Research article
● Open access
Seed Germination of Tropical Trees under Polyethylene Glycol-Induced Osmotic Stress: A Comprehensive Study for Early Screening of Drought Tolerance
Abstract
Drought-induced water stress is a major environmental factor affecting seed germination and plant establishment in tropical forest ecosystems. This study examined the effects of polyethylene glycol (PEG)-induced osmotic stress on the germination of seven tropical tree species: Hardwickia binnata, Butea monosperma, Acacia catechu, Acacia nilotica, Holoptelea integrifolia, Diospyros melanoxylon, and Pithecellobium dulce. Seeds were subjected to three osmotic levels: 0 MPa (control), −0.5 MPa (moderate stress), and −1.0 MPa (severe stress). Germination experiments were conducted under controlled laboratory conditions using a factorial completely randomized design.
Results showed that increasing osmotic stress significantly reduced germination in all species. Under control conditions, Hardwickia binnata showed the highest germination (90%), while other species exhibited moderate germination rates. Under moderate stress (−0.5 MPa), germination declined substantially, though Hardwickia binnata and Butea monosperma maintained relatively higher tolerance. Severe stress (−1.0 MPa) almost completely inhibited germination in most species. Statistical analysis confirmed significant effects of species, treatment, and their interaction on germination response.
The findings indicate strong species-specific differences in drought tolerance during the germination stage. Hardwickia binnata and Butea monosperma demonstrated greater resilience to water stress and may be suitable for afforestation and restoration programs in drought-prone regions.
Keywords
Drought tolerance; osmotic stress; polyethylene glycol 6000; seed germination; tropical tree species; water stress; Hardwickia binnata; Butea monosperma; Acacia catechu; Acacia nilotica; Holoptelea integrifolia; Diospyros melanoxylon; Pithecellobium dulce; afforestation; forest restoration; climate resilience
References
Ahmad, J., & Bano, M. (1992). The effect of sodium chloride on the physiology of cotyledons and mobilization of reserve food in Cicer arietinum. Pakistan Journal of Botany, 24, 40-48.
Ashraf, M. Y. (2003). Time-course changes in the inorganic and organic components of germinating sunflower achenes under salt (NaCl) stress. Flora, 198, 26-36.
Gaspar, M. J., Velasco, T., Feito, I., Alía, R., & Majada, J. (2013). Genetic variation of drought tolerance in Pinus pinaster at three hierarchical levels: A comparison of induced osmotic stress and field testing. PLOS ONE, 8(7), e79094. https://doi.org/10.1371/journal.pone.0079094
Hadas, A. (1976). Water uptake and germination of leguminous seeds under changing external water potential in osmoticum solution. Journal of Experimental Botany, 27(98), 480-489.
Kaya, M. D., Okcu, G., Atak, M., Cikili, Y., & Kolsarici, O. (2006). Seed treatments to overcome salt and drought stress during germination in sunflower (Helianthus annuus L.). European Journal of Agronomy, 24, 291-295.
Khan, M. A., & Gulzar, S. (2003). Germination responses of Sporobolus ioclados: A saline desert grass. Journal of Arid Environments, 53, 387-394.
Khurana, E., & Singh, J. S. (2000). Influence of seed size on seedling growth of Albizia procera under different soil water levels. Annals of Botany, 86(6), 1185-1192. https://doi.org/10.1006/anbo.2000.1288
Kim, H. J., Feng, H., Kushad, M. M., & Fan, X. (2006). Effects of ultrasound, irradiation, and acidic electrolyzed water on germination of alfalfa and broccoli seeds and Escherichia coli O157:H7. Journal of Food Science, 71(6), M168-M173.
Lin, C. C., & Kao, C. H. (1995). NaCl stress in rice seedlings: Starch mobilization and the influence of gibberellic acid on seedling growth. Botanical Bulletin of Academia Sinica, 36, 169-173.
Lin, K. H. R., Tsou, C. C., Hwang, S. Y., Chen, L. F., & Lo, H. F. (2006). Paclobutrazol pretreatment enhanced flooding tolerance of sweet potato. Journal of Plant Physiology, 163(7), 750-760.
