Occurrence and Biosynthesis of Melatonin and Its Exogenous Effect on Plants

Anayat Rasool Mir, Mohammad Faizan, Andrzej Bajguz, Fareen Sami, Husna Siddiqui, Shamsul Hayat

Abstract


Melatonin is an endogenous indolamine found in many plants. It has been shown to generate a wide range of metabolic, physiological, and cellular responses, thus affecting growth and development, particularly under different environmental stresses. In the present review, we focus on its role in germination, growth and development, photosynthesis, senescence, and antioxidant activity in plants. Further, an effort has been made to discuss its occurrence, biosynthesis, and relationship with other phytohormones in plants. Moreover, melatonin-mediated signaling and its mechanisms of action under stress conditions in plants have been comprehensively discussed. Finally, its role under various abiotic stress conditions has also been discussed in this review.

Keywords


antioxidant; abiotic stress; biosynthesis; melatonin; regulation; signaling

Full Text:

PDF XML (JATS)

References


Aguilera, Y., Herrera, T., Liébana, R., Rebollo-Hernanz, M., Sanchez-Puelles, C., & Martín- Cabrejas, M. A. (2015). Impact of melatonin enrichment during germination of legumes on bioactive compounds and antioxidant activity. Journal of Agricultural and Food Chemistry, 63(36), 7967–7974. https://doi.org/10.1021/acs.jafc.5b03128

Ahammed, G. J., Xu, W., Liu, A., & Chen, S. (2019). Endogenous melatonin deficiency aggravates high temperature-induced oxidative stress in Solanum lycopersicum L. Environmental and Experimental Botany, 161, 303–311. https://doi.org/10.1016/j.envexpbot.2018.06.006

Allegrone, G., Razzano, F., Pollastro, F., & Grassi, G. (2019). Determination of melatonin content of different varieties of hemp (Cannabis sativa L.) by liquid chromatography tandem mass spectrometry. Sn Applied Sciences, 1(7), Article 720. https://doi.org/10.1007/s42452-019-0759-y

Arnao, M. B., & Hernández-Ruiz, J. (2006). The physiological function of melatonin in plants. Plant Signaling and Behavior, 1(3), 89–95. https://doi.org/10.4161/psb.1.3.2640

Arnao, M. B., & Hernández-Ruiz, J. (2007). Melatonin promotes adventitious- and lateral root regeneration in etiolated hypocotyls of Lupinus albus L. Journal of Pineal Research, 42(2), 147–152. https://doi.org/10.1111/j.1600-079X.2006.00396.x

Arnao, M. B., & Hernández-Ruiz, J. (2009a). Chemical stress by different agents affects the melatonin content of barley roots. Journal of Pineal Research, 46(3), 295–299. https://doi.org/10.1111/j.1600-079X.2008.00660.x

Arnao, M. B., & Hernández-Ruiz, J. (2009b). Protective effect of melatonin against chlorophyll degradation during the senescence of barley leaves. Journal of Pineal Research, 46(1), 58–63. https://doi.org/10.1111/j.1600-079X.2008.00625.x

Arnao, M. B., & Hernández-Ruiz, J. (2014a). Melatonin: Plant growth regulator and/or biostimulator during stress? Trends in Plant Science, 19(12), 789–797. https://doi.org/10.1016/j.tplants.2014.07.006

Arnao, M. B., & Hernández-Ruiz, J. (2014b). Melatonin: Possible role as light-protector in plants. In J. Radosevich (Ed.), UV radiation: Properties, effects, and applications (pp. 79–92). Nova Science Publishers.

Arnao, M. B., & Hernández-Ruiz, J. (2015a). Functions of melatonin in plants: A review. Journal of Pineal Research, 59(2), 133–150. https://doi.org/10.1111/jpi.12253

Arnao, M. B., & Hernández-Ruiz, J. (2015b). Melatonin: Synthesis from tryptophan and its role in higher plants. In J. P. F. D’Mello (Ed.), Amino acids in higher plants (pp. 390– 435). CAB International.

Arnao, M. B., & Hernández-Ruiz, J. (2017). Growth activity, rooting capacity, and tropism: Three auxinic precepts fulfilled by melatonin. Acta Physiologiae Plantarum, 39(6), Article 127. https://doi.org/10.1007/s11738-017-2428-3

Arnao, M. B., & Hernández-Ruiz, J. (2019). Melatonin and reactive oxygen and nitrogen species: A model for the plant redox network. Melatonin Research, 2, 152–168. https://doi.org/10.32794/11250036

Back, K., Tan, D. X., & Reiter, R. J. (2016). Melatonin biosynthesis in plants: Multiple pathways catalyze tryptophan to melatonin in the cytoplasm or chloroplasts. Journal of Pineal Research, 61(4), 426–437. https://doi.org/10.1111/jpi.12364

Bajwa, V. S., Shukla, M. R., Sherif, S. M., Murch, S. J., & Saxena, P. K. (2014). Role of melatonin in alleviating cold stress in Arabidopsis thaliana. Journal of Pineal Research, 56(3), 238–245. https://doi.org/10.1111/jpi.12115

Balzer, I., & Hardeland, R. (1991). Photoperiodism and effects of indoleamines in a unicellular alga, Gonyaulax polyedra. Science, 253(5021), 795–797. https://doi.org/10.1126/science.1876838

Balzer, I., & Hardeland, R. (1996). Melatonin in algae and higher plants – possible new roles as a phytohormone and antioxidant. Botanica Acta, 109(3), 180–183. https://doi.org/10.1111/j.1438-8677.1996.tb00560.x

Beyer, C. E., Steketee, J. D., & Saphier, D. (1998). Antioxidant properties of melatonin an emerging mystery. Biochemical Pharmacology, 56(10), 1265–1272. https://doi.org/10.1016/S0006-2952(98)00180-4

Burkhardt, S., Tan, D. X., Manchester, L. C., Hardeland, R., & Reiter, R. J. (2001). Detection and quantification of the antioxidant melatonin in Montmorency and Balaton tart cherries (Prunus cerasus). Journal of Agricultural and Food Chemistry, 49(10), 4898–4902. https://doi.org/10.1021/jf010321

Byeon, Y., & Back, K. (2014a). An increase in melatonin in transgenic rice causes pleiotropic phenotypes, including enhanced seedling growth, delayed flowering, and low grain yield. Journal of Pineal Research, 56(4), 408–414. https://doi.org/10.1111/jpi.12129

