Cheng BZ, Li Z. Effects of the Seed Soaking with DA-6 on Germination Characteristics and Stress Tolerance of White Clover under Salt Stress. Acta Agrest. Sin. 2023, 31, 140-147. DOI:10.11733/j.issn.1007-0435.2023.01.016

[19] Li H, Liu L, Kong X, Wang X, Si A, Zhao F, et al. Time-Course Transcriptomics Analysis Reveals Molecular Mechanisms of Salt-Tolerant and Salt-Sensitive Cotton Cultivars in Response to Salt Stress. Int. J. Mol. Sci. 2025, 26, 329. DOI:10.3390/ijms26010329

[20] Zhou ZG, Deng C, Feng X. The effect of exogenous melatonin on physiological characteristics of eggplant seedlings under salt stress. Chin. J. Veg. 2025, 1, 126-133. DOI:10.19928/j.cnki.1000-6346.2025.5006

[21] Qin J, Luo GX, Li T, Li Y, Hu T. Analysis of NaCl tolerance in seed germination and seedling growth of two types of Sichuan pepper. Seed 2016, 35, 24-28+31. DOI:10.16590/j.cnki.1001-4705.2016.09.024

[22] Kang GZ, Li GZ, Liu GQ, Xu W, Peng XQ, Wang CY, et al. Exogenous salicylic acid enhanc-es wheat drought tolerance by influence on the expression of genes related to ascorbate-glutathione cycle. Biol. Plant. 2013, 57, 718-724. DOI:10.1007/s10535-013-0335-z

[23] Dai HY, Hua JS, Zhang RP, Cai GZ. The effect of DA-6 soaking on germination and seedling traits of colored red rice seeds. Seed 2018, 37, 38-44. DOI: 10.16590/j.cnki.1001-4705.2018.05.038.

[24] Li Y, Zhou H, Feng N, Zheng D, Ma G, Feng S, et al. Physiological and transcriptome analysis reveals that prohexadione-calcium promotes rice seedling’s development under salt stress by regulating antioxidant processes and photosynthesis. PLoS ONE 2023, 18, e0286505. DOI:10.1371/journal.pone.0286505

[25] Aydinoglu F, Kahriman TY, Balci H. Seed bio-priming enhanced salt stress tolerance of maize (Zea mays L.) seedlings by regulating the antioxidant system and miRNA expression. 3 Biotech 2023, 13, 378. DOI:10.1007/s13205-023-03802-w

[26] Wei L, Feng L, Liu Y, Liao W. Mitogen-Activated Protein Kinase Is Involved in Salt Stress Response in Tomato (Solanum lycopersicum) Seedlings. Int. J. Mol. Sci. 2022, 23, 7645. DOI:10.3390/ijms23147645

[27] Hassan MJ, Zhou M, Ling Y, Li Z. Diethyl aminoethyl hexanoate ameliorates salt tolerance associated with ion transport, osmotic adjustment, and metabolite reprograming in white clover. BMC Plant Biol. 2024, 24, 950. DOI:10.1186/s12870-024-05657-6

[28] Athar HU, Zulfiqar F, Moosa A, Ashraf M, Zafar ZU, Zhang L, et al. Salt stress proteins in plants: An overview. Front. Plant Sci. 2022, 13, 999058. DOI:10.3389/fpls.2022.999058

[29] Zhang C, He P, Li Y, Li Y, Yao H, Duan J, et al. Exogenous diethyl aminoethyl hexanoate, a plant growth regulator, highly improved the salinity tolerance of important medicinal plant Cassia obtusifolia L. J. Plant Growth Regul. 2015, 35, 330-344. DOI:10.1007/s00344-015-9536-3