Salt stress and alkali stress are major factors that affect the growth and production of Chinese cabbage. To explore their tolerant mechanism to salt and alkali stress, three salinity levels (0, 50, 100 mmol/L NaCl) and three different pH levels (pH6.5, pH7.5, pH8.5) were interactively applied on Qinghua (salt-tolerant–alkali-sensitive) and Biyu (salt-sensitive–alkali-tolerant) cultivars; the root morphology, ion content and antioxidant enzymes were determined. The results showed that the root morphology and root water content of Qinghua under S₀pH_7.5 and S₀pH_8.5 were seriously affected, and the content of H₂O₂ and MDA increased by 143%, 190% and 234%, 294%, respectively, compared with S₀pH_6.5; when Biyu was under S₅₀pH_6.5 and S₁₀₀pH_6.5 stress, the content of H₂O₂ and MDA increase to 152%, 208% and to 240%, 263%, respectively, but the activities and genes expression of SOD, POD, CAT, AAO, APX, DHAR and MDHAR did not change. The root and the contents of H₂O₂ and MDA were not affected when Qinghua was treated with salt and Biyu was treated with alkali, but the activities of the antioxidant enzymes increased to 150–200%, and their relative expression was overexpressed and 2.5–3.5-fold of the S₀pH6.5. The increase of Na⁺ in Qinghua was limited under salt stress, Mg²⁺ in Biyu increased significantly under alkali stress. These all indicated that the adaptability of roots could reflect the degree of tolerance; Chinese cabbage with high salt and alkali tolerance enhanced the regulation of their absorption of ions and increased the relative expression and activities of related antioxidant enzymes.

盐胁迫和碱胁迫是影响大白菜生长和产量的主要因素。为了探索它们对盐碱胁迫的耐受机制，在清华（盐-耐-耐碱）和碧玉（耐盐-耐碱）品种；测定了根形态、离子含量和抗氧化酶。结果表明，S ₀ pH _7.5和 S ₀ pH _8.5对青花根系形态和根系含水量影响严重，H ₂ O _2含量与S ₀ pH _6.5相比，MDA分别增加了143%、190%和234%、294% ；碧玉在S ₅₀ pH _6.5和S ₁₀₀ pH _6.5胁迫下，H ₂ O ₂和MDA含量分别增加至152%、208%和240%、263%，但SOD的活性和基因表达， POD、CAT、AAO、APX、DHAR 和 MDHAR 没有变化。_{H 2} O ₂的根和含量清花加盐、碧玉加碱处理不影响MDA和MDA，但抗氧化酶活性提高到150-200%，且相对表达量高，是S ₀ pH6的2.5-3.5倍。 5. 盐胁迫下清华Na ⁺增加有限，碱胁迫碧玉Mg ²⁺增加显着。这些都表明根系的适应性可以反映耐受程度；高耐盐碱大白菜增强了对离子吸收的调节，增加了相关抗氧化酶的相对表达和活性。