Analysis of freezable water content by DSC for apple dormant bud cryopreservation

Abstract

Dormant bud cryopreservation is a valuable tool for the germplasm of temperate trees preservation. Freezable water content, as an important cryopreservation characteristic, was analysed by DSC. Scions of modern apple tree varieties (Malus domestica) were collected during the winter season from orchards, freeze-dehydrated to 26–32% of water content at –5°C and cryopreserved by the two-step procedure. Samples were rehydrated in moist peat after 4 months of cryopreservation and grafted on rootstocks in a field. Regeneration by sprouting buds on rootstocks was evaluated. The varieties were divided into three groups according to their water content and percentage of crystallized water. The regeneration in the three groups decreased with decreasing bud water content. Regeneration was higher than 80% in most of the varieties and reached 100% in almost 1/3 of the tested varieties. In only one variety, was regeneration lower than 40%, which is still a high regeneration rate for considering apple genotypes as successfully cryopreserved. According to this study, the two-step cryoprotocol was successfully optimized for Central European conditions.

Screening acacia mearnsii (black wattle) seedlings for frost tolerance using an artificial frost technique, combined with proteomic analysis.

“…Stegner et al, 2020;Villouta et al, 2021 Differential Scanning Calorimetry Measures heat flows that take place during endothermic and exothermic events, ice nucleation temperatures and amounts of freezable water. Vertucci and Stushnoff, 1992;Bilavčík et al, 2019;Han et al, 2021;Impe et al, 2022 Differential thermal analysis (DTA)…”