In order to clarify the best intercropping medicinal plants, this paper studied the allelopathy of medicinal plants on seed germination and seedling growth of C. oleifera, and studied the effects of different extracts of five medicinal plants on the growth of C. oleifera, in order to lay a theoretical foundation for the development of C. oleifera forest economy.

Taking the water extract of five medicinal plants as the research objects, the effects of medicinal plants on C. oleifera were determined by measuring the indexes of seed germination, seedling growth, seedling growth, physiology and defense enzyme activity.

Curcuma longa (C. longa) extract has a significant promoting effect on the germination rate of C. oleifera seeds, and the effect of stem and leaf extract is the most obvious. The extract of Clinacanthus nutans inhibits the germination rate of C. oleifera seeds. The medium and low concentrations of C. longa and recluse extract promote the growth of C. oleifera seedlings. Among them, 50 g/L extract and 25 g/L recluse extract significantly promote the root length and fresh weight of seedlings. The extract of 200 g/L C. longa and 25g/L C. nutans significantly increased the plant height, shoot length and shoot diameter of C. oleifera seedlings. The 200 g/L C. longa extract has a significant inhibitory effect on the malondialdehyde content of C. oleifera, which is 12.29 μmol/g. The soluble sugar content of C. oleifera is the highest when the concentration of C. longa extract is 200 g/L, which is 6.81 mg/g. The chlorophyll content of C. oleifera treated with 100 g/L C. longa extract is the highest, which is 1.898 6 mg/g. The higher the concentration of C. longa extract, the higher the POD activity and the lower the SOD activity, and the PPO activity shows a phenomenon of low promotion and high inhibition. Under the treatment of two medicinal plant extracts, the CAT activity decreased as a whole.

The extract of C. longahas a promoting effect on the growth of C. oleifera. Combined with the influence of the intercropping of medicinal plants on the soil in the early stage, it is suggested to promote the intercropping mode of C. longa -C. oleifera.