SHORT-TERM FLOODING AFFECTS GAS-EXCHANGE CHARACTERISTICS OF CONTAINERIZED SOUR CHERRY TREES

The effects of short-term soil flooding on gas exchange characteristics of containerized sour cherry trees (Prunus cerasus L. cv. Montmorency/P. mahaleb L.) were studied under laboratory conditions. Soil flooding reduced net CO2 assimilation (A) within 24 hours. Net CO2 assimilation and residual conductance to CO2 (g(r)') declined to almost-equal-to 30% of control values after 5 days of flooding. Effects on stomatal conductance to CO2 (g(s)) and intercellular CO2 (C(i)) were not significant during the 5 days of treatment. Apparent quantum yield (PHI) gradually declined to 52% that of controls during these 5 days. In a second experiment, CO2 response curves suggested that, initially, stomatal and nonstomatal limitations to A were of about equal importance; however, as flooding continued, nonstomatal limitations became dominant.