Figure 1.

Overview of CCMs in the Portullugo. Simplified C₄ (A) and CAM (B) pathways showing shared carboxylation and decarboxylation pathways. ASP, aspartateaminotransferase; BCA, beta carbonic anhydrase; CBC, Calvin–Benson cycle; MDH, malate dehydrogenase; ME, malic enzyme; PEPC, PEP carboxylase. Cartoon dendrogram of the Portullugo (Portulacineae + Molluginaceae), highlighting major Portulaca clades (C), which are colored by primary C₄ biochemical pathway. Mean age estimates for focal Portulaca clades are from Ocampo and Columbus (2012). Boxplots of night-day differences in titratable acidity (n = 6) of experimental P. amilis (orange) and P. oleracea plants (purple) (D); boxplots show median and interquartile range; whiskers show 1.5 × interquartile range. WW, well-watered; D, drought. Asterisks connecting lines indicate significant differences between well-watered and drought treatments (independent t test; “***”, P < 0.001; “NS”, P = 0.121). Images of P. amilis when well-watered and after 8 days without water (E); images were digitally extracted for comparison.