Abstract: In order to study the effects of different substrates and light conditions on the growth and planting of Hydrilla verticillata tissue cultured seedlings, the four light quality (white light, red light, blue light, red and blue mixed light) and three photoperiods (8, 12, 16 h/d) under the condition of tissue culture research, and tissue culture seedlings in three substrates (soil, sand, sediment mixed) and three shading levels (no shade, 40% shade, 80% shade) under the condition of plant research were studied. The results showed that red light significantly increased the dry weight and soluble sugar accumulation of Hydrilla verticillata, and significantly reduced the content of soluble protein. Blue light promoted the synthesis of chlorophyll a and inhibited the synthesis of chlorophyll b. The dry weight was the heaviest under the 12 h/d photoperiod, and the stem length was the longest, which was beneficial to the synthesis of chlorophyll. The increase of photoperiod improved the antioxidant enzyme activity of Hydrilla verticillate. The soil substrate was more conducive to the growth of Hydrilla verticillata than the sand substrate, and 80% shading was beneficial to increase the height and stem dry weight. This research not only supplied and improved the Hydrilla verticillata tissue culture system, but also provided a technical reference for the engineering application of tissue culture seedlings.

Key words: Hydrilla verticillata, tissue culture, light quality, photoperiod, sediment, degree of shading