Living the high life
The cover image shows plants growing at altitude on Altar Volcano in Chimborazo, Ecuador. Extreme altitudes pose challenges for most forms of life, and flowering plants are no exception. But flowering plants have been found growing as high as 6,400 metres above sea level. In this week’s issue, Michael Holdsworth and his colleagues reveal a molecular mechanism that helps plants to adapt to the extremes of altitude. The researchers studied a range of plants, representing four diverse clades of flowering plants — thale cress (Arabidopsis thaliana), tomato, poppy and the grass Brachypodium distachyon. They found that plants use genetic adaptations to adjust their sensitivity to atmospheric oxygen, whose partial pressure decreases with altitude. By decoding the ambient oxygen level, the plants are able to sense the altitude at which they grow and optimize internal biochemical processes.