Abstract: The aim of this study was to better understand the regulatory mechanism of growth and development of Reaumuria songorica seedlings, and to provide some references for the cultivation and restoration of desert plants.This study uses one-year-old seedlings of R. songorica as materials to investigate the effects of photoperiods and light quality ratios on their growth.LED lights were used as the light source, and three photoperiods and six light quality ratios were set up for cross-cultivation. The plant height, branch number, biomass and photosynthetic pigment content of the R. songorica seedlings were measured to evaluate their growth, and the effects of photoperiod and light quality ratio on their growth were investigated.The proper photoperiod and light quality ratio played an important role in the growth and development of R. songorica seedlings. Increasing the light time can promote the growth of R. songorica. When the ratio of red to blue was 3:1, the growth rate of plant height increased by 20.20% and 88.47% for 14 and 16 hours compared with 12 hours, respectively. When the ratio of red to blue light was 1:3 and the daily light duration was 14 and 16 hours, the number of primary branches increased by 6.67% and 66.67%, and the underground biomass increased by 259.85% and 551.82%, respectively. High proportion of red light and high proportion of blue light treatment can promote the growth of R. songorica seedlings, but the growth rate of plant height and the change trend of primary branch number is opposite. Under the light quality ratio of R:B=4:1, the growth rate of plant height increased with photoperiod, while the number of primary branches decreased. However, under the light quality ratio of R:B=1:4, the growth rate of plant height and the number of primary branches were opposite. Through the comprehensive application of principal component analysis and membership function analysis, the results show that the growth condition of R. songorica seedlings is better under treatments T2 (12-hour light, red-blue light ratio of 4:1) and T5 (12-hour light, red-blue light ratio of 1:4).

Key words: Reaumuria songorica seedlings, LED lights, morphological index, photoperiod, light quality ratio