Carbon isotope ratio measurements of succulent plants in southern Africa

Abstract

Succulent plants representing 16 families and a variety of growth forms originating from winter, summer, and year-round rainfall regimes in southern Africa were analyzed for carbon isotope ratios. Most families had species with δ¹³C values indicative of CAM, particularly those from winter and year-round rainfall regimes. Plants with δ¹³C values intermediate between CAM and C₃, indicating flexible photosynthetic pathways, were generally leafy perennials subject to seasonal tissue dehydration. Reproductive tissue tended to have less negative δ¹³C values than vegetative tissue on the same plant, indicating drought-season origin of the former.