Growth characteristics of the as mutant in sugar-supplied culture. A) Cotyledon phenotypes of the CK grown on MS basic medium, the as mutant grown on MS basic medium, and the as mutant grown in MS medium with sugar (from left to right). B) Seedling phenotypes of the CK and as mutant grown on MS medium supplemented with sugar. Chloroplast ultrastructure of CK C) and as mutant D) grown on sugar-supplied medium. E) Comparison of the net photosynthetic rate between CK and as mutant cultured on sugar-supplied medium. Error bars represent mean ± Sd (n = 3). Student's t-test was performed and statistically significant differences were indicated by **P < 0.01. Scale bar = 1 cm in A and B) and 1 μm in C and D).