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Giant cacti: Isotopic recorders of climate variation in warm deserts of the Americas

journal contribution
posted on 30.01.2020, 00:00 authored by KR Hultine, DL Dettman, Nathanael Brooks-EnglishNathanael Brooks-English, DG Williams
The plant family Cactaceae is considered among the most threatened groups of organisms on the planet. The threatened status of the cacti family has created a renewed interest in the highly evolved physiological and morphological traits that underpin their persistence in some of the harshest subtropical environments in the Americas. Among the most important anatomical features of cacti is the modification of leaves into spines, and previous work has shown that the stable isotope chemistry of cacti spines records potential variations in stem water balance, stress, and Crassulacean acid metabolism (CAM). We review the opportunities, challenges, and pitfalls in measuring δ 13C, δ 2H, and δ 18O ratios captured in spine tissues that potentially reflect temporal and spatial patterns of stomatal conductance, internal to atmospheric CO2 partial pressures, and subsequent patterns of photosynthetic gas exchange. We then evaluate the challenges in stable isotope analysis in spine tissues related to variation in CAM expression, stem water compartmentalization, and spine whole-tissue composition among other factors. Finally, we describe how the analysis of all three isotopes can be used in combination to provide potentially robust analysis of photosynthetic function in cacti, and other succulent-stemmed taxa across broad spatio-temporal environmental gradients.

Funding

Other

History

Volume

70

Issue

22

Start Page

6509

End Page

6519

Number of Pages

11

eISSN

1460-2431

ISSN

0022-0957

Publisher

Oxford University Press (OUP)

Peer Reviewed

Yes

Open Access

No

Acceptance Date

28/06/2019

External Author Affiliations

University of Wyoming, University of Arizona, Department of Research, Conservation and Collections, USA;

Era Eligible

Yes

Journal

Journal of Experimental Botany