Ice Propagation in Dehardened Alpine Plant Species Studied by Infrared Differential Thermal Analysis (IDTA)

• DOI: 10.1657/1523-0430(07-077)[hacker]2.0.co;2
• Publication Date: 2008-11-13T18:48:40Z
• Authors: Jürgen Hacker; Gilbert Neuner
• Keywords: Alpine plant; Frost (temperature); Ice nucleus; Herbaceous plant

Infrared differential thermal analysis (IDTA) was used to study ice propagation and whole plant freezing patterns in dehardened intact individuals of various alpine species, including a shrub (Rhododendron ferrugineum), herbaceous (Senecio incanus), cushion (Silene acaulis), two graminoids (Poa alpina Juncus trifidus). Freezing differed markedly among species reflected peculiarities the shoot structure vascular system. In graminoids, each single leaf required separate nucleation event, as polystele prevents between leaves via stem. Additionally, enhanced supercooling resulted temperature range up 10°C, which corroborates high summer frost resistance graminoids. This could have ecological significance for survival. contrast, dicotyledonous one event usually sufficient freezing. Controlled ice-seeding experiments on with droplets water bacterial suspension (Pseudomonas syringae) showed that into tissue from surface inhibited long were undamaged. The rate veins significantly higher at lower temperatures reached 24 cm s−1 J. trifidus, is much than reported earlier findings. Ice faster, may indicate propagates within protoxylem lacunae large vessels.