The Effects Of Light Quality On Growth And Anthocyanin Synthesis Gene Expression Of Purple Cabbage

Light is an indispensable outside condition for plant to ensure the normal individual development. It can promote plant tissue and organ differentiation, at the same, can provide the energy for plant photosynthesis. The effect of light quality was multifaceted, it can affect plant photomorphogenesis, synthesis metabolism, gene regulation and so on. Anthocyanin synthesis on light quality had also deeply studied. The study of the effects on plant growth, related matter contents and anthocyanin synthesis, and the regulation of light quality on anthocyanin synthesis genes, but also can provide research materials on study of facilities vegetables about light quality-regulation.The study used purple cabbage, "purple crown No.l" as the experimental material, cloned the key genes in anthocyanin synthesis of purple cabbage leaf. LED lights which can precisely modulate light intensity and light quality were used as the light sources. The experiment explained effects of white(CK), red(R), blue(B), red and blue combination light(R/B) (the ratio is 3:7,5:5,7:3,8:2 and 9:1) on plant growth, photosynthetic pigment synthesis and the key anthocyanin synthesis gene expression pattern in leaf of purple cabbage. By analyzing the anthocyanin synthesis and gene expression level, we explicated the effects and mechanisms of plant regulators on plant anthocyanin synthesis, the main results were as follows:(1) The effects of light quality on the root morphology and root-shoot ratio of purple cabbage. The results showed red, blue and a percentage of red and blue combination light can significantly increase plant root-shoot ratio at the the early stage of process(5days and 1 Odays). At the later processing treatment time(20days and 25days), blue and red and blue combination light could significantly increase plant root-shoot ratio, but red light induced or had no differences on plant root-shoot ratio. In the whole growth of purple cabbage, red and blue combination light (7:3)and blue light could significantly increase root average diameter, average root length and root volume, red light had no influence on the formation of root morphology or inhibit the growth of root. At the later processing treatment time, blue and red and blue combination light (3:7,7:3 and 8:2) could significantly increase plant root surface area and root volume. Light did not show obvious effect on root at the early treatment time, after 25 days, it had significant difference (p< 0.05).(2) The effects of light quality on the growth of purple cabbage. The results showed all of the light quality can increase stem diameter, and its effects were obvious under the red and blue combination light(3:7,5:5,7:3 and 9:1)(p< 0.05). Red and blue combination light(3:7) could expand or significantly expand leaf blade stretching.(3) The effects of light quality on some nutrients of purple cabbage leaf. Red, blue and red and blue combination light could increase the content of soluble protein. Blue light and some red and blue combination light could improve soluble sugar content of purple cabbage leaf, but it was not obvious. In the 15 days, red light and red and blue combination light could obviously increase the content of vitamin C of purple cabbage leaf. However, red light quality could inhibit the increase of vitamin C content.(4) The effects of light quality on photosynthetic pigment and anthocyanin synthesis of purple cabbage leaf. The results showed that red and blue combination light could significantly increase content of chlorophyll a. Red and blue light had no obvious effects. The content of chlorophyll b under red and blue combination light(3:7) was significantly higher than that under red light and blue light, but there was no difference between them. Red and blue combination light(8:2) could significantly increase the content of chlorophyll, and red light and blue light did not significantly improve chlorophyll content. It was not significant to promote the increase of the content of the car under red light, blue light and red and blue combination light, however car content had the higher levels under red and blue combination light. At the early stage of the light quality processing treatment time(5days,10days and 15days), anthocyanin content was on the decline. In 15 treatment days, anthocyanin content had the lowest level. Later treatment times(20days and 25days), the contents of anthocyanin in leaf rose significantly. And blue light, red and blue combination light could increase anthocyanin contents, especially red and blue combination light(7:3) made the most significant. In the whole treatment stage, red light did not promote anthocyanin synthesis, its effects was weaker than white light.(5) The anthocyanin synthesis key gene CHS and ANS were isolated from purple cabbage leaf by using homologous cloning technology. CHS and ANS coding-length was 894 bp and 774 bp by PCR, and respectively code 297 and 257 amino acid. They shared high sequence identity with Brassica pekinensis and Arabidopsis. The cloning of CHS and ANS genes would have benefits to modify the anthocyanin synthesis and accumulations by using genetic ways.(6) Quantitative PCR (qPCR) was used to analysis the expression levels of the key anthocyanin synthesis genes CHS, F3H, DFR of purple cabbage leaf in different days and different light quality. At the early stage of the light quality treatment(5days,10days and 15days), blue light and red and blue combination light(3:7,7:3 and 8:2) increased leaf CHS expression level. In the whole processing times, red light did not up-regulate the expression of CHS gene. F3H gene expression regulation was rolling, in different treatment days, light qualities modified gene expression rolling with treatment days. Also found that red light, blue light and red and blue combination light could raise and lower DFR gene expression levels, it depended on the light quality treatment days.