OBJECTIVETo study the effect of water content in soil on physiological characters and yield of Artemisia annua.

METHODThe pot experiment was applied and activity of protective enzyme, biomass and artemisinin accumulation were measured under different water treatments.

RESULT AND CONCLUSIONThe results showed that contents of osmotic adjustable substances, activity of protective enzyme, biomass and artemisinin accumulation were greatly affected by water content in the soil. Under water stress the water content in leave decreased, relative plasmalemma permeability increased, proline quickly accumulated to promote water retaining capability of cell, POD, CAT and SOD cooperated to reduce lipid peroxidation and reduced cell damage, and biomass decreased. At the seedling stage, the content of artemisinin and yield reached the maximal when the water content in soil was between 50%-55%. At the beginning of the branching stage, the content of artemisinin was the highest at the water content of 50%-55%, while the yield reached the maximal at the water content of 70%-75%. At the end of branching stage, the content of artemisinin was the highest at the water content of 40%-45%, while the yield reached the maximal at the water content of 60%-65%. In conclusion, the optimum water content in soil was between 50%-55% at the seedling stage, at the branching stage, higher water content was beneficial for the higher yield.