Luo, Y., Cheng, J., Yan, X., Zhang, J., & Zhang, J. (2022). Germination of seeds subjected to temperature and water availability: Implications for ecological restoration. Forests, 13(11), 1854. https://doi.org/10.3390/f13111854
Ma, L., Wei, J., Han, G., Sun, X., & Yang, X. (2024). Seed osmopriming with polyethylene glycol (PEG) enhances seed germination and seedling physiological traits of Coronilla varia L. under water stress. PLOS ONE, 19(5), e0303145. https://doi.org/10.1371/journal.pone.0303145
Michel, B. E., & Kaufmann, M. R. (1973). The osmotic potential of polyethylene glycol 6000. Plant Physiology, 51, 914-916.
Mwale, S., Hamusimbi, C., & Mwansa, K. (2003). Germination, emergence and growth of sunflower (Helianthus annuus L.) in response to osmotic seed priming. Seed Science and Technology, 31, 199-206.
Rahemi, M., Gholami, M., & Kholdebarin, B. (2010). Effect of drought stress induced by polyethylene glycol on seed germination of four wild almond species. Australian Journal of Basic and Applied Sciences, 4(5), 785-791.
Ribeiro, S., Gaspar, M. J., Lima-Brito, J., Fonseca, T., Soares, P., Cerveira, A., Fernandes, P. M., Louzada, J., & Carvalho, A. (2023). Impact of fire recurrence and induced water stress on seed germination and root mitotic cell cycle of Pinus pinaster Aiton. Forests, 14(1), 78. https://doi.org/10.3390/f14010078
Rodrigues, C. M., Alves, E. U., Silva, R. dos S., Cruz, F. R. da S., Silva, M. L. M. da, Ursulino, M. M., Santos, E. N., & Moura, M. F. de. (2020). Seeds of Caesalpinia echinata Lam. under water stress at different temperatures. Journal of Agricultural Science, 12(7), 66. https://doi.org/10.5539/jas.v12n7p66
Sevik, H., & Cetin, M. (2016). Effects of water stress on seed germination for select landscape plants. Polish Journal of Environmental Studies, 24(2), 689-693. https://doi.org/10.15244/pjoes/30119
Shitole, S. M., & Dhumal, K. N. (2012). Effect of water stress by polyethylene glycol 6000 and sodium chloride on seed germination and seedling growth of Cassia angustifolia. International Journal of Pharmaceutical Sciences Review and Research, 3(2), 1-5.
Sidari, M., Mallamaci, C., & Muscolo, A. (2008). Drought, salinity and heat differently affect seed germination of Pinus pinea. Journal of Forest Research, 13(5), 326-330. https://doi.org/10.1007/s10310-008-0086-4
Singh, S., & Ansari, S. A. (2019). Screening Dalbergia sissoo Roxb. populations for drought stress tolerance through seed germination under induced osmotic stress regimes. Indian Journal of Tropical Biodiversity, 27(1), 45-52.
Singh, Y., & Singh, A. (2020). Response of Albizia lebbock to moisture stress on seed germination and moisture gradient on seedling growth. Journal of Krishi Vigyan, 8(2), 229-233. https://doi.org/10.5958/2349-4433.2020.00050.1
Swapna, B., & Rajendrudu, G. (2015). Seed germination of Pongamia pinnata (L.) Pierre under water stress. Research Journal of Recent Sciences, 4(6), 1-5.
Tiwari, S., Lata, C., Chauhan, P. S., & Nautiyal, C. S. (2016). Pseudomonas putida attunes morphophysiological, biochemical and molecular responses in Cicer arietinum L. during drought stress and recovery. Plant Physiology and Biochemistry, 99, 108-117.
