Fig 3. Effect of ALA and NO on electrolyte leakage, MDA content, H₂O₂ and superoxide radical accumulation in leaves of E. nutans (DX, Damxung and ZD, Zhengdao) under chilling stress.

Four-week-old seedlings were pretreated with distilled water, 6 μM ALA, 100 μM SNP, 6 μM ALA + 200 μM PTIO, 6 μM ALA + 150 μM L-NNA, 200 μM PTIO, 150 μM L-NNA, 100 μM SNP + 200 μM PTIO, and 100 μM SNP + 150 μM L-NNA for 12 h, respectively, and then exposed to chilling stress (5°C) for 5 d. Plants treated with distilled water under the normal conditions (25°C) served as controls. Each value represents the mean ± SD (n = 3). Bars with different letters are significantly different at the 5% level.