Effects of parental light environments on growth and morphological responses of clonal offspring.

● Environments experienced by parent ramets of clonal plants can potentially influence fitness of clonal offspring ramets. Such clonal parental effects may result from heritable epigenetic changes such as DNA methylation, which can be removed by application of DNA de-methylation agents such as 5-azacytidine. ● To test whether parental shading effects occur via clonal generation and whether DNA methylation plays a role in such effects, parent plants of the clonal herb Alternanthera philoxeroides were first subjected to two levels of light intensity (high vs. low) crossed with two levels of DNA de-methylation (no or with de-methylation by the application of 5-azacytidine), and then clonal offspring taken from each of the four types of parent plants were subjected to the same two light levels. ● Parental shading effects transmitted via clonal generations, which decreased growth and modified morphology of clonal offspring. Offspring responses were also influenced by DNA methylation levels of parent plants. For clonal offspring growing under low light, parental shading effects on growth and morphology were always negative, irrespective of the parental de-methylation treatments. For clonal offspring growing under high light, parental shading effects on offspring growth and morphology were negative when the parents were not treated with 5-azacytidine, but neutral when they were treated with 5-azacytidine. ● Overall, there are parental shading effects on clonal offspring performance of A. philoxeroides and DNA methylation is likely involved in such effects. However, parental shading effects contributed little to the tolerance of clonal offspring to shading. This article is protected by copyright. All rights reserved.