Lichens and Bryophytes: Light Stress and Photoinhibition in Desiccation/Rehydration Cycles – Mechanisms of Photoprotection

Heber, U.; Lüttge, Ulrich

doi:10.1007/978-3-642-19106-0_7

Cited by 12 publications

(11 citation statements)

References 48 publications

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“…Thus, highly-effective dissipation centers are formed in which excitation energy is trapped (Heber et al 2010). In such centers, the first excited state of chlorophyll molecule is thermally taken back to ground state before charge separation takes place (Heber et Lüttge 2011). In such way, overenergization of PSII and ROS formation is avoided.…”

Section: Discussionmentioning

confidence: 99%

Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. I. Light intensity- and light duration-dependent changes in functioning of photosystem II

Barták¹,

Hájek²,

Očenášová³

2012

Czech Polar Rep.

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The paper deals with the differences in sensitivity of Antarctic lichen to photoinhibition. Thalli of Usnea antarctica were collected at the James Ross Island, Antarctica (57°52´57´´W, 63°48´02´´S) and transferred in dry state to the Czech Republic. After rewetting in a laboratory, they were exposed to 2 high light treatments: short-term (30 min), and long-term (6 h). In short-term treatment, the sample were exposed to 1000 and 2000 µmol m -2 s -1 of photosynthetically active radiation (PAR). In long-term experiment, PAR of 300, 600, and 1000 µmol m -2 s -1 were used. Photosynthetic efficiency of U. antarctica thalli was monitored by chlorophyll fluorescence parameters, potential (F V /F M ) and actual ( PSII ) quantum yield of photochemical processes in photosystem II in particular. In short-term treatments, the F 0 , F V and F M signals, as well as the values of F V /F M , and  PSII showed light-induced decrease, however substantial recovery after consequent 30 min. in dark. Longer exposition (60 min) to high light led to more pronounced decrease in chlorophyll fluorescence than after 30 min treatment, however dark recovery was faster in the thalli treated before for longer time (60 min). Long-term treatment by high light caused gradual decrease in F V /F M and  PSII with the time of exposition. The extent of the decrease was found light dose-dependent. The time course was biphasic for F V /F M but not for  PSII . The study showed that wet thalli of Usnea antarctica had high capacity of photoprotective mechanisms to cope well either with short-or long-term high light stress. This might be of particular importance in the field at the James Ross Island, particularly at the begining of growing season when melting water is available and, simultaneously, high light stress may happen on fully sunny days. 43

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Section: Discussionmentioning

confidence: 99%

Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. I. Light intensity- and light duration-dependent changes in functioning of photosystem II

Barták¹,

Hájek²,

Očenášová³

2012

Czech Polar Rep.

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“…One similarity found here is the light level required to saturate positive NP, which differs little between the BSC from the three sites, despite large differences in other habitat conditions. Light is known to generate physiological variability in lichens (Heber and Lü ttge, 2011), light saturation of the photosystems can be habitat specific (Pardow et al, 2010) and high light-saturation points classify lichen species as favoring high light conditions (Singh et al, 2013). The lack of difference in this parameter is, therefore, not surprising because an open habitat is typical of BSC environments.…”

Section: Photosynthetic Performancementioning

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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“…the water status of plants is completely dependent on their environment) is commonly exhibited in lithobiontic microorganism communities of which the physiology is under the close control of light (Lange et al, 1994;Heber and Lüttge, 2011). Since the lack of capacity for photosynthetic energy conservation, poikilohydry (i.e.…”

Section: Discussionmentioning

confidence: 99%

Experimental investigations into the influence of biofilms and environmental factors on short‐term microtopographic fluctuations of supratidal sandstone

Yuan

Kennedy

Stephenson

et al. 2019

Earth Surf Processes Landf

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In this study laboratory experiments were used to explore the role of biofilms, formed by lithobiontic microorganism communities, in causing hourly surface changes of supratidal sandstone and the potential linkage to long‐term rock decay. To isolate the influence of individual environmental factors (temperature and humidity) on rock surface changes (expansion and contraction), a colonized (biofilm‐covered) and a non‐colonized sandstone block (biofilm‐free) underwent the same univariate microclimatic simulations closely controlled by an environmental chamber. Simulations were run under three different light conditions, with a natural light lamp on, on and off at 20‐min intervals and off, to investigate the impact of light on rock surface dynamics. Measured with a traversing micro‐erosion meter (TMEM), two‐hourly microtopographic fluctuations of these two sandstone blocks were compared in the same environment. Induced by microclimatic variations, surface movements of significantly higher magnitude (12–120% under varying tempeature and 121–154% under varying humidity) and different change patterns were observed on the colonized block, indicating the primary role of biofilm in driving microtopographic fluctuations of supratidal sandstone. However, thermally driven changes of similar magnitude and pattern were observed on both surfaces, suggesting other mechanisms also operating on the non‐colonized rock surface in this process. Due to the sensitivity of biofilm microorganism communities to light, the magnitude and pattern of surface changes was impacted by light condition. Because biofilms increased the magnitude and number of cycles of expansion and contraction of the experimental rock surface, we propose that lithobiontic biofilms facilitate the detachment of grains and granular disintegration on the rock surface, consequently contributing to rock decay and accelerating the rate of breakdown of supratidal rock. This short‐term episode therefore needs to be superimposed on longer term studies to fully understand the role of biofilms in rock surface change. © 2019 John Wiley & Sons, Ltd.

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Lichens and Bryophytes: Light Stress and Photoinhibition in Desiccation/Rehydration Cycles – Mechanisms of Photoprotection

Cited by 12 publications

References 48 publications

Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. I. Light intensity- and light duration-dependent changes in functioning of photosystem II

Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. I. Light intensity- and light duration-dependent changes in functioning of photosystem II

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

Experimental investigations into the influence of biofilms and environmental factors on short‐term microtopographic fluctuations of supratidal sandstone

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