Chlorophyll fluorescence in two strawberry (Fragaria x ananassa Duch.) cultivars/Fluorescencja chlorofilu u dwoch odmian truskawki (Fragaria x ananassa Duch.)

The study of chlorophyll fluorescence (CF) parameters i.e.: Fo, Fm, Fv/Fm, Y, qP, qN, F'o, F'm was conducted in two strawberry cultivars 'Honeoye' and 'Teresa'. Measurements of their values were done twice: in an early autumn and late spring. Fluorescence of five dark-adapted mature leaves derived from each cultivar was measured in the laboratory at room temperature with the use of a portable pulse amplitude modulation (PAM) fluorometer in 15. replicates for each parameter. Statistical analysis of the obtained results showed significant differences between values of CF parameters in both cultivars. Mean values of CF, excluding F'o and F'm were significantly higher in cv.'Teresa' when compared with cv. 'Honeoye'. In both cultivars, the values of Fo, F'o, Fm, F'm were significantly higher in the spring measurements. In cv.'Teresa' the CF parameters i.e. Fv/Fm, Y, qP and qN achieved the higher values in the autumnal measurement, but in cv. 'Honeoye' values of these parameters except Y, were significantly higher in the spring. In the conclusion, it could be emphasized, that cv.'Teresa' distinguished a more efficient photosynthetic apparatus than cv. 'Honeoye' and the significant differences observed between the autumnal and spring CF values in the analyzed cultivars revealed the different, dependent on the genotype, response in the functioning of this apparatus to the various environmental conditions characterizing both seasons of the year.