The Campo Rupestre (CR) harbors a diversified flora including both C₃ and CAM tank-bromeliads growing side by side. This scenario facilitates the investigation of whether different species of tank-bromeliads possess convergent physiological responses to drought with regard to their different water-use strategies. To determine the drought response of tank-bromeliads we evaluated seasonal variation in titratable acidity, stomatal conductance (g_s), chlorophyll fluorescence, leaf water content (LWC), and pigment content of the CAM species Aechmea nudicaulis and Neoregelia bahiana and the C₃ species Vriesea minarum. A decrease in g_s was observed in the dry season for plants of both types of photosynthetic pathways, which accompanied a reduction in LWC and a decrease in tissue acidity for the CAM species. Vriesea minarum presented a thinner hydrenchyma and stronger stomatal restriction in the dry season compared to the CAM species. Irrespective of photosynthetic pathway, drought led to a decrease in total chlorophyll and the Chla:Chlb ratio and an increase in carotenoid content, but these changes were not sufficient to prevent photoinhibition. These results indicate that water and light stress during the dry season promoted a convergence of responses in gas-exchange and PSII damage in the studied co-occurring C₃ and CAM tank-bromeliads of CR.

Campo Rupestre (CR) 拥有多样化的植物群，包括并排生长的C ₃和 CAM 罐凤梨科植物。这种情况有助于调查不同种类的水箱凤梨科植物是否对其不同的用水策略具有对干旱的趋同生理反应。为了确定罐凤梨科植物的干旱反应，我们评估了 CAM 物种Aechmea nudicaulis和Neoregelia bahiana以及 C _{3 的}可滴定酸度、气孔导度 ( g _s )、叶绿素荧光、叶含水量 (LWC) 和色素含量的季节性变化种Vriesea minarum。g _s减少在旱季观察到两种光合作用途径的植物，这伴随着 LWC 的减少和 CAM 物种的组织酸度的降低。与 CAM 物种相比，Vriesea minarum 在旱季表现出更薄的水藻和更强的气孔限制。不考虑光合作用途径，干旱导致总叶绿素和 Chl a : Chl b比率下降以及类胡萝卜素含量增加，但这些变化不足以防止光抑制。这些结果表明，在所研究的 CR 的共生C ₃和 CAM 罐凤梨科植物中，旱季的水和光胁迫促进了气体交换和 PSII 损伤反应的收敛。