Self-incompatibility inAcacia retinodes: Site of pollen-tube arrest is the nucellus

摘要

In self-incompatibleAcacia retinodesSchldl. var.uncifoliaJ.M. Black there is no inhibition of self pollen tubes before entry into the ovule, but the frequency of fertilized embryo sacs observed after self pollination is only 0.09–0.24 of that observed after outcrossing. Fluorescence- and light-microscope studies of sectioned, squashed or cleared whole ovules indicate that most self pollen tubes are arrested within the first or second layer of cells of the nucellus. The probability that nucellar arrest represents a primitive feature of self-incompatibility is discusse