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The application of light-emitting diode (LED) in agriculture and bio-industry has been concerned by all over the world along with the development of LED technology. LED not only has many advantages, such as small size, long life, low energy consumption, securing wave length and low production of heat, but also can emit the exact spectrum based on the need of plant. LED can actualize a lot of functions, such as energy saving, environment protection and efficient space utilization, which can not be achieved by conventional light source.Light spectrum plays an important role in plant development, morphogenesis, metabolism and gene expression. Application of light spectrum of LED on plantlets is important for plant cultivation and bud seeding vegetable In this thesis, rice and black pea seeds were tested to investigate the effects of light spectrum on growth of plantlets in different stages.The results are as follows:1. Effects of light quality on growth and physiological characteristics of rice seedlings of’wuyunjing 7’and’kangyou 63’. The results suggested light quality had remarkable effects and significant difference on the growth of two rice cultivars at different growth stage. Under blue LED, the plant heights were restrained remarkably, but the soluble protein content of’wuyunjing 7’and healthy index of two rice cultivars at five leaf stage were increased significantly. Under red LED, the stem diameter and healthy index at three leaf stage were increased remarkably, and also the soluble sugar and starch contents were increased significantly at five leaf stage. Under red-blue LED, the root number, stem diameter, healthy index, root activity and soluble sugar content in roots of the seedlings at three leaf stage were significantly promoted, the fresh mass, dry mass, healthy index, soluble sugar and sucrose content in leaf at five leaf stage were increased remarkably. Under yellow LED, the plant height were significantly increased at the initial growth stage. Generally, the red-blue LED could be more benefit to culture strong seedlings. 2. Stomatal density were increased and catheter diameter was increased significantly under blue LED. Under red-blue LED, catheter number was increased, stomatal length and width had significant negative correlation, and the difference of stomatal length and width were decreased significantly. Under blue, yellow and red-blue LED, the Fv/Fm and Fv/Fo were higher than those of the control, but respiration rate was decreased significantly. qp,ΦPSⅡand ETR were increased significantly under blue and yellow LED. Under red light, respiration rate was decreased remarkably. Photo synthetic rate of the leaves were increased significantly under red LED.3. Effects of Light intensity on growth and nutrient component of black bean sprouting seedlings were studied. From the experimental results, vitamin C was significantly increased. under the light intensity of 3μmol·m-2·s-1.The hypocotyls length, aboveground fresh mass, POD activity, soluble sugar and sucrose content were significantly increased. Under the light intensity of 3-9μmol·m-2·s-1, chlorophyll a, chlorophyll b and chlorophyll a+b content were increased remarkably. The content of hypocotyls diameter and amino acid were higher under the light intensity of 3～15μmol·m-2·s-1.The results suggested that the light intensity of 9μmol·m-2·s-1 could be more benefit to the growth of black bean sprouting seedlings.4. There were significantly increased on morphological index, enzyme activity and amino acid at early growth stage, but protein content gradually decreased. The hypocotyls length, hypocotyls diameter, aboveground fresh mass, aboveground dry mass, chlorophyll content and sod activity reach a stable state after seven days, but cellulose content were increased significantly. The soluble sugar, sucrose and vitamin C content were gradually increased at early growth stage, but decreased after six days. The ash and cellulose content were increased remarkably after seven days. The reducing sugar content was decreased significantly with growing. The results suggested that it had better morphological index on the seventh day and higher nutrient components on the sixth day.5. Blue light significantly increased aboveground fresh mass, hypocotyls elongation, hypocotyls diameter and POD activity in the black bean sprouting seedlings, maintained high vitamin C, vitamin E and protein content. Under red LED, aboveground dry mass were significantly increased chlorophyll a, chlorophyll b and chlorophyll a+b content, SOD activity and POD activity were maintained effectively. Under red-blue LED, the aboveground fresh mass, aboveground dry mass and root length were increased remarkably. Under yellow LED, the fresh mass of hypocotyls was increased significantly. Aboveground fresh mass and root length and were increased remarkably. Generally, the blue LED could be more benefit to the growth of black bean sprouting seedlings.6. Soluble sugar sucrose and starch content were increased significantly on 11 h-d-1 illumination. It was beneficial to the hypocotyls growth, ash and cellulose content were increased remarkably on 13 h-d-1. Chlorophyll a/b and amino acid content were increased significantly, but the content of MDA was decreased remarkably with increasing of the time of illumination. The results suggested that it had higher nutrient components on 11 h-d-1 illumination and better hypocotyls growth on 13 h-d-1 illumination.In conclude, this study supported the feasibility of application of light spectrum regulation of LED on agriculture and bio-industry, which would replace fluorescent and be widely used in plant cultivation and bud seeding vegetable
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