Byeon, Y., & Back, K. (2014b). Melatonin synthesis in rice seedlings in vivo is enhanced at high temperatures and under dark conditions due to increased serotonin N-acetyltransferase and N-acetylserotonin methyltransferase activities. Journal of Pineal Research, 56(2), 189–195. https://doi.org/10.1111/jpi.12111

Byeon, Y., Choi, G. H., Lee, H. Y., & Back, K. (2015). Melatonin biosynthesis requires N- acetylserotonin methyltransferase activity of caffeic acid O-methyltransferase in rice. Journal of Experimental Botany, 66(21), 6917–6925. https://doi.org/10.1093/jxb/erv396

Byeon, Y., Lee, H. Y., Lee, K., & Back, K. (2014). Caffeic acid O-methyltransferase is involved in the synthesis of melatonin by methylating N-acetylserotonin in Arabidopsis. Journal of Pineal Research, 57(2), 219–227. https://doi.org/10.1111/jpi.12160

Calvo, J. R., González-Yanes, C., & Maldonado, M. D. (2013). The role of melatonin in the cells of the innate immunity: A review. Journal of Pineal Research, 55(2), 103–120. https://doi.org/10.1111/jpi.12075

Cassone, V. M. (1998). Melatonin’s role in vertebrate orcadian rhythms. Chronobiology International, 15(5), 457–473. https://doi.org/10.3109/07420529808998702

Champney, T. H., Holtorf, A. P., Steger, R. W., & Reiter, R. J. (1984). Concurrent determination of enzymatic activities and substrate concentrations in the melatonin synthetic pathway within the same rat pineal gland. Journal of Neuroscience Research, 11(1), 59–66. https://doi.org/10.1002/jnr.490110107

Chen, G., Huo, Y., Tan, D. X., Liang, Z., Zhang, W., & Zhang, Y. (2003). Melatonin in Chinese medicinal herbs. Life Sciences, 73(1), 19–26. https://doi.org/10.1016/S0024- 3205(03)00252-2

Chen, Q., Qi, W. B., Reiter, R. J., Wei, W., & Wang, B. M. (2009). Exogenously applied melatonin stimulates root growth and raises endogenous indoleacetic acid in roots of etiolated seedlings of Brassica juncea. Journal of Plant Physiology, 166(3), 324–328. https://doi.org/10.1016/j.jplph.2008.06.002

Cui, G., Zhao, X., Liu, S., Sun, F., Zhang, C., & Xi, Y. (2017). Beneficial effects of melatonin in overcoming drought stress in wheat seedlings. Plant Physiology and Biochemistry, 118, 138–149. https://doi.org/10.1016/j.plaphy.2017.06.014

Dubbels, R., Reiter, R. J., Klenke, E., Goebel, A., Schnakenberg, E., Ehlers, C., Schiwara, H. W., & Schloot, W. (1995). Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry. Journal of Pineal Research, 18(1), 28–31. https://doi.org/10.1111/j.1600- 079X.1995.tb00136.x

Feng, X., Wang, M., Zhao, Y., Han, P., & Dai, Y. (2014). Melatonin from different fruit sources, functional roles, and analytical methods. Trends in Food Science & Technology, 37(1), 21–31. https://doi.org/10.1016/j.tifs.2014.02.001

Fuhrberg, B., Balzer, I., Hardeland, R., Werner, A., & Lüning, K. (1996). The vertebrate pineal hormone melatonin is produced by the brown alga Pterygophora californica and mimics dark effects on growth rate in the light. Planta, 200(1), 125–131. https://doi.org/10.1007/bf00196659

Galano, A. (2011). On the direct scavenging activity of melatonin towards hydroxyl and a series of peroxyl radicals. Physical Chemistry Chemical Physics, 13(15), 7178–7188. https://doi.org/10.1039/C0CP02801K

Galano, A., Tan, D. X., & Reiter, R. J. (2011). Melatonin as a natural ally against oxidative stress: A physicochemical examination. Journal of Pineal Research, 51(1), 1–16. https://doi.org/10.1111/j.1600-079X.2011.00916.x

Gao, W., Zhang, Y., Feng, Z., Bai, Q., He, J., & Wang, Y. (2018). Effects of melatonin on antioxidant capacity in naked oat seedlings under drought stress. Molecules, 23(7), Article 1580. https://doi.org/10.3390/molecules23071580

Gonzalez-Gomez, D., Lozano, M., Fernandez-Leon, M. F., Ayuso, M. C., Bernalte, M. J., & Rodriguez, A. B. (2009). Detection and quantification of melatonin and serotonin in eight sweet cherry cultivars (Prunus avium L.). European Food Research and Technology, 229(2), 223–229. https://doi.org/10.1007/s00217-009-1042-z

Gu, Q., Chen, Z., Yu, X., Cui, W., Pan, J., Zhao, G., Xu, S., Wang, R., & Shen, W. (2017). Melatonin confers plant tolerance against cadmium stress via the decrease of cadmium accumulation and reestablishment of microRNA-mediated redox homeostasis. Plant Science, 261, 28–37. https://doi.org/10.1016/j.plantsci.2017.05.001

Han, Q. H., Huang, B., Ding, C. B., Zhang, Z. W., Chen, Y. E., Hu, C., Zhou, L. J., Huang, Y., Liao, J. Q., Yuan, S., & Yuan, M. (2017). Effects of melatonin on anti-oxidative systems and photosystem II in cold-stressed rice seedlings. Frontiers in Plant Science, 8, Article 785. https://doi.org/10.3389/fpls.2017.00785

Hardeland, R. (2015). Melatonin in plants and other phototrophs: Advances and gaps concerning the diversity of functions. Journal of Experimental Botany, 66(3), 627–646. https://doi.org/10.1093/jxb/eru386

Hardeland, R. (2016). Melatonin in plants – diversity of levels and multiplicity of functions. Frontiers in Plant Science, 7, Article 198. https://doi.org/10.3389/fpls.2016.00198

Hasan, M. K., Ahammed, G. J., Yin, L., Shi, K., Xia, X., Zhou, Y., Yu, J., & Zhou, J. (2015). Melatonin mitigates cadmium phytotoxicity through modulation of phytochelatins biosynthesis, vacuolar sequestration, and antioxidant potential in Solanum lycopersicum L. Frontiers in Plant Science, 6, Article 601. https://doi.org/10.3389/fpls.2015.00601

Hattori, A., Migitaka, H., Iigo, M., Itoh, M., Yamamoto, K., Ohtani-Kaneko, R., Hara, M., Suzuki, T., & Reiter, R. J. (1995). Identification of melatonin in plants and its effects on plasma melatonin levels and binding to melatonin receptors in vertebrates. Biochemistry and Molecular Biology International, 35(3), 627–634.

