High thallus water content severely limits photosynthetic carbon gain of central European epilithic lichens under natural conditions

Oecologia ◽  
1996 ◽  
Vol 108 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Otto L. Lange ◽  
T. G. Allan Green

1997 ◽  
Vol 29 (1) ◽  
pp. 67-82 ◽  
Author(s):  
L. G. Sancho ◽  
B. Schroeter ◽  
F. Valladares

AbstractNet photosynthesis (NP) and dark respiration (DR) of thalli of the lichen species Umbilicaria grisea and U. freyi growing together in the same habitat the Sierra de Guadarrama, central Spain, were measured under controlled conditions in the laboratory and under natural conditions in the field over a range of photosynthetic photon flux densities (PPFD), thallus temperatures and thallus water contents. Laboratory experiments revealed that the photosynthetic response to PPFD at optimum thallus water content is very similar in both species. The light compensation points of NP increased from PPFD of c. 20 µmol m−2 s−1 at 0°C up to c. 100 µmol m−2 s−1 PPFD at 25°C. In both species light saturation was not reached up to 700 µmol m−2 s−1 PPFD except at 0°C. By contrast, the temperature dependence of CO2 gas exchange differed substantially between U. grisea and U. freyi. Both species gave significant rates at 0°C. Optimal temperatures of NP were always higher in U. grisea at various PPFD levels if the samples were kept at optimal thallus water content. NP showed maximal rates at 95% dw in U. grisea and 110% dw in U. freyi respectively. In U. grisea a much stronger depression of NP was observed with only 5% of maximal NP reached at 180% dw. At all PPFD and temperature combinations U. freyi showed higher rates of NP and more negative rates of DR if calculated on a dry weight basis. This was also true under natural conditions at the same site, when U. freyi was always more productive than U. grisea. The differences in the photosynthetic response to temperature between both species correlated well with the different distribution patterns of both species. The possibility of genetic control of the physiological performance of these species and its influence on their distribution patterns and autecology is discussed.



2004 ◽  
Vol 36 (5) ◽  
pp. 329-342 ◽  
Author(s):  
Otto L. LANGE ◽  
Burkhard BÜDEL ◽  
Angelika MEYER ◽  
Hans ZELLNER ◽  
Gerhard ZOTZ

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.



Oecologia ◽  
2014 ◽  
Vol 175 (2) ◽  
pp. 457-470 ◽  
Author(s):  
Sari Palmroth ◽  
Lisbet Holm Bach ◽  
Annika Nordin ◽  
Kristin Palmqvist


2019 ◽  
Vol 26 (2) ◽  
pp. 682-696 ◽  
Author(s):  
Zhihua Liu ◽  
John S. Kimball ◽  
Nicholas C. Parazoo ◽  
Ashley P. Ballantyne ◽  
Wen J. Wang ◽  
...  


2019 ◽  
Vol 256 ◽  
pp. 108630 ◽  
Author(s):  
Qingming Li ◽  
Yuping Liu ◽  
Subo Tian ◽  
Zengwen Liang ◽  
Shuhao Li ◽  
...  


Oecologia ◽  
2012 ◽  
Vol 169 (3) ◽  
pp. 661-672 ◽  
Author(s):  
Sheel Bansal ◽  
Marie-Charlotte Nilsson ◽  
David A. Wardle


2011 ◽  
Vol 11 (1) ◽  
pp. 123 ◽  
Author(s):  
David M Rosenthal ◽  
Anna M Locke ◽  
Mahdi Khozaei ◽  
Christine A Raines ◽  
Stephen P Long ◽  
...  


2020 ◽  
pp. 171-178
Author(s):  
Evgeniy Nikolayevich Sechin ◽  
Oleg Anatolyevich Marakaev ◽  
Gavriil Borisovich Gavrilov

For the first time, the phytosterol state of the underground and aboveground organs of the tuberoid species of the orchid Dactylorhiza maculata (L.) Soó (Orchidaceae), which grows in the natural conditions of the Central European part of Russia, was studied using gas chromatography with a mass spectrometric detector. The plant material contains cycloartenol, cycloeukalenol, campesterol, brassicasterin, β-sitosterol, stigmasterol and ergosterol, which was found in underground organs and belong to mycosymbiont. The ergosterol content in the adventitious roots is five times higher compared to the endings of stem root tuberoids. The phytosterols content of the aboveground organs of D. maculata is more diverse than that of the underground organs. The basic sterol of D. maculata is β-sitosterol (60%), which is present in all organs. Also a high amount was noted for cycloartenol (20%), which is absent in the stem. Cycloeukalenol (7%) was found in inflorescences and leaves, campesterol (2%) in inflorescences, brassicasterin (5%) in the adventitious roots, stigmasterol (5%) in the leaves. Differences in the sterol statuses of organs can be explained by the biochemical characteristics of their tissues and the uneven functional significance of the identified compounds for the growth and development of generative individuals of D. maculata in the budding phase. The results obtained indicate the diversity of phytosterol compounds and their uneven content in various organs of the studied plant object.



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