| Summary: | 碩士 === 國立清華大學 === 生物資訊與結構生物研究所 === 104 === This study investigated the effects of three artificial light sources on the growth of plants. We used mung beans (V. radiate) and Arabidopsis (A. thaliana, Col 0) as model plants. To compare the effects of three light groups on the morphological, biochemical, and molecular alternation.
The results showed that both the beans and Arabidopsis had more biomass at seedling stage when grown under halogen lamps (HL). However, at later stages, HL-Arabidopsis had the smallest biomass, far less than grown under fluorescence tubes (FT) and red/blue light-emitted diode (LED), and had more inflorescence apex and flowered earlier. The spectrum of HL contained more infar-red (FR), which will induce the shade avoidance response (SAR), and the lamp could generate higher leaf temperature, both may contribute to the major differences between HL and other light sources.
Biochemical measurement agreed with the results of morphological examination. HL-mung beans and FT- Arabidopsis after 30 DAP (day after planted), have more carbohydrates accumulation (e.g. c), and showed lower concentration of MDA (malonaldehyde), which is an indicator for oxidative stress. These plants perhaps experienced less stress or had better ability to dealing with the stress. Chlorophyll fluorescence was resemble to draw the conclusion that those “healthy” plants were under less stress.
At molecular level, we checked the expression of genes involved in the phytohormones biosynthesis pathway. The expression of these genes displayed not much difference across the three groups of light sources. The hormones are probably the signals at the upstream of their response, and a network-style of regulation tends to offset any perturbation to the system. However, the results can still provide some evidence for the involvement of hormone regulation. For example, AAO1 (acetaldehyde oxidase 1), an auxin related genes, which participates in the last step of auxin synthesis, was upregulated during plant growth, and was statistically significant at 10 and 40 DAP. It probably played a role of signaling in SAR.
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