Hernández, I. G., Gomez, F. J. V., Cerutti, S., Arana, M. V., & Silva, M. F. (2015). Melatonin in Arabidopsis thaliana acts as plant growth regulator at low concentrations and preserves seed viability at high concentrations. Plant Physiology and Biochemistry, 94, 191–196. https://doi.org/10.1016/j.plaphy.2015.06.011

Hernández-Ruiz, J., & Arnao, M. B. (2008). Distribution of melatonin in different zones of lupin and barley plants at different ages in the presence and absence of light. Journal of Agricultural and Food Chemistry, 56(22), 10567–10573. https://doi.org/10.1021/jf8022063

Hernández-Ruiz, J., Cano, A., & Arnao, M. B. (2004). Melatonin: A growth- stimulating compound present in lupin tissues. Planta, 220(1), 140–144. https://doi.org/10.1007/s00425-004-1317-3

Hu, W., Tie, W. W., Ou, W. J., Yan, Y., Kong, H., Zuo, J., Ding, X. P., Ding, Z. H., Liu, Y., Wu, C. L., Guo, Y. L., Shi, H. T., Li, K. M., & Guo, A. P. (2018). Crosstalk between calcium and melatonin affects postharvest physiological deterioration and quality loss in cassava. Postharvest Biology and Technology, 140, 42–49. https://doi.org/10.1016/j.postharvbio.2018.02.007

Hu, Z., Fan, J., Chen, K., Amombo, E., Chen, L., & Fu, J. (2016). Effects of ethylene on photosystem II and antioxidant enzyme activity in Bermuda grass under low temperature. Photosynthesis Research, 128(1), 59–72. https://doi.org/10.1007/s11120-015-0199-5

Huang, X., & Mazza, G. (2011). Simultaneous analysis of serotonin, melatonin, piceid and resveratrol in fruits using liquid chromatography tandem mass spectrometry. Journal of Chromatography A, 1218(25), 3890–3899. https://doi.org/10.1016/j.chroma.2011.04.049

Huang, Y., Guo, Y., Liu, Y., Zhang, F., Wang, Z., Wang, H., Wang, F., Li, D., Mao, D., Luan, S., Liang, M., & Chen, L. (2018). 9-cis-Epoxycarotenoid dioxygenase 3 regulates plant growth and enhances multi-abiotic stress tolerance in rice. Frontiers in Plant Science, 9, Article 162. https://doi.org/10.3389/fpls.2018.00162

Iriti, M., & Varoni, E. M. (2017). Melatonin in grapes and wine: A bioactive phytochemical. In G. A. Ravishankar & A. Ramakrishna (Eds.), Serotonin and melatonin. Their functional role in plants, food, phytomedicine, and human health (pp. 305–310). CRC Press.

Janas, K. M., Ciupińska, E., & Posmyk, M. M. (2009). Melatonin applied by hydropriming, as phytobiostimulator improving corn (Zea mays L.) seedlings growth at abiotic stresses conditions. In S. Li, Y. Wang, F. Cao, P. Huang, & Y. Zhang (Eds.), Progress in environmental science and technology (Vol. IIA, pp. 383–388). Science Press.

Janas, K. M., & Posmyk, M. M. (2013). Melatonin, an underestimated natural substance with great potential for agricultural application. Acta Physiologiae Plantarum, 35(12), 3285–3292. https://doi.org/10.1007/s11738-013-1372-0

Kang, K., Kang, S., Lee, K., Park, M., & Back, K. (2008). Enzymatic features of serotonin biosynthetic enzymes and serotonin biosynthesis in plants. Plant Signaling and Behavior, 3(6), 389–390. https://doi.org/10.4161/psb.3.6.5401

Kang, K., Kong, K., Park, S., Natsagdorj, U., Kim, Y. S., & Back, K. (2011). Molecular cloning of a plant N-acetylserotonin methyltransferase and its expression characteristics in rice. Journal of Pineal Research, 50(3), 304–309. https://doi.org/10.1111/j.1600- 079X.2010.00841.x

Kang, K., Lee, K., Park, S., Byeon, Y., & Back, K. (2013). Molecular cloning of rice serotonin N-acetyltransferase, the penultimate gene in plant melatonin biosynthesis. Journal of Pineal Research, 55(1), 7–13. https://doi.org/10.1111/jpi.12011

Kang, K., Lee, K., Park, S., Kim, Y. S., & Back, K. (2010). Enhanced production of melatonin by ectopic overexpression of human serotonin N-acetyltransferase plays a role in cold resistance in transgenic rice seedlings. Journal of Pineal Research, 49(2), 176–182. https://doi.org/10.1111/j.1600-079X.2010.00783.x

Ke, Q., Ye, J., Wang, B., Ren, J., Yin, L., Deng, X., & Wang, S. (2018). Melatonin mitigates salt stress in wheat seedlings by modulating polyamine metabolism. Frontiers in Plant Science, 9, Article 914. https://doi.org/10.3389/fpls.2018.00914

Kim, M., Seo, H., Park, C., & Park, W. J. (2016). Examination of the auxin hypothesis of phytomelatonin action in classical auxin assay systems in maize. Journal of Plant Physiology, 190, 67–71. https://doi.org/10.1016/j.jplph.2015.11.009

Kładna, A., Aboul-Enein, H. Y., & Kruk, I. (2003). Enhancing effect of melatonin on chemiluminescence accompanying decomposition of hydrogen peroxide in the presence of copper. Free Radical Biology and Medicine, 34(12), 1544–1554. https://doi.org/10.1016/S0891-5849(03)00180-1

Kolář, J., Macháčková, I., Eder, J., Prinsen, E., Dongen, W., Onckelen, H., & Illnerová, H. (1997). Melatonin: Occurrence and daily rhythm in Chenopodium rubrum. Phytochemistry, 44(8), 1407–1413. https://doi.org/10.1016/S0031-9422(96)00568-7

Kołodziejczyk, I., Bałabusta, M., Szewczyk, R., & Posmyk, M. (2015). The levels of melatonin and its metabolites in conditioned corn (Zea mays L.) and cucumber (Cucumis sativus L.) seeds during storage. Acta Physiologiae Plantarum, 37, Article 105. https://doi.org/10.1007/s11738-015-1850-7

Kołodziejczyk, I., & Posmyk, M. M. (2016). Melatonin – a new plant biostimulator? Journal of Elementology, 21(4), 1187–1198. https://doi.org/10.5601/jelem.2015.20.3.1012

Korkmaz, A., Karaca, A., Kocacinar, F., & Cuci, Y. (2017). The effects of seed treatment with melatonin on germination and emergence performance of pepper seeds under chilling stress. Tarim Bilimleri Dergisi – Journal of Agricultural Sciences, 23, 167–176.

