Drought-stress-induced up-regulation of CAM in seedlings of a tropical cactus, Opuntia elatior, operating predominantly in the C3 mode

Winter, Klaus, Garcia, Milton, and Holtum, Joseph A.M. (2011) Drought-stress-induced up-regulation of CAM in seedlings of a tropical cactus, Opuntia elatior, operating predominantly in the C3 mode. Journal of Experimental Botany, 62 (11). 4037-4042 .

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1093/jxb/err106
 
20
2


Abstract

Immediately after unfolding, cotyledons of the tropical platyopuntoid cactus, Opuntia elatior Mill., exhibited a C3-type diel CO2 exchange pattern characterized by net CO2 uptake in the light. Significant nocturnal increases in titratable acidity typical of crassulacean acid metabolism (CAM) were not detected at this early developmental stage. As cotyledons matured and the first cladode (flattened stem) developed, features of CAM were observed and the magnitude of CAM increased. Nonetheless, in well-watered seedlings up to 10 cm tall, C¬3 photosynthetic CO2 fixation in the light remained the major pathway of carbon fixation. Reduced soil water availability led to an up-regulation of net dark CO2 fixation and greater nocturnal increases in tissue acidity, consistent with facultative CAM. These observations demonstrate that C3 photosynthesis, drought-stress related facultative CAM and developmentally controlled constitutive CAM can all contribute to the early growth of O. elatior. The strong C3 component and facultative CAM features expressed in young O. elatior contrast with mature plants in which obligate CAM is the major pathway of carbon acquisition.

Item ID: 15503
Item Type: Article (Research - C1)
ISSN: 1460-2431
Keywords: carbon dioxide uptake; constitutive CAM; crassulacean acid metabolism; C3 photosynthesis; development; drought stress; environment; facultative CAM; Opuntia
Date Deposited: 03 Aug 2011 04:55
FoR Codes: 06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060705 Plant Physiology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
Downloads: Total: 2
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page