ZINC-INDUCED BIPHASIC MODULATION OF CHLOROPLAST PIGMENTS AND ANTIOXIDATIVE ENZYME ACTIVITIES IN ACID LIME (Citrus aurantiifolia Swingle): IMPLICATIONS ON PHOTOSYNTHETIC EFFICIENCY AND STRESS MANAGEMENT
DOI:
https://doi.org/10.48165/abr.2025.27.01.55Keywords:
Acid lime, antioxidant enzymes, chloroplast pigments, nutrient management, Rubisco, oxidative stress, zincAbstract
Zinc is an essential micronutrient vital for various physiological processes in plants; however, its narrow gap between deficiency and toxicity demands careful nutrient management. This study assessed the impact of zinc (zinc sulphate heptahydrate @ 0.0–15.0 mM L⁻¹) on the composition of chloroplast pigments and anti-oxidative enzyme activities within the chloroplasts of acid lime (Citrus aurantiifolia Swingle) leaves over two consecutive years.Moderate zinc concentrations (7.5–10.0 mM L⁻¹) significantly improved chlorophyll (a, b and total), carotenoids, xanthophylls and plastoquinone contents, indicating enhanced chloroplast development and improved photosynthetic capacity. Rubisco activity, a key enzyme involved in carbon fixation, was highest at 10.0 mM L⁻¹ zinc.In contrast, both zinc deficiency (0.0 mM L⁻¹) and zinc toxicity (≥12.5 mM L⁻¹) caused a significant reduction in pigment levels and Rubisco activity, which was associated with increased oxidative stress. Activities of superoxide dismutase, glutathione, and ascorbate peroxidase in the chloroplasts increased under these stress conditions, reflecting the activation of antioxidant defense mechanisms.This biphasic response demonstrates the dual role of zinc in plant metabolism—supporting physiological balance at optimal concentrations while inducing oxidative stress and metabolic disruption under deficiency or excess. The study highlights the importance of maintaining a critical zinc threshold to sustain photosynthetic efficiency and redox balance in acid lime.
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Ahmad, P., Alyemeni, M.N., Ahanger, M.A., Wijaya, L., Alam, P. & Ashraf, M. (2018). Zinc application improves growth and antioxidant system in tomato plants under arsenic stress. Physiology and Molecular Biology of Plants, 24(6), 1307–1320.
Ahmad, W., Shah, Z., Hassan, W. & Ullah, F. (2018). Zinc-induced antioxidant defense system in citrus under Zn stress. Scientia Horticulturae, 240, 309–317.
Ali, S., Rizwan, M., Noureen, S., Anwar, H. & Rehman, M.Z. (2021). Zinc-induced anti-oxidative defense and osmotic adjustments to alleviate cadmium stress in wheat. Ecotoxicology and Environmental Safety, 208, 111685. https://doi.org/10.1016/j.ecoenv.2020.111685
Ali, S., Rizwan, M., Qayyum, M.F., Ok, Y.S., Ibrahim, M., Riaz, M., et al. (2022). Oxidative stress and antioxidant defense mechanisms in plants under metal stress: A review. Ecotoxicology and Environmental Safety, 147, 602–621.
Ali, S., Rizwan, M., Qayyum, M.F., Ok, Y.S., Ibrahim, M., Riaz, M., et al. (2022). Role of zinc in plant nutrition and possible mechanisms of its tolerance. Environmental Pollution, 308, 119660. https://doi.org/10.1016/j.envpol.2022.119660
Alloway, B.J. (2009). Soil factors associated with zinc deficiency in crops and humans. Environmental Geochemistry and Health, 31(5), 537–548.
Aronsson, H. & Jarvis, P. (2002). A simple method for isolating import-competent Arabidopsis chloroplasts. FEBS Letters, 529(2–3), 215–220.
Bairwa, S.L., Meena, H.R., Lakra, K. & Sharma, J.P. (2018). Citrus cultivation and livelihood security: An Indian perspective. Agricultural Reviews, 39(1), 13–18.
Broadley, M.R., White, P.J., Hammond, J.P., Zelko, I. & Lux, A. (2012). Zinc in plants. New Phytologist, 195(3), 659–679.
