Crassulacean acid metabolism in the Basellaceae (Caryophyllales)

• Published in: Plant biology (Stuttgart, Germany) Vol. 20; no. 3; pp. 409 - 414
• Main Authors: Holtum, J A M, Hancock, L P, Edwards, E J, Winter, K
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.05.2018
• Subjects: Acidity; Acids; Basellaceae; Carbon dioxide; Carbon Dioxide - metabolism; Carbon dioxide fixation; Carbon sequestration; Caryophyllales; Caryophyllales - metabolism; Crassulacean acid metabolism; Darkness; Dehydration - metabolism; Drought; Gas exchange; Leaves; Light; Metabolism; Photosynthesis; Plant Leaves - metabolism; C4 photosynthesis; portullugo; facultative CAM; Caryophyllales; Anredera baselloides
• ISSN: 1435-8603; 1438-8677
• DOI: 10.1111/plb.12698

C and crassulacean acid metabolism (CAM) have evolved in the order Caryophyllales many times but neither C nor CAM have been recorded for the Basellaceae, a small family in the CAM-rich sub-order Portulacineae. 24 h gas exchange and day-night changes in titratable acidity were measured in leaves of Anredera baselloides exposed to wet-dry-wet cycles. While net CO uptake was restricted to the light period in well-watered plants, net CO fixation in the dark, accompanied by significant nocturnal increases in leaf acidity, developed in droughted plants. Plants reverted to solely C photosynthesis upon rewatering. The reversible induction of nocturnal net CO uptake by drought stress indicates that this species is able to exhibit CAM in a facultative manner. This is the first report of CAM in a member of the Basellaceae.