Influence of continuous cropping years on yield and active compounds in Salvia miltiorrhiza f. alba

Biological characteristic of Salvia miltiorrhiza f. alba in field was studied. HPLC method was used to determine the lipophilic constituents (dihydrotanshinone, cryptotanshinone, tanshinone, tanshinone II (A) and miltione) and hydrophilic constituents (salvianolic acid, rosemarinic acid). The results showed that the fresh weight of S. miltiorrhiza f. alba which cropped for 2 years was decreased by 80.47%, while dry weight decreased by 79.42%. The normal diameter of the root was 0.3-0.5 cm, however, the diameter was 0.2-0.4 cm after 2 years, it was said that the decrease of the root diameter was the main reason for the decrease of the yield. The average contents of dihydrotanshinone, cryptotanshinone, tanshinone, tanshinone II (A), miltione, salvianolic acid and rosemarinic acid were decreased by 35.26%, 32.26%, 19.35%, 3.39%, 64.40%, 66.93% in plant which continuously cropped for 2 years, respectively. The yield and active constituents were mostly effected in the plant of S. miltiorrhiza f. alba, which continuously cropped for 2 years.