scholarly journals Comparative Study of Temporal Changes in Pigments and Optical Properties in Sepals of Helleborus odorus and H. niger from Prebloom to Seed Production

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 119
Author(s):  
Mateja Grašič ◽  
Maja Dacar ◽  
Alenka Gaberščik
Keyword(s):  
Optical Properties ◽  
Photosystem Ii ◽  
Forest Canopy ◽  
Photosynthetic Pigment ◽  
Photochemical Efficiency ◽  
Chemical Properties ◽  
Canopy Layer ◽  
Evergreen Species ◽  
Understorey Plants ◽  
Developmental Phases

Helleborus niger is an evergreen species, while H. odorus is an herbaceous understorey species. They both develop flowers before the forest canopy layer closes. Their sepals remain after flowering and have multiple biological functions. To further elucidate the functions of sepals during flower development, we examined their optical and chemical properties, and the photochemical efficiency of photosystem II in the developing, flowering, and fruiting flowers. Sepals of the two species differed significantly in the contents of photosynthetic pigments and anthocyanins, but less in the UV-absorbing substances’ contents. Significant differences in photosynthetic pigment contents were also revealed within different developmental phases. The sepal potential photochemical efficiency of photosystem II was high in all developmental phases in H. odorus, whereas in H. niger, it was initially low and later increased. In the green H. odorus sepals, we obtained typical green leaf spectra with peaks in the green and NIR regions, and a low reflectance and transmittance in the UV region. On the other hand, in the white H. niger sepals in the developing and flowering phases, the response was relatively constant along the visible and NIR regions. Pigment profiles, especially chlorophylls, were shown to be important in shaping sepal optical properties, which confirms their role in light harvesting. All significant parameters together accounted for 44% and 34% of the reflectance and transmittance spectra variability, respectively. These results may contribute to the selection of Helleborus species and to a greater understanding of the ecological diversity of understorey plants in the forests.

scholarly journals Biomass accumulation, photochemical efficiency of photosystem II, nutrient contents and nitrate reductase activity in young rosewood plants (Aniba rosaeodora Ducke) submitted to different NO3-:NH4+ ratios

2007 ◽  
Vol 37 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Denize Caranhas de Sousa Barreto ◽  
José Francisco de Carvalho Gonçalves ◽  
Ulysses Moreira dos Santos Júnior ◽  
Andreia Varmes Fernandes ◽  
Adriana Bariani ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Nitrate Reductase ◽  
Growth Performance ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Photochemical Efficiency ◽  
Biomass Accumulation ◽  
Nitrate Content ◽  
Chl A ◽  
Culture Substrate

The rosewood (Aniba rosaeodora Ducke) is a native tree species of Amazon rainforest growing naturally in acidic forest soils with reduced redox potential. However, this species can also been found growing in forest gaps containing oxide soils. Variations in the forms of mineral nitrogen (NO3- or NH4+) may be predicted in these different edaphic conditions. Considering that possibility, an experiment was carried out to analyze the effects of different NO3-:NH4+ ratios on the growth performance, mineral composition, chloroplastid pigment contents, photochemical efficiency photosystem II (PSII), and nitrate redutase activity (RN, E.C.1.6.6.1) on A. rosaeodora seedlings. Nine-month-old seedlings were grown in pots with a washed sand capacity of 7.5 kg and submitted to different NO3-:NH4+ ratios (T1 = 0:100%, T2 = 25:75%, T3 = 50:50%, T4 = 75:25%, and T5 = 100:0%). The lowest relative growth rate was observed when the NO3-:NH4+ ratio was equal to 0:100%. In general, high concentrations of NO3- rather than NH4+ favored a greater nutrient accumulation in different parts of the plant. For the chloroplastid pigment, the highest Chl a, Chl b, Chl tot, Chl a/b and Chl tot/Cx+c contents were found in the treatment with 75:25% of NO3-:NH4+, and for Chl b and Cx+c it was observed no difference. In addition, there was a higher photochemical efficiency of PSII (Fv/Fm) when high NO3- concentrations were used. A linear and positive response for the nitrate reductase activity was recorded when the nitrate content increased on the culture substrate. Our results suggest that A. rosaeodora seedlings have a better growth performance when the NO3- concentrations in the culture substrate were higher than the NH4+ concentrations.