Cakmak, I. (2000). Possible roles of zinc in protecting plant cells from damage by reactive oxygen species. New Phytologist, 146(2), 185–205.
Chen, Y., Zhang, Y. & Zhang, Y. (2023). Chloroplast antioxidant reactions associated with zinc alleviating iron deficiency in wheat. Frontiers in Plant Science, 14, 11726291. https://doi.org/10.3389/fpls.2023.11726291
Demmig-Adams, B. & Adams, W.W. (2006). Photoprotection in an ecological context: The remarkable complexity of thermal energy dissipation. New Phytologist, 172(1), 11–21.
Dimkpa, C.O. & Bindraban, P.S. (2016). Fortification of micronutrients for efficient agronomic production: A review. Agronomy for Sustainable Development, 36(1), 7. https://doi.org/10.1007/s13593-015-0346-6
Fukao, T., Yeung, E. & Bailey-Serres, J. (2021). Plant responses to hypoxia—Is survival a balancing act. Trends in Plant Science, 26(7), 632–645.
Fukao, T., Yeung, E. & Bailey-Serres, J. (2021). The submergence tolerance gene SUB1A delays leaf senescence under prolonged darkness through hormonal and metabolic regulation. Plant Physiology, 186(1), 106–120.
Ghasemi, A., Pour-Bonakdari, H. & Hassani, M. (2020). Effects of Zn toxicity on pigment biosynthesis in plants: A review. Plant Physiology and Biochemistry, 156, 303–311.
Ghasemi, S., Modarresi, M. & Mohammadi, M. (2020). Zinc stress influences photosynthetic pigment biosynthesis and expression of related genes in wheat. Plant Physiology and Biochemistry, 147, 90–100.
Giannopolitis, C.N. & Ries, S.K. (1977). Superoxide dismutases: I. Occurrence in higher plants. Plant Physiology, 59(2), 309–314.
Gill, S.S. & Tuteja, N. (2010). Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants. Plant Physiology and Biochemistry, 48(12), 909–930.
Gomez, K.A. & Gomez, A.A. (1984). Statistical Procedures for Agricultural Research (2nd ed.). John Wiley and Sons, New York, USA.
Hafeez, B., Khanif, Y.M. & Saleem, M. (2013). Role of zinc in plant nutrition: A review. American Journal of Experimental Agriculture, 3(2), 374–391.
Hasanuzzaman, M., Bhuyan, M.H.M.B., Zulfiqar, F., Raza, A., Mohsin, S.M., Mahmud, J.A., et al. (2020). Reactive oxygen species and antioxidantdefense in plants under abiotic stress. Antioxidants, 9(8), 681. https://doi.org/10.3390/antiox9080681
Hussain, M.I., Reigosa, M.J. & Sánchez-Moreiras, A. (2020). Mechanistic insights into ROS and antioxidant system under environmental stress in plants. Journal of Plant Interactions, 15(1), 43–55.
Kumar, P., Yadav, R.K. & Meena, R.K. (2020). Nutritional importance and production trends of acid lime in India. International Journal of Current Microbiology and Applied Sciences, 9(5), 1–8.
Kumar, S., Pandey, A. & Rai, A. (2023). Zinc toxicity modulates antioxidant defense and metabolic responses in tomato. Plant Physiology Reports, 28(3), 569–581.
Lichtenthaler, H.K. & Wellburn, A.R. (1983). Determination of total carotenoids and chlorophylls a and b. Biochemical Society Transactions, 11(5), 591–592.
Lindsay, W.L. & Norvell, W.A. (1978). Development of a DTPA soil test for zinc, iron, manganese and copper. Soil Science Society of America Journal, 42(3), 421–428.
Marschner, H. (2012). Marschner’s Mineral Nutrition of Higher Plants (3rd ed.). Academic Press, London.
Nakano, Y. & Asada, K. (1981). Hydrogen peroxide is scavenged by ascorbate-specific peroxidase in spinach chloroplasts. Plant and Cell Physiology, 22(5), 867–880.
