Penotypes of cloned conifer embryos can be strongly influenced by a number of in vitro factors and in some instances clonal variation can exceed that found in nature. von Aderkas et al. study embryos of hybrid larch, Larix × marschlinsii, and find that zygotic embryos, which mature in darkness inside seed cones, never accumulate phenolics whereas embryos cultured in vitro (i.e. somatic) accumulate phenolics readily. In contrast, light has a negative effect on protein accumulation. Somatic embryos that mature in light accumulate phenolics such as quercetrin in their embryonal root caps, which turn red. The results suggest that further study of abiotic factors is required to gain a better understanding of events during embryogenesis.
