THE MORICANDIA-SYNDROME IN SPECIES OF THE BRASSICACEAE - EVOLUTIONARYASPECTS

The CO2 compensation concentration (Gamma) and leaf anatomy were deter mined in 107 species of six tribes of Brassicaceae. There was an abund ant bundle-sheath in all investigated species. The Moricandia syndrome , characterized by a high concentration of chloroplasts in the bundle- sheath cells and Gamma values < 30 cm(3)(CO2) m(-3) was found within s pecies of the genera Moricandia, Diplotaxis and Brassica. Available re sults from molecular systematics indicate a common phylogenetic ancest or, suggesting monophyletic evolution of the syndrome within the tribe Brassiceae. Nevertheless, Gamma values of about 30 cm(3) m(-3) in som e other genera of the tribes Brassiceae and Sisymbrieae indicate an ev olutionarily sliding, gradual transition from C-3 ancestors.