Arabidopsis on the rocks.

With the sun setting and no more light to distinguish plants on the ground, an exhaustive day of fieldwork comes to an end. To study the population dynamics of the model plant Arabidopsis thaliana, we collect many samples from the plant in its natural habitat. Leaves are picked off, stored in little bags, and frozen in liquid nitrogen. The bags containing the tissue are kept cold in a vapor shipper – an oversized thermos flask that maintains a core temperature of around -80°C.
by Alex Pluess