Sunflowers appear to recover from drought, but hidden damage remains
- News
- Rocks on Galaxy
- Plantes
- 08 Sep, 2026
Water a wilted plant and within a day it stands back up, looking healed. Inside the stem, it's a different story: researchers have shown that a sunflower can look completely recovered from drought while air bubbles still block its water pipes for weeks.
A medical scanner to see the invisible
Jared Stewart and colleagues at the University of Colorado Boulder placed 55 three-week-old sunflowers inside a medical CT scanner. They examined the same stems dry, then again after watering: nothing reopened.
The decades-old assumption ran the other way — that plants cleared these bubbles (embolisms) on their own. According to co-author Troy Ocheltree (Colorado State University), pulling water from dry soil introduces air into the water-transport tissue, keeping leaves from getting what they need to photosynthesize.
Blockages that persist for three weeks
Two plants tell the story: one finished with about 10% of its stem blocked, the other with nearly 90%. Neither cleared anything, even a week after returning to the greenhouse. One plant kept its blockages for three weeks while its stem grew by 240% — it grew around the damage instead of repairing it.
Every re-watered sunflower survived, including those with more than half their stem blocked. But their water and CO₂ exchange still ran below normal a week later. The study appears in the Journal of Experimental Botany.