Double Fertilization in Compositae

Cell-cell communication during double fertilization.

Double fertilization in flowering seed plants requires intercellular signaling events between many interacting partners. The four cell types of the seven-celled female gametophyte communicate with each other to establish and maintain their identity. They secrete signaling molecules to guide the male gametophyte and to mediate sperm cell discharge and transport towards the two female gametes (th...

Three Cell Fusions during Double Fertilization

Fertilization of both egg and central cell is a major distinguishing feature of flowering plants. Now, Maruyama et al. report a third cell fusion event between the persistent synergid and the fertilized central cell shortly after double fertilization in Arabidopsis. This causes rapid dilution of pollen tube attractant(s), preventing polytubey.

Live imaging of calcium spikes during double fertilization in Arabidopsis

Ca(2+) waves and oscillation are key signalling elements during the fertilization process of animals, and are involved, for example, in egg activation. In the unique double fertilization process in flowering plants, both the egg cell and the neighbouring central cell fuse with a sperm cell each. Here we succeeded in imaging cytosolic Ca(2+) in these two cells, and in the two synergid cells that...

Wood Anatomy of Vernonieae (Compositae)

Systematics of Isocarpha (Compositae: Eupatorieae)

Isocarpha comprises five species ranging from southern Texas and the Bahamas to northern Peru and northeastern Brazil. The genus belongs in Eupatorieae rather than Heliantheae, but structure of the head of Isocarpha with its elongate, chaffy receptacle is anomalous within Eupatorieae. An hypothesis is presented suggesting the evolutionary derivation of this type of head through formation of flo...