Chapter editor: Rana Munns
Contributing Authors: John Angus, Owen Atkin, David Brummell, Aidan Farrell, Peter Gorsuch, EW Hewett,Vaughn Hurry, Howard Rawson
1CSIRO Plant Industry, 2Australian National University, 3Plant and Food Research NZ, 4University of the West Indies, Trinidad, 5Massey University NZ, 6Umeâ University, Sweden
This chapter is updated from a previous version by PE Kriedemann, SE Hetherington, IF Wardlaw and EW Hewett for Plants in Action 1st Edition
Life on earth is restricted to a narrow thermal band (Figure 14.1). Within that range, global conditions can still be extreme with air temperatures as low as –70°C in Antarctica and as high as +57°C in North Africa. Remarkably, life can endure those circumstances, and worse. Thermophilic bacteria exist in hot volcanic springs at +94°C and seeds, lichens and mosses may survive down to –260°C as forms of latent life. However, the temperature range for active growth in higher plants is much more modest and generally constrained between about 5°C and 45°C. The minimum temperature for active growth in tropical and subtropical plants that are chilling sensitive is from 10°C to 15°C (Section 14.4).
On a global scale (Figure 14.2) vegetation types have broad mean annual temperature ranges, from the arctic and alpine tundra at the low end of the temperature scale to tropical forests at the high end. Within this classification Australia and New Zealand cover a wide range of temperature conditions with mean annual temperatures varying from 4°C in the alpine areas of Australia and New Zealand to 28°C along the tropical northern coast of Western Australia.