Influence of temperature on pollen germination and pollen tube growth of plum cultivars

Abstract

The temperature is an important environmental factor that affects pollen performance during the reproductive phase of fruit tree species. Pollen germination is one of the main factors for successful fertilization and fruit set in plum (Prunus domestica L.). The study was carried out to determine the effect of three different temperatures (5, 15 and 25°C) on the pollen germination and pollen tube growth in vitro of six European plum cultivars: ‘Cacanska Lepotica’, ‘Cacanska Rana’, ‘Jojo’, ‘Top’, ‘Toper’ and ‘Stanley’. Germination rate and pollen tube growth were determined on a culture medium containing 15% sucrose and 0.7% agar. Temperature significantly affected pollen germination of all studied cultivars. High germination rates (50‒76%) were obtained at the temperatures of 15°C and 25°C. However, satisfactory germination rates (29‒47%) were also obtained at the temperature of 5°C in some cultivars (‘Toper’, ‘Cacanska Rana’, ‘Cacanska Lepotica’ and ‘Top’). The influence of temperature was more prominent on the pollen tube growth. The length of pollen tubes was six to twelve times higher at 15°C and 25°C in comparison with 5°C. This has led to the conclusion that the temperature of 5°C, although it could be enough for pollen germination, is not enough for optimal pollen tube growth.