Koyama, F. C., Carvalho, T. L. G., Alves, E., Silva, H. B., Azevedo, M. F., Hemerly, A. S., & Garcia, C. R. S. (2013). The structurally related auxin and melatonin tryptophan- derivatives and their roles in Arabidopsis thaliana and in the human malaria parasite Plasmodium falciparum. Journal of Eukaryotic Microbiology, 60(6), 646–651. https://doi.org/10.1111/jeu.12080

Lee, H. Y., & Back, K. (2016). Mitogen-activated protein kinase pathways are required for melatonin-mediated defense responses in plants. Journal of Pineal Research, 60(3), 327–335. https://doi.org/10.1111/jpi.12314

Lee, H. Y., Byeon, Y., Lee, K., Lee, H. J., & Back, K. (2014). Cloning of Arabidopsis serotonin N-acetyltransferase and its role with caffeic acid O-methyltransferase in the biosynthesis of melatonin in vitro despite their different subcellular localizations. Journal of Pineal Research, 57(4), 418–426. https://doi.org/10.1111/jpi.12181

Lee, K., Lee, H. Y., & Back, K. (2018). Rice histone deacetylase 10 and Arabidopsis histone deacetylase 14 genes encode N-acetylserotonin deacetylase, which catalyzes conversion of N-acetylserotonin into serotonin, a reverse reaction for melatonin biosynthesis in plants. Journal of Pineal Research, 64(2), Article e12460. https://doi.org/10.1111/jpi.12460

Lei, Q., Wang, L., Tan, D. X., Zhao, Y., Zheng, X. D., Chen, H., Li, Q. T., Zuo, B. X., & Kong, J. (2013). Identification of genes for melatonin synthetic enzymes in ‘Red Fuji’ apple (Malus domestica Borkh. cv. Red) and their expression and melatonin production during fruit development. Journal of Pineal Research, 55(4), 443–451. https://doi.org/10.1111/jpi.12096

Lerner, A. B., Case, J. D., Takahashi, Y., Lee, T. H., & Mori, W. (1958). Isolation of melatonin, the pineal gland factor that lightens melanocytes. Journal of the American Chemical Society, 80(10), 2587. https://doi.org/10.1021/ja01543a060

Li, C., Liang, B., Chang, C., Wei, Z., Zhou, S., & Ma, F. (2016). Exogenous melatonin improved potassium content in Malus under different stress conditions. Journal of Pineal Research, 61(2), 218–229. https://doi.org/10.1111/jpi.12342

Li, C., Tan, D. X., Liang, D., Chang, C., Jia, D. F., & Ma, F. W. (2015). Melatonin mediates the regulation of ABA metabolism, free-radical scavenging, and stomatal behaviour in two Malus species under drought stress. Journal of Experimental Botany, 66(3), 669–680. https://doi.org/10.1093/jxb/eru476

Li, C., Wang, P., Wei, Z., Liang, D., Liu, C., Yin, L., Jia, D., Fu, M., & Ma, F. (2012). The mitigation effects of exogenous melatonin on salinity-induced stress in Malus hupehensis. Journal of Pineal Research, 53(3), 298–306. https://doi.org/10.1111/j.1600- 079X.2012.00999.x

Li, H., Chang, J., Chen, H., Wang, Z., Gu, X., Wei, C., Zhang, Y., Ma, J., Yang, J., & Zhang, X. (2017). Exogenous melatonin confers salt stress tolerance to watermelon by improving photosynthesis and redox homeostasis. Frontiers in Plant Science, 8, Article 295. https://doi.org/10.3389/fpls.2017.00295

Li, J., Zeng, L., Cheng, Y., Lu, G., Fu, G., Ma, H., Liu, Q., Zhang, X., Zou, X., & Li, C. (2018). Exogenous melatonin alleviates damage from drought stress in Brassica napus L. (rapeseed) seedlings. Acta Physiologiae Plantarum, 40(3), Article 43. https://doi.org/10.1007/s11738-017-2601-8

Li, J., Zhao, C., Zhang, M., Yuan, F., & Chen, M. (2019). Exogenous melatonin improves seed germination in Limonium bicolor under salt stress. Plant Signaling and Behavior, 14(11), Article 1659705. https://doi.org/10.1080/15592324.2019.1659705

Li, M. Q., Hasan, M. K., Li, C. X., Ahammed, G. J., Xia, X. J., Shi, K., Zhou, Y. H., Reiter, R. J., Yu, J. Q., Xu, M. X., & Zhou, J. (2016). Melatonin mediates selenium-induced tolerance to cadmium stress in tomato plants. Journal of Pineal Research, 61(3), 291–302. https://doi.org/10.1111/jpi.12346

Li, X., Brestic, M., Tan, D. X., Zivcak, M., Zhu, X., Liu, S., Song, F., Reiter, R. J., & Liu, F. (2018). Melatonin alleviates low PS I-limited carbon assimilation under elevated CO2 and enhances the cold tolerance of offspring in chlorophyll b-deficient mutant wheat. Journal of Pineal Research, 64(1), Article e12453. https://doi.org/10.1111/jpi.12453

Liang, C., Zheng, G., Li, W., Wang, Y., Hu, B., Wang, H., Wu, H., Qian, Y., Zhu, X. G., Tan, D. X., Chen, S. Y., & Chu, C. (2015). Melatonin delays leaf senescence and enhances salt stress tolerance in rice. Journal of Pineal Research, 59(1), 91–101. https://doi.org/10.1111/jpi.12243

Liang, D., Shen, Y., Ni, Z., Wang, Q., Lei, Z., Xu, N., Deng, Q., Lin, L., Wang, J., Lv, X., & Xia, H. (2018). Exogenous melatonin application delays senescence of kiwifruit leaves by regulating the antioxidant capacity and biosynthesis of flavonoids. Frontiers in Plant Science, 9, Article 426. https://doi.org/10.3389/fpls.2018.00426

Ma, Q. X., Zhang, T., Zhang, P., & Wang, Z. Y. (2016). Melatonin attenuates postharvest physiological deterioration of cassava storage roots. Journal of Pineal Research, 60(4), 424–434. https://doi.org/10.1111/jpi.12325

