Effect of Watering Regimen on Secondary Metabolites, Physiology, and Yield of Amaranthus cruentus
DOI:
https://doi.org/10.67601/njbls.v3i2a.82Keywords:
Proline, Ascorbic Acid, Stomatal Conductance, Relative Water Content, Root-to-Shoot RatioAbstract
Water availability is one of the most important factors that affects leafy vegetables' growth and physiological stability and accumulation of metabolites. Amaranthus cruentus is an economically and nutritionally valuable vegetable crop that is grown in arid and semi-arid regions. This study evaluated the comparative effect of four watering regimens; T1 (120% crop water requirement (CWR); overwatered/waterlogged), T2 (100% CWR; control/optimal), T3 (70% CWR; moderate stress), and T4 (40% CWR; severe stress); on the secondary metabolites, physiology, and growth parameters of A. cruentus. Optimal irrigation (T2) resulted in the maximum vegetative growth (P < 0.05), with the highest leaf area (870.34 cm2), fresh shoot weight (71.23 g), dry shoot weight (9.32 g), relative water content (93.28%), chlorophyll content (2.91 mg/g FW), carotenoid content (2.91 mg/g FW), and stomatal conductance (392.34 mmol H2O m-2s-1). Secondary metabolite accumulation significantly increased when exposed to moderate drought stress (T3) with the highest accumulation of total phenolics (33.09 mg GAE/g DW), total flavonoids (22.44 mg QE/g DW) and ascorbic acid (95.34 mg/100g FW) and moderate reduction in biomass (P < 0.05). Severe drought stress (T4) caused maximum accumulation of proline (45.33 µmol/g FW) and increased root-to-shoot ratio (0.34), but significantly reduced stomatal conductance (38.43 mmol H2O m-2s-1), leaf area (120.11 cm2), fresh shoot weight (13.12 g) and ascorbic acid content (20.34 mg/100g FW) (P < 0.05). Overwatering/waterlogging (T1) caused a decrease in the total phenolics content (11.52 mg GAE/g DW), total flavonoids content (6.41 mg QE/g DW), chlorophyll/carotenoid content (0.81 mg/g FW) and root to shoot ratio (0.06) (P < 0.05). In total, moderate stress (T3) will be an effective irrigation protocol to produce high levels of bioactive secondary metabolites in A. cruentus in a controlled manner.
References
Ábrahám, E., Hourton-Cabassa, C., Erdei, L., & Szabados, L. (2010). Methods for determination of proline in plants. In Plant stress tolerance: methods and protocols (pp. 317-331). https://doi.org/10.1007/978-1-60761-702-0_20
Asargew, M. F., Masutomi, Y., Kobayashi, K., & Aono, M. (2024). Water stress changes the relationship between photosynthesis and stomatal conductance. Science of the total environment, 907, 167886. https://doi.org/10.1016/j.scitotenv.2023.167886
Chroho M, Bouymajane A, Aazza M, Oulad El Majdoub Y, Cacciola F, Mondello L, Zair T, Bouissane L. (2022). Determination of the Phenolic Profile, and Evaluation of Biological Activities of Hydroethanolic Extract from Aerial Parts of Origanum compactum from Morocco. Molecules 27(16)5189. https://doi.org/10.3390/molecules27165189
Demo, A. H., & Asefa Bogale, G. (2024). Enhancing crop yield and conserving soil moisture through mulching practices in dryland agriculture. Frontiers in Agronomy, 6, 1361697. https://doi.org/10.3389/fagro.2024.1361697
Feng, K., Wang, X., Zhou, Q., Dai, T., Cao, W., Jiang, D., & Cai, J. (2022). Waterlogging priming enhances hypoxia stress tolerance of wheat offspring plants by regulating root phenotypic and physiological adaption. Plants, 11(15), 1969. https://doi.org/10.3390/plants11151969
Hemati, A., Moghiseh, E., Amirifar, A., Mofidi-Chelan, M., & Asgari Lajayer, B. (2022). Physiological effects of drought stress in plants. In Plant stress mitigators: Action and application (pp. 113-124). Singapore: Springer Nature Singapore. https://doi.org/10.1007/978-981-16-7759-5_6
Khan, P., Abdelbacki, A. M. M., Albaqami, M., Jan, R., & Kim, K.-M. (2025). Proline Promotes Drought Tolerance in Maize. Biology, 14(1), 41. https://doi.org/10.3390/biology14010041
Munné-Bosch, S. (2025). Drought stress-induced leaf senescence in plants: how to detect it and why. Annals of Botany, mcaf157. https://doi.org/10.1093/aob/mcaf157
Ninkuu, V., Aluko, O. O., Yan, J., Zeng, H., Liu, G., Zhao, J., & Dakora, F. D. (2025). Phenylpropanoids metabolism: Recent insight into stress tolerance and plant development cues. Frontiers in Plant Science, 16, 1571825. https://doi.org/10.3389/fpls.2025.1571825
Oguji, O. A., Obiegbuna, J. E., Ubaka, I. T., & Chukwunenye, V. C. (2024). Effect of Drying Techniques on Phytochemical and Vitamin Compositions of Three Species of Amaranth. Asian Journal of Food Research and Nutrition, 3(4), 792-798.
Oksana, S., Marek, K., Marian, B., & Marek, Z. (2023). Cultivar-dependent and drought-induced modulation of secondary metabolites, adaptative defense in Fagopyrum esculentum L. Physiology and Molecular Biology of Plants, 29(10), 1605-1618. https://doi.org/10.1007/s12298-023-01376-8
Shil, S., & Dewanjee, S. (2022). Impact of drought stress signals on growth and secondary metabolites (SMs) in medicinal plants. J Phytopharmacol, 11(5), 371-6. https://doi.org/10.31254/phyto.2022.11511
Topali, C., Antonopoulou, C., & Chatzissavvidis, C. (2024). Effect of waterlogging on growth and productivity of fruit crops. Horticulturae, 10(6), 623. https://doi.org/10.3390/horticulturae10060623
Yan, S., Weng, B., Jing, L., & Bi, W. (2023). Effects of drought stress on water content and biomass distribution in summer maize (Zea mays L.). Frontiers in Plant Science, 14, 1118131. https://doi.org/10.3389/fpls.2023.1118131
Zahra, N., Hafeez, M. B., Kausar, A., Al Zeidi, M., Asekova, S., Siddique, K. H., & Farooq, M. (2023). Plant photosynthetic responses under drought stress: Effects and management. Journal of Agronomy and Crop Science, 209(5), 651-672. https://doi.org/10.1111/jac.12652
