SELF-INCOMPATIBILITY IN CROCUS-VERNUS SUBSP VERNUS (IRIDACEAE)

Outcross, self- and mixed pollinations were performed in Crocus vernus subsp. vernus, a species with bicellular pollen, dry stigmas and hollow style. No differences were noted among the above pollinations concerning the germination of pollen and the growth of pollen tubes until the top of ovary. Within 45 min after pollinations 62% of pollen grains germinated. Pollen tubes penetrated the papilla cuticle extending along the papilla wall; on entry into stigmatic lobes they continued growth in the stylar secretion to ovarian locules. Here, however, self-pollen tubes failed to reach or to enter the ovule micropyle; while pollen tubes from either outcross- or mixed pollinations grew until fertilizing ovules. These observations gave evidence of a self-incompatibility system in Crocus, which appeared to be neutralized by mentor effect. The ovary as site of incompatibility response is discussed. © 1990 Springer-Verlag.