scholarly journals Leaf wax composition and distribution of Tillandsia landbeckii reflects moisture gradient across the hyperarid Atacama Desert

2022 ◽  
Vol 308 (1) ◽  
Author(s):  
Sergio Contreras ◽  
Manlio Landahur ◽  
Karla García ◽  
Claudio Latorre ◽  
Mark Reyers ◽  
...  

AbstractIn the hyperarid Atacama Desert, water availability plays a crucial role in allowing plant survival. Along with scant rainfall, marine advective fog frequently occurs along the coastal escarpment fueling isolated mono-specific patches of Tillandsia vegetation. In this study, we investigate the lipid biomarker composition of the bromeliad Tillandsia landbeckii (CAM plant) to assess structural adaptations at the molecular level as a response to extremely arid conditions. We analyzed long-chain n-alkanes and fatty acids in living specimens (n = 59) collected from the main Tillandsia dune ecosystems across a 350 km coastal transect. We found that the leaf wax composition was dominated by n-alkanes with concentrations (total average 160.8 ± 91.4 µg/g) up to three times higher than fatty acids (66.7 ± 40.7 µg/g), likely as an adaptation to the hyperarid environment. Significant differences were found in leaf wax distribution (Average Chain Length [ACL] and Carbon Preference Index [CPI]) in the northern zone relative to the central and southern zones. We found strong negative correlations between fatty acid CPI and n-alkane ACL with precipitation and surface evaporation pointing at fine-scale adaptations to low moisture availability along the coastal transect. Moreover, our data indicate that the predominance of n-alkanes is reflecting the function of the wax in preventing water loss from the leaves. The hyperarid conditions and good preservation potential of both n-alkanes and fatty acids make them ideal tracers to study late Holocene climate change in the Atacama Desert.

Author(s):  
Reilly M. Blocho ◽  
Richard W. Smith ◽  
Mark R. Noll

AbstractThe purpose of this study was to observe how the composition of organic matter (OM) and the extent of anoxia during deposition within the Marcellus Formation in New York varied by distance from the sediment source in eastern New York. Lipid biomarkers (n-alkanes and fatty acids) in the extractable organic component (bitumen) of the shale samples were analyzed, and proxies such as the average chain length (ACL), aquatic to terrestrial ratio (ATR) and carbon preference index (CPI) of n-alkanes were calculated. Fatty acids were relatively non-abundant due to the age of the shale bed, but n-alkane distributions revealed that the primary component of the OM was terrigenous plants. The presence of shorter n-alkane chain lengths in the samples indicated that there was also a minor component of phytoplankton and algal (marine) sourced OM. Whole rock analyses were also conducted, and cerium anomalies were calculated as a proxy for anoxia. All samples had a negative anomaly value, indicating anoxic conditions during deposition. Two samples, however, contained values close to zero and thus were determined to have suboxic conditions. Anoxia and total organic matter (TOM) did not show any spatial trends across the basin, which may be caused by varying depths within the basin during deposition. A correlation between nickel concentrations and TOM was observed and indicates that algae was the primary source of the marine OM, which supports the lipid biomarker analysis. It was determined that the kerogen type of the Marcellus Formation in New York State is type III, consistent with a methane-forming shale bed.


2020 ◽  
Vol 15 (5) ◽  
pp. 1934578X2092607
Author(s):  
Biljana Nikolić ◽  
Marina Todosijević ◽  
Iris Đorđević ◽  
Jovana Stanković ◽  
Zorica S. Mitić ◽  
...  

In leaf cuticular wax of Pinus pinaster, content of nonacosan-10-ol is high (77.1% on average). n-Alkanes ranged from C18 to C35 with the most dominant C29 (24.8%). The carbon preference index (CPItotal) ranged from 3.1 to 5.6 (4.0 on average), while the average chain length (ACLtotal) ranged from 14.0 to 17.0 (14.8 on average). Long-chain n-alkanes ( n-C25-35) strongly dominated (80.1%) over middle-chain ( n-C21-24 = 18.9%) and short-chain ( n -C18-20 = 0.9%) n-alkanes.


2010 ◽  
Vol 75 (10) ◽  
pp. 1337-1346 ◽  
Author(s):  
Biljana Nikolic ◽  
Vele Tesevic ◽  
Iris Djordjevic ◽  
Milka Jadranin ◽  
Marina Todosijevic ◽  
...  

This is the first report of n-alkanes in needle epicuticular waxes of variety of Bosnian pine, Pinus heldreichii var. pancici. n-Hexane extracts of needle samples, originated from seven isolated localities in Serbia, were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The results exhibited nalkanes in epicuticular waxes ranging from C18 to C33. The most abundant alkanes were C27, C23, C25 and C29 (12.53 %, 12.46 %, 12.00 % and 10.38 % on average, respectively). The carbon preference index (CPItotal) of Pinus heldreichii var. pancici ranges from 1.1 to 2.1 (1.6 on average), while average chain length (ACLtotal) ranges from 25.0 to 25.8 (25.3 on average). A high level of individual quantitative variation in all of these hydrocarbon parameters was also obtained. The obtained results were compared with the bibliographic references for Pinus heldreichii var. leucodermis and other species of the Pinus genus.


