UV -B Exposure of Indoor-Grown Picea abies Seedlings Causes an Epigenetic Effect and Selective Emission of Terpenes

摘要

Terpenoids are involved in various defensive functions in plants, especially conifers. Epigenetic mechanisms, for example DNA methylation, can in? uence plant defence systems. The purpose of the present study was to investigate the in? uence of UV-B exposure on the release of terpenoids from spruce seedlings and on needle DNA methylation. Ten-weekold seedlings grown indoors were exposed to UV-B radiation during 4 h, and the volatile compounds emitted from the seedlings were analysed. Analysis of the volatiles 1, 3, and 22 d after this UV-B exposure showed that bornyl acetate, borneol, myrcene, and limonene contents increased during the ? rst 3 days, while at day 22 the level of emission had returned to the control level. UV-B exposure decreased the level of DNA methylation in needles of young seedlings, re? ected in methylation changes in CCGG sequences. Exposure of young seedlings to UV-B radiation might be a way to potentiate the general defensive capacity, improving their ability to survive in outdoor conditions. UV-B-induced defence is discussed in the light of epigenetic mechanisms.