Maitra, S. K., & Hasan, K. N. (2016). The role of melatonin as a hormone and an antioxidant in the control of fish reproduction. Frontiers in Endocrinology, 7, Article 38. https://doi.org/10.3389/fendo.2016.00038

Manchester, L. C., Tan, D. X., Reiter, R. J., Park, W., Monis, K., & Qi, W. (2000). High levels of melatonin in the seeds of edible plants: Possible function in germ tissue protection. Life Sciences, 67(25), 3023–3029. https://doi.org/10.1016/S0024-3205(00)00896-1

Martinez, V., Nieves-Cordones, M., Lopez-Delacalle, M., Rodenas, R., Mestre, T. C., Garcia- Sanchez, F., Rubio, F., Nortes, P. A., Mittler, R., & Rivero, R. M. (2018). Tolerance to stress combination in tomato plants: New insights in the protective role of melatonin. Molecules, 23(3), Article 535. https://doi.org/10.3390/molecules23030535

Mena, P., Gil-Izquierdo, A., Moreno, D. A., Martí, N., & García-Viguera, C. (2012). Assessment of the melatonin production in pomegranate wines. LWT – Food Science and Technology, 47(1), 13–18. https://doi.org/10.1016/j.lwt.2012.01.009

Mukherjee, S., David, A., Yadav, S., Baluška, F., & Bhatla, S. C. (2014). Salt stress-induced seedling growth inhibition coincides with differential distribution of serotonin and melatonin in sunflower seedling roots and cotyledons. Physiologia Plantarum, 152(4), 714–728. https://doi.org/10.1111/ppl.12218

Murch, S. J., & Saxena, P. K. (2006). A melatonin-rich germplasm line of St John’s wort (Hypericum perforatum L.). Journal of Pineal Research, 41(3), 284–287. https://doi.org/10.1111/j.1600-079X.2006.00367.x

Murch, S. J., Simmons, C. B., & Saxena, P. K. (1997). Melatonin in feverfew and other medicinal plants. Lancet, 350(9091), 1598–1599. https://doi.org/10.1016/S0140-6736(05)64014-7

Nawaz, M. A., Huang, Y., Bie, Z., Ahmed, W., Reiter, R. J., Niu, M., & Hameed, S. (2016). Melatonin: Current status and future perspectives in plant science. Frontiers in Plant Science, 6, Article 1230. https://doi.org/10.3389/fpls.2015.01230

Oladi, E., Mohamadi, M., Shamspur, T., & Mostafavi, A. (2014). Spectrofluorimetric determination of melatonin in kernels of four different Pistacia varieties after ultrasound-assisted solid–liquid extraction. Spectrochimica Acta Part A – Molecular and Biomolecular Spectroscopy, 132, 326–329. https://doi.org/10.1016/j.saa.2014.05.010

Padumanonda, T., Johns, J., Sangkasat, A., & Tiyaworanant, S. (2014). Determination of melatonin content in traditional Thai herbal remedies used as sleeping aids. DARU Journal of Pharmaceutical Sciences, 22, Article 6. https://doi.org/10.1186/2008-2231-22- 6

Parida, A. K., & Das, A. B. (2005). Salt tolerance and salinity effects on plants: A review. Ecotoxicology and Environmental Safety, 60(3), 324–349. https://doi.org/10.1016/j.ecoenv.2004.06.010

Park, S., Lee, D. E., Jang, H., Byeon, Y., Kim, Y. S., & Back, K. (2013). Melatonin-rich transgenic rice plants exhibit resistance to herbicide-induced oxidative stress. Journal of Pineal Research, 54(3), 258–263. https://doi.org/10.1111/j.1600-079X.2012.01029.x

Park, S., Lee, K., Kim, Y. S., & Back, K. (2012). Tryptamine 5-hydroxylase-deficient Sekiguchi rice induces synthesis of 5-hydroxytryptophan and N-acetyltryptamine but decreases melatonin biosynthesis during senescence process of detached leaves. Journal of Pineal Research, 52(2), 211–216. https://doi.org/10.1111/j.1600-079X.2011.00930.x

Perez-Llorca, M., Munoz, P., Muller, M., & Munne-Bosch, S. (2019). Biosynthesis, metabolism and function of auxin, salicylic acid and melatonin in climacteric and non-climacteric fruits. Frontiers in Plant Science, 10, Article 136. https://doi.org/10.3389/fpls.2019.00136

Pöggeler, B., Balzer, I., Fischer, J., Behrmann, G., & Hardeland, R. (1989). A role of melatonin in dinoflagellates? European Journal of Endocrinology, 120, S97. https://doi.org/10.1530/acta.0.120S097

Pöggeler, B., Balzer, I., Hardeland, R., & Lerchl, A. (1991). Pineal hormone melatonin oscillates also in the dinoflagellate Gonyaulax polyedra. Naturwissenschaften, 78(6), 268–269. https://doi.org/10.1007/bf01134354

Posmyk, M. M., Bałabusta, M., & Janas, K. M. (2009). Melatonin applied by osmopriming as a biostimulator improving cucumber (Cucumis sativus L.) seedling growth at abiotic stress conditions. In S. Li, Y. Wang, F. Cao, P. Huang, & Y. Zhang (Eds.), Progress in environmental science and technology (Vol. IIA, pp. 362–369). Science Press.

Posmyk, M. M., Bałabusta, M., Wieczorek, M., Sliwinska, E., & Janas, K. M. (2009). Melatonin applied to cucumber (Cucumis sativus L.) seeds improves germination during chilling stress. Journal of Pineal Research, 46(2), 214–223. https://doi.org/10.1111/j.1600- 079X.2008.00652.x

Posmyk, M. M., & Janas, K. M. (2009). Melatonin in plants. Acta Physiologiae Plantarum, 31(1), 1–11. https://doi.org/10.1007/s11738-008-0213-z

Posmyk, M. M., Kuran, H., Marciniak, K., & Janas, K. M. (2008). Presowing seed treatment with melatonin protects red cabbage seedlings against toxic copper ion concentrations. Journal of Pineal Research, 45(1), 24–31. https://doi.org/10.1111/j.1600- 079X.2007.00552.x

Qian, Y., Tan, D. X., Reiter, R. J., & Shi, H. (2015). Comparative metabolomic analysis highlights the involvement of sugars and glycerol in melatonin-mediated innate immunity against bacterial pathogen in Arabidopsis. Scientific Reports, 5, Article 15815. https://doi.org/10.1038/srep15815

Ramakrishna, A., Giridhar, P., Sankar, K. U., & Ravishankar, G. A. (2012). Melatonin and serotonin profiles in beans of Coffea species. Journal of Pineal Research, 52(4), 470–476. https://doi.org/10.1111/j.1600-079X.2011.00964.x

