scholarly journals Desiccation tolerance of three moss species from continental Antarctica

2000 ◽  
Vol 27 (5) ◽  
pp. 379 ◽  
Author(s):  
Sharon A. Robinson ◽  
Jane Wasley ◽  
Marianne Popp ◽  
Catherine E. Lovelock
Keyword(s):  
Desiccation Tolerance ◽  
Global Climate ◽  
Wide Distribution ◽  
Soluble Carbohydrates ◽  
Moss Species ◽  
Physiological Tolerance ◽  
Continental Antarctica ◽  
Relative Water ◽  
Intermediate Response ◽  
Bryum Pseudotriquetrum

Tolerance of desiccation was examined in three species of moss, Grimmia antarctici Card., Ceratodon purpureus (Hedw.) Brid. and Bryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb. collected from two sites of contrasting water availability in the Windmill Islands, continental Antarctica. Physiological tolerance to desiccation was measured using chlorophyll fluorescence in plugs of moss during natural drying in the laboratory. Differences in relative water content, rate of drying and the response of photosynthesis to desiccation were observed among the three species and between sites. Of the three species studied, G. antarctici showed the lowest capacity to sustain photosynthetic processes during desiccation, B. pseudotriquetrum had an intermediate response and showed the greatest plasticity and C. purpureus showed the greatest capacity to sustain photosynthesis during desiccation. These results fit well with the known distribution of the three species with G. antarctici being limited to relatively wet sites, C. purpureus being common in the driest sites and B. pseudotriquetrum showing a wide distribution between these two extremes. Levels of soluble carbohydrates were also measured in these samples following desiccation and these indicate the presence of stachyose, an oligosaccharide known to be important in desiccation tolerance in seeds, in B. pseudotriquetrum. Both gross morphology and carbohydrate content are likely to contribute to differences in desiccation tolerance of the moss species. These results indicate that if the Casey region continues to dry out, as a result of local geological uplifting or global climate change, we would expect to see not only reductions in the moss community but also changes in community composition. G. antarctici is likely to become more limited in distribution as C. purpureus and B. pseudotriquetrum expand into drying areas.

scholarly journals The effects of salt stress on growth, nitrate reduction and proline and glycinebetaine accumulation in Prosopis alba

2004 ◽  
Vol 16 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Diego Ariel Meloni ◽  
Marta Rosalía Gulotta ◽  
Carlos Alberto Martínez ◽  
Marco Antonio Oliva
Keyword(s):  
Reductase Activity ◽  
Soluble Carbohydrates ◽  
Nitrate Content ◽  
Prosopis Alba ◽  
Root Shoot Ratio ◽  
Nacl Concentration ◽  
Root And Shoot Growth ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Leaves And Roots

Prosopis alba (algarrobo) is one of the most important salt-tolerant legumes used in the food and furniture industries. The effects of salinity on some growth and physiological parameters in algarrrobo seedlings were investigated. 17-Day-old seedlings were subjected to three salt treatments by adding NaCl to the growth medium in 50 mmol.L-1 increments every 24 h until the final concentrations of 0, 300 and 600 mmol.L-1 were reached. Only the highest NaCl concentration affected all of the considered parameters. Thus, 600 mmol.L-1 NaCl caused a significant reduction in root and shoot growth, but an increase in the root/shoot ratio. Leaf relative water content, nitrate content and nitrate reductase activity in leaves and roots were also decreased. At 300 and 600 mmol.L-1, the glycinebetaine content was significantly increased in both leaves and roots but this was not found for proline content. Total soluble carbohydrates increased only in roots. The results suggest that glycinebetaine enhancement may be important for osmotic adjustment in Prosopis alba under salinity stress.

Chromosome numbers in some mosses from western Canada

1983 ◽  
Vol 61 (9) ◽  
pp. 2384-2387
Author(s):  
Helen P. Ramsay
Keyword(s):  
British Columbia ◽  
Chromosome Numbers ◽  
First Record ◽  
Western Canada ◽  
Moss Species ◽  
New Localities ◽  
Bryum Pseudotriquetrum ◽  
Dicranum Scoparium

Chromosome numbers are reported for six moss species from western Canada, four from British Columbia, two from Alberta. These give data on chromosome numbers from new localities in Canada for populations of five species and the first record for Kiaeria starkei from Canada. Chromosome numbers reported are n = 13, Grimmia afftnis; n = 14, Kiaeria starkei; n = 14 (13 + m), Dicranum scoparium; n = 20, Bryum pseudotriquetrum; n = 11, Ptilium crista-castrensis; and n = 6, Hypnum circinale.

