Response to Extreme Environments

Kappen, L.

doi:10.1016/b978-0-12-044950-7.50015-5

Cited by 145 publications

(72 citation statements)

References 110 publications

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“…Lichens are known to colonise the harshest terrestrial environments (Kappen, 1973) and have been described from the hottest (Nash et al, 1977), the driest (Bewley and Krochko, 1982) and the coldest (Wynn-Williams et al, 2000) places on earth. According to the Competitor-Stress toleratorRuderal Triangle theory, they are stress tolerators, a grouping that is typically found in areas of highintensity stress and low-intensity disturbance (Grime, 2002) such as alpine or arid habitats, deep shade, nutrient deficient soils and areas of extreme pH levels (Grime and Pierce, 2012).…”

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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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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“…Indeed, lichens can lose water rapidly when the environment is dry and they can also rapidly recover to normal water content when water becomes available [2]. Specifically, different from most plants, a low water content is typically nonlethal to lichens and most lichens can withstand drying to water contents of 5% or less for a long period of time [3,4]. Furthermore, in the presence of water, not only does the water content recover, lichens can rapidly return to normal physiological state to carry out photosynthesis and respiration during rehydration [5,6].…”

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Comparative transcriptome analysis of the lichen-forming fungus Endocarpon pusillum elucidates its drought adaptation mechanisms

Wang

Zhang

Zhou

et al. 2014

Sci. China Life Sci.

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The lichen-forming fungus was isolated from the desert lichen Endocarpon pusillum that is extremely drought resistant. To understand the molecular mechanisms of drought resistance in the fungus, we employed RNA-seq and quantitative real-time PCR to compare and characterize the differentially expressed genes in pure culture at two different water levels and with that in desiccated lichen. The comparative transcriptome analysis indicated that a total of 1781 genes were differentially expressed between samples cultured under normal and PEG-induced drought stress conditions. Similar to those in drought resistance plants and non-lichenized fungi, the common drought-resistant mechanisms were differentially expressed in E. pusillum. However, the expression change of genes involved in osmotic regulation in E. pusillum is different, which might be the evidence for the feature of drought adaptation. Interestingly, different from other organisms, some genes involved in drought adaption mechanisms showed significantly different expression patterns between the presence and absence of drought stress in E. pusillum. The expression of 23 candidate stress responsive genes was further confirmed by quantitative real-time PCR using dehydrated E. pusillum lichen thalli. This study provides a valuable resource for future research on lichen-forming fungi and shall facilitate future functional studies of the specific genes related to drought resistance. lichen, mycobiont, dehydration, drought adaption, drought resistant Citation:Wang YY, Zhang XY, Zhou QM, Zhang XL, Wei JC. Comparative transcriptome analysis of the lichen-forming fungus Endocarpon pusillum elucidates its drought adaptation mechanisms.

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“…Within the vascular plants, desiccation toler ance is currently known in 18 genera of ferns, 23 genera of monocotyledons and ten genera of di cotyledons (Gaff, 1989). It is commonplace in li chens and bryophytes (Kappen, 1973;Proctor, 1981). These small cryptogamic DT plants are im portant, characteristic and sometimes dominant constituents of many vegetation types from the tropics to the polar regions (Kappen, 1973;Smith, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…It is commonplace in li chens and bryophytes (Kappen, 1973;Proctor, 1981). These small cryptogamic DT plants are im portant, characteristic and sometimes dominant constituents of many vegetation types from the tropics to the polar regions (Kappen, 1973;Smith, 1982). Their importance lies not only in their bio mass production but also in their ability to modify their environment in terms of microclimate, water economy, soil characteristics and decomposition rate (Oechel and Lawrence, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…Their importance lies not only in their bio mass production but also in their ability to modify their environment in terms of microclimate, water economy, soil characteristics and decomposition rate (Oechel and Lawrence, 1985). The D T plants tend to increase in abundance and significance un der unfavorable climate conditions, where non-DT plants maintain much of their biomass below ground, or are unable to establish (Tenhunen et al, 1992;Kappen, 1973;Porembski et al, 1994). Since large pools of nutrients and carbon can be found in the D T plants of these extreme vegetation-types, significant aspects of ecosystem func tion depend on their physiological responses, pro duction and turnover pattern.…”

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Desiccation-Tolerant Plants under Elevated Air CO₂: A Review

Tuba

Proctor

Takács

1999

Zeitschrift Für Naturforschung C

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IntroductionThe concentration of C 0 2 in the atmosphere has been increasing in the two last centuries from about 280 ppm to a present value of 360 ppm, and is expected to reach more than twice the pre-indu strial concentration in the next century (Houghton et al., 1990). The increasing concentrations COz might be expected to have substantial impacts on plants and vegetation through changes caused to photosynthesis and other physiological processes (Drake et al., 1997). Variations in atmospheric C 0 2 concentration are nothing new. Evidence from air trapped in polar ice shows that C 0 2 con centration fell to 180-200 ppm during the Pleisto cene glaciations, rising to around 280 ppm during the interglacials (Barnola et al., 1987), and C 0 2 concentrations were higher during some earlier geological periods (Berner, 1998). What is new is that the present increase appears to be driven by human activity through burning of fossil fuels and clearance of forest, that it is faster than most changes that have taken place in the geologically recent past, that it has already reached levels hith erto unknown in Pleistocene and recent times, and that our own and immediately succeeding genera tions will have to cope with whatever conse quences it may bring.Over the last few years an enormous body of experimental data has become available on the re sponses of non-DT plants to elevated concentra tions of C 0 2 (see recently published comprehen sive reviews and books, e.g. Körner and Bazzaz, 1996; Drake et al., 1997; Raschi et al., 1997 and references cited). Reports on the changes in non-DT plant responses (physiology, growth, pro duction and ecology) have shown various patterns. The responses of plants growing under elevated C 0 2 largely depend on the type and degree of physiological acclimation to the high C 0 2 environ ment. Elevated tropospheric C 0 2 level affects photosynthesis most directly, therefore studies generally concentrate on photosynthesis and its acclimation.The most extreme tolerance of water loss occurs in the desiccation-tolerant (DT) or 'resurrection' plants (Gaff, 1989), which can survive the loss of 8 0 -9 5 % or more of their cell water content, so that the plants appear completely dry and no li quid phase remains in their cells. After a shorter or longer period in the desiccated state, they re vive and resume normal metabolism on remoisten ing (Oliver and Bewley, 1997;Proctor, 1981). This is a qualitatively different phenomenon from drought tolerance as ordinarily understood in higher-plant physiology. Physiologically, D T plants function in ways that are significantly different from vascular plants. DT plants have in general evolved physiological adaptions to intermittent supply of water, rather than structural adaptions for maintaining a constant water supply (Proctor, 1981(Proctor, , 1982Tuba et al., 1998a). The D T plants are metabolically active when water is available, and when water is lacking their life is suspended.D T plants span a wide range of adaptation. Poikilochlorophyllous DT (PD T) spec...

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Response to Extreme Environments

Cited by 145 publications

References 110 publications

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

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

Comparative transcriptome analysis of the lichen-forming fungus Endocarpon pusillum elucidates its drought adaptation mechanisms

Desiccation-Tolerant Plants under Elevated Air CO₂: A Review

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Response to Extreme Environments

Cited by 145 publications

References 110 publications

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

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

Comparative transcriptome analysis of the lichen-forming fungus Endocarpon pusillum elucidates its drought adaptation mechanisms

Desiccation-Tolerant Plants under Elevated Air CO2: A Review

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Desiccation-Tolerant Plants under Elevated Air CO₂: A Review