Reiter, R. J., Manchester, L. C., & Tan, D. X. (2005). Melatonin in walnuts: Influence on levels of melatonin and total antioxidant capacity of blood. Nutrition, 21(9), 920–924. https://doi.org/10.1016/j.nut.2005.02.005

Reiter, R. J., Tan, D. X., & Burkhardt, S. (2002). Reactive oxygen and nitrogen species and cellular and organismal decline: Amelioration with melatonin. Mechanisms of Ageing and Development, 123(8), 1007–1019. https://doi.org/10.1016/S0047-6374(01)00384-0

Reiter, R. J., Tan, D. X., Manchester, L. C., & Qi, W. (2001). Biochemical reactivity of melatonin with reactive oxygen and nitrogen species. Cell Biochemistry and Biophysics, 34(2), 237–256. https://doi.org/10.1385/cbb:34:2:237

Reiter, R. J., Tan, D. X., Zhou, Z., Cruz, M. H. C., Fuentes-Broto, L., & Galano, A. (2015). Phytomelatonin: Assisting plants to survive and thrive. Molecules, 20(4), 7396–7437. https://doi.org/10.3390/molecules20047396

Riga, P., Medina, S., García-Flores, L. A., & Gil-Izquierdo, A. (2014). Melatonin content of pepper and tomato fruits: Effects of cultivar and solar radiation. Food Chemistry, 156, 347–352. https://doi.org/10.1016/j.foodchem.2014.01.117

Rodriguez, C., Mayo, J. C., Sainz, R. M., Antolín, I., Herrera, F., Martín, V., & Reiter, R. J. (2004). Regulation of antioxidant enzymes: A significant role for melatonin. Journal of Pineal Research, 36(1), 1–9. https://doi.org/10.1046/j.1600-079X.2003.00092.x

Russel, J. R., Susanne, B., Javier, C., & Joaquin, J. G. (2002). Beneficial neurobiological effects of melatonin under conditions of increased oxidative stress. Current Medicinal Chemistry – Central Nervous System Agents, 2(1), 45–58. https://doi.org/10.2174/1568015024606583

Sae-Teaw, M., Johns, J., Johns, N. P., & Subongkot, S. (2013). Serum melatonin levels and antioxidant capacities after consumption of pineapple, orange, or banana by healthy male volunteers. Journal of Pineal Research, 55(1), 58–64. https://doi.org/10.1111/jpi.12025

Sarropoulou, V., Dimassi-Theriou, K., Therios, I., & Koukourikou-Petridou, M. (2012). Melatonin enhances root regeneration, photosynthetic pigments, biomass, total carbohydrates and proline content in the cherry rootstock PHL-C (Prunus avium Prunus cerasus). Plant Physiology and Biochemistry, 61, 162–168. https://doi.org/10.1016/j.plaphy.2012.10.001

Sarropoulou, V., Therios, I., & Dimassi-Theriou, K. (2012). Melatonin promotes adventitious root regeneration in in vitro shoot tip explants of the commercial sweet cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus P. canescens), and MxM 60 (P. avium P. mahaleb). Journal of Pineal Research, 52(1), 38–46. https://doi.org/10.1111/j.1600-079X.2011.00914.x

Sarrou, E., Therios, I., & Dimassi-Theriou, K. (2014). Melatonin and other factors that promote rooting and sprouting of shoot cuttings in Punica granatum cv. Wonderful. Turkish Journal of Botany, 38(2), 293–301. https://doi.org/10.3906/bot-1302-55

Shi, H., Jiang, C., Ye, T., Tan, D. X., Reiter, R. J., Zhang, H., Liu, R., & Chan, Z. (2015). Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin. Journal of Experimental Botany, 66(3), 681–694. https://doi.org/10.1093/jxb/eru373

Shi, H., Wei, Y., & He, C. (2016). Melatonin-induced CBF/DREB1s are essential for diurnal change of disease resistance and CCA1 expression in Arabidopsis. Plant Physiology and Biochemistry, 100, 150–155. https://doi.org/10.1016/j.plaphy.2016.01.018

Simlat, M., Ptak, A., Skrzypek, E., Warchoł, M., Morańska, E., & Piórkowska, E. (2018). Melatonin significantly influences seed germination and seedling growth of Stevia rebaudiana Bertoni. PeerJ – the Journal of Life and Environmental Sciences, 6, Article e5009. https://doi.org/10.7717/peerj.5009

Stege, P. W., Sombra, L. L., Messina, G., Martinez, L. D., & Silva, M. F. (2010). Determination of melatonin in wine and plant extracts by capillary electrochromatography with immobilized carboxylic multi-walled carbon nanotubes as stationary phase. Electrophoresis, 31(13), 2242–2248. https://doi.org/10.1002/elps.200900782

Stürtz, M., Cerezo, A. B., Cantos-Villar, E., & Garcia-Parrilla, M. C. (2011). Determination of the melatonin content of different varieties of tomatoes (Lycopersicon esculentum) and strawberries (Fragaria ananassa). Food Chemistry, 127(3), 1329–1334. https://doi.org/10.1016/j.foodchem.2011.01.093

Sun, Q., Zhang, N., Wang, J., Zhang, H., Li, D., Shi, J., Li, R., Weeda, S., Zhao, B., Ren, S., & Guo, Y. D. (2015). Melatonin promotes ripening and improves quality of tomato fruit during postharvest life. Journal of Experimental Botany, 66(3), 657–668. https://doi.org/10.1093/jxb/eru332

Szafrańska, K., Glińska, S., & Janas, K. M. (2013). Ameliorative effect of melatonin on meristematic cells of chilled and re-warmed Vigna radiata roots. Biologia Plantarum, 57(1), 91–96. https://doi.org/10.1007/s10535-012-0253-5

Szafrańska, K., Reiter, R. J., & Posmyk, M. M. (2016). Melatonin application to Pisum sativum L. seeds positively influences the function of the photosynthetic apparatus in growing seedlings during paraquat-induced oxidative stress. Frontiers in Plant Science, 7, Article 1663. https://doi.org/10.3389/fpls.2016.01663

Szafrańska, K., Szewczyk, R., & Janas, K. M. (2014). Involvement of melatonin applied to Vigna radiata L. seeds in plant response to chilling stress. Central European Journal of Biology, 9(11), 1117–1126. https://doi.org/10.2478/s11535-014-0330-1

Tal, O., Haim, A., Harel, O., & Gerchman, Y. (2011). Melatonin as an antioxidant and its semi-lunar rhythm in green macroalga Ulva sp. Journal of Experimental Botany, 62(6), 1903–1910. https://doi.org/10.1093/jxb/erq378

Tan, D. X., Chen, L. D., Poeggeler, B., Manchester, L. C., & Reiter, R. (1993). Melatonin: A potent endogenous hydroxyl radical scavenger. Endocrine Journal, 1, 57–60.

