ression of AtGRF2 or other GRF genes. First, the increased cell number enlarged the leaf area in BnGRF2a transgenic lines. However, in Arabidopsis, overexpression of AtGRF2 resulted in larger leaves because of an increase in cell size. Secondly, the adult leaf colour of the transgenic line was dark green. Thirdly, because of the longer pistil and normal stamen, near sterility was induced compared with AtGRF2 transgenic plants. Finally, the seed phenotype was not referred to in previous studies. It is thought that this discrepancy is due to the difference in gene sequences. Although BnGRF2 and AtGRF2 show good conservation of key domains, they only exhibit 69% identity overall, and these sequence differences might be responsible for the phenotypic differences. Research on ZmGRF2 and ZmGIF3 in Arabidopsis which only showed delayed bolting of the inflorescence stem and 2883-98-9 acceleration of the elongation of the stem seemed to confirm this view point. To elucidate how the metabolic pathways participate in the phenotypic changes observed, genome-wide 
analyses of the BnGRF2a-responsive transcriptome were performed by a microarray method. Generally, genes regulate seed mass by changing the cell number, cell size, or both. In the present experiments, the cell number in the leaf and seed was found to be increased in BnGRF2a-overexpressing transgenic lines, which was consistent with the AtGRF5 gene in the leaf, but different from AtGRF1 and AtGRF2 genes which increase the leaf cell size in Arabidopsis. With respect to the increased cell number, it was found that some genes related to cell division and the cell cycle were up-regulated. Improvement of the photosynthetic rate in transgenic lines was found, which was supported by some up-regulated genes related to light harvesting and chlorophyll biosynthesis. Just like the phenotype of the leaf in the 35SBnGRF2a transgenic lines, the chlorophyll content of developing seeds was also higher in transgenic NapinBnGRF2a Arabidopsis, which coincided with differences in the leaf and ovule between zy036 and 51070. Interestingly, the transgenic seeds contained 10% more oil than WT seeds, possibly as a result of improved photosynthetic efficiency. Light reactions of photosynthesis play an important role in defining plant fitness and productivity by influencing a seed’s carbon PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19811088 economy and how that carbon is stored. Previous studies with developing rapeseed embryos had shown that lipid accumulation was stimulated by light. This finding suggested that FA synthesis in the embryo might be dependent on the supply of reducing power and ATP provided by the light reactions of photosynthesis. To a certain extent, photosynthetic efficiency increases with an increasing concentration of light and, thus, light stimulates lipid accumulation by increasing photosynthetic efficiency. Some genes relating to FA Fig. 6. Analyses of dfferentially expressed genes induced by the BnGRF2a gene in Arabidopsis. Gene Ontology analyses of differentially expressed genes. Data from microarray analyses. Data from real-time PCR analyses. Data expression was normalized to b-actin1 and relative to the expression of genes in the WT control. Data presented are mean values of three biological replicates, and error bars represent standard deviations. Acknowledgements This study was supported by the National Key Basic Research Program of China and the National Transgenic Research Projects of China. synthesis and oil storage were up-regulated in the tran