Noctor, G. & Foyer, C.H. (1998). Ascorbate and glutathione: Keeping active oxygen under control. Plant Physiology, 119(3), 849–856.
Parry, M.A.J., Andralojc, P.J., Scales, J.C., Salvucci, M.E., Carmo-Silva, A.E., Alonso, H., et al. (1997). Rubisco activity and regulation as targets for crop improvement. Plant Physiology and Biochemistry, 35(5), 411–417.
Pereira, A.S., dos Santos, T.B. & Nunes-Nesi, A. (2020). Carotenoid biosynthesis and photoprotection in plants. Plant Cell Reports, 39(2), 139–151.
Pérez-Sanz, A., López-Millán, A.F. & Abadía, J. (2021). Zinc foliar applications improve leaf pigment levels and photosynthetic activity in citrus. Frontiers in Plant Science, 12, 637502. https://doi.org/10.3389/fpls.2021.637502
Rout, G.R. & Das, P. (2003). Effect of metal toxicity on plant growth and metabolism: I. Zinc. Agronomie, 23(1), 3–11.
Saleem, M., Ali, S. & Farid, M. (2022). Zinc nutrition in fruit crops. Journal of Plant Nutrition, 45(5), 769–784.
Shahid, M.A., Sarkhosh, A., Khan, N., Balal, R.M., Ali, S., Rossi, L., et al. (2021). Zinc oxide nanoparticles and citrus under salt stress. Plants, 10(1), 90. https://doi.org/10.3390/plants10010090
Shahid, M., Tanveer, A., Abbas, G. & Rizwan, M. (2021). Zinc-mediated modulation of photosynthesis in citrus. Environmental Science and Pollution Research, 28(35), 47525–47537.
Singh, Y.H., Sawant, C.G. & Lalhmingsanga, R. (2021). Leaf analysis in citrus. Journal of Plant Nutrition, 44(3), 321–333.
Tikkanen, M. & Aro, E.M. (2014). Integrative regulatory network of plant thylakoid energy transduction. Trends in Plant Science, 19(1), 10–17.
Varalakshmi, L.R. & Bhargava, B.S. (1998). Nutrient status and leaf diagnostic norms in acid lime. Indian Journal of Agricultural Sciences, 68(8),457–460.
Xie, Y., Zhang, Y. & Wang, Y. (2022). Effects of exogenous zinc on potato physiology. PeerJ, 10, e16280. https://doi.org/10.7717/peerj.16280
Yamamoto, H.Y. & Kamite, L. (1987). Plastoquinone determination in chloroplasts. Plant and Cell Physiology, 28(7), 1301–1306.
Yamori, W. & Shikanai, T. (2016). Cyclic electron transport around PSI. Annual Review of Plant Biology, 67, 81–106.
Yang, X., Xu, M. & Zhu, Y. (2019). Zinc-induced oxidative damage in Brassica napus. Ecotoxicology and Environmental Safety, 174, 544–552.
Yang, Y., Wang, L., Xu, L. & Zhang, X. (2019). Zinc stress in oilseed rape. Ecotoxicology and Environmental Safety, 170, 739–746.
Yang, Y., Wu, Y., Ma, L., Yang, L., Zhang, L. & Wang, H. (2021). Excess Zn disrupts plant metabolic homeostasis. Plant Physiology and Biochemistry, 163, 143–154.
Zhang, Y., Guo, J., Hu, J. & Chen, Y. (2023). Zinc-mediated regulation of chlorophyll. Frontiers in Plant Science, 14, 1123852. https://doi.org/10.3389/fpls.2023.1123852
Zhou, J., Li, F., Wu, Y. & Dong, J. (2023). Redox regulation of plastoquinone pool under metal stress. Journal of Experimental Botany, 74(3), 765–778.
Zhou, Y., Jin, R., Wang, W., Liu, W. & Zeng, X. (2019). Zinc toxicity and xanthophyll cycle in rice. Environmental and Experimental Botany, 163, 39–46.
Zhou, Y., Wang, Y., Li, X. & Zhang, Z. (2023). Photosystem II photoinhibition under zinc stress. Plant Physiology Reports, 28(1), 35–42
