Effect of drought on pigments, osmotic adjustment and antioxidant enzymes in six woody plant species in karst habitats of southwestern China

▶ The accumulations of proline and soluble sugars could improve drought tolerance of karst plants. ▶ Higher activities of antioxidant enzymes permitted higher photosynthetic efficiency of karst plants. ▶ There were intimate relationships between enhanced or constitutive antioxidant enzyme activities in response to drought stress. ▶ The accumulations of proline and soluble sugars could activate the antioxidant defense mechanisms. ▶ The site-species matching work can contribute to the success of re-vegetation programs.