2020 ◽  
Vol 15 (5) ◽  
pp. 1934578X2092097
Author(s):  
Biljana Nikolić ◽  
Marina Todosijević ◽  
Iris Đorđević ◽  
Jovana Stanković ◽  
Zorica S. Mitić ◽  
...  

In needle cuticular wax of Pinus halepensis, nonacosan-10-ol is high (77.08% on average). n-Alkanes ranged from C18 to C35 with the most dominant C27 and C29 (32.4% and 25.8%, respectively). The carbon preference index ranged from 3.2 to 5.4 (3.4 on average), while the average chain length ranged from 14.0 to 18.0 (17.2 on average). Long-chain n-alkanes strongly dominated (95.1%).


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hidekazu Yoshida ◽  
Ryusei Kuma ◽  
Hitoshi Hasegawa ◽  
Nagayoshi Katsuta ◽  
Sin-iti Sirono ◽  
...  

AbstractIsolated silica concretions in calcareous sediments have unique shapes and distinct sharp boundaries and are considered to form by diagenesis of biogenic siliceous grains. However, the details and rates of syngenetic formation of these spherical concretions are still not fully clear. Here we present a model for concretion growth by diffusion, with chemical buffering involving decomposition of organic matter leading to a pH change in the pore-water and preservation of residual bitumen cores in the concretions. The model is compatible with some pervasive silica precipitation. Based on the observed elemental distributions, C, N, S, bulk carbon isotope and carbon preference index (CPI) measurements of the silica-enriched concretions, bitumen cores and surrounding calcareous rocks, the rate of diffusive concretion growth during early diagenesis is shown using a diffusion-growth diagram. This approach reveals that ellipsoidal SiO2 concretions with a diameter of a few cm formed rapidly and the precipitated silica preserved the bitumen cores. Our work provides a generalized chemical buffering model involving organic matter that can explain the rapid syngenetic growth of other types of silica accumulation in calcareous sediments.


The Holocene ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 16-27
Author(s):  
Lilei Chen ◽  
Feng Li ◽  
Jian Liu ◽  
Xingliang He

The use of lipid biomarkers as paleoenvironmental proxies relies on an accurate assessment of their organic matter (OM) sources. In this study, we analyzed multiple lipids in core sediments recovered from the Zhejiang–Fujian coastal mud area to provide a 160-year record of OM input to the East China Sea (ECS) coastal sediments and to reconstruct paleoenvironmental conditions over this interval. The molecular composition of the samples was characterized by a mixture of natural lipids, particularly those derived from terrestrial vascular plants, marine/riverine plankton and macrophytes, and bacteria. The sources of some lipid components were ambiguous/mixed as they were potentially derived from multiple precursor organisms and because of limitations associated with modern survey techniques. There is evidence that early diagenesis caused the preferential degradation of labile aquatic lipids and that the degradation of terrestrial lipids was more severe when subjected to complex horizontal–vertical transportation processes associated with deposition, resuspension, and redeposition. These processes may have led to an enhanced terrestrial OM signal in the normal ( n)-alkane and n-alkanol records, which is at odds with, for example, those of the n-fatty acids, hopanoids, steranes, and sterols, which suggest a dominant marine OM source. Furthermore, we conclude that the occurrence of multiple sources, selective diagenesis, and test error has led to the distortion of redox and maturity indicators based on evidence from pristane-to-phytane (Pr/Ph) ratios and sterane/hopane indices in century scale. Overall, the phytol record suggests an increase in productivity after the early 20th century. Correspondingly, the diatom lipid biomarker records (based on C25 highly branched isoprenoid alkenes and C18:1ω9 fatty acids) reveal a fluctuating but overall increasing diatom productivity after the early 20th century, which coincides with a decreased proportion of the contribution from diatoms relative to that of total phytoplankton. This is believed to correspond to natural environmental changes, as well as anthropogenic impact.


1991 ◽  
Vol 31 (1) ◽  
pp. 325 ◽  
Author(s):  
R. Alexander ◽  
P.G. Kralert ◽  
R. Marzi ◽  
R.I. Kagi ◽  
E J. Evans

The ester content in kerogen is depleted as sediment maturation progresses in a process which has been shown to correlate with change in the carbon preference index (CPI) of the associated soluble organic matter. We have carried out accurate laboratory measurements of the kinetics of the reaction which causes ester depletion in sediments, and we show how this information can be used to assess the thermal history of sediments. Two wells were selected, Grunter-1 and Volador-1, to provide samples from the Latrobe Group in the Gippsland Basin. The CPI values were measured to assess the extent of reaction at points down each well, and these values were then used with the kinetic parameters for the ester depletion process to obtain thermal histories which are consistent with the available maturity information.This treatment enabled the heat flow from 50 Ma to the present to be assessed and it suggests that at both locations a constant low heat flow during the Gippsland stable phase was followed by a gradual increase from the beginning of the Miocene to present-day values.


