[Selection of light source used for plant cultivation in controlled ecological life support system]

To select suitable light source for higher plant cultivation in the controlled ecological life support system of the future space station.

The experiment was carried out in the Space Higher Plant Cultivation Ground-based Experimental Facility (SHPCGEF); four combinations of two red and blue light-emitting diode (LED) were utilized as light sources; soilless cultivation technique with porous ceramic tubes and porous ceramic particles was utilized in the growth system.

The plants grown under the shelf of pure red LED showed a lying-down state in early stage, and stood erect in later period with slender and long stems; the plants under various combinations of red and blue LED grew with nearly normal state, but the plants under the combination of 90% red and 10% blue LED possessed the best comprehensive indexes.

The normal growth and development of plantlets needs two light sources of red and blue LED, and the combination of 90% red and 10% blue LED is the optimum one among those tested combinations.