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| Authors: | T. Slavtcheva, V. Dimitrova |
| Keywords: | grapevine, in vitro culture, acclimatization, sucrose, gas exchange, growth |
Abstract:
Gas exchange of in vitro cultured ‘Dimiat’ and ‘Italian Riesling’ grapevines was studied.
The explants were cultured on a modified MS medium.
Two concentrations of sucrose in the nutrient medium were tested: 15 and 30 g L-1. Rates of photosynthesis (Pn) and dark respiration (Rd) were determined with an infra-red gas analyzer.
Photosynthesis was measured at four light levels: 20, 100, 200 and 400 µmol m-2 s-1. Measurements of Pn and Rd were made: a) on days 10, 9, 8 (1st series) and 3, 2, 1 (2nd series) before transfer from in vitro culture and b) on days 21, 22, 23 (3rd series) after the transfer.
Transpiration (E) was determined gravimetrically on days 7 and 1 before transfer from in vitro culture and on days 24 and 31 after the transfer.
The plantlets cultured on the medium with a sucrose concentration of 30 g L-1 rooted better compared to those cultured with 15 g L-1. Photosynthesis was strongly influenced by the light conditions with all series.
During in vitro culture, Pn increased significantly with the sucrose content in the nutrient medium.
During ex vitro cultivation, the influence of sucrose on Pn and Rd was mostly non-significant.
Transpiration was only slightly affected by the sucrose in the culture medium.
However, E was higher for the in vitro plantlets compared to the ex vitro ones and decreased significantly with time during their cultivation.
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