Influence of residual roots on growth of Panax notoginseng

In order to analyze of the effects of residual roots decomposed on growth of two-year-old Panax notoginseng，the fibrous roots were added in the pot experiment and hydroponic experiment. The morphological index and enzyme activity were measured timely. The results showed that the number of fibrous root decreased with the increase of residual root addition in potted treatment for 30 days and hydroponic conditions for 10 days. The POD activity was relatively lower in fibrous roots and leaves of P. notoginseng which grew under treatments of pot experiment and hydroponic experiment without any addition or high proportion to addition of powdery fibrous roots. The SOD activity in fibrous roots of P. notoginseng which grew under pot condition decreased with the increase of additive amount of powdery fibrous roots，however，the contrary was found in hydroponic experiment. The root activity increased in various degrees under the condition of additive amount of powdery fibrous roots greater than 0.5 g/ kg in pot experiment and 1 g/10 L in hydroponic experiment. But the root activity decreased with the increase of test processing days in all treatments. The results suggested that the release of chemical substances of roots left in soil in the process of harvesting may be another factor leading to autotoxicity of P. notoginseng.