Chloroplast division is affected in the bsd2 mutant a Ultra structure of the chloroplasts (proplastid stage) in the first leaf of 6-day-old wild type and bsd2 plants. Black triangles indicate dividing chloroplasts. BS, bundle sheath cell; M, mesophyll cell. Scale bars: 2μm. b Transcript levels of selected chloroplast-division genes were determined by quantitative RT-PCR in the first leaf of 6-day-old wild type and bsd2 plants. The error bars represent SD. Asterisk means significantly difference that assessed by Student’s t-tests, *p<0.05.