I. The Dead Can Nurture: Novel Insights into the Function of Dead Organs Enclosing Embryos
Plants have evolved a variety of dispersal units whereby the embryo is enclosed by various
dead protective layers derived from maternal organs of the reproductive system, including
seed coats (integuments), pericarps (ovary wall, e.g., indehiscent dry fruits) as well as floral
bracts (e.g., glumes) in grasses. Commonly, dead organs enclosing embryos (DOEEs) are
assumed to provide a physical shield for embryo protection and means for dispersal in the
ecosystem. In recent years we showed that DOEEs of various species across families also
have the capability for long-term storage of various substances, including active proteins
(hydrolases, ROS detoxifying enzymes), nutrients and metabolites that have the potential to
support the embryo during storage in the soil and assist in germination and seedling
establishment. Thus we discovered a feature not recognized previously where DOEEs
function as natural coatings capable of ‘engineering’ the seed microenvironment for the
the benefit of the embryo, the seedling, and the plant.