Desert Shrubs Sacrifice Shoot to Protect Root System against Drought

More and more plants are reported to die of intensifying drought with the aggravation of global climate change. These cases are more serious in arid and semi arid regions. Studies on the mechanism of the plant’s death caused by drought became a necessity for countermeasures against future climate change. 

A team of scientists led by LI Yan from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences recently found that desert shrubs may choose to sacrifice its shoot above the ground to the maximum benefit of its root system. 

Haloxylon ammodendron is a highly drought-resistant plant distributed in sandy deserts, on sand dunes in Middle and Central Asia. Being highly drought-tolerant, the shrub has played an important role in the establishment of shelter belts and the fixation of sand dunes as a counter to desertification. 

LI and his team studied various water- and carbon-related physiological indicators in drought and control conditions throughout a grow season in greenhouse, in order to test how the root system benefits survival and resprouting of Haloxylon ammodendron seedlings. 

Their study showed that the interaction of water and carbon processes determined death or survival of the seedlings in drought environment. When the seedling is stressed with drought, the plant will give priority to the supply of water and carbon to the root system. 

“Investment into the root contributed to the survival and the later resprouting following drought,” said LI.  

LI explained that the root system of the seedling lasted 70 days after drought, twice the survival time of the shoot. “Difference in survival time between shoot and root resulted from sustained root respiration supported by increased NSC in roots under drought,” he said. 

The findings revealed that the ‘root protection’ strategy is critical in determining survival and resprouting of this species, and provided insights into the effects of carbon and water dynamics on tree mortality.  

The study entitled “Effects of increasing root carbon investment on the mortality and resprouting of Haloxylon ammodendron seedlings under drought” was published on Plant Biology.