Asexual reproductive adaptation to simulated cretaceous climatic variables by Norway spruce cells in vitro

Conifers rarely undergo asexual reproduction by parthenogenesis (haploid or diploid). When cells of Finnish Norway spruce genotypes are grown in a bioreactor under environmental conditions more typical of the Mesozoic (high temperatures, carbon dioxide, and humidity, abundant food supply, etc.), the barriers to asexual reproduction are removed. Gene(s) for apomixis are now expressed in cell suspensions of the rescued early embryo. A new population of diploid embryos is reconstituted from these cells by an apomeiotic and parthenogenetic process. This signifies that asexual gene expression is latent and suppressed under climatic conditions at the current seed sources. Moreover, cells are reverting to conservative ontogenetic strategies for adapting to atmosphere-biosphere variables that have seen conifers survive through “bottle-neck” selective regimes in the deep past. The control of culture parameters with bioreactors enables the experimental testing of genotypes in todayʹs forests for their adaptive reproductive responses to critical parameters in models for atmosphere-biosphere change. Environmental preconditions for reproductive fitness and survival from one generation to the next apomictic population can now be explored under controlled conditions. This enables a new study of experimental phylogenetics as a function of changes in atmosphere-biosphere models.