Responses of lichens to salinity: concentration and time‐course relationships and variability among Californian species

Nash, Thomas H.; Lange, O. L.

doi:10.1111/j.1469-8137.1988.tb04206.x

Cited by 30 publications

(22 citation statements)

References 24 publications

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“…-4 MPa, net photosynthesis was decreased to zero in sea salt, whereas the same water potential permitted more than 75% of the control rate of net photosynthesis under osmotic (sorbitol) stress or atmospheric desiccation. In agreement with our earlier findings (Nash & Lange, 1988), the photosynthetic apparatus of this species exhibited a specific ion sensitivity, which is consistent with its restriction to habitats far from the infiuence of the coastal salt spray.…”

Section: Discussionsupporting

confidence: 92%

“…During the measurement period of 2-5 to 3 h, the lichen samples remained wetted with the treatment solution. Previous studies had established that no further decline in gas exchange rates occurred subsequent to the exposure to salt solutions over this period of time (Nash & Lange, 1988).…”

Section: Pre-experimental Conditionsmentioning

confidence: 72%

“…The salt-sensitive lichen These values correspond well to those obtained in species Evernia prunastri (L.) Ach. and Pseudo-our previous study (Nash & Lange, 1988 …”

Section: Methodsmentioning

confidence: 80%

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The effect of atmospheric desiccation and osmotic water stress on photosynthesis and dark respiration of lichens

et al. 1990

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SUMMARYFour species of epiphytic lichens from California with varying responses to salinity were studied to determine the response of CO^ exchange to decreasing water potential (^). Changes in ^ were induced either by allowing dry thalh to come into equilibrium with atmospheres of defined water vapour pressure, or by osmotic stress through mcubation of the thalh in sea salt or sorbitol solutions. In two species the gradual decline of CO^ uptake rates with decreasmg ^ was independent of the method which was used to establish xjr (and therefore relatively independent of the bulk water content of the thalli); measurable CO^ fixation occurred in Dendrographa minor Darb and Ramahna menziesii Tayl. to values of x}r as low as -38 and -22 MPa, respectively. Photosynthesis of Evernia prunastri (L.) Ach. responded similarly to low xjr which was induced either through atmospheric desiccation or osmotic dehydration (sorbitol). However, E. prunastri was much more sensitive to low ijr when the thallus was treated with NaCl solutions. Photosynthesis in Pseudocyphellaria anthraspis Magn., the only species investigated with a blue-green (cyanobacterial) photobiont, was strictly dependent on wetting of the thallus with water Net photosynthesis was detectable to -3-5 MPa in sorbitol and salt solutions, but in moist air of a similar tjr P. anthraspis showed no CO^ uptake. In all four species, dark respiration was markedly less sensitive to osmotic dehydration in sorbitol or salt solutions than at the same ^ under atmospheric desiccation. In E. prunastri, salt stress combined with high light resulted in a much more pronounced decrease in the rate of photosynthesis than either salt stress in low light, or high light alone. These species provide a model system to differentiate the effect of atmospheric desiccation and osmotic stress on lichen metabolism, and to study the interaction of drought per se with other stress factors such as salt and high light.

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Section: Discussionsupporting

confidence: 92%

Section: Pre-experimental Conditionsmentioning

confidence: 72%

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The effect of atmospheric desiccation and osmotic water stress on photosynthesis and dark respiration of lichens

et al. 1990

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“…Matthes-Sears et al (1987) showed that in R. menziesii overall photosynthesis rates were unaffected by intrathallus Na^ levels; they speculated that the primary physiological effect of NaCl was osmotic dehydration. In contrast, Nash & Lange (1988) demonstrated that different lichen species responded differently to sorbitol, sea salt, and NaCl. Broader studies are needed in which osmotic, matric, and salt stresses are compared.…”

Section: Discussionmentioning

confidence: 93%

Water relations, thallus structure and photosynthesis in Negev Desert lichens

Palmer

Friedmann

1990

New Phytologist

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SUMMARYThe role of lichen thallus structure in water relations and photosynthesis was studied in Ramalina maciformis (Del.) Bory and Teloschistes lacunosus (Rupr.) Sav. Water-vapour adsorption and photosynthesis are dependent upon thallus integrity and are significantly lower in crushed thalli. Cultured phycobiont (Trebouxia sp.) cells are capable of photosynthesis over the same relative humidity range (> 80 % RH) as are intact lichens. Thus, watervapour adsorption by the thallus and physiological adaptation of the phycobiont contribute to the ability of these lichens to photosynthesize in an arid environment. Despite differences in their anatomical structure and wateruptake characteristics, their COj incorporation is similar. The two lichens use liquid water differently and they occupy different niches.

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“…The negative correlation of lichen richness and rock exposure may be related to the fact that areas of bedrock contained few shrubs and trees and therefore little habitat for the potential suite of epiphytic species. Although lichens exhibit a wide range of salt tolerance (Nash and Lange 1988), higher lichen richness in areas further from the coast and correspondingly lower in salinity may indicate that the majority of barrens macrolichens are salt-sensitive.…”

Section: Conservation Strategiesmentioning

confidence: 98%

Species richness, abundance, rarity and environmental gradients in coastal barren vegetation

Oberndorfer

Lundholm

2008

Biodivers Conserv

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Coastal barrens in Nova Scotia are heathlands characterised by short, predominantly ericaceous vegetation, sparse tree cover, exposed bedrock, pockets of Sphagnum bog, and stressful climatic conditions. Although coastal barrens are prominent in the physical and cultural landscape, they are largely unprotected. We selected six barrens along the Atlantic coast, and surveyed 20 1-m 2 plots at each barren for vascular plants, macrolichens, mosses and environmental factors. We recorded 173 species (105 vascular, 41 macrolichen, 27 moss), including six provincially rare vascular species found predominantly in nearshore areas with high levels of substrate salt and nutrients, variable substrate depth, and short vegetation. Although vascular plant and moss richness were similarly correlated with vegetation height, substrate depth, organic matter content, and rock exposure, there were no clear correlations between vascular plant, macrolichen and moss richness across all sites. Vascular plant rarity and species richness were not correlated, but had inverse relationships with key environmental gradients. Tailoring conservation efforts to protect areas of high richness may thus mean that rare species are missed, and vice versa. Ordination and ANOSIM show that barrens vegetation differs widely among sites; therefore, protecting any singular coastal barren will not protect the entire range of vegetation communities and species in this heathland type. Conservation planning should emphasize protecting environmental gradients correlated with richness, rarity and plant community structure, including substrate depth and moisture, and vegetation height. Additionally, protected areas should include a coastal-inland gradient and a diversity of substrate types, including exposed rock and trees.

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Responses of lichens to salinity: concentration and time‐course relationships and variability among Californian species

Cited by 30 publications

References 24 publications

The effect of atmospheric desiccation and osmotic water stress on photosynthesis and dark respiration of lichens

The effect of atmospheric desiccation and osmotic water stress on photosynthesis and dark respiration of lichens

Water relations, thallus structure and photosynthesis in Negev Desert lichens

Species richness, abundance, rarity and environmental gradients in coastal barren vegetation

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