How Does Salt Affect Plant Growth?
An increased concentration of salt in soil inhibits plant growth, eventually leading to plant death, and high salinity in soil is a major issue facing the agriculture industry. However, there is a subset of plants called halophytes that have adapted to growing in high-saline areas.
Plants take in nutrients through their roots systems. In areas of high salinity, plants absorb large amounts of salt, which disrupts their cellular function. Salt specifically affects a layer of tissue within the branching root system of plants that causes the release of a stress hormone that inhibits root growth. Additionally, sodium can cause early onset leaf death, decreasing the photosynthetic ability of the plant. These factors halt plant growth and eventually cause the plant to die.
In natural systems, salt is removed from the soil through proper drainage that brings sodium down away from plants’ roots. Agricultural practices, such as logging and irrigation, disrupt the drainage system, causing more sodium to collect at the surface. Mineral weathering also adds to the saline concentration in soil. Increased sodium in agricultural lands is dangerous for crop productivity.
Halophytes are a group of plants that have adapted to high-saline environments. These plants are able to discriminate between valuable nutrients and unneeded salt at the roots and are able to store salt in organelles called vacuoles. Scientists are studying halophytes to create agricultural crops that are more saline resistant.