Chitosan and humic acid as biostimulant seed coatings enhance germination and seedling growth in two forage pea varieties (Pisum sativum var. arvense (L.)) under drought stress

Document Type : Full Article

Authors

1 Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, I. R. Iran

2 Department of Agrotechnology, School of Agriculture, Ferdowsi University of Mashhad, Mashhad, I. R. Iran

Abstract

Forage pea is an important legume used as livestock feed; however, environmental stresses, particularly drought, significantly affect its germination and seedling growth. Seed coating technology is an effective strategy for enhancing seed germination and seedling growth under drought conditions. This study was conducted to evaluate the potential of seed coating with chitosan (0.1%, 0.15%, 0.2%, and 0.3%) and humic acid (16, 17, 18, and 19 g kg-1 seeds) under drought stress (0, -3, -6, and -9 bar) in two forage pea varieties (Pionir and Arda). Evaluations considered final germination percentage, mean germination rate, and shoot and root length. Overall, the Pionir variety showed higher final germination percentage, mean germination rate, and shoot and root length than the Arda variety under both normal and drought stress conditions. In the Arda variety, significant decreases in the measured traits were observed under -6 bar drought stress. The two cultivars showed significant differences in shoot length, whereas no significant differences were observed in root length The results for the Pionir variety indicated that seed coating with chitosan (0.2%) improved shoot length by 41.95% and root length by 30.15%, whereas humic acid (19 g kg⁻¹ seeds) increased shoot length by 28.79% and root length by 14.03%. Similarly, in the Arda variety, chitosan (0.2%) increased shoot length by 57.44% and root length by 8.07%, while humic acid (19 g kg⁻¹ seeds) improved shoot length by 32.87% and root length by 30.25%. Thus, these biostimulants can enhance forage pea seed germination and seedling growth. 

Graphical Abstract

Chitosan and humic acid as biostimulant seed coatings enhance germination and seedling growth in two forage pea varieties (Pisum sativum var. arvense (L.)) under drought stress