Valdovinos, T. M., Paula, R. C. de, Silva, P. C. da C., & Fanchini, G. (2021). Seed germination of three species of Bignoniaceae trees under water stress. Revista Ciência Agronômica, 52(4), e20210072. https://doi.org/10.5935/1806-6690.20210072
Verslues, P. E., Agarwal, M., Katiyar-Agarwal, S., Zhu, J., & Zhu, J.-K. (2006). Methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status. The Plant Journal, 45(4), 523-539. https://doi.org/10.1111/j.1365-313X.2005.02593.x
Worbes, M., Blanchart, S., & Fichtler, E. (2013). Relations between water balance, wood traits and phenological behavior of tree species from a tropical dry forest in Costa Rica: A multifactorial study. Tree Physiology, 33, 527-553.
Yordanov, I., Velikova, V., & Tsonev, T. (2003). Plant responses to drought and stress tolerance. Bulgarian Journal of Plant Physiology, Special Issue, 187-206.
Zhu, J., Kang, H., Tan, H., & Xu, M. (2006). Effects of drought stresses induced by polyethylene glycol on germination of Pinus sylvestris var. mongolica seeds from natural and plantation forests on sandy land. Journal of Forest Research, 11(5), 319-328. https://doi.org/10.1007/s10310-006-0214-y
Ashraf, M. Y. (2003). Time-course changes in the inorganic and organic components of germinating sunflower achenes under salt (NaCl) stress. Flora, 198, 26-36.
Gaspar, M. J., Velasco, T., Feito, I., Alía, R., & Majada, J. (2013). Genetic variation of drought tolerance in Pinus pinaster at three hierarchical levels: A comparison of induced osmotic stress and field testing. PLOS ONE, 8(7), e79094. https://doi.org/10.1371/journal.pone.0079094
Hadas, A. (1976). Water uptake and germination of leguminous seeds under changing external water potential in osmoticum solution. Journal of Experimental Botany, 27(98), 480-489.
Kaya, M. D., Okcu, G., Atak, M., Cikili, Y., & Kolsarici, O. (2006). Seed treatments to overcome salt and drought stress during germination in sunflower (Helianthus annuus L.). European Journal of Agronomy, 24, 291-295.
Khan, M. A., & Gulzar, S. (2003). Germination responses of Sporobolus ioclados: A saline desert grass. Journal of Arid Environments, 53, 387-394.
Khurana, E., & Singh, J. S. (2000). Influence of seed size on seedling growth of Albizia procera under different soil water levels. Annals of Botany, 86(6), 1185-1192. https://doi.org/10.1006/anbo.2000.1288
Kim, H. J., Feng, H., Kushad, M. M., & Fan, X. (2006). Effects of ultrasound, irradiation, and acidic electrolyzed water on germination of alfalfa and broccoli seeds and Escherichia coli O157:H7. Journal of Food Science, 71(6), M168-M173.
Lin, C. C., & Kao, C. H. (1995). NaCl stress in rice seedlings: Starch mobilization and the influence of gibberellic acid on seedling growth. Botanical Bulletin of Academia Sinica, 36, 169-173.
Lin, K. H. R., Tsou, C. C., Hwang, S. Y., Chen, L. F., & Lo, H. F. (2006). Paclobutrazol pretreatment enhanced flooding tolerance of sweet potato. Journal of Plant Physiology, 163(7), 750-760.
Luo, Y., Cheng, J., Yan, X., Zhang, J., & Zhang, J. (2022). Germination of seeds subjected to temperature and water availability: Implications for ecological restoration. Forests, 13(11), 1854. https://doi.org/10.3390/f13111854
Ma, L., Wei, J., Han, G., Sun, X., & Yang, X. (2024). Seed osmopriming with polyethylene glycol (PEG) enhances seed germination and seedling physiological traits of Coronilla varia L. under water stress. PLOS ONE, 19(5), e0303145. https://doi.org/10.1371/journal.pone.0303145
Michel, B. E., & Kaufmann, M. R. (1973). The osmotic potential of polyethylene glycol 6000. Plant Physiology, 51, 914-916.
Mwale, S., Hamusimbi, C., & Mwansa, K. (2003). Germination, emergence and growth of sunflower (Helianthus annuus L.) in response to osmotic seed priming. Seed Science and Technology, 31, 199-206.
