[Plastome dependent pollen sterility inOenothera]

Pollen in which the genome complexesflavens (derived fromOe. suaveolens) orgaudens (derived fromOe. lamarckiana) are combined withparviflora plastids (plastome IV) fails to germinate even though it is well developed otherwise. This inability to germinate, however, is not always complete. Those exceptional pollen grains which do germinate do not get this ability by a change of their genome. The germination rate varies modificatively. Furthermore it has clearly been demonstrated that the degree of sterility is influenced by the genotype of the sporophyte. But this influence of the diploid sporophyte on the haploid gametophyte does not go as far as to completely suspend differences in germination behaviour of pollen with plastome IV on the one hand and of (normal) pollen with other plastome types on the other hand.