Abstract:

【Objective】 Effects of different light spectral energy distributions on growth and development of tomato was studied in order to provide theoretic references for the commercial production of seedlings. 【Method】 The dysprosium lamp used as a control light source, six kinds of spectra were obtained by using light-emitting diode(LED). Tomato seedlings were grown in AGRI-LED plants cultivation system where other environmental factors were the same. Morphological parameters such as plant height, stem diameter, leaf area and physiological parameters such as root activity, content of sugar and nitrogen, enzyme activities of leaves were studied at seeding stage. At the same time, the stomata traits on leaf subsurface were observed. 【Result】 Plants under blue light, combinations of light (RB, RBG) treatment grown stronger and had a larger root-shoot ratio and also had smaller specific leaf area, but the red light had the opposite effect. Combinations of light benefited the growth and morphogenesis of seedlings. Monochrome red, yellow and green light induced seedling spindling and blue light inhibited the effects. Under blue light treatment, plants exhibited the highest total soluble sugar content, total amino acid content, and the dry weight was also the largest. The root activity and total starch content of tomato under the combinations of light (RBG) treatment was the highest. The combination of light (RB) made the leaves show highest photosynthetic rate and enzyme activity and accelerated carbon and nitrogen balanced distribution in leaves, crowns and roots. Meanwhile, the density of stomata of tomato leaves was higher and the area of stomata, stomata area per unit leaf area was larger under blue light and the combinations of light (RB, RBG). Though the total sucrose of tomato in yellow light treatment was the highest, but other kinds of indexes were smaller and it had unfavorable effect on growth and development of seedling. 【Conclusion】 It is concluded that blue light or the combinations of light (RB, RBG) benefit the growth and development of tomato seedling.

Key words: light spectral energy distribution')">light spectral energy distribution, tomato seedlings, light-emitting diode, carbon and nitrogen metabolism, stomata traits