Rahemi, M., Gholami, M., & Kholdebarin, B. (2010). Effect of drought stress induced by polyethylene glycol on seed germination of four wild almond species. Australian Journal of Basic and Applied Sciences, 4(5), 785-791.
Ribeiro, S., Gaspar, M. J., Lima-Brito, J., Fonseca, T., Soares, P., Cerveira, A., Fernandes, P. M., Louzada, J., & Carvalho, A. (2023). Impact of fire recurrence and induced water stress on seed germination and root mitotic cell cycle of Pinus pinaster Aiton. Forests, 14(1), 78. https://doi.org/10.3390/f14010078
Rodrigues, C. M., Alves, E. U., Silva, R. dos S., Cruz, F. R. da S., Silva, M. L. M. da, Ursulino, M. M., Santos, E. N., & Moura, M. F. de. (2020). Seeds of Caesalpinia echinata Lam. under water stress at different temperatures. Journal of Agricultural Science, 12(7), 66. https://doi.org/10.5539/jas.v12n7p66
Sevik, H., & Cetin, M. (2016). Effects of water stress on seed germination for select landscape plants. Polish Journal of Environmental Studies, 24(2), 689-693. https://doi.org/10.15244/pjoes/30119
Shitole, S. M., & Dhumal, K. N. (2012). Effect of water stress by polyethylene glycol 6000 and sodium chloride on seed germination and seedling growth of Cassia angustifolia. International Journal of Pharmaceutical Sciences Review and Research, 3(2), 1-5.
Sidari, M., Mallamaci, C., & Muscolo, A. (2008). Drought, salinity and heat differently affect seed germination of Pinus pinea. Journal of Forest Research, 13(5), 326-330. https://doi.org/10.1007/s10310-008-0086-4
Singh, S., & Ansari, S. A. (2019). Screening Dalbergia sissoo Roxb. populations for drought stress tolerance through seed germination under induced osmotic stress regimes. Indian Journal of Tropical Biodiversity, 27(1), 45-52.
Singh, Y., & Singh, A. (2020). Response of Albizia lebbock to moisture stress on seed germination and moisture gradient on seedling growth. Journal of Krishi Vigyan, 8(2), 229-233. https://doi.org/10.5958/2349-4433.2020.00050.1
Swapna, B., & Rajendrudu, G. (2015). Seed germination of Pongamia pinnata (L.) Pierre under water stress. Research Journal of Recent Sciences, 4(6), 1-5.
Tiwari, S., Lata, C., Chauhan, P. S., & Nautiyal, C. S. (2016). Pseudomonas putida attunes morphophysiological, biochemical and molecular responses in Cicer arietinum L. during drought stress and recovery. Plant Physiology and Biochemistry, 99, 108-117.
Valdovinos, T. M., Paula, R. C. de, Silva, P. C. da C., & Fanchini, G. (2021). Seed germination of three species of Bignoniaceae trees under water stress. Revista Ciência Agronômica, 52(4), e20210072. https://doi.org/10.5935/1806-6690.20210072
Verslues, P. E., Agarwal, M., Katiyar-Agarwal, S., Zhu, J., & Zhu, J.-K. (2006). Methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status. The Plant Journal, 45(4), 523-539. https://doi.org/10.1111/j.1365-313X.2005.02593.x
Worbes, M., Blanchart, S., & Fichtler, E. (2013). Relations between water balance, wood traits and phenological behavior of tree species from a tropical dry forest in Costa Rica: A multifactorial study. Tree Physiology, 33, 527-553.
Yordanov, I., Velikova, V., & Tsonev, T. (2003). Plant responses to drought and stress tolerance. Bulgarian Journal of Plant Physiology, Special Issue, 187-206.
Zhu, J., Kang, H., Tan, H., & Xu, M. (2006). Effects of drought stresses induced by polyethylene glycol on germination of Pinus sylvestris var. mongolica seeds from natural and plantation forests on sandy land. Journal of Forest Research, 11(5), 319-328. https://doi.org/10.1007/s10310-006-0214-y