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Chinese Agricultural Science Bulletin ›› 2025, Vol. 41 ›› Issue (15): 51-58.doi: 10.11924/j.issn.1000-6850.casb2024-0502

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Effect of Malic Acid on the Growth and Photosynthesis of Industrial Hemp

LUO Yan1(), LIU Chen1, XIA Xin1, ZHAO Kaiyuan2, CHENG Xia1()   

  1. 1 College of Agronomy and Life Sciences, Kunming University, Kunming 650214
    2 Institute of Resource Botany, Yunnan University, Kunming 650500
  • Received:2024-07-31 Revised:2024-10-15 Online:2025-05-25 Published:2025-05-29

Abstract:

To explore environmentally sustainable methods for enhancing industrial hemp yield, this study used 'Yunma 7' as the material to screen the most suitable malic acid concentration and the best application method, so as to provide a theoretical basis for the realization of the yield increase mode combining multiple cultivation measures. Seed germination was evaluated under five malic acid concentrations (0, 1000, 2000, 3000, and 4000 mg/L) using filter paper culture, while pot experiments assessed plant growth and photosynthetic characteristics under two application methods(soil irrigation and foliar spraying). Germination tests demonstrated that 2000 mg/L malic acid significantly increased germination rate by 20.46% compared to the control, while 1000 mg/L treatment resulted in maximum shoot and root length. Pot experiments revealed that soil irrigation with 2000 mg/L malic acid produced optimal growth performance, increasing plant height, stem diameter, and root length by 45.62%, 14.55%, and 88.12%, respectively, with concurrently highest net photosynthetic rate and stomatal conductance, and lowest intercellular CO2 concentration. Foliar spraying with 3000 mg/L malic acid showed superior effects, enhancing plant height, stem diameter, and root length by 47.00%, 16.64%, and 80.74%, respectively, while significantly improving net photosynthetic rate and stomatal conductance and reducing intercellular CO2 concentration compared to other treatments. These results indicate that appropriate malic acid application can effectively promote hemp growth and yield. For practical production, we recommend soil irrigation with 2000 mg/L malic acid combined with integrated cultivation practices to achieve sustainable yield improvement.

Key words: industrial hemp, malic acid, method of application, seed germination, growth effects, photosynthesis