Freezing stress deteriorates tea quality of new flush by inducing photosynthetic inhibition and oxidative stress in mature leaves

•Freezing (−5°C for 3, 6 or 12h) drastically reduced Pn, Gs, Tr and WUE in tea plant.•Freezing stress increased H2O2 accumulation but decreased Fv/Fm in mature tea leaves.•Residual effect of freezing reduced water content and dry weight of new leaf and bud.•Freezing imprint increased polyphenol but decreased amino acid content in new flush.•Freezing-induced reduction in tea yield and quality is dependent on freezing duration.