Photosynthesis and transpiration rates of seedlings of 4 citrus rootstocks under flooded conditions were measured over a 10-day period. For all rootstocks photosynthesis and transpiration decreased, but photosynthesis decreased relatively less than transpiration. Stomatal closure is inferred to account in part for the reductions observed.
Flooding did not increase ethanol concentration in either tops or roots, suggesting that ethanol is not an end-product of. anaerobic respiration in citrus seedlings. Only in the neutral soil was rough lemon (Citrus limon L. Burm. f.) found to be more tolerant to short-term flooding than ‘Cleopatra’ mandarin (Citrus reticulata Blanco) and trifoliate orange (Poncirus trifoliata L. Raf.). Tolerance to flood injury was greater at a soil pH of 7 than 4.5.
Received for publication November 1, 1975. Contribution from the Soil-Water-Atmosphere Plant (SWAP) Project cooperative between Florida Agricultural Experiment Stations and the Agricultural Research Service, U.S. Department of Agriculture, Journal Series No. 5415.
Formerly Graduate Research Assistant, now Postdoctoral Fellow, Soil Science and Agricultural Engineering Department, University of California, Riverside.
Formerly Plant Physiologist, Agricultural Research Service, USD A, Gainesville, Florida.