Turgid, water stressed, and recovered leaf tissue from barley (var. Barbless) and tomato (var. VF 36 ) were analyzed for total chlorophyll, soluble protein, RuDPCase concentration, and RuDPCase specific activity. Water stress caused a reduction in all physiological characteristics measured. The reduction in concentration of chlorophyll, soluble protein and RuDPCase specific activity in both plants paralleled decreased water potential during first wilt. Changes associated with barley plants as compared to tomato first wilt plants were more pronounced. Barley lost 25% more water than tomato. Repeated wilt cycles increased sensitivity of tomato plants to reduction in chlorophyll content, soluble protein concentration, and RuDPCase specific activity. After a period of rewatering (24 hours) levels of chlorophyll content, soluble protein concentration, and RuDPCase specific activity returned to approximately control levels. Specific activity of RuDPCase is reduced even under low levels of water stress. Concentration of all soluble proteins are not equally reduced as a result of water stress. Total soluble protein was reduced 33% and RuDPCase 11% of control level.