Effects of meta-topolin riboside and meta-methoxy topolin riboside on the in vitro micropropagation of Pyrus communis L. | Effects of meta–topolin riboside and meta–methoxy topolin riboside on the in vitro micropropagation of Pyrus communis L.

English. The present study aimed to evaluate the effects of new meta-topolin derivatives meta-topolin riboside (mTR) and meta-methoxy topolin riboside (memTR) on the ultiplication and subsequent rooting and ex vitro acclimatization of Pyrus communis L. (‘OHF 333’). The cytokinins mTR and memTR were included in the nutrient medium (0 μM, 3 μM, 6 μM, 9 μM, 12 μM). In plants from three passages of three-week-old cultures grown on different nutrient media, the following parameters were evaluated: multiplication coefficient, fresh (FW) and dry (DW) weight (mg), average length of shoots (mm), average number of leaves, leaf length and width (mm). At the rooting stage, data on the rooting frequency, number of roots per rooted micro-cutting and the length of roots were recorded 18 days after the start of the experiment. In the acclimatized plants, leaf area, FW and DW, and the content of photosynthetic pigments were determined 40 days after the transfer to ex vitro conditions. Gas exchange rate and chlorophyll fluorescence were also evaluated for the control and the variants with 6 and 9 μM mTR and memTR. The plantlets grown on cytokinin-supplemented media showed a higher number of leaves than the control. Plantlets grown on nutrient media with 6 and 12 μM mTR were distinguished by the highest FW and DW. In these variants, the shoots were of the greatest length. The plants grown on medium with 6 μM mTR had the highest number of leaves. Control plants had larger leaves. Тhe highest rooting percentage (70%) was achieved in plantlets grown with 9 μM mTR. A higher ex vitro acclimatization survival rate (76–100%) was found in all plants cultured with mTR or memTR compared to control plants (65%).

Polish. The present study aimed to evaluate the effects of new meta-topolin derivatives meta-topolin riboside (mTR) and meta-methoxy topolin riboside (memTR) on the ultiplication and subsequent rooting and ex vitro acclimatization of Pyrus communis L. (‘OHF 333’). The cytokinins mTR and memTR were included in the nutrient medium (0 μM, 3 μM, 6 μM, 9 μM, 12 μM). In plants from three passages of three-week-old cultures grown on different nutrient media, the following parameters were evaluated: multiplication coefficient, fresh (FW) and dry (DW) weight (mg), average length of shoots (mm), average number of leaves, leaf length and width (mm). At the rooting stage, data on the rooting frequency, number of roots per rooted micro-cutting and the length of roots were recorded 18 days after the start of the experiment. In the acclimatized plants, leaf area, FW and DW, and the content of photosynthetic pigments were determined 40 days after the transfer to ex vitro conditions. Gas exchange rate and chlorophyll fluorescence were also evaluated for the control and the variants with 6 and 9 μM mTR and memTR. The plantlets grown on cytokinin-supplemented media showed a higher number of leaves than the control. Plantlets grown on nutrient media with 6 and 12 μM mTR were distinguished by the highest FW and DW. In these variants, the shoots were of the greatest length. The plants grown on medium with 6 μM mTR had the highest number of leaves. Control plants had larger leaves. Тhe highest rooting percentage (70%) was achieved in plantlets grown with 9 μM mTR. A higher ex vitro acclimatization survival rate (76–100%) was found in all plants cultured with mTR or memTR compared to control plants (65%).