Lichen carbon gain under tropical conditions: water relations and CO2 exchange of Lobariaceae species of a lower montane rainforest in Panama

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.

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Lichen carbon gain under tropical conditions : water relations and CO2 exchange of three Leptogium species of a lower montane rainforest in Panama

Flora ◽

10.1016/s0367-2530(17)30965-9 ◽

2000 ◽

Vol 195 (2) ◽

pp. 172-190 ◽

Cited By ~ 28

Author(s):

Otto L. Lange ◽

Angelika Meyer ◽

Hans Zellner ◽

Bürkhard Budel ◽

Gerhard Zotz

Keyword(s):

Water Relations ◽

Co2 Exchange ◽

Carbon Gain ◽

Tropical Conditions ◽

Montane Rainforest

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Growth of Haematococcus pluvialis on a Small-Scale Angled Porous Substrate Photobioreactor for Green Stage Biomass

Applied Sciences ◽

10.3390/app11041788 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1788

Author(s):

Thanh-Tri Do ◽

Binh-Nguyen Ong ◽

Tuan-Loc Le ◽

Thanh-Cong Nguyen ◽

Bich-Huy Tran-Thi ◽

...

Keyword(s):

Light Intensity ◽

Algal Biomass ◽

Haematococcus Pluvialis ◽

Biomass Productivity ◽

Pilot Scale ◽

Small Scale ◽

Porous Substrate ◽

Low Light ◽

Green Algal ◽

Green Stage

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.

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Design and in vitro realization of carbon-conserving photorespiration

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1812605115 ◽

2018 ◽

Vol 115 (49) ◽

pp. E11455-E11464 ◽

Cited By ~ 33

Author(s):

Devin L. Trudeau ◽

Christian Edlich-Muth ◽

Jan Zarzycki ◽

Marieke Scheffen ◽

Moshe Goldsmith ◽

...

Keyword(s):

Carbon Fixation ◽

Calvin Cycle ◽

Computational Design ◽

Carbon Loss ◽

Fixation Rate ◽

Bisphosphate Carboxylase ◽

Stoichiometric Model ◽

Synthetic Routes ◽

Coa Reductase

Photorespiration recycles ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) oxygenation product, 2-phosphoglycolate, back into the Calvin Cycle. Natural photorespiration, however, limits agricultural productivity by dissipating energy and releasing CO2. Several photorespiration bypasses have been previously suggested but were limited to existing enzymes and pathways that release CO2. Here, we harness the power of enzyme and metabolic engineering to establish synthetic routes that bypass photorespiration without CO2 release. By defining specific reaction rules, we systematically identified promising routes that assimilate 2-phosphoglycolate into the Calvin Cycle without carbon loss. We further developed a kinetic–stoichiometric model that indicates that the identified synthetic shunts could potentially enhance carbon fixation rate across the physiological range of irradiation and CO2, even if most of their enzymes operate at a tenth of Rubisco’s maximal carboxylation activity. Glycolate reduction to glycolaldehyde is essential for several of the synthetic shunts but is not known to occur naturally. We, therefore, used computational design and directed evolution to establish this activity in two sequential reactions. An acetyl-CoA synthetase was engineered for higher stability and glycolyl-CoA synthesis. A propionyl-CoA reductase was engineered for higher selectivity for glycolyl-CoA and for use of NADPH over NAD+, thereby favoring reduction over oxidation. The engineered glycolate reduction module was then combined with downstream condensation and assimilation of glycolaldehyde to ribulose 1,5-bisphosphate, thus providing proof of principle for a carbon-conserving photorespiration pathway.

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Increased high‐latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition

Global Change Biology ◽

10.1111/gcb.14863 ◽

2019 ◽

Vol 26 (2) ◽

pp. 682-696 ◽

Cited By ~ 8

Author(s):

Zhihua Liu ◽

John S. Kimball ◽

Nicholas C. Parazoo ◽

Ashley P. Ballantyne ◽

Wen J. Wang ◽

...

Keyword(s):

High Latitude ◽

Carbon Gain ◽

Carbon Loss ◽

Warm Winter ◽

Spring Transition ◽

Photosynthetic Carbon

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Short-Term Stable Isotope Probing of Proteins Reveals Taxa Incorporating Inorganic Carbon in a Hot Spring Microbial Mat

Applied and Environmental Microbiology ◽

10.1128/aem.01829-19 ◽

2020 ◽

Vol 86 (7) ◽

Cited By ~ 1

Author(s):

Laurey Steinke ◽

Gordon W. Slysz ◽

Mary S. Lipton ◽

Christian Klatt ◽

James J. Moran ◽

...

Keyword(s):

Stable Isotope ◽

Inorganic Carbon ◽

Microbial Mats ◽

Carbon Fixation ◽

Hot Springs ◽

Hot Spring ◽

Stable Isotope Probing ◽

Short Term ◽

Low Light ◽

Assembly Sequences

ABSTRACT The upper green layer of the chlorophototrophic microbial mats associated with the alkaline siliceous hot springs of Yellowstone National Park consists of oxygenic cyanobacteria (Synechococcus spp.), anoxygenic Roseiflexus spp., and several other anoxygenic chlorophototrophs. Synechococcus spp. are believed to be the main fixers of inorganic carbon (Ci), but some evidence suggests that Roseiflexus spp. also contribute to inorganic carbon fixation during low-light, anoxic morning periods. Contributions of other phototrophic taxa have not been investigated. In order to follow the pathway of Ci incorporation into different taxa, mat samples were incubated with [13C]bicarbonate for 3 h during the early-morning, low-light anoxic period. Extracted proteins were treated with trypsin and analyzed by mass spectrometry, leading to peptide identifications and peptide isotopic profile signatures containing evidence of 13C label incorporation. A total of 25,483 peptides, corresponding to 7,221 proteins, were identified from spectral features and associated with mat taxa by comparison to metagenomic assembly sequences. A total of 1,417 peptides, derived from 720 proteins, were detectably labeled with 13C. Most 13C-labeled peptides were derived from proteins of Synechococcus spp. and Roseiflexus spp. Chaperones and proteins of carbohydrate metabolism were most abundantly labeled. Proteins involved in photosynthesis, Ci fixation, and N2 fixation were also labeled in Synechococcus spp. Importantly, most proteins of the 3-hydroxypropionate bi-cycle for Ci fixation in Roseiflexus spp. were labeled, establishing that members of this taxocene contribute to Ci fixation. Other taxa showed much lower [13C]bicarbonate incorporation. IMPORTANCE Yellowstone hot spring mats have been studied as natural models for understanding microbial community ecology and as modern analogs of stromatolites, the earliest community fossils on Earth. Stable-isotope probing of proteins (Pro-SIP) permitted short-term interrogation of the taxa that are involved in the important process of light-driven Ci fixation in this highly active community and will be useful in linking other metabolic processes to mat taxa. Here, evidence is presented that Roseiflexus spp., which use the 3-hydroxypropionate bi-cycle, are active in Ci fixation. Because this pathway imparts a lower degree of selection of isotopically heavy Ci than does the Calvin-Benson-Bassham cycle, the results suggest a mechanism to explain why the natural abundance of 13C in mat biomass is greater than expected if only the latter pathway were involved. Understanding how mat community members influence the 13C/12C ratios of mat biomass will help geochemists interpret the 13C/12C ratios of organic carbon in the fossil record.

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Change in photosynthesis and water relations with age and season in Abiesamabilis

Canadian Journal of Forest Research ◽

10.1139/x84-015 ◽

1984 ◽

Vol 14 (1) ◽

pp. 77-84 ◽

Cited By ~ 54

Author(s):

R. O. Teskey ◽

C. C. Grier ◽

T. M. Hinckley

Keyword(s):

Water Stress ◽

Stomatal Conductance ◽

Water Relations ◽

Net Photosynthesis ◽

Carbon Gain ◽

Xylem Water Potential ◽

Needle Age ◽

Stressful Environment ◽

Competitive Success ◽

One Year

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.

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The photosynthetic response of American chestnut seedlings to differing light conditions

Canadian Journal of Forest Research ◽

10.1139/x07-039 ◽

2007 ◽

Vol 37 (9) ◽

pp. 1714-1722 ◽

Cited By ~ 14

Author(s):

Heather M. Joesting ◽

Brian C. McCarthy ◽

Kim J. Brown

Keyword(s):

Deciduous Forest ◽

Photosynthetic Capacity ◽

Dark Respiration ◽

Nitrogen Concentration ◽

American Chestnut ◽

Control Treatment ◽

Carbon Gain ◽

Leaf Mass Per Area ◽

Light Conditions ◽

Eastern Deciduous Forest

Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.

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Comparative studies on the use of green manuring, organic manuring and Azolla and blue-green algal biofertilizers to rice

The Journal of Agricultural Science ◽

10.1017/s0021859600081375 ◽

1988 ◽

Vol 110 (2) ◽

pp. 337-343 ◽

Cited By ~ 7

Author(s):

A. L. Singh ◽

P. K. Singh ◽

P. L. Singh

Keyword(s):

Organic Carbon ◽

Nitrogen Concentration ◽

Farmyard Manure ◽

Available Phosphorus ◽

Green Manures ◽

Rice Varieties ◽

Organic Manures ◽

Green Manuring ◽

Fresh Biomass ◽

Green Algal

SummaryAzolla and blue-green algae (BGA) biofertilizers in rice cultures were compared with farmyard manure (FYM), Azolla and Eichhornia compost, green manuring with Sesbania and chemical nitrogen fertilizer as urea. Growing Azolla crop in rice field once before transplanting and twice after transplanting produced a fresh biomass of Azolla of 46·7–47·6 and 36·4–40·6 t/ha, containing 83·4–92·2 and 64·7–70·4 kg N/ha, with the rice varieties IR-36 and Mahsuri, respectively. The BGA produced only 7·9–8·9 and 5·2–7·2 t fresh biomass/ha, containing 19·5–20·6 and 14·8–19·3 kg N/ha with IR-36 and Mahsuri, respectively.In the 1st year of the experiment application of FYM, Eichhornia and Azolla compost and green manuring of Sesbania produced lower grain and straw yields and panicles than 60 kg N/ha as urea, but during the 2nd year all these treatments showed responses equal to that of 60 kg N/ha as urea. Nitrogen concentration and uptake by rice in these treatments were, however, lower than that of 60 kg N/ha as urea. Growing and incorporating Azolla once before and twice after transplanting produced higher grain and straw yields, and more panicles, and also showed higher nitrogen concentration and uptake by rice than those of organic and green manures. The BGA inoculation to rice with 30 kg N/ha as urea produced less grain and straw, and fewer panicles, and also showed lower nitrogen concentration and uptake by rice than 60 kg N/ha as urea and other organic manures. Of the two rice varieties, IR-36 produced more grain and panicles than Mahsuri, but Mahsuri produced more straw.Total nitrogen, organic carbon and available phosphorus of soil after harvest of the rice increased owing to the application of organic manures, green manures and Azolla and BGA biofertilizers. The green manuring of Sesbania and using Azolla once before and twice after transplanting and FYM showed highest organic carbon and available phosphorus in soil after harvest.

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