[Effects of stereoscopic traction on photosynthetic characteristics, yield, and quality of Codonopsis pilosula under organic cultivation].

To solve the serious problem of stem and leaf shading in the middle and late stage of traditional flat planting of Codonopsis pilosula, this study analyzed the effects of different stereoscopic traction heights on the photosynthetic characteristics and growth of C. pilosula and explored the optimal traction height to improve the yield and quality of C. pilosula. The experiment designed three stereo-scopic traction heights [H1(60 cm), H2(90 cm), and H3(120 cm)] with natural growth without traction as the control(CK). The results showed that the increase in stereoscopic traction heights broadened the growth space of stems and leaves of C. pilosula, enhanced the ventilation effect, significantly increased the average daily net photosynthetic rate of C. pilosula, promoted the absorption of intercellular CO_2, decreased the transpiration rate, and reduced the evaporation of water. Moreover, it effectively avoided the problem of weakened photosynthesis, maintained the carbon balance of individual plants, and promoted the growth and development of the C. pilosula roots. In terms of the seed yield of C. pilosula, it was ranked as H2>H1>H3>CK. To be specific, H1 increased by 213.41% compared with CK, H2 increased by 282.43% compared with CK, and H3 increased by 133.95% compared with CK. The yield and quality of C. pilosula were the highest in the H3 treatment group, with the fresh yield of 6 858.33 kg·hm~(-2), 50.59% higher than CK, dry yield of 2 398.33 kg·hm~(-2), 76.54% higher than CK, and lobetyolin content of 0.56 mg·g~(-1), 45.22% higher than CK. Therefore, the stereoscopic traction height has a great influence on the photosynthetic characteristics, yield, and quality of C. pilosula. Particularly, the yield and quality of C. pilosula can be optimized and improved in the traction height treatment of H3(120 cm). This planting method is worth popularizing and applying in the cultivated management of C. pilosula.