Induction by drought of crassulacean acid metabolism in the terrestrial bromeliad, Puya floccosa

Abstract

In the terrestrial bromeliad, Puya floccosa, a value of carbon isotopic composition (δ 13 C) of -22‰ has been previously reported, suggesting the operation of weak and/or intermediate (C 3 -CAM) crassulacean acid metabolism (CAM). In order to characterize the operation of CAM in P. floccosa and its possible induction by drought, plants were grown in Caracas and subjected to four independent drought cycles. Additionally, since plants of this species grow in Venezuela in a large range of elevations, leaf samples were collected at elevations ranging from 725 to 2,100 m a.s.l. in the Venezuelan Andes and the Coastal Range, in order to evaluate the effect of elevation on CAM performance. Even though nocturnal acid accumulation occurred in both watered and droughted plants, mean ΔH + was higher in droughted than watered plants [ΔH + = 60.17.5 and 22.9 ± 5.2 μmol g -1 (FM), respectively]. The majority of plants from all the natural populations sampled had low values of δ 13 C not differing significantly from those of C 3 plants collected as standards and δ 13 C did not change with elevation. We conclude that P. floccosa is capable of a weak CAM activity, with a large variability among populations and drought experiments probably due to local and temporal differences in microclimatic variables and drought stress; elevation bears no influence on values of δ 13 C in this species.Additional key words: Bromeliaceae, elevation, nocturnal acid accumulation.

Crassulacean acid metabolism-cycling in Euphorbia milii

“…(1996) Talinum triangulare 6.0FacultativeHerrera et al . (1991) Puya floccosa 6.2FacultativeHerrera et al . (2010) Sedum morganianum 13.0ConstitutiveKluge and Ting (1978)…”

CAM Photosynthesis in Bromeliads and Agaves: What Can We Learn from These Plants?

“…[88] showed more nocturnal CO 2 fixation by Bromelia humilis in the presence of nitrogen and higher irradiance. On the other hand, it was also demonstrated that another species, Puya floccosa, is capable of increasing nocturnal acid accumulation in response to drought and/or other unfavorable microclimatic cues [92]. Working with Achmea magdalenae, Bromelia plumieri and Ananas comosus, Skillman and cols.…”

Think tank: water relations of Bromeliaceae in their evolutionary context

“…It is important to note that extreme care should be taken when performing such analyses to use best practice in terms of model calibration and sampling methodology. Herrera et al, 2010;Quezada, Zotz & Gianoli, 2014). First, the putative phylogenetic relationships used in this analysis are not consistent with those supported by the most comprehensive molecular phylogenetic analyses.…”

“…CAM-cycling, thought to be the least evolutionarily advanced state along the CAM continuum (Silvera et al, 2010), involves nocturnal fixation of respiratory CO 2 behind closed stomata accompanying typical diurnal C 3 fixation. In many cases, CAM-cycling andidling appear to be reversibly inducible, and drought-inducible CAM has been observed in some species such as the terrestrial Puya floccosa (Linden) E.Morren ex Mez (Herrera et al, 2010). CAM-idling, conversely, is an extreme form of CAM in which the stomata remain continuously closed and the only fixation is of respired CO 2 at night.…”