Electrolyte leakage (EL) was measured according to Sun et al. (2018 (link)). The total chlorophyll was extracted with 80% acetone, and a UV‐2250 spectrophotometer (Shimadzu, Kyoto, Japan) was used to measure the chlorophyll content according to Liu et al. (2021 (link)). RWC was calculated following the method of Jia et al. (2021b (link)). The leaf angle was the angle between the straight part of the leaf and the stem. A CIRAS‐3 portable photosynthesis system (CIRAS‐3; PP Systems, Amesbury, MA) was used to measure photosynthetic parameters. The chlorophyll fluorescence was detected using a chlorophyll fluorescence imaging system (IMAGING‐PAM, WALZ, Bavaria, Germany).
NBT and DAB were used to detect the accumulation of superoxide radical (O2−) and hydrogen peroxide (H2O2), respectively (Fryer et al., 2002 (link)). Free proline content, as well as MDA, H2O2, O2− and P5CS activity were detected using their corresponding detection kits (Suzhou Comin Biotechnology Co., Ltd., Suzhou, China).