PROCESS ENGINEERING AS A MEANS OF REGULATING THE MICROCLIMATE IN A PHOTOAUTOTROPHIC IN VITRO CULTURE

A new system combining a temporary-immersion system (TIS) and sugar-free cultivation is currently being tested and optimized for the micropropagation and rooting of apple shoots (Malus × domestica ‘Holsteiner Cox’). The shoots were cultivated under photoautotrophic conditions for 4 weeks.
CO₂ was regulated to (1,400 ± 200) μmol mol^-1 and the photosynthetic photon flux (PPF) was 115 μmol m^-2 s^-1 (lateral) and 75 µmol m^-2 s^-1 (overhead) (high PPF). This method was compared to a shaken submersion culture and a conventional agar culture, both with and without the addition of sucrose (3%) under a PPF of 75 μmol m^-2 s^-1 (low PPF). Rooting was most successful on MS agar (100% with 3% sucrose) and in photoautotrophic TIS (PA-TIS) (60%), even the plants on agar without the addition of sugar rooted to some extent (27.7%) whereas shoots under submersion vitrified and did not develop roots.
It could be shown that the net photosynthetic rate (P_n) of plants grown in PA-TIS is strongly influenced by PPF, increasing it significantly from a maximum of 3.32 μmol CO₂ h^-1 plantlet^-1 under low PPF to 11.85 μmol CO₂ h^-1 plantlet^-1 at the most under high PPF.

I International Symposium on Horticulture in Europe

S. Fuljahn, H.-J. Tantau

apple, rooting, sugar-free culture, temporary-immersion system, CO₂ dynamics

https://doi.org/10.17660/ActaHortic.2009.817.13