| Summary: | Salinity affects plant growth and development in various ways through its impact on
photosynthesis, water relations and nutrient absorption. Additionally, the biochemical
composition of plants is also affected by salinity through changes in the concentration and type
of proteins, amino acids, sugars and other carbohydrates. This chapter elucidates with examples
the changes that occur in the plant‟s physiological functions and biochemical composition as a
result of increased salinity of the plant‟s environment. It is highlighted that the fundamental
mechanism of salinity‟s effects on plant function is the increase in the osmotic pressure of the
plant‟s environment that inhibits the absorption of water and nutrients. Invariably, salinity
inhibits photosynthesis through its effects on stomatal conductance, water and nutrient uptake
and decrease in the chlorophyll concentration. Subsequently, higher levels of salinity create an
excessive accumulation of salts in plant tissues that causes toxicity. Prolonged salinity will thus
reduce plant growth and yield and with increasing severity of salinity, toxic levels of salts that
build up in plant tissues will further aggravate the stress. Plants exhibit several mechanisms that
can alleviate the deleterious effects of salinity including compartmentalization of ions, synthesis
of compatible solutes, induction of plant hormones and alteration of membrane structure.
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