Ovule, embryo sac, embryo, and endosperm development in leafy spurge (<i>Euphorbia esula</i>)

Abstract

Leafy spurge (Euphorbia esula L.) is a noxious, invasive weed that dominates many agriculturally important regions. While many research efforts are currently aimed at controlling the spread of this plant, relatively little is known about its sexual reproductive biology, especially from a structural perspective. This report describes key features of ovule development, embryogenesis, and endosperm formation in leafy spurge. Ovules are anatropous, bitegmic, and form a zigzag micropyle. A distinct elaisome (caruncle) and hypostase are formed as ovules mature. Obturators are present and are derived from placental tissue. The embryo sac conforms to the Polygonum type. A single embryo is formed in each seed and stores nutrients primarily as globoid protein bodies. Endosperm is persistent and also contains protein bodies as its primary nutrient reserve. Preliminary structural evidence is presented that indicates the potential for apomixis.Key words: leafy spurge, Euphorbiaceae, Euphorbia, ovule, endosperm, embryo.