Results
Polyploid J. curcas induction and identification
The J. curcas seedlings were treated with different concentrations of colchicine solution for different times. The survival rates of the seedlings decreased with increasing colchicine concentration and the extension of treatment time; the highest mortality rate was 30% in the 0.4% colchicine treatments for 4 and 10 d (Table 1). At the same colchicine concentration, the efficiency of induction increased at first and then decreased as the treatment time increased. Our results showed that the highest induction rate was 15%, in the 0.1% colchicine treatment for 7 d, while the lowest induction rate was 2.5% at colchicine concentrations of 0.2%, 0.4% and 0.8% applied for 1, 10 and 7 d, respectively (Table 1).