Ion balance is a key factor in plant development to produce yield. Too high salt concentration in soil lowers the water potential in root tissue which becomes toxic; stunting growth and inhibiting flowering by dehydrating the plant. Stomatal closure is also a response to high salinity, leading to lowered sugar production and transpiration rates. Plants respond to high salinity soils by accumulating sodium and chlorine, and reducing uptake of macronutrients and other ions. This accumulation results in inhibition of calcium signaling. In order to combat this type of stress, plants must have strategies and adaptations in place for survival, such as osmotic stress pathways. RNA sequencing and qRT-PCR analysis has made finding these gene expression pathways possible, such as the MAPK, allowing for the scrutiny of candidate genes responsible for greater tolerance to salinity. Candidate genes for this type of stress response have also been found in plant hormone signal transduction pathways. Different species of Cannabis carry unique variations of gene expression, with some having a greater ability to utilize salt tolerance by keeping potassium levels high enough as to deny sodium uptake.
Removing sodium from the cytoplasm by means of sodium or hydrogen anti-porters is another mechanism to resist desiccation from high salinity environments by using the salt overly sensitive (SOS) regulation pathway. The SOS pathway exchanges excess sodium for hydrogen, and it is set into action by calcium signal flux.
Modifying the cytoskeleton or utilizing an osmotic stress pathway are two other physiological defenses plants use to handle salinity. The ability to sense excess salinity is a valuable tool, where excess sodium can trigger an influx of calcium and reactive oxygen species (ROS). Without the ability to notice sodium, calcium wouldn't be triggered into a signaling cascade to flow into the cytosol. This flow notifies the system to block salt ions from entering into the roots by using any available defenses, such as modifying the cell wall. A plant without these sensing and signaling capabilities is considered salt-sensitive, known as a glycophyte.