OPTIMIZING THE NUTRITIONAL CONDITIONS OF DUCKWEED RAPID ASEXUAL PROPAGATION BASED ON ARTIFICIAL CULTURE

Duckweed plants reproduce fast and can be used as raw material for non-food biomass energy production, and also be used as feed for fish, poultry, etc., which can produce high quality edible protein. To optimize the artificial cultivation technology of duckweed for further resource development and utilization, this study explored the fresh weight and frond number variation in Hoagland and Hunter culture medium with different nutrient levels using the widespread species Spirodela polyrrhiza and Lemna minor. The results showed as follows: (1) The fresh weights of S. polyrrhiza and L. minor increased first and then decreased under different nutrient levels of Hoagland medium, while the fresh weight of S. polyrrhiza and L. minor showed a continuous increased trend in Hunter medium; The maximum relative growth rate (RGR) of S. polyrrhiza and L. minor were 0.11 and 0.18, respectively. The fresh weight was significantly affected by duckweed varieties, medium type and nutrient level (P<0.05), and the L. minor in Hunter stock had the highest biomass. (2) The number of fronds of S. polyrrhiza and L. minor in Hoagland and Hunter medium had the same trends as fresh weight. The maximum relative growth rates of fronds of S. polyrrhiza and L. minor were 0.14 and 0.19, respectively. The fronds variation also significantly affected by duckweed varieties, medium type and nutrient levels (P<0.05), and the L. minor in Hunter stock had the highest fronds. (3) The fresh weight/fronds ratio of the two duckweeds in different nutrient levels of Hoagland and Hunter medium showed a downward trend, indicating that the progeny frond prefer to reproduce to expand the fitness of the species when adapted to different nutritional levels. In summary, the Hunter stock solution is the optimal cultivation condition for widespread species L. minor to have large fresh biomass and great frond number in a short time and provide raw material for further resource utilization.