Water stress can be induced in plant tissues, directly or indirectly, by a number of environmental conditions. Plants exposed to drought, heat, cold, wind, flooding, or saline conditions often synthesize foliar anthocyanins in response. Although previously thought to function as a UV screen, anthocyanins may instead serve to decrease leaf osmotic potential. This depression of leaf water potential could increase water uptake and/or reduce transpirational losses. Combined with other anti-stress activities attributed to anthocyanins (including their solar shield and antioxidative capacities), this phenomenon may allow anthocyanin-containing leaves to tolerate suboptimal water levels. Preliminary information linking leaf anthocyanin content to dehydration tolerance of several species will be presented.

Key words: drought, resistance, stress