Expression of floral MADS-box genes in Sinofranchetia

The second-whorl floral organs of Sinofranchetia chinensis (Lardizabalaceae) are nectar leaves. Hu et al. study the expression patterns of floral MADS-box genes in S. chinensis and find that SIchAP3-3 is significantly expressed only in nectar leaves at the late stages of floral development, and SIchAG is expressed not only in stamens and carpels, but also in nectar leaves. The results imply that the nectar leaves in S. chinensis could be referred to as petals, and the nectar leaves in some Ranunculales species might be derived from stamens.