scholarly journals Response of common buckwheat and Tartary buckwheat from different elevations to selenium treatment

Fagopyrum ◽  
2021 ◽  
Vol 38 (1) ◽  
pp. 15-23
Author(s):  
Aleksandra Golob ◽  
Neja Luzar ◽  
Mateja Germ
Keyword(s):  
Photosystem Ii ◽  
Photochemical Efficiency ◽  
Morphological Characteristics ◽  
Tartary Buckwheat ◽  
Control Group ◽  
Common Buckwheat ◽  
Biochemical Characteristics ◽  
Selenium Treatment ◽  
Uv Absorbing Compounds ◽  
Effective Photochemical Efficiency

Common buckwheat and Tartary buckwheat were grown in Slovenia outdoors at different elevations – 300 m, 600 m and 1180 m a.s.l. Both species were foliarly treated with selenium twice (in the vegetative phase and in the flowering phase). The effects of Se treatment and different growing locations on selected biochemical, physiological and anatomical traits were monitored. In Se treated common buckwheat, amount of chlorophylls was higher in plants from Ljubljana (the lowest elevation – 300 m a.s.l.) than in plants grown in Podbeže (600 m a.s.l.), whereas in control group, plants grown in Ljubljana contained more chlorophylls than plants from Javorje (the highest elevation – 1180 m a.s.l.). In both buckwheat species, Se alone did not affect amount of chlorophylls in any of location. In Se treated common buckwheat plants, the amount of UV absorbing compounds was the highest in plants, grown at the highest elevation. In common buckwheat, Se lowered the number of CaOx in plants, grown in Javorje. Conditions at different elevations, as well as treatments with Se, did not affect potential and effective photochemical efficiency of Photosystem II. Keywords: common buckwheat, Tartary buckwheat, elevation, selenium, morphological characteristics, biochemical characteristics

scholarly journals Relating hygroscopicity and optical properties to chemical composition and structure of secondary organic aerosol particles generated from the ozonolysis of α-pinene

2014 ◽  
Vol 14 (7) ◽  
pp. 10543-10596 ◽  
Author(s):  
C. Denjean ◽  
P. Formenti ◽  
B. Picquet-Varrault ◽  
E. Pangui ◽  
P. Zapf ◽  
...  
Keyword(s):  
Optical Properties ◽  
Secondary Organic Aerosol ◽  
Complex Refractive Index ◽  
Glassy State ◽  
Particle Surface ◽  
Chemical Properties ◽  
Organic Aerosol ◽  
Atomic Ratio ◽  
Scattering Coefficient ◽  
Size Growth

Abstract. Secondary Organic Aerosol (SOA) were generated from the ozonolysis of α-pinene in the CESAM simulation chamber. The formation and ageing of the SOA were studied by following their optical, hygroscopic and chemical properties. The optical properties investigated by determining the particle Complex Refractive Index (CRI). The hygroscopicity was quantified by measuring the effect of RH on particle size (Growth Factor, GF) and scattering coefficient (f(RH)). The oxygen to carbon (O : C) atomic ratio of the particle surface and bulk were used as a sensitive parameter to correlate the changes in hygroscopic and optical properties of the SOA composition in CESAM. The real CRI at 525 nm wavelength decreased from 1.43–1.60 (±0.02) to 1.32–1.38 (±0.02) during the SOA formation. The decrease in real CRI correlates with a decrease in the O : C ratio of SOA from 0.68 (±0.20) to 0.55 (±0.16). In contrast, the GF stayed roughly constant over the reaction time, with values of 1.02–1.07 (±0.02) at 90% (±4.2) RH. Simultaneous measurements of O : C ratio of the particle surface revealed that the SOA