Vol.:(0123456789) 1 3 Journal of Plant Growth Regulation https://doi.org/10.1007/s00344-018-9849-0 Epigallocatechin-3-Gallate Alleviates Salinity-Retarded Seed Germination and Oxidative Stress in Tomato Golam Jalal Ahammed 1  · Yang Li 2  · Xin Li 2  · Wen‑Yan Han 2  · Shuangchen Chen 1 Received: 3 June 2018 / Accepted: 9 August 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Salinity is a global environmental problem, restricting crop production in a vast area of agricultural land. Although epi- gallocatechin-3-gallate (EGCG), the most abundant polyphenol in tea plants, has a strong antioxidative action in vitro, the role of EGCG in the plant response to salt stress remains unknown. In the present study, using a series of EGCG concentra- tions (10, 100, and 1000 µM), we showed that EGCG could alleviate salt stress-induced inhibition in seed germination and root growth in tomato. Exogenous EGCG increased not only the seed germination rate, but also the germination energy and germination index under salt stress. The 150 mM NaCl treatment signifcantly increased lipid peroxidation in roots by excessive accumulation of reactive oxygen species (ROS). In contrast, EGCG treatment, particularly at 100 µM concentra- tion, mitigated NaCl-induced oxidative stress as evidenced by the decreased H 2 O 2 and malondialdehyde content in roots. Analysis of the antioxidant enzyme system reveals that EGCG increased the activity of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase under salt stress. Considering the benefcial efect of EGCG on seed germination, root growth, ROS scavenging, and antioxidant enzyme activity, the 100 µM EGCG treatment appears to be the most efective concentration of those tested under salt stress in tomato. Our results suggest that the EGCG-promoted tomato tolerance to salt stress is associated with the mitigation of oxidative stress through an efcient ROS scavenging mechanism by the action of enhanced antioxidant enzyme activity. Thus, the enhancement of plant tolerance by exogenous EGCG can potentially expand crop cultivation in saline soils. Keywords Antioxidant · Epigallocatechin-3-gallate · Flavonoids · Salinity · Reactive oxygen species · Tomato Introduction Salinity is a serious environmental problem, afecting agri- cultural productivity around the world. Approximately 20% of the world’s cultivated land, including one-ffth of the irrigated agricultural land, faces threats of salinity (Alsaeedi et al. 2018; Hernandez et al. 2004). Notably, the problems regarding soil salinity are more severe particularly in arid and semi-arid regions due to limited rainfall and rising tem- perature associated with climate change. On a global scale, potential crop yield losses caused by salinity have been esti- mated at 20%. Alarmingly, the non-productive lands due to salinity are increasing year after year (Hawrylak-Nowak 2009). Considering the severity of the salinity hazard, enhancement of crop tolerance to salt stress by pharmaco- logical approaches can potentially expand crop cultivation in saline areas. Tomato (Solanum lycopersicum L.) is a widely cultivated annual vegetable crop (Cuartero and Fernández-Muñoz 1998). It is one of the most popular vegetables in the world for its pleasant taste, health benefts, and multiple consump- tion methods such as fresh, cooked, and processed foods. Despite the adaptability of tomato to a wide variety of cli- mates, this glycophyte plant species is salt-sensitive and Golam Jalal Ahammed and Yang Li have contributed equally to this work. * Golam Jalal Ahammed ahammed@haust.edu.cn * Xin Li lixin@tricaas.com 1 College of Forestry, Henan University of Science and Technology, Luoyang 471023, People’s Republic of China 2 Key Laboratory of Tea Quality and Safety Control, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling Road, Hangzhou 310008, People’s Republic of China