Tan, D. X., Hardeland, R., Back, K., Manchester, L. C., Alatorre-Jimenez, M. A., & Reiter, R. J. (2016). On the significance of an alternate pathway of melatonin synthesis via 5- methoxytryptamine: Comparisons across species. Journal of Pineal Research, 61(1), 27–40. https://doi.org/10.1111/jpi.12336

Tan, D. X., Manchester, L. C., Mascio, P. D., Martinez, G. R., Prado, F. M., & Reiter, R. J. (2007). Novel rhythms of N1-acetyl-N2-formyl-5-methoxykynuramine and its precursor melatonin in water hyacinth: Importance for phytoremediation. FASEB Journal, 21(8), 1724–1729. https://doi.org/10.1096/fj.06-7745com

Tan, D. X., Xu, B., Zhou, X., & Reiter, R. J. (2018). Pineal calcification, melatonin production, aging, associated health consequences and rejuvenation of the pineal gland. Molecules, 23(2), Article 301. https://doi.org/10.3390/molecules23020301

Tan, D. X., Zheng, X., Kong, J., Manchester, L. C., Hardeland, R., Kim, S. J., Xu, X., & Reiter, R. J. (2014). Fundamental issues related to the origin of melatonin and melatonin isomers during evolution: Relation to their biological functions. International Journal of Molecular Sciences, 15(9), 15858–15890. https://doi.org/10.3390/ijms150915858

Tang, Y., Lin, L., Xie, Y., Liu, J., Sun, G., Li, H., a Liao, M., Wang, Z., Liang, D., Xia, H., Wang, X., Zhang, J., Liu, Z., Huang, Z., He, Z., & Tu, L. (2018). Melatonin affects the growth and cadmium accumulation of Malachium aquaticum and Galinsoga parviflora. International Journal of Phytoremediation, 20(4), 295–300. https://doi.org/10.1080/15226514.2017.1374341

Turk, H., Erdal, S., Genisel, M., Atici, O., Demir, Y., & Yanmis, D. (2014). The regulatory effect of melatonin on physiological, biochemical and molecular parameters in cold-stressed wheat seedlings. Plant Growth Regulation, 74(2), 139–152. https://doi.org/10.1007/s10725-014-9905-0

van Tassel, D., Roberts, N., Lewy, A., & O’Neill, S. D. (2001). Melatonin in plant organs. Journal of Pineal Research, 31(1), 8–15. https://doi.org/10.1034/j.1600- 079X.2001.310102.x

Venegas, C., García, J. A., Escames, G., Ortiz, F., López, A., Doerrier, C., García-Corzo, L., López, L. C., Reiter, R. J., & Acuña-Castroviejo, D. (2012). Extrapineal melatonin: Analysis of its subcellular distribution and daily fluctuations. Journal of Pineal Research, 52(2), 217–227. https://doi.org/10.1111/j.1600-079X.2011.00931.x

Vitalini, S., Gardana, C., Zanzotto, A., Simonetti, P., Faoro, F., Fico, G., & Iriti, M. (2011). The presence of melatonin in grapevine (Vitis vinifera L.) berry tissues. Journal of Pineal Research, 51(3), 331–337. https://doi.org/10.1111/j.1600-079X.2011.00893.x

Wang, J., Liang, C., Li, S., & Zheng, J. (2009). Study on analysis method of melatonin and melatonin content in corn and rice seeds. Chinese Agricultural Science Bulletin, 25, 20–24.

Wang, L., Zhao, Y., Reiter, R. J., He, C., Liu, G., Lei, Q., Zuo, B., Zheng, X. D., Li, Q., & Kong, J. (2014). Changes in melatonin levels in transgenic ‘Micro-Tom’ tomato overexpressing ovine AANAT and ovine HIOMT genes. Journal of Pineal Research, 56(2), 134–142. https://doi.org/10.1111/jpi.12105

Wang, P., Sun, X., Chang, C., Feng, F., Liang, D., Cheng, L., & Ma, F. (2013). Delay in leaf senescence of Malus hupehensis by long-term melatonin application is associated with its regulation of metabolic status and protein degradation. Journal of Pineal Research, 55(4), 424–434. https://doi.org/10.1111/jpi.12091

Wang, P., Sun, X., Li, C., Wei, Z., Liang, D., & Ma, F. (2013). Long-term exogenous application of melatonin delays drought-induced leaf senescence in apple. Journal of Pineal Research, 54(3), 292–302. https://doi.org/10.1111/jpi.12017

Wang, P., Yin, L., Liang, D., Li, C., Ma, F., & Yue, Z. (2012). Delayed senescence of apple leaves by exogenous melatonin treatment: Toward regulating the ascorbate–glutathione cycle. Journal of Pineal Research, 53(1), 11–20. https://doi.org/10.1111/j.1600- 079X.2011.00966.x

Wang, Y. P., Reiter, R. J., & Chan, Z. L. (2018). Phytomelatonin: A universal abiotic stress regulator. Journal of Experimental Botany, 69(5), 963–974. https://doi.org/10.1093/jxb/erx473

Weeda, S., Zhang, N., Zhao, X., Ndip, G., Guo, Y., Buck, G. A., Fu, C., & Ren, S. (2014). Arabidopsis transcriptome analysis reveals key roles of melatonin in plant defense systems. PLoS One, 9(3), Article e93462. https://doi.org/10.1371/journal.pone.0093462

Wei, J., Li, D. X., Zhang, J. R., Shan, C., Rengel, Z., Song, Z. B., & Chen, Q. (2018). Phytomelatonin receptor PMTR1-mediated signaling regulates stomatal closure in Arabidopsis thaliana. Journal of Pineal Research, 65(2), Article e12500. https://doi.org/10.1111/jpi.12500

Wei, W., Li, Q. T., Chu, Y. N., Reiter, R. J., Yu, X. M., Zhu, D. H., Zhang, W. K., Ma, B., Lin, Q., Zhang, J. S., & Chen, S. Y. (2015). Melatonin enhances plant growth and abiotic stress tolerance in soybean plants. Journal of Experimental Botany, 66(3), 695–707. https://doi.org/10.1093/jxb/eru392

