Search Results
Flowers of two cultivars of Rosa hybrida were treated or not with putrescine before being pollinated from 2 to 8 days after anther emasculation. On both cultivars the 10-3 M putrescine treatment extended the effective pollination period, as shown by the best hip formation rates and mean number of seeds per hip. On one cultivar, the 10-5 M putrescine treatment increased fertilization efficiency (more hips obtained). The effect of putrescine was proportionally more important on the cultivar characterized by the highest stigmatic exudate pH. Putrescine also influenced in vitro pollen germination by increasing the length of emitted pollen tubes (10-3 and 10-5 M-putrescine) and the quantity of germinated pollen grains (10-5 M putrescine).
Rose achenes of different genetic origins, all belonging to the species Rosa hybrids L., subjected to radiography films, germination tests, in situ observations of embryo development, and different temperature conditions during maturation showed that achene germination is affected by endocarp thickness. Furthermore, a relation between embryo development rate and endocarp thickness is demonstrated.