The Study On The Regulation Mechanism Of The Yield And Quality Of Biomass Controlled By Flowering Genes In Arabidopsis

Cellulosic ethanol is a clean, resourceful and reproducible energy, and will be one of the best ways to meet the challenges of energy safety, ecological protection and issues concerning agriculture, countryside and farmers in our contry. In order to get more cellulosic ethanol, it is needed to increase both the biomass and quality of energy plants. Increasing the quality of energy plants is not only to increase the content of cellulose but also to decrease the content of lignin.The mutation or overexpression of some flowering genes will delay flowering and extend the vegetative phase of plants, which can increase the biomass of plants. Therefore, we carried out an investigation in the model plant—Arabidopsis in order to make clear the relations between the flowering genes and the genes concerned with bio-energy (for example: some genes concerned with the synthesis of cellulose and lignin). We expect to attain the combination of some mutants which can both increase the content of cellulose and reduce the content of lignin.The mutation of promoters of flowering, such as CRY2(CRYPTOCHROME 2),CONSTANS(CO)and FLOWERING TIME LUCOS T(FT), and overexpression of inhibitors of flowering, such as FLOWERING TIME LOCUS C(FLC)can delay flowering of plants, which will results in the extend of vegetative phase and the increase of biomass. So we pay more attention to these mutants of cry2, FLC-OX, ft-1, co-2 when we studied flowering mutants of Arabidopsis. In this study, I measured the contents of lignin and cellulose of these mutants above and analysed the expression patterns including circadian patterns of genes concerning with the synthesis of cellulose and lignin in different flowering mutants.The primary conclusions of the study are shown as follows:1. The mutation of CRY2 increase not only the biomass but also the ratio values of cellulose content/lignin content.2. The genes of 4CL1, FAH1, CESA4, CESA7, CESA8 have circadian expression patterns. (The gene 4CL1 encodes the synthase of lignin, the gene FAH1 encodes the synthase of S-lignin, and the genes CESA4, CESA7,CESA8 encode the synthase of cellulose.)3. The mutation of CRY2 remarkably increase both the expression level of FAH1 and that of CESA4, CESA7, CESA8.Based on the results and analysis above, cry2 is the preferable flowering mutant that can improve the bio-energy characters of plants.