Keywords

Main Subjects


Amirkhani, M., Mayton, H. S., Netravali, A. N., & Taylor, A. G. (2019). A seed coating delivery system for bio-based biostimulants to enhance plant growth. Sustainability, 11(19), 5304. https://doi.org/10.3390/su11195304
Arslan, E., Agar, G., & Aydin, M. (2021). HAas a biostimulant in improving drought tolerance in wheat: The expression patterns of drought-related genes. Plant Molecular Biology Reporter, 39(3), 508-519. https://doi.org/10.1007/s11105-020-01266-3
Behboud, R., Moradi, A., Piri, R., Dedicova, B., Fazeli-Nasab, B., & Ghorbanpour, M. (2024). Sweet corn (Zea mays L.) seed performance enhanced under drought stress by CH and minerals coating. BMC Plant Biology, 24(1), 991. https://doi.org/10.1186/s12870-024-05704-2
Canellas, L. P., & Olivares, F. L. (2014). Physiological responses to humic substances as plant growth promoter. Chemical and Biological Technologies in Agriculture, 1(1), 3. https://doi.org/10.1186/2196-5641-1-3
Canellas, L. P., Olivares, F. L., Aguiar, N. O., Jones, D. L., Nebbioso, A., Mazzei, P., & Piccolo, A. (2015). Humic and fulvic acids as biostimulants in horticulture. Scientia Horticulturae, 196, 15-27. doi.org/10.1016/j.scienta.2015.09.013
Choudhary, R. C., Kumaraswamy, R. V., Kumari, S., Sharma, S. S., Pal, A., Raliya, R., & Saharan, V. (2017). Cu-CH nanoparticle boost defense responses and plant growth in maize (Zea mays L.). Scientific Reports, 7(1), 9754. https://doi.org/10.1038/s41598-017-08571-0
De Avila, M. O. T., Moreira, S. G., Lima, F. R. D., Pimentel, G. V., Macedo, J. R., Nunes, M. R., & Morais, E. G. (2024). Effect of coating phosphorus with humic acids and micronutrients on yield of soybean and maize in succession. Journal of Agriculture and Food Research, 18, 101318. https://doi.org/10.1016/j.jafr.2024.101318
Demirkol, G., & Yilmaz, N. (2019). Forage pea (Pisum sativum var. arvense L.) landraces reveal morphological and genetic diversities. Turkish Journal of Botany, 43(3), 331-342. https://doi.org/10.3906/bot-1812-12
Durgadevi, P., Girigoswami, K., & Girigoswami, A. (2025). Biodegradable nanomaterials in boosting seed vigor and germination: Seed coating towards sustainability. Discover Applied Sciences, 7(7), 695. https://doi.org/10.1007/s42452-025-06737-4
Farooq, M., Ahmad, R., Shahzad, M., Sajjad, Y., Hassan, A., Shah, M. M., & Khan, S. A. (2021). Differential variations in total flavonoid content and antioxidant enzymes activities in pea under different salt and drought stresses. Scientia Horticulturae, 287, 110258. https://doi.org/10.1016/j.scienta.2021.110258.
Griga, M., & Novak, F. J. (1990). Pea (Pisum sativum L.). In Legumes and Oilseed Crops I (pp. 65-99). Berlin, Heidelberg: Springer Berlin Heidelberg.
Guan, Y. J., Hu, J., Wang, X. J., & Shao, C. X. (2009). Seed priming with CH improves maize germination and seedling growth in relation to physiological changes under low temperature stress. Journal of Zhejiang University Science B, 10(6), 427-433. https://doi.org/10.1631/jzus. B0820373
Gursoy, M. (2024). Alone or combined effect of seaweed and humic acid applications on rapeseed (Brassica napus L.) under salinity stress. Journal of Soil Science and Plant Nutrition, 24(2), 3364-3376. https://doi.org/10.1007/s42729-024-01759-0
Hirano, S., Hayashi, M., & Okuno, S. (2001). Soybean seeds surface‐coated with depolymerized chitins: Chitinase activity as a predictive index for the harvest of beans in field culture. Journal of the Science of Food and Agriculture, 81(2), 205-209.
ISTA (2022). International Rules for Seed Testing. The International Seed Testing Association, Bassersdorf, Switzerland.
Isik, M. I., Turkoglu, A., Yaman, M., Haliloglu, K., Ozturk, H.I., Erkol, S., & Bocianowski, J. (2025). Understanding genetic diversity and population structure in forage pea (Pisum sativum var. arvense L.) using inter-primer binding site (iPBS) retrotransposon marker. Genetic Resources and Crop Evolution, 72, 8389–8403. https://doi.org/10. 1007/s10722- 025- 02469-x
Izadi, M. H., Ashraf, M., & Emam, Y. (2025). Regulation of physiological attributes in wheat crops under terminal drought stress: A review. International Journal of Plant Production, 19(4), 781-797. https://doi.org/10.1007/s42106-025-00368
Jabeen, N., & Ahmad, R. (2013). The activity of antioxidant enzymes in response to salt stress in safflower (Carthamus tinctorius L.) and sunflower (Helianthus annuus L.) seedlings raised from seed treated with CH. Journal of the Science of Food and Agriculture, 93(7), 1699-1705. https://doi.org/10.1002/jsfa.5953
Katiyar, D., Hemantaranjan, A., & Singh, B. (2015). CH as a promising natural compound to enhance potential physiological responses in plant: A review. Indian Journal of Plant Physiology, 20(1), 1-9. https://doi.org/10.1007/s40502-015-0139-6
Kucukozcu, G., & Avcı, S. (2020). Tolerance of forage pea cultivars to salinity and drought stress during germination and seedling growth. International Journal of Agriculture Environment and Food Sciences, 4(3), 368-375. https://doi.org/10.31015/jaefs.2020.3.17
Lasheen, F. F., Hewidy, M., Abdelhamid, A. N., Thabet, R. S., Abass, M. M., Fahmy, A. A., & Hassan, K. M. (2024). Exogenous application of humic acid mitigates salinity stress on pittosporum (Pittosporum tobira) plant by adjusting the osmolytes and nutrient homeostasis. Journal of Crop Health, 76(1), 317-325. https://doi.org/10.1007/s10343-023-00939-9
Neamatollahi, E., Mohammadi, M., & Afshari, R. T. (2024). Assessing of sugar beet Seed adaptation under salt and drought stress conditions with coating technology based on Fuzzy inference system. Heliyon, 10(19), 38618. https://doi.org/10.1016/j.heliyon. 2024.e38618
Makhlouf, B. S. I., Khalil, S. R. A. E., & Saudy, H. S. (2022). Efficacy of humic acids and CH for enhancing yield and sugar quality of sugar beet under moderate and severe drought. Journal of Soil Science and Plant Nutrition, 22(2), 1676-1691. https://doi.org/10.1007/s42729-022-00762-7
Moran, J. F., Becana, M., Iturbe-Ormaetxe, I., Frechilla, S., Klucas, R. V., & Aparicio-Tejo, P. (1994). Drought induces oxidative stress in pea plants. Planta, 194(3), 346-352. https://doi.org/10.1007/BF00197534
Pilar-Izquierd, M. C., Ortega, N., Perez-Mateos, M. A. N. U. E. L., & Busto, M. D. (2012). Barley seed coating with free and immobilized alkaline phosphatase to improve P uptake and plant growth. The Journal of Agricultural Science, 150(6), 691-701. https://doi.org/10.1017/S0021859612000019
Rasheed, R., Ashraf, M. A., Arshad, A., Iqbal, M., & Hussain, I. (2020). Interactive effects of CH and cadmium on growth, secondary metabolism, oxidative defense, and element uptake in pea (Pisum sativum L.). Arabian Journal of Geosciences, 13(17), 847. https://doi.org/10.1007/s12517-020-05871-0
Taylor, A. G., Amirkhani, M., & Hill, H. (2021). Modern seed technology. Agriculture, 11(7), 630. https://doi.org/10.3390/agriculture11070630
Xu, D., Li, H., Lin, L., Lsiao, M. A., Deng, Q., Wang, J., & Xia, H. (2020). Effects of carboxymethyl CH on the growth and nutrient uptake in Prunus davidiana seedlings. Physiology and Molecular Biology of Plants, 26(4), 661-668. https://doi.org/10.1007/s12298-020-00791-5
Zhang, X. R. B. J., & Bai, R. (2003). Mechanisms and kinetics of HAadsorption onto CH-coated granules. Journal of Colloid and Interface Science, 264(1), 30-38. https://doi.org/10.1016/S0021-9797(03)00393-X
Zhuo, L., Tu, Y., Xu, Y., Peng, Y., Liang, J., Li, Z., & Huang, J. (2026). Improvement of germination and growth of tomato seeds under phenolic acid stress by humic acid-medium and trace element compounds. Scientia Horticulturae, 355, 114557. https://doi.org/10.1016/j.scienta.2025.114557