Abstract: Epigenetics has not only become a popular field in biology, but also undergone rapid development in plant ecology due to an increasing number of studies. However, few assessments of the spectra and structures of epigenetic variation have been reported on wild plant populations. The epigenetic diversity and structure of naturally occurring Phragmites australis populations, occupying two different habitats on a small spatial scale in the Songnen Meadow in northeastern China, were investigated by assessing methylation-sensitive amplified polymorphisms (MSAPs) through fluorescent capillary detection. The habitat 1( i.e. H1) was a low-lying alkalized meadow with seasonal rainfall and pH 8-8.5. The habitat 2 ( i.e. H2) did not accumulate rainwater with pH higher than 10 as an alkaline patch. Among the methylation-susceptible loci (MSL), 71.09%-88.38% of which were polymorphic. At the intra-habitat level, 82.75% and 79.93% of the loci observed from H1 and H2 were polymorphic, with I indiex of 0.3712 and 0.3580, respectively, showing higher values in H1 than in H2. The AMOVA-based MSAP analysis showed significant epigenetic differentiation between habitats（P＜0.01）. Epigenetic variations of individuals would provide more phenotypes and evolutionary flexibility. Remarkable epigenetic differentiation between habitats would underly the basis of different phenotypes of P. australis. In a word, this study attempted to explore the ecological adaptation of reeds in different habitats on a small scale, which would provide guidelines when seeking to understand processes that drive phenotypic evolution and adaptation.

Key words:  Phragmites australis, methylation-sensitive amplified polymorphisms, epigenetic diversity, epigenetic structure, habitat, molecular ecology