Relative expression of DNA methylation-associated genes at the four developmental stages.

<p>In the X-axis, 1, 2, 3 and 4 indicate the four cotyledon development stages from young to senescent. The y-axis indicates relative expression values of qRT-PCR compared with the first stage. The bars show the standard deviation of three technical replications. * indicates significant difference at <i>P</i><0.05 level, ** indicates extremely significant difference at <i>P</i><0.01 level.