Abstract
Diplotaxis includes C3-C4 intermediates as well as C3 species. D. muralis (Dm, 2n=42) is thought to be originated from natural hybridization between D. tenuifolia (Dt, 2n=22; C3-C4) and D. viminea (Dv, 2n=20; C3). We investigated leaf anatomical and photosynthetic traits of these species to elucidate the genetic background of Dm. The BSCs of Dt contained centripetally arranged many chloroplasts and mitochondria, whereas those of Dv did few organelles. The BSCs of Dm showed intermediate traits between Dt and Dv. In Dt, GDC P-protein was localized in the BSCs, whereas in Dv it occurred mainly in the mesophyll cells. In Dm, GDC occurred in both cell types, but more densely in the BSCs. Correspondingly, Dm showed intermediate values of CO2 compensation point between Dt and Dv. These data support the hypothesis that Dm was created by natural hybridization between the C3-C4 intermediate and the C3 species.
