Viability of Embryo Sacs and Fruit Set in Different Plum (Prunus domestica L.) Cultivars Grown under Norwegian Climatic Conditions

Abstract

Compatibility and synchrony between specialized tissues of the pistil, female gametophytes and male gametophytes, are necessary for successful pollination, fertilization, and fruit set in angiosperms. The aim of the present work was to study the development and viability of embryo sacs, as well as fertilization success, in relation to the fruit set of the cultivars ‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’, under specific Norwegian climatic conditions. Emasculated, unpollinated, and open-pollinated flowers were collected at the beginning of flowering, and on the 3rd, 6th, 9th, and 12th days after flowering, from all four plum cultivars over two years (2018/2019). Ovaries were dehydrated, embedded in paraffin wax, sectioned, stained, and observed under a light microscope. Results showed the existence of synchronization between successive phases in the development of the embryo sac and individual phases of flowering. All plum cultivars had higher percentages of viable embryo sacs, fertilized embryo sacs, and fruit set in 2018 than in 2019. These differences may be related to the very low temperatures during the post-full-flowering period in 2019, and to the low adaptation of some studied cultivars to unfavorable conditions. In our study, the cultivar ‘Jubileum’ showed the highest percentage of viable embryo sacs, fertilized embryo sacs, and fruit set compared to other cultivars, i.e., the best low-temperature adaptation.

The Effect of Different Temperatures on the Viability and Senescence of Plum Ovules (Prunus domestica L.)

“…The highest percentage of viable ovules was observed with the 'Jubileum' cultivar at all temperatures. This cultivar exhibited the highest percentage of viable and fertilized embryo sacs and fruit sets, whereas the lowest was observed in 'Reeves', as Cerović et al [48] reported. Previous research by Fotirić Akšić et al [1] indicated that 'Jubileum' has a longer effective pollination period of five days, in contrast to 'Edda', 'Mallard', and 'Reeves', where it lasts only three days.…”

Genetic Characterization of European Plum (Prunus domestica L.) Accessions from Norway Using ECPGR-Selected SSR Markers

“…At that time, fruit cultivation was mainly conducted within monasteries, from where the practice then spread [2]. Plum production is currently located in the most suitable climatic regions, along the fjord sides in Western Norway and around lakes in Eastern Norway [3], where the short and relatively cool growing season limits the choices of plum cultivars that can be grown [4].…”