The effect of temperature on pollen germination and pollen tube growth of apricot cultivars

Abstract

The effect of three different temperatures (5, 15 and 25 degrees C) on pollen germination and pollen tube growth in vitro was studied in six apricot cultivars: 'Goldrich', 'Hungarian Best', 'Laycot', 'Novosadska Rodna', 'Pisana' and 'Sylred'. 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 (41-84%) were obtained at 15 and 25 degrees C. Germination rates at 5 degrees C were significantly lower than those at higher temperatures. However, germination rates at 5 degrees C were significantly higher in early-flowering cultivars ('Laycot', 'Sylred' and 'Goldrich') compared to late-flowering cultivars ('Novosadska Rodna', 'Hungarian Best' and 'Pisana'). 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 and 25 degrees C, respectively, in comparison with those recorded at 5 degrees C. The obtained results indicate differential cultivar response to the temperature during the pollination period.