A flowering desert shrub that thrives in blistering heat stumped researchers for decades — until a recent discovery at the cellular level revealed a striking adaptation. Siddhant Pusdekar reports for SN on how the Arizona honeysweet’s shapeshifting insides helps it flourish in extreme climates.

🎋 Photosynthetic acclimation

The Arizona honeysweet (Tidestromia oblongifolia) grows best in blistering heat. In 1972, researchers demonstrated that this plant’s ability to perform photosynthesis — the vital process of converting sunlight into energy — peaks at over 116° Fahrenheit (47° Celsius), marking the highest known peak-performance temperature for any plant. But they didn’t know why this was the case.

In a paper published this past November in the journal Current Biology, another team of researchers investigated T. oblongifolia’s photosynthesis rates in the lab. They kept plants for eight weeks at nearly 89° F (31° C) before turning the heat up for some to over 116° F (47° C). Plants in the hotter setting tripled in size over another eight days. The researchers call this adaptation “photosynthetic acclimation.”

But the team didn’t stop there — they looked under the microscope at the shrubs’ chloroplasts, or the cell organelles that perform photosynthesis. While most plants’ chloroplasts sustain damage in such heat, T.