Effects of Different Plant Growth Regulators and Minerals on Pollen Germination of “İstanbul” Medlar Variety

Abstract

This study was carried out to examine the effects of some plant growth regulators and mineral substances on pollen germination and pollen tube length in the pollen of 'Istanbul' cultivar of medlar, which is one of the important minor fruit species. For this purpose potassium nitrate (50 ppm), thioure (50 ppm), benzyladenine (5ppm), gibberellic acid (10 ppm) and indole butyric acid (10 ppm) solutions were added germination medium (20% sucrose + 1% Agar-Agar + 5ppm H3BO3). Pollens were counted after 2h, 6h, 12h and 24 hours later after sowing. Pollen tube growth was measured by ocular micrometer after 24 hours later germination. Statistical analyses were performed by SPSS 22.0 version. The effects of chemicals on pollen germination and tube growth were found as statistically different according to plant growth regulators minerals substances. Pollen germination rate and pollen tube length were increased by incubation time. Potassium nitrate and gibberellic acid were determined as promoter while thioure and benzyladenine effected as inhibitory. The highest pollen germination rate and pollen tube length were obtained from the germination medium supplemented with gibberellic acid (26.25% and 100.28 µm respectively). Potassium Nitrate also increased the germination rate and pollen tube length as control (mean: 21.95%and 85.33 µm). Thioure (2.35%) and benzyladenine (2.80% effected as inhibitory in pollen germination and tube growth. Results close to the control group were obtained in the germination medium supplemented with indolebutyric acid (14.25% pollen germination rate and 36.31 µm pollen tube length). Recommended doses of gibberellic acid and potassium nitrate can be applied in the pollination period.