Photosynthetic oxygen evolution by four Coffea arabica genotypes subjected to a dehydration/rehydration cycle

摘要: SummaryPhotosynthetic oxygen evolution by eight month old plants of the Coffea arabica hybrids H-421 (cv. Yellow Catuai × cv. Timor Hybrid) and H-430 Red Hybrid), a Catimor progeny, one line was followed polarographically during dehydration/rehydration cycle. Fully hydrated showed maximum photosynthetic rate (Amax) in range 20.6 to 34.6 µmol m−2 s−1 an apparent quantum yield 0.074 0.086. During dehydration Amax steadily decreased as water potential declined. Changes were not found among slope intercept values, with exception value hybrid H-421. The recovery regained 96.0, 96.5, 85.0 78.0 h after rehydration for genotypes Catimor, H-430, H-421, respectively. In response stress, mesophyll resistance restricts carbon dioxide fixation, after-effects variable duration.