The frost resistance of some native plants from the Central Volcanic Plateau, North Island, New Zealand, in relation to plant succession

Abstract

The frost resistance (T ₅₀) of several key species of the tussock grasslands, tussock shrublands, and forest on the Central Volcanic Plateau was measured, using the electrical conductivity method. The frost resistance of Chionochloa rubra, Dracophyllum filifolium, Phyllocladus alpinus, Leptospermum scoparium, Nothofagus solandri var cliffortioides, and Brachyglottis bidwillii was measured in autumn, mid winter, spring, and summer. Additional species were tested in mid winter for their maximum frost resistance. In mid winter, the T ₅₀ ranged from -4.2°C for Pseudopanax arboreus to -27.4°C for Chionochloa rubra. Phyllocladus alpinus from different areas (including the South Island) showed significant differences in T ₅₀ (from -9.2°C up to -16.3°C). Species which were measured throughout the year showed, with the exception of Chionochloa rubra, a significant hardening from summer to winter and a significant dehardening after winter. The seasonal and midwinter frost hardiness of the different species can be related to the actual succession in the field after disturbance.

Keywords:

• frost resistance
• electrical conductivity method
• plant succession
• Central Volcanic Plateau
• ecotypes
• New Zealand