Cordyceps militaris is widely cultivated for functional food in China and Southeast Asia. Daylight was commonly used for development of C. militaris fruit bodies. In this study, effects of light wavelengths (pink light = 1/3,450–460 nm + 2/3,620–630 nm; red light = 620–630 nm; blue light = 450–460 nm) on fruit body's production and contents of bioactive components were investigated. The results are: pink light increased dried matter contents and bioefficiency of fruit bodies to the highest (40.06/6.77%) compared with blue light (24.44/4.86%), daylight (22.69/4.55%) and red light (22.06/4.17%), respectively. Pink light significantly enhanced accumulation of carotenoids. Red light obtained the highest contents of adenosine. Pink light is the most optimal for cordycepin accumulation. In order to get the highest production of adenosine, cordycepin, carotenoids and fruit body at the same time, pink light rather than only traditional daylight should be used in the fruit body development, or light wavelengths were regulated according to target compounds of the fruit bodies.
This study indicated that different light wavelengths have significant influences on fruit body development and accumulation of the main active compounds as cordycepin, adenosine and carotenoids. Pink light (1/3,450–460 nm + 2/3,620–630 nm) was optimal for production of adenosine, cordycepin and carotenoids. While the traditionally used daylight proved not suitable for cultivation of Cordyceps militaris. These results provided technological basis for cultivation of C. militaris and a insight to light reaction study on light wavelengths regulating accumulation of secondary metabolites.