The best plant growth regulator to increase seedling drought-resistance was PP333+6-BA, 6-BA was better for Acer mono Maxim, and Cotinus Coggyia (Royal purple).

• 6-BA、PP333+6-BA、CCC+6-BA组合处理提高了植物叶片的IAA含量及IAA/ABA值，内源IAA含量的提高及IAA/ABA值的提高有助于保持叶片气孔的开度、维持较高的光合作用，在干旱症状较轻时利于抗旱；