Water relations and CO2 exchange of the terrestrial lichen Teloschistes capensis in the Namib fog desert: Measurements during two seasons in the field and under controlled conditions

Lange, O. L.; Green, T.G. Allan; Melzer, B. Thomas; Meyer, A.; Zellner, H.

doi:10.1016/j.flora.2005.08.003

Cited by 97 publications

(90 citation statements)

References 17 publications

(20 reference statements)

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“…One species of Lecanographa , L. subdryophila (Follmann & Vězda) Egea & Torrente, is known from California and Chile, but is epiphytic rather than saxicolous, whereas the saxicolous L. subcaesioides Egea & Torrente has a South American-South African distribution ( Egea and Torrente, 1994 ) and also occurs in Galapagos. The mostly epiphytic genus Fulvophyton , a re- dependence on dew or fog in the early morning hours greatly reduces net photosynthesis ( Rundel, 1978 ;Lange et al, 1991Lange et al, , 2006Lange et al, , 2008. Therefore, it is possible that these lichens indeed have low substitution rates, with only few species evolving in this clade over the past 150 Myr.…”

Section: Discussionmentioning

confidence: 99%

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

Lücking

Tehler²,

Bungartz

et al. 2013

American J of Botany

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• Premise of the study: This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi.• Methods: We used maximum likelihood and Bayesian approaches to reconstruct a three‐gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis.• Key results: The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species: Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorum comb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous.• Conclusions: The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical‐epiphytic. Thus, even if Redonographoideae is subtropical‐saxicolous, the hypothesis that Graphidoideae evolved from a subtropical‐saxicolous ancestor is not supported.

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Section: Discussionmentioning

confidence: 99%

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

Lücking

Tehler²,

Bungartz

et al. 2013

American J of Botany

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“…Acclimation occurs due to ambient light also (Green et al, 1997). Even their water balance can acclimate to different conditions and, for soil crust lichens from the Namib Desert, it was not only shown that minimum thallus water content (WC) allowing positive NP can be extremely low (Lange et al,1994), but also that photosynthesis is reactivated by water vapour uptake alone (Lange et al, 2006). Finally, Poorter et al (2012) showed that carbon partitioning acclimates to different habitat conditions and patterns of assimilate allocation are known to serve as excellent indicators for growth performance in vascular plants.…”

Section: Introductionmentioning

confidence: 99%

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts

et al. 2014

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Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO 2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using 14 CO 2 ) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them.

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“…When only limited precipitation occurs, such as fog and dew, the free-living algae in the inner crusts are always dehydrated and in an inactive state, because most of the crust surface is covered by the lichen thalli. However, symbiotic algae in the thalli can utilize this limited water efficiently and exhibit a short period of positive net photosynthesis before and after the sunrise [37]. Lichens with green algae as photobionts can even use humid air to reactivate photosynthesis [38].…”

Section: Crust Structure and Photosynthetic Efficiencymentioning

confidence: 99%

“…When sufficient water is available, light intensity becomes the primary limiting factor for photosynthesis. Crustal lichens show obvious "sun-plant" characteristics with high light saturation points even more than 1,000 μ mol m −2 s −1 [37,39]. Because of the attenuation of the incident light intensity with increasing depth, the free-living algae that inhabit the inner crusts receive more limited light compared with the symbiotic algae on the surface.…”

Section: Crust Structure and Photosynthetic Efficiencymentioning

confidence: 99%

Small-Scale Vertical Distribution of Algae and Structure of Lichen Soil Crusts

Lan

Zhang

et al. 2011

Microb Ecol

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Although many studies have been conducted on the ecological functions and ecophysiological characteristics of lichen soil crusts (LSCs), no explanation of these results has been provided based on crust structures. Using algae soil crusts (ASCs) as comparison, this work studied the small-scale vertical distribution of algal biomass and stratification in two types of LSCs, by combining the binocular stereomicroscope observations, microscope observations, plate cultures, chlorophyll analysis, and polysaccharides analysis. The results showed an obvious difference in the proportion but not the composition of the algae species between the ASCs and the two LSCs. Approximately 60% and 80% of the total algal biomass were concentrated in the top 1 mm of the soil profile and thalli in the ASCs and LSCs, respectively. This implies that symbiotic algae are the dominant species and primary organic carbon producers in LSCs, and the algal biomass decreased with the depth in both the ASCs and LSCs. The small-scale vertical distributions of the crustal algal biomass and polysaccharides were characterized by obvious successional stage, whereas these were unrelated to the crust type within the successional stage. Additionally, a large amount of fungi, which were always piercing the entire crusts, were observed in the LSCs, but only occasionally in the ASCs. These special structures are purported to cause the LSCs to achieve specific ecological functions, such as higher carbon fixation and greater compressive strength. High biomass, large living space, and advantageous resource utilization privilege suggest that the lichen association is mutualistic and the direction from ASCs to LSCs is developmental.

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Water relations and CO2 exchange of the terrestrial lichen Teloschistes capensis in the Namib fog desert: Measurements during two seasons in the field and under controlled conditions

Cited by 97 publications

References 17 publications

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts

Small-Scale Vertical Distribution of Algae and Structure of Lichen Soil Crusts

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