Object 20 | Desert Mobile Lab

In summer, the floor of Death Valley reaches temperatures that would kill most plants outright. In the 1970s, Carnegie plant scientists realized that these conditions presented a rare opportunity to study how plants adapt to extreme environments. To take advantage of this natural experimental venue the Department of Plant Biology converted a mobile home into a roving laboratory, custom-equipped with its own generator, computers, and analysis equipment—everything a team would need to measure photosynthesis in the field in real time. This desert mobile lab is Object 20 in our #Carnegie125 series.

The story starts in 1968, when Carnegie researchers came across a scrubby plant blooming in the punishing summer temperatures at Death Valley, long after everything else nearby had withered. It was Tidestromia oblongifolia, commonly known as Arizona honeysweet, and it caught the attention of Olle Björkman, a scientist who had arrived at Carnegie’s Department of Plant Biology from Sweden a few years earlier. Björkman teamed up with Carnegie colleague Joe Berry and Stanford University's Harold Mooney to launch a multi-year study to figure out how the plant could survive, and even thrive, in conditions that killed nearly everything else around it.

Setting out each summer in the mobile lab, the team measured the plant’s photosynthetic activities as it grew under natural desert conditions. They also brought specimens back to the laboratory for controlled experiments. And to compare how the plants responded in dramatically different climates, they established two experimental gardens: one near the Ranger Station at Furnace Creek in Death Valley and another at Bodega Head, a cool, fog-bound stretch of coastline north of San Francisco.

Their findings, published in Science in 1972, were striking: Arizona honeysweet performed photosynthesis best at around 47 degrees Celsius, or 117 degrees Fahrenheit, a temperature that would shut down most other plants entirely.

Björkman explained the stakes of the work in a 1975 interview with the New York Times: "All biological activity on Earth is ultimately limited by how well photosynthesis is able to operate within all the diverse environments on Earth. We need to know the adaptive limits of photosynthesis and how various adaptive mechanisms work."

That question kept the mobile lab running for years, hauled back into Death Valley summer after summer. The sweltering work paid off and Björkman's research on leaf photosynthesis in relation to environmental conditions would earn international recognition. Today, the story of the desert mobile laboratory stands as a reminder of how far a good research question, and a well-built vehicle, can go.