Photosynthetic carbon acquisition in the lichen photobionts Coccomyxa and Trebouxia (Chlorophyta)

Palmqvist, Kristin; Ríos, Asunción de los; Ascaso, Carmen; Samuelsson, Göran

doi:10.1034/j.1399-3054.1997.1010110.x

Cited by 13 publications

(15 citation statements)

References 12 publications

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“…The second mode of CO # acquisition is expressed by the genus Trebouxia and those species of Stichococcus that have pyrenoids (Badger et al, 1993 ;Palmqvist, 1993 ;Palmqvist et al, 1994cPalmqvist et al, , 1997Smith & Griffiths 1996). Of these, Trebouxia has been the most extensively characterized , but not as well as Coccomyxa or as free-living green algae with a CCM (Badger et al, 1998).…”

Section: Photobiont Comentioning

confidence: 99%

“…Both of these features have consequences for their performance. Moreover, most green algae lack vacuoles and have only one large chloroplast (Friedl & Bu$ del, 1996 ;Palmqvist et al, 1997), features that might restrict their carbohydrate storage capacity. Differences in lichen photosynthetic performance that can be related to the photobiont are therefore specifically addressed in the following survey.…”

Section:  mentioning

confidence: 99%

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Tansley Review No. 117

Palmqvist

2000

New Phytologist

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221

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Lichens are nutritionally specialized fungi (the mycobiont component) that derive carbon and in some cases nitrogen from algal or cyanobacterial photobionts. The mycobiont and photobiont live together in an integrated thallus, but they lack specific tissue for the transport of metabolites and resources between them. Carbon is acquired through photosynthesis in the photobiont, which is active when the lichen is wet and exposed to light. Lichen photosynthesis is limited primarily by water, light and nitrogen, but can also be constrained by slow diffusion of CO # within the wet thallus. The assimilated carbon is exported from photobiont to mycobiont, which also predominates in terms of biomass, and apparently regulates the size of the photobiont population. It has therefore generally been assumed that most of the carbon is used for growth and maintenance of the fungal hyphae. However, the extent of photobiont respiration in relation to mycobiont respiration has seldom been quantified ; neither do we know the pool sizes of various carbon sinks within lichens. Owing to this lack of fundamental data we do not know whether, or how, carbohydrate resources are regulated to maintain an optimal balance between energy input and expenditures in these symbiotic organisms. This review summarizes data on growth, carbon gain and carbon expenditures in lichens, with particular emphasis on factors determining the photosynthetic capacity of their photobionts. An attempt is made to introduce an economic analysis of lichen growth processes, a view that has often been adopted in studies of higher plants. Areas in which more data are needed for the construction of a model on ' lichen resource allocation patterns ' are discussed.

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Section: Photobiont Comentioning

confidence: 99%

Section:  mentioning

confidence: 99%

Tansley Review No. 117

Palmqvist

2000

New Phytologist

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221

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“…All terrestrial cyanobacteria (free-living or lichenized) have CCMs, as do some terrestrial free-living and lichenized green algae, and hornworts (Palmqvist 1993;Palmqvist et al 1994;Smith and Griffiths 1996;Palmqvist et al 1997;Badger et al 1997;Meyer et al 2008;Gadd and Raven 2010;Raven 2010a). Terrestrial cyanobacteria, algae and hornworts are desiccation tolerant and poikilohydric, contrasting with the great majority of terrestrial vascular plant sporophytes: this influences their response to changed CO 2 and temperature regimes (Meyer et al 2008;Gadd and Raven 2010;Raven and Andrews 2010).…”

