Effects of temperature and hypoxic atmosphere on preservation and further development of in vitro shoots of peach (‘Armking’) and peach × almond hybrid (‘GF 677’)

Abstract

To improve planning of in vitro plant production and/or to preserve germplasm, micropropagated shoots of peach (‘Armking’) and peach × almond (‘GF 677’) were submitted to low oxygen concentrations (0.25-0.2%, plus air as control) combined with decreasing temperatures (25°C, 12°C, 0°C). This method is frequently used in post-harvest physiology to slow down the senescence processes of organs. ‘Armking’ shoots survived for at least 8 months and ‘GF 677’ for 10 months at 0°C. At this temperature, hypoxic conditions had no effect on survival but enhanced regrowth of the shoots afterwards, leading to the maintenance of the multiplication rate. At 25°C and 12°C, hypoxic regimes replaced low-temperature storage, but for shorter times: 2 months for ‘Armking’ and 4 months for ‘GF 677’ at 25°C and at least 4–6 months for the two genotypes at 12°C. This method should thus be used for in vitro preservation of cold-susceptible plants. In addition, hypoxia increased shoot branching capacity, and could be used to promote in vitro micropropagation of species with strong apical dominance.