[Light quality regulation of growth and endogenous IAA metabolism of Ganoderma lucidum mycelium]

To study the effect and mechanism of the light quality acting on Ganoderma lucidum, and provide a theoretical basis for G. lucidum mycelium cultivation, we focused on growth and endogenous IAA metabolism of G. lucidum mycelium under different light-emitting diode (LED) condition. The growth index, endogenous levels of IAA and Enzymes related to IAA metabolism and Polysaccharides content were investigated in different growth periods. Results showed that blue light irradiation was the best from the viewpoint of steady growth and polysaccharides accumulation, red light irradiation improved endogenous IAA level and promoted growth of mycelium in early stage of cultivation, green light irradiation decreased growth rate and fresh weight of mycelium, but increased drying rate. Enzymes related to IAA metabolism also significantly influenced by light quality. The activity of indole acetic acid oxidase (IAAO), peroxidase (POD) and tryptophan synthetase with blue light irradiation were showed high level in early time, but decreased later, and the IAA content was consistently at lower level than that in other treatments, while mycelium irradiated with yellow light showed the highest activity of both IAAO and tryptophan synthetase, and medium level of IAA content. In conclusion, the light quality affects growth and regulation of the level of endogenous IAA of G. lucidum mycelium.