Competition, and therefore diversity, is most intense when productivity is high and environmental stress is low. The stress of salinity on halophytes causes these plants to reduce their growth capacity in an effort to conserve water. While it may be true that halophytes are able to survive in more habitats, glycophytes generally have higher reproductive and growth rates across the board. In general, assuming competition is constant, diversity and species richness is higher in communities of less stressful habitats. Thus, communities that inhabit high salinity environments are less diverse and rich in species.
High salinity elicits water conservation tactics within the plant.
The enzyme PEPCase is observed to rapidly increase in response to CAM, but it is rather unclear whether this enzyme triggers salt tolerance. CAM also triggers the accumulation of the amino acid proline. Proline, however, is yet to be defined as a contributor to salt tolerance. It may be that researchers are placing too much emphasis on trying to identify the mechanisms of salt tolerance when they should be trying to apply existing salt tolerant species to agricultural use. It is desirable that researchers investigate the agricultural uses of halophytic plants and how these plants might help to eradicate our pollution problem.