Epigenetics regulation, including DNA methylation, histone modifications and non-coding RNAs-mediated regulation of gene expression, is involved in plant development, adaptation to environmental stresses and genome stability. Previously, we have identified and dissected the functional roles of some epigenetic factors involving histone modification and small RNA biogenesis in Arabidopsis and rice. We identified the first plant H3K27me3 demethylase, REF6/JMJ12, demethylating H3K27me3 by recognizing a specific DNA motif, which is inhibited by DNA methylation, revealing the cross-talk between histone modification and DNA methylation. We also revealed the key roles of histone H3 lysine 9 (H3K9) methyltransferase, H3K4 demethylase and small RNA processing enzyme DICER-Like in maintaining the stability of different types of transpose elements in rice. However, the plasticity and hereditability of epigenetic regulation as well as their contribution to plant evolution and domestication are almost unknown. In this talk, I will discuss transcriptional regulation of plant developmental plasticity and will highlight our recent progresses regarding the trans-generational inheritance of DNA methylation and their roles in acquired cold tolerance of rice during adaptation to low temperature.