Researchers have discovered the reason why salt can potentially stop the growth of a plant-root system. The discovery led a breakthrough which was unknown until now, reports Science Daily.
Lead researchers from the Carnegie Institution, José Dinneny, Lina Duan and team discovered that a stress hormone is activated in the inner layer of the roots when in contact with salt that leads to the discontinuation in the growth of the roots, says the report. When the water is evaporated in the soil, it leaves behind contents of salt.
The study explained how the growth of roots is stopped when the stress hormone is triggered in the roots.
"An important missing piece of the puzzle to understanding how plants cope with stressful environments is knowing when and where stressors act to affect growth," Dinneny said, according to Science Daily.
In order to understand the process of root growth and its response to salt, researchers grew a seedling of a plant named Arabidopsis-small flowering plants associated with cabbage and mustard, in the lab using a custom imaging system. This helped the researchers monitor the entire process of root growth and its response with salt.
During the process, roots of a growing plant became inactive when salt was introduced. Lina Duan further analyzed the reason how that occurred by studying different plant hormones undergoing the same process and learned that a very important hormone, Abscisic Acid, that controls the growth of the plant, was activated, says the report.
"We are familiar with how animals use a fight or flight strategy to face external challenges. While plants can't run for safety, they can control how much they grow into dangerous territory," Dinneny added. "It turns out that Abscisic Acid, a stress hormone produced in the plant when it is exposed to drought or salty environments, is important in controlling the plant equivalent of fight or flight."
Duan explained that a protective 'inner-skin' of the root is very important as it controls the substances that can enter the root system from the soil.
This inner layer is called endodermis, which "also acts as a guard, with Abscisic Acid, to prevent a plant from growing in dangerous environments," Dinneny said. "Irrigation of agricultural land is a major contributor to soil salinity. And as sea levels rise with climate change, understanding how plants, particularly crops, react to salt might allow us to develop plant varieties that can grow in the saltier soils that will likely occur in coastal zones."
The findings of the study is published in the current issue of The Plant Cell.
