Consequences to fertilization of the developmental stage of apricot ovulesat anthesis

Flowers at anthesis from the apricot cvs Palstein and Goldrich were examine d to determine their ovule maturity stage. Further, flowers from both culti vars were pollinated and collected after 2000 and 3000 growing degree hours (GDH) in two consecutive years. Numbers of fertilized ovules were recorded in those flowers. Ovules of 'Palstein' from flowers at anthesis showed pre dominantly an embryo sac at the eight nuclei stage of development while emb ryo sacs in 'Goldrich' were mainly in a four nuclei stage. After 2000 GDH f rom pollination 90% of viable ovules were fertilized in 'Palstein' whereas only 37.5% of them were fertilized in 'Goldrich'. After 3000 GDH, Goldrich presented the same percentage of fertilized ovules that was recorded after 2000 GDH. Non-fertilized ovules did not degenerate and developed normally i n pollinated and non-pollinated flowers from both cultivars. Further, non-f ertilized pollinated flowers were not different from non-pollinated flowers in the development of the embryo sac, indicating that the chances for fert ilization would not be increased by pollination in apricot. We suggest that the lack of fertilization in 'Goldrich' is due to degeneration of the male gametophyte, which would have a limited life, not long enough for the embr yo sacs to develop to maturity.