Exogenous indole acetic acid alleviates Cd toxicity in tea (Camellia sinensis)

• Published in: Ecotoxicology and environmental safety 2020-03, Vol.190, p.110090, Article 110090
• Main Authors: Zhang, Chenyu, He, Qun, Wang, Minghan, Gao, Xizhi, Chen, Jianjiao, Shen, Chengwen
• Format: Article
• Language: English
• Subjects: Antioxidants - metabolism; Cadmium; Cadmium - analysis; Cadmium - metabolism; Cadmium - toxicity; Camellia sinensis; Camellia sinensis - chemistry; Indole acetic acid; Indoleacetic Acids - metabolism; Photosynthesis - drug effects; Plant Growth Regulators - metabolism; Plant Leaves - metabolism; Seedlings - drug effects; Soil Pollutants - analysis; Soil Pollutants - metabolism; Soil Pollutants - toxicity; Tea
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2019.110090

Cadmium (Cd), a toxic heavy metal, restrains the growth and development of plants and threatens global food safety. Many studies on the alleviation of heavy metal toxicity by exogenous phytohormones have emerged, but reports on tea (Camellia sinensis) are still scarce. In this study, the effects of indole acetic acid (IAA) (2 μM and 10 μM) on Cd uptake and on the physiological and biochemical characteristics of the ‘Xiangfeicui’ tea cultivar were investigated for the first time. The order of Cd accumulation in tea seedlings was root > stem > mature leaf > tender leaf. Under Cd stress (30 mg kg−1), photosynthetic pigment levels, antioxidant enzyme activity, root vigor, root IAA content, and the levels of most metabolites (including caffeine, soluble sugar, total amino acids, some amino acid components, and most catechins) were significantly reduced, while levels of malondialdehyde, proline, epicatechin, and some amino acids increased. We therefore propose that by reducing Cd accumulation, exogenous IAA can lessen the adverse effects of Cd on the physiology and biochemistry of tea seedlings, promoting the growth of healthier tea plants. •Effects of IAA on Cd uptake, and physiology and metabolism of tea investigated.•Cd accumulation order in tea seedlings was root > stem > mature leaf > tender leaf.•Cd stress affected physiology and metabolism including photosynthesis.•Exogenous IAA significantly alleviated Cd toxicity to restore physiology and metabolism.•Exogenous IAA can lessen the adverse effects of Cd in tea by reducing its accumulation.