Wei, Y., Zeng, H., Hu, W., Chen, L., He, C., & Shi, H. (2016). Comparative transcriptional profiling of melatonin synthesis and catabolic genes indicates the possible role of melatonin in developmental and stress responses in rice. Frontiers in Plant Science, 7, Article 676. https://doi.org/10.3389/fpls.2016.00676

Wei, Y. X., Liu, G. Y., Bai, Y. J., Xia, F. Y., He, C. Z., & Shi, H. T. (2017). Two transcriptional activators of N-acetylserotonin O-methyltransferase 2 and melatonin biosynthesis in cassava. Journal of Experimental Botany, 68(17), 4997–5006. https://doi.org/10.1093/jxb/erx305

Wen, D., Gong, B., Sun, S., Liu, S., Wang, X., Wei, M., Yang, F., Li, Y., & Shi, Q. (2016). Promoting roles of melatonin in adventitious root development of Solanum lycopersicum L. by regulating auxin and nitric oxide signaling. Frontiers in Plant Science, 7, Article 718. https://doi.org/10.3389/fpls.2016.00718

Xiao, S., Liu, L., Wang, H., Li, D., Bai, Z., Zhang, Y., Sun, H., Zhang, K., & Li, C. (2019). Exogenous melatonin accelerates seed germination in cotton (Gossypium hirsutum L.). PLoS One, 14(6), Article e0216575. https://doi.org/10.1371/journal.pone.0216575

Zhang, H. J., Zhang, N., Yang, R. C., Wang, L., Sun, Q. Q., Li, D. B., Cao, Y. Y., Weeda, S., Zhao, B., Ren, S., & Guo, Y. D. (2014). Melatonin promotes seed germination under high salinity by regulating antioxidant systems, ABA and GA4 interaction in cucumber (Cucumis sativus L.). Journal of Pineal Research, 57(3), 269–279. https://doi.org/10.1111/jpi.12167

Zhang, J., Li, H., Xu, B., Li, J., & Huang, B. (2016). Exogenous melatonin suppresses dark-induced leaf senescence by activating the superoxide dismutase-catalase antioxidant pathway and down-regulating chlorophyll degradation in excised leaves of perennial ryegrass (Lolium perenne L.). Frontiers in Plant Science, 7, Article 1500. https://doi.org/10.3389/fpls.2016.01500

Zhang, J., Shi, Y., Zhang, X., Du, H., Xu, B., & Huang, B. (2017). Melatonin suppression of heat-induced leaf senescence involves changes in abscisic acid and cytokinin biosynthesis and signaling pathways in perennial ryegrass (Lolium perenne L.). Environmental and Experimental Botany, 138, 36–45. https://doi.org/10.1016/j.envexpbot.2017.02.012

Zhang, J., Zeng, B., Mao, Y., Kong, X., Wang, X., Yang, Y., Zhang, J., Xu, J., Rengel, Z., & Chen, Q. (2017). Melatonin alleviates aluminium toxicity through modulating antioxidative enzymes and enhancing organic acid anion exudation in soybean. Functional Plant Biology, 44(10), 961–968. https://doi.org/10.1071/FP17003

Zhang, N., Sun, Q., Zhang, H., Cao, Y., Weeda, S., Ren, S., & Guo, Y. D. (2015). Roles of melatonin in abiotic stress resistance in plants. Journal of Experimental Botany, 66(3), 647–656. https://doi.org/10.1093/jxb/eru336

Zhang, N., Zhang, H. J., Sun, Q. Q., Cao, Y. Y., Li, X., Zhao, B., Wu, P., & Guo, Y. D. (2017). Proteomic analysis reveals a role of melatonin in promoting cucumber seed germination under high salinity by regulating energy production. Scientific Reports, 7(1), Article 503. https://doi.org/10.1038/s41598-017-00566-1

Zhang, N., Zhao, B., Zhang, H. J., Weeda, S., Yang, C., Yang, Z. C., Ren, S., & Guo, Y. D. (2013). Melatonin promotes water-stress tolerance, lateral root formation, and seed germination in cucumber (Cucumis sativus L.). Journal of Pineal Research, 54(1), 15–23. https://doi.org/10.1111/j.1600-079X.2012.01015.x

Zhang, R., Sun, Y., Liu, Z., Jin, W., & Sun, Y. (2017). Effects of melatonin on seedling growth, mineral nutrition, and nitrogen metabolism in cucumber under nitrate stress. Journal of Pineal Research, 62(4), Article e12403. https://doi.org/10.1111/jpi.12403

Zhao, D., Yu, Y., Shen, Y., Liu, Q., Zhao, Z., Sharma, R., & Reiter, R. J. (2019). Melatonin synthesis and function: Evolutionary history in animals and plants. Frontiers in Endocrinology, 10, Article 249. https://doi.org/10.3389/fendo.2019.00249

Zhao, H., Ye, L., Wang, Y., Zhou, X., Yang, J., Wang, J., Cao, K., & Zou, Z. (2016). Melatonin increases the chilling tolerance of chloroplast in cucumber seedlings by regulating photosynthetic electron flux and the ascorbate-glutathione cycle. Frontiers in Plant Science, 7, Article 1814. https://doi.org/10.3389/fpls.2016.01814

Zhao, Y., Tan, D. X., Lei, Q., Chen, H., Wang, L., Li, Q. T., Gao, Y., & Kong, J. (2013). Melatonin and its potential biological functions in the fruits of sweet cherry. Journal of Pineal Research, 55(1), 79–88. https://doi.org/10.1111/jpi.12044

Zhou, X., Zhao, H., Cao, K., Hu, L., Du, T., Baluška, F., & Zou, Z. (2016). Beneficial roles of melatonin on redox regulation of photosynthetic electron transport and synthesis of D1 protein in tomato seedlings under salt stress. Frontiers in Plant Science, 7, Article 1823. https://doi.org/10.3389/fpls.2016.01823

Zohar, R., Izhaki, I., Koplovich, A., & Ben-Shlomo, R. (2011). Phytomelatonin in the leaves and fruits of wild perennial plants. Phytochemistry Letters, 4(3), 222–226. https://doi.org/10.1016/j.phytol.2011.04.002

Zuo, Z., Sun, L., Wang, T., Miao, P., Zhu, X., Liu, S., Song, F., Mao, H., & Li, X. (2017). Melatonin improves the photosynthetic carbon assimilation and antioxidant capacity in wheat exposed to nano-ZnO stress. Molecules, 22(10), Article 1727. https://doi.org/10.3390/molecules22101727