Section: Terrestrial Algae and Hornwortsmentioning

confidence: 99%

Algal and aquatic plant carbon concentrating mechanisms in relation to environmental change

et al. 2011

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Abstract.Carbon dioxide concentrating mechanisms (also known as inorganic carbon concentrating mechanisms; both abbreviated as CCMs) presumably evolved under conditions of low CO 2 availability. However, the timing of their origin is unclear since there are no sound estimates from molecular clocks, and even if there were, there are no proxies for the functioning of CCMs. Accordingly, we cannot use previous episodes of high CO 2 (e.g. the Palaeocene-Eocene Thermal Maximum) to indicate how organisms with CCMs responded. Present and predicted environmental change in terms of increased CO 2 and temperature are leading to increased CO 2 and HCO 3 -and decreased CO 3 2-and pH in surface seawater, as well as decreasing the depth of the upper mixed layer and increasing the degree of isolation of this layer with respect to nutrient flux from deeper waters. The outcome of these forcing factors is to increase the availability of inorganic carbon, photosynthetic active radiation (PAR) and ultraviolet B radiation (UVB) to aquatic photolithotrophs and to decrease the supply of the nutrients (combined) nitrogen and phosphorus and of any non-aeolian iron. The influence of these variations on CCM expression has been examined to varying degrees as acclimation by extant organisms. Increased PAR increases CCM expression in terms of CO 2 affinity, while increased UVB has a range of effects in the organisms examined; little relevant information is available on increased temperature. Decreased combined nitrogen supply generally increases CO 2 affinity, decreased iron availability increases CO 2 affinity, and decreased phosphorus supply has varying effects on the organisms examined. There are few data sets showing interactions among the observed changes, and even less information on genetic (adaptation) 2 changes in response to the forcing factors. In freshwaters, changes in phytoplankton species composition may alter with environmental change with consequences for frequency of species with or without CCMs. The information available permits less predictive power as to the effect of the forcing factors on CCM expression than for their overall effects on growth. CCMs are currently not part of models as to how global environmental change has altered, and is likely to further alter, algal and aquatic plant primary productivity.Keywords CO 2 concentrating mechanism -combined nitrogen -inorganic carboniron -mixing depth -photosynthetically active radiation -phosphorus -temperature -UVA-UVB Abbreviations CCM CO 2 concentrating mechanism DOC Dissolved organic carbon PAR Photosynthetically active radiation (400-700 nm)Rubisco Ribulose bisphosphate carboxylase-oxygenase UVA Ultraviolet A radiation (320-400 nm) UVB Ultraviolet B radiation (280-320 nm)

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“…STM appeared small compared with most non-aquatic lichens (Palmqvist et al, 1997(Palmqvist et al, , 1998(Palmqvist et al, , 2002 but some forest species have even lower values (Esseen et al, 2015). Because changes in STM of freshwater lichens were associated with opposite and proportional changes in Chla+ ergosterol concentrations in the tissues, living STM (photobiont + mycobiont) was similar in the various freshwater lichens.…”

Section: Discussionmentioning

confidence: 81%

Photosynthetic traits of freshwater lichens are consistent with the submersion conditions of their habitat

Coste

Chauvet

Grieu

et al. 2016

Ann. Limnol. - Int. J. Lim.

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 15742 Abstract -In this study, we compared the photosynthetic performance of epilithic freshwater lichens on siliceous stream rock submerged for: more than 9 (hyper-), 6-9 (meso-) or 3-6 months (sub-hydrophilic lichens). In the dry state, neither variable fluorescence nor respiration activity could be detected. In the wet state, rates of dark respiration (O 2 uptake and CO 2 production for immerged and in-air samples) were in the lower range of that reported for non-aquatic lichens. With 200 (under water) or 500 mmol.m , aerial), photosynthesis increased in sub-but became negative in hyper-hydrophilic species. After hydration, dry samples increased photosystem II (PSII) efficiency, which reached near steady state in < 6-7 min. Hyper-hydrophilic lichen took longer than sub-hydrophilic species. A long period of desiccation (4 months) had a negative effect on subsequent PSII photochemistry of hyper-but not of sub-hydrophilic hydrated lichens. When thalli were allowed to dehydrate, all types of lichens lost PSII activity after about 15-20 min. Deactivation was faster in the hyper-than in the sub-hydrophilic species. The metabolic traits presented here are thus consistent with the ecological amplitude of the freshwater lichens studied.

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Photosynthetic carbon acquisition in the lichen photobionts Coccomyxa and Trebouxia (Chlorophyta)

Cited by 13 publications

References 12 publications

Tansley Review No. 117

Tansley Review No. 117

Algal and aquatic plant carbon concentrating mechanisms in relation to environmental change

Photosynthetic traits of freshwater lichens are consistent with the submersion conditions of their habitat

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