Medicinal and aromatic plants production under salt stress. A review
Abstract
Salinization of soils or waters is one of the world’s most serious environmental problems
in agriculture. It is necessary to determine the environmental factors under which medicinal
and aromatic plants give higher yields and better quality. The problem of salinity
is characterized by an excess of inorganic salts and is common in the arid and semi-arid
lands, where it has been naturally formed under the prevailing climatic conditions and due
to higher rates of evapotranspiration and lack of leaching water. Although more frequent
in arid lands, salt-affected soils are also present in areas where salinity is caused by poor
quality of irrigation water. Saline soil induces physiological and metabolic disturbances in
plants, affecting development, growth, yield, and quality of plants. Plants affects adversely
as a result of salinity, seed germination, survival percentage, morphological characteristics,
development and yield and its components. In general, salt stress decreases the photosynthesis
and respiration rate of plants. Total carbohydrate, fatty acid and protein content
were adversely affected due to salinity effect, but increased the level of amino acids,
particularly proline. The content of some secondary plant products is significantly higher
in plants grown under salt stress than in those cultivated in normal conditions. The salinity
tolerance depends on the interaction between salinity and other environmental factors.