Why is one nut different from another?

Why does the palm-sized seed of the hairy walnut hate being dried, making it a tough nut to preserve? How can the macadamia withstand being frozen at minus 192 degrees celsius, and still revive to produce new seedlings – as new research discovered a few weeks ago – but other oily nuts won't survive in these conditions?

Far from questions leading to a punchline, these are the challenges facing scientists at the Royal Botanic Gardens in Sydney and Mt Annan who are racing to develop effective ways of preserving seeds from rainforest plants (like the macadamia) before they become extinct.

New research has called for urgent measures to conserve the diversity of plants found in rainforests. It looked at how rainforest plants in the South Pacific, including Australia and New Zealand, could be preserved for the future if their remaining habitats were destroyed.