Effects Of Light Environment On Growth Development Of Protected Allium Sativum L. And Gynura Bicolor DC.

Gynura bicolor DC.,‘er shui zao’ garlic were used,respectively,to investigate the effect of different light,photoperiod on the growth and secondary metabolites. The results indicated that:1. The 14 h(7 h natural light + 7 h artificial light)uninterrupted illumination was necessary for garlic bulbing enlargement. However,under 7 h natural light,all supplements of light from 1 h to 7 h to break darkness at night could increase the bulbing enlargement more quickly than continuous 14 h illumination treatment. The difference of bulb weights among treatments of darkness break(1-7 h)was not significant. With the extension of light supplying at night(1-7 h),contents of leaf pigment,allicin,soluble sugars,vitamin C,soluble proteins and free amino acids of bulb were increased first and then decreased,and the treatment of 5 h darkness break showed the highest levels of pigment,vitamin C,soluble proteins and free amino acids content in the bulb,which is about 30.0%,7.7%,36.2% and 25.3% higher than 14 h uninterrupted illumination,respectively. Furthermore,both the content of total phenol and the free radical scavenging rate also showed the highest level in the treatment of 5 h darkness break. If the main purpose of protected garlic production was to get the yield,1 h darkness break treatment was enough,if both yield and quality were considered,5 h darkness break was the proper treatment.2. Light significantly affect the growth of Gynura bicolor DC. The growth, dry matter and sugar content were promoted when the plants grown under the red light, but the growth was inhibited under the blue light. The content of chlorophyll significantly decreased when the plants were grown under colored LEDs. The content of total phenols, flavonoids and anthocyanidin significantly increased when plants were grown under the RBY compared to the W, but the dry matter of the RBY and W showed no significant difference. The yield of between the BRY and W treatments showed no difference. The secondary metabolites and the tolerance to stress were promoted by the RBY treatment.