Effect of gibberellic acid and potassium nitrate on seed germination of the resurrection plants Ramonda serbica and Ramonda nathaliae
Ramonda serbica and Ramonda nathaliae are rare resurrection plants, endemic and relict species from Balkan Peninsula. The effect of gibberellic acid (GA3) and potassium nitrate (KNO3) were conducted to determine the seed germination response for these two species. An experiment was conducted with four replications and three treatments including: different concentrations of GA3 (0, 250, 500 and 1000 part per million (ppm)) and KNO3 (0, 0.1, 0.2 and 0.3% v/v) and their combination. Final germination percentage (FGP), mean germination time (MGT), germination rate index (GRI) and corrected germination rate index (CGRI) were measured. The highest FGP, GRI and CGRI of R. serbica were recorded in seeds treated with 1000 ppm GA3 + 0.3% KNO3, while MGT in seeds control. The highest FGP and GRI of R. nathaliae were recorded in the seeds treated with 500 ppm GA3, while CGRI in seeds treated with 500 ppm GA3 + 0.2% KNO3. The seeds of R. nathaliae treated with different concentration of KNO3 had significantly higher germination compared to the control seeds, while the seeds of R. serbica did not have an effect on seed germination. The GA3 and KNO3 treatments of Ramondas seeds are suitable for the higher percentage of germinations.
Key words: Ramonda serbica, Ramonda nathaliae, seed germination, GA3, KNO3.