Vegetative desiccation tolerance of Tripogon spicatus (Poaceae) from the tropical semiarid region of northeastern Brazil

2017 ◽  
Vol 44 (11) ◽  
pp. 1124 ◽  
Author(s):  
Saulo de T. Aidar ◽  
Agnaldo R. de M. Chaves ◽  
Paulo I. Fernandes Júnior ◽  
Melquisedec de S. Oliveira ◽  
Benjamim P. da Costa Neto ◽  
...  
Keyword(s):  
Amino Acids ◽  
Desiccation Tolerance ◽  
Northeastern Brazil ◽  
Semiarid Region ◽  
Total Carotenoids ◽  
Sod Activity ◽  
Relative Water ◽  
Mda Content ◽  
Leaf Relative Water Content ◽  
Amino Acid Contents

The vegetative desiccation tolerance of Tripogon spicatus (Nees) Ekman was confirmed by its ability to recover the physiological functionality of intact plants previously subjected to extreme dehydration. Photosynthesis became undetectable when leaf relative water content (RWCleaf) achieved ~60%, whereas photochemical variables showed a partial decrease. Until the minimum RWCleaf of 6.41%, total chl decreased by 9%, and total carotenoids increased by 29%. Superoxide dismutase (SOD) activity decreased by 57%, on average, during dehydration, but catalase (CAT) and peroxidase (APX) activities showed no significant differences throughout the experiment. Malondialdehyde (MDA) content increased by 151%, total leaf and root amino acids decreased by 62% and 77%, respectively, whereas leaf and root proline decreased by 40% and 61%, respectively, until complete desiccation. After rehydration, leaves completely recovered turgidity and total chl contents. Carotenoids and MDA remained high, whereas SOD was 60% lower than the measured average measured before dehydration. With the exception of root amino acid contents, total amino acids and proline concentrations recovered completely. Gas exchange and photochemical variables remained substantially higher 4 days after rehydration, compared with the control. Besides increasing MDA, the overall physiological results showed that membrane functionality was preserved, leading to the vegetative desiccation tolerance of T. spicatus during the dehydration–rehydration cycle.

Ecology of Cladonia lichens. II. Comparative physiological ecology of C. mitis, C. rangiferina, and C. uncialis

1974 ◽  
Vol 52 (2) ◽  
pp. 411-422 ◽  
Author(s):  
Martin J. Lechowicz ◽  
Michael S. Adams
Keyword(s):  
Seasonal Variation ◽  
Physiological Ecology ◽  
Net Photosynthesis ◽  
Pine Barrens ◽  
Physiological Tolerance ◽  
Interspecific Differences ◽  
Significant Seasonal Variation ◽  
Relative Water ◽  
Photosynthetic Responses ◽  
Response To Temperature

The net CO2 exchange responses of Cladonia mitis, C. rangiferina, and C. uncialis from the Wisconsin Pine Barrens to irradiance, thallus temperature, and thallus relative water content were statistically compared for fall, spring, and summer. The absolute net photosynthetic rate of C. rangiferina exceeded that of C. uncialis under essentially all conditions and in all seasons; C. mitis's absolute net photosynthesis fluctuated with the seasons between these two contrasting species. Cladonia mitis showed significant intraspecific seasonal variation in net photosynthetic responses to temperature and irradiance. Cladonia rangiferina showed significant seasonal variation in dark respiratory response to temperature. Cladonia uncialis showed no significant intraspecific seasonal variation in net CO2 exchange responses. Significant interspecific differences in net CO2 exchange responses centered on the net photosynthetic responses to thallus temperature and relative water content.Despite its low net photosynthetic rates, C. uncialis is the most prevalent lichen in the Wisconsin Pine Barren ground-layer community. We attribute this not to broad physiological tolerance, but to its significantly slower drying rate. Lichens photosynthesize only when wetted. Cladonia uncialis photosynthesizes at generally lower rates than C. mitis or C. rangiferina, but it photosynthesizes longer under comparable environmental drying regimes. This and other aspects of the physiological ecology of the three species are discussed in relation to microdistribution and microhabitats within the Wisconsin Pine Barrens.

scholarly journals A Label-Free Proteomic and Complementary Metabolomic Analysis of Leaves of the Resurrection Plant Xerophyta schlechteri during Dehydration

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1242
Author(s):  
Hawwa Gabier ◽  
David L. Tabb ◽  
Jill M. Farrant ◽  
Mohamed Suhail Rafudeen
Keyword(s):  
Desiccation Tolerance ◽  
Early Response ◽  
Resurrection Plant ◽  
Late Response ◽  
Biological Processes ◽  
Label Free ◽  
Relative Water ◽  
Leaf Tissues ◽  
Insight Into ◽  
Selection Of

Vegetative desiccation tolerance, or the ability to survive the loss of ~95% relative water content (RWC), is rare in angiosperms, with these being commonly called resurrection plants. It is a complex multigenic and multi-factorial trait, with its understanding requiring a comprehensive systems biology approach. The aim of the current study was to conduct a label-free proteomic analysis of leaves of the resurrection plant Xerophyta schlechteri in response to desiccation. A targeted metabolomics approach was validated and correlated to the proteomics, contributing the missing link in studies on this species. Three physiological stages were identified: an early response to drying, during which the leaf tissues declined from full turgor to a RWC of ~70–80%, a mid-response in which the RWC declined to 40% and a late response where the tissues declined to 10% RWC. We identified 517 distinct proteins that were differentially expressed, of which 253 proteins were upregulated and 264 were downregulated in response to the three drying stages. Metabolomics analyses, which included monitoring the levels of a selection of phytohormones, amino acids, sugars, sugar alcohols, fatty acids and organic acids in response to dehydration, correlated with some of the proteomic differences, giving insight into the biological processes apparently involved in desiccation tolerance in this species.

Structured Data Facilitate Learning Design for Energetic Transition

2018 ◽  
Vol 8 (2) ◽  
pp. 1-22
Author(s):  
Gilbert Ahamer
Keyword(s):  
Adaptive Learning ◽  
Global Climate ◽  
Wide Distribution ◽  
Social Processes ◽  
Structured Data ◽  
Learning Design ◽  
Educational Strategies ◽  
Power Politics ◽  
Global Power ◽  
Path Dependent

For the immense but necessary task of global climate protection, avenues for action should be designed to consider the intrinsically autopoietic and self-guided behaviour of global power politics. Thus, pragmatic approaches may provide solutions and educational strategies have to prepare global society. This article proposes a “design of social processes” as a lasting global educational strategy that may enhance the societal and institutional transition to a non-fossil future, as called for by the recent Paris climate conference. In a path-dependent world, self-adaptive learning is needed, given the wide distribution of learners' profiles – and their interests. Sound education is identified as the genesis of structures that lead to changes in action. Three principles for such a design of social processes are proposed: rhythmisation, multi-perspectivism, and underdeterminism, as found in game play.

Responses of Terrestrial Mosses to Simulated Climate Change in a Secondary Evergreen Broad-leaved Forest in Southern China

2021 ◽  
Author(s):  
Jiewei Hao ◽  
L.M. Chu
Keyword(s):  
Climate Change ◽  
Tropical Forest ◽  
Forest Ecosystems ◽  
Southern China ◽  
Global Climate ◽  
Moss Species ◽  
Tropical Regions ◽  
Simulated Climate ◽  
Terrestrial Mosses ◽  
Simulated Climate Change

Abstract Tropical regions are biodiversity hotspots and are well suited to explore the potential influence of global climate change on forest ecosystems. Bryophytes have essential ecological functions in tropical forest ecosystems. Knowledge of the potential impact of global warming and possible changes in water availability patterns on terrestrial bryophytes is limited. We transplanted eight moss species from two elevations (900 and 500 m) to warmer and drier elevations (500 and 100 m) during a half-year observation period on Tai Mo Shan, southern China. The simulated climate change resulted in a marked decrease in growth and a negative effect on the health of the transplanted species. Few moss species survived six months after transplanting to the warmer and drier lowlands, and their health status deteriorated severely. Three moss species, Sematophyllum subhumile, Pseudotaxiphyllum pohliaecarpum, and Brachythecium buchananii, were highly susceptible to changes in temperature and moisture and might be used as suitable bioindicators. As the tropics are expected to become hotter and drier, terrestrial mosses might be negatively affected or even be at risk of extinction. The cascading negative effects on the forest ecosystem might be induced by the dying back or even disappearance of terrestrial moss species. Thus, conservation of bryophyte communities is important to sustain and improve the stability and resilience of tropical forest ecosystems to climate change.

Loss of soluble carbohydrates and changes in freezing point of Antarctic bryophytes after leaching and repeated freeze-thaw cycles

1992 ◽  
Vol 4 (4) ◽  
pp. 399-404 ◽  
Author(s):  
D. R. Melick ◽  
R. D. Seppelt
Keyword(s):  
Freezing Point ◽  
Thermal Analyses ◽  
Late Summer ◽  
Total Sugar ◽  
Control Treatment ◽  
Soluble Carbohydrates ◽  
Freeze Thaw ◽  
The Dead ◽  
Bryum Pseudotriquetrum ◽  
Sugar Loss

Healthy samples of Grimmia antarctici (turf and cushion ecodemes), Ceratodon purpureus, Bryum pseudotriquetrum and Cephaloziella exiliflora were collected in late summer in Wilkes Land together with senescing and dead G. antarctici material. Plant material was subjected to leaching in water and up to 16 freeze-thaw cycles. Gas chromatography revealed that following 16 days immersion, loss of carbohydrates (mainly glucose and fructose) was relatively low (c. 10–29% of the total sugar pool) for healthy material, with the loss of 69% from the dead G. antarctici material. Freeze-thaw cycles greatly increased rates of sucrose leakage and led to a 2–3 times rise in total sugar loss in all samples except the dead brown tissue which was not significantly different from the leached control treatment. After 16 freeze-thaw cycles Bryum pseudotriquetrum had lost 65% of total sugar pool. Losses for other species were below 28%. Differential thermal analyses showed freezing points of tissue varied from −8.3 to −3.5°C with dead material having the highest freezing temperatures. There was no significant correlation within species of freezing temperature changes with progressive sugar loss. The results are discussed in relation to nutrient cycling, soil microbial activity and the viability of bryophyte species in the Antarctic environment.

Soluble carbohydrates in desiccation tolerance of yellow lupin seeds during maturation and germination

1997 ◽  
Vol 7 (2) ◽  
pp. 107-116 ◽  
Author(s):  
R. J. Górecki ◽  
A. I. Piotrowicz-Cieślak ◽  
L. B. Lahuta ◽  
R. L. Obendorf
Keyword(s):  
Desiccation Tolerance ◽  
Tolerance Test ◽  
Soluble Carbohydrates ◽  
Raffinose Family Oligosaccharides ◽  
Yellow Lupin ◽  
Seed Growth ◽  
Before And After ◽  
Lupin Seeds ◽  
Root Tissues ◽  
Galactosyl Cyclitols

AbstractMaturing yellow lupin seeds were desiccation tolerant. Glucose, sucrose and cyclitols (mainly D-pinitol, D-chiro-inositol and myo-inositol) were predominant at the early stages of seed growth. Accumulation of the raffinose family oligosaccharides (RFOs) and the galactosyl cyclitols including galactinol, digalactosyl myo-inositol, galactopinitol A, galactopinitol B, trigalactopinitol A, ciceritol, fagopyritol B1 and fagopyritol B2 appeared during seed maturation; their increase correlated with seed germinability after desiccation. The loss of desiccation tolerance after seed germination was also studied. For the desiccation tolerance test, intact seedlings were dried rapidly or slowly followed by rehydration. Soluble carbohydrates were assayed before and after drying. Root tissues were more sensitive to desiccation than hypocotyl tissues and completely lost desiccation tolerance within 36 h of imbibition after both fast and slow-drying treatments. Survival of hypocotyls decreased gradually up to 96 h after imbibition. Loss of RFOs and galactosyl cyclitols in axis tissues preceded visible germination. Loss of desiccation tolerance was accompanied by loss of RFOs and galactosyl cyclitols and an increase in reducing sugars in cotyledon, hypocotyl and radicle tissues. Drying did not induce the accumulation of RFOs and galactosyl cyclitols in seedling tissues.

scholarly journals Some like it wet — biological characteristics underpinning tolerance of extreme water stress events in Antarctic bryophytes

2006 ◽  
Vol 33 (5) ◽  
pp. 443 ◽  
Author(s):  
Jane Wasley ◽  
Sharon A. Robinson ◽  
Catherine E. Lovelock ◽  
Marianne Popp
Keyword(s):  
Water Stress ◽  
Water Availability ◽  
Community Dynamics ◽  
Present Species ◽  
Future Climate Change ◽  
Soluble Carbohydrates ◽  
Ecological Niches ◽  
Moss Species ◽  
Membrane Structure And Function ◽  
Study Species

Antarctic bryophyte communities presently tolerate physiological extremes in water availability, surviving both desiccation and submergence events. We investigated the relative ability of three Antarctic moss species to tolerate physiological extremes in water availability and identified physiological, morphological, and biochemical characteristics that assist species performance under such conditions. Tolerance of desiccation and submergence was investigated using chlorophyll fluorescence during a series of field- and laboratory-based water stress events. Turf water retention and degree of natural habitat submergence were determined from gametophyte shoot size and density, and δ13C signatures, respectively. Finally, compounds likely to assist membrane structure and function during desiccation events (fatty acids and soluble carbohydrates) were determined. The results of this study show significant differences in the performance of the three study species under contrasting water stress events. The results indicate that the three study species occupy distinctly different ecological niches with respect to water relations, and provide a physiological explanation for present species distributions. The poor tolerance of submergence seen in Ceratodon purpureus helps explain its restriction to drier sites and conversely, the low tolerance of desiccation and high tolerance of submergence displayed by the endemic Grimmia antarctici is consistent with its restriction to wet habitats. Finally the flexible response observed for Bryum pseudotriquetrum is consistent with its co-occurrence with the other two species across the bryophyte habitat spectrum. The likely effects of future climate change induced shifts in water availability are discussed with respect to future community dynamics.

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