2010 ◽  
Vol 65 (9-10) ◽  
pp. 533-536 ◽  
Author(s):  
Indranil Bhattacharjee ◽  
Anupam Ghosh ◽  
Nandita Chowdhury ◽  
Soroj Kumar Chatterjee ◽  
Goutam Chandra ◽  
...  

An n-hexane extract of fresh, mature leaves of Argemone mexicana (Papaveraceae), containing thin-layer epicuticular waxes, has been analysed for the first time by TLC, IR and GLC using standard hydrocarbons. Seventeen long-chain alkanes (n-C18 to n-C34) were identified and quantified. Nonacosane (n-C29) was established as the n-alkane with the highest amount, whilst octadecane (n-C18) was the least abundant component of the extracted wax fraction. The carbon preference index (CPI) calculated for the hydrocarbon sample with the chain lengths between C18 and C34 was 1.2469, showing an odd to even carbon number predominance.


2020 ◽  
Author(s):  
Rong Bi ◽  
Stefanie M. H. Ismar-Rebitz ◽  
Ulrich Sommer ◽  
Hailong Zhang ◽  
Meixun Zhao

Abstract. Global change concurrently alters multiple environmental factors, with uncertain consequences for marine ecosystems. Lipids, in their function as trophic markers in food webs and organic matter source indicators in water column and sediments, provide a tool for reconstructing the complexity of global change effects. It remains unclear how ongoing changes in multiple environmental drivers affect the production of key lipid biomarkers in marine phytoplankton. Here, we tested the responses of sterols, alkenones and fatty acids (FAs) in the diatom Phaeodactylum tricornutum, the cryptophyte Rhodomonas sp. and the haptophyte Emiliania huxleyi under a full-factorial combination of three temperatures (12, 18 and 24 °C), three N : P supply ratios (molar ratios 10 : 1, 24 : 1 and 63 : 1) and two pCO2 levels (560 and 2400 µatm) in semi-continuous culturing experiments. Overall, N and P deficiency had a stronger effect on per-cell contents of sterols, alkenones and FAs than warming and enhanced pCO2. Specifically, P deficiency caused an overall increase in biomarker production in most cases, while N deficiency, warming and high pCO2 caused non-systematic changes. Under future ocean scenarios, we predict an overall decrease in carbon-normalized contents of sterols and polyunsaturated fatty acids (PUFAs) in E. huxleyi and P. tricornutum, and a decrease in sterols but an increase in PUFAs in Rhodomonas sp. Variable contents of lipid biomarkers indicate a diverse carbon allocation between marine phytoplankton species in response to changing environments. Thus, it is necessary to consider the changes in key lipids and their consequences for food web dynamics and biogeochemical cycles, when predicting the influence of global change on marine ecosystems.


2017 ◽  
Author(s):  
Amanda L.D. Bender ◽  
Daniel H. Chitwood ◽  
Alexander S. Bradley

AbstractLeaf wax n-alkanes are broadly used to reconstruct paleoenvironmental information. However, the utility of the n-alkane paleoclimate proxy is modulated by the extent to which genetic as well as environmental factors influence the structural and isotopic variability of leaf waxes. In paleoclimate applications, there is an implicit assumption that most variation of leaf wax traits through a time series can be attributed to environmental change and that biological sources of variability within plant communities are small. For example, changes in hydrology affect the δ2 H of waxes though rainwater and the δ13C of leaf waxes by changing plant communities (i.e., C3 versus C4 input). Here we test the assumption of little genetic control over 5 C variation of leaf wax by presenting the results of an experimental greenhouse growth study in which we estimate the role of genetic variability on structural and isotopic leaf wax traits in a set of 76 introgression lines (ILs) between two interfertile Solanum (tomato) species: S. lycopersicum cv M82 (hereafter cv M82) and S. pennellii. We found that the leaves of S. pennellii, a wild desert tomato relative, produces significantly more iso-alkanes than cv M82, a domesticated tomato cultivar adapted to water-replete conditions; we introduce a methylation index to summarize the ratio of branched (iso- and anteiso-) to total alkanes. Between S. pennellii and cv M82, the iso-alkanes were found to be enriched in 13C by 1.2–1.4%o over n-alkanes. By modeling our results from the ILs, we report the broad-sense heritability values (H2) of leaf wax traits to describe the degree to which genetic variation contributes to variation of these traits. Individual carbon isotope values of alkanes are of low heritability (H2 = 0.13–0.19), suggesting that δ13C of leaf waxes from this study are strongly influenced by environmental variance, which supports the interpretation that variation in the 5 C of wax compounds recorded in sediments reflects paleohydrological changes. Average chain length (ACL) values of n-alkanes are of intermediate heritability (H2 = 0.30), suggesting that ACL values are strongly influenced by genetic cues.


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