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Publication Type J
Authors Konnerup, D., L. Moir-Barnetson, O. Pedersen, E. J. Veneklaas and T. D. Colmer
Title Contrasting submergence tolerance in two species of stem-succulent halophytes is not determined by differences in stem internal oxygen dynamics
Source Annals of Botany
Author Keywords Flooding tolerance gas film halophyte oxygen dynamics submergence tolerance Tecticornia auriculata Tecticornia medusa underwater photosynthesis underwater respiration Salicornioideae samphire EELGRASS ZOSTERA-MARINA RICE ORYZA-SATIVA GAS FILMS UNDERWATER PHOTOSYNTHESIS TECTICORNIA-PERGRANULATA FLOODING TOLERANCE SALINITY AERATION PLANTS CHENOPODIACEAE
Abstract Background and Aims Many stem-succulent halophytes experience regular or episodic flooding events, which may compromise gas exchange and reduce survival rates. This study assesses submergence tolerance, gas exchange and tissue oxygen (O-2) status of two stem-succulent halophytes with different stem diameters and from different elevations of an inland marsh. Methods Responses to complete submergence in terms of stem internal O-2 dynamics, photosynthesis and respiration were studied for the two halophytic stem-succulents Tecticornia auriculata and T. medusa. Plants were submerged in a glasshouse experiment for 3, 6 and 12 d and O-2 levels within stems were measured with microelectrodes. Photosynthesis by stems in air after de-submergence was also measured. Key Results Tecticornia medusa showed 100 % survival in all submergence durations whereas T. auriculata did not survive longer than 6 d of submergence. O-2 profiles and time traces showed that when submerged in water at air-equilibrium, the thicker stems of T. medusa were severely hypoxic (close to anoxic) when in darkness, whereas the smaller diameter stems of T. auriculata were moderately hypoxic. During light periods, underwater photosynthesis increased the internal O-2 concentrations in the succulent stems of both species. Stems of T. auriculata temporally retained a gas film when first submerged, whereas T. medusa did not. The lower O-2 in T. medusa than in T. auriculata when submerged in darkness was largely attributed to a less permeable epidermis. The submergence sensitivity of T. auriculata was associated with swelling and rupturing of the succulent stem tissues, which did not occur in T. medusa. Conclusions The higher submergence tolerance of T. medusa was not associated with better internal aeration of stems. Rather, this species has poor internal aeration of the succulent stems due to its less permeable epidermis; the low epidermal permeability might be related to resistance to swelling of succulent stem tissues when submerged.
Author Address [Konnerup, Dennis; Moir-Barnetson, Louis; Pedersen, Ole; Veneklaas, Erik J.; Colmer, Timothy D.] Univ Western Australia, Sch Plant Biol, Crawley, WA 6009, Australia. [Pedersen, Ole] Univ Western Australia, Inst Adv Studies, Crawley, WA 6009, Australia. [Pedersen, Ole] Univ Copenhagen, Freshwater Biol Lab, Inst Biol, DK-2100 Copenhagen, Denmark. Konnerup, D (reprint author), Univ Western Australia, Sch Plant Biol, 35 Stirling Highway, Crawley, WA 6009, Australia. dennis.konnerup@uwa.edu.au
ISSN 0305-7364
ISBN 0305-7364
29-Character Source Abbreviation Ann. Bot.
Publication Date Feb
Year Published 2015
Volume 115
Issue 3
Beginning Page 409-418
Digital Object Identifier (DOI) 10.1093/aob/mcu216
Unique Article Identifier WOS:000349560400008
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