A137 1 1

PAL activity was assayed using a plant PAL kit (A137-1-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China) following the manufacturer’s instructions and absorbance measurement at 290 nm and expressed in U·min⁻¹·g⁻¹ FW.

The physiological indicators: PAL, H₂O₂, MDA, Pro, and POD were measured using detection assay kits (Cat. No. A137-1-1, A064-1-1, A003-3-1, A107-1-1 and A084-3-1 respectively; Nanjing Jiancheng Bioengineering Institute, China). All the tests were performed according to the manufacturer’s instructions (http://www.njjcbio.com/, accessed on 1 December 2022). A lignin test kit was obtained from COMIN company (Cat. No. MZS-1-G; Suzhou, China). The leaves were used for physiological detection. Expanded leaves were collected from L96 and NT plants after salt stress (0 d, 2 d and 5 d). Each sample was repeated 4 times. At the same time, root were collected, washed, and frozen in −80 °C for the following RNA extraction and plant hormone detection via HPLC (Agilent 1260, Santa Clara, CA, USA).