In vitro propagation of Herreria salsaparilha Martius (Herreriaceae) as affected by different sealing materials and gaseous exchanges

Abstract

The effects of sealing material on the gaseous composition inside flasks containing Herreria salsaparilha in vitro cultures, and on axillary shoot propagation of this species were evaluated. Axillary shoots (1.5 cm in size) were cultured in 200 ml flasks containing 45 ml MS medium supplemented with 30 g l−1sucrose, 100 mg l^−1 myo-inositol, MS vitamins and 5 g l^−1 agar. Flasks were sealed with polypropylene rigid closure (C), polypropylene rigid closure with a filter (CF), or single- or double-layer polyvinylchloride films (PVC1 and PVC2, respectively). Cultures were maintained at 26 ± 1°C, and a 16/8 h light/dark photoperiod with 35 μmol m^−2 s^−1 irradiance. After 60 days, water loss (%), internal O2 concentration (%), plant height (cm), leaf and root fresh and dry weights (g), and root number and length (cm) were evaluated. Using an open system infrared gas analyzer, the photosynthetic and respiratory rates of in vitro H. salsaparilha cultures were also estimated. The sealing material influenced water loss in flasks, with CF closure showing higher percentage of water loss. O2 concentration was significantly higher in PVC-sealed flasks than in other treatments, leading to the formation of a small dome on top of the flask. Despite the high oxygen accumulation, shoot development was not affected.