RESUMO
<p><b>OBJECTIVE</b>To study the reason for the deep dormancy of the aged Cuscuta chinensis seed and find the solving method.</p><p><b>METHOD</b>The separated and combined treatments were applied in the orthogonal designed experiments.</p><p><b>RESULT</b>The aged seed had well water-absorbency; the water and ethanol extracts of the seeds showed an inhibition effect on germination capacity of the seeds.</p><p><b>CONCLUSION</b>The main reason for the deep dormancy of aged C. chinensis seed is the inhibitors existed in seed. There are two methods to solve the problem. The seeds is immersed in 98% of H2SO4 for 2 min followed by 500 mg x L(-1) of GA3 treatment for 60 min, or in 100 mg x L(-1) of NaOH for 20 min followed by 500 mg x L(-1) of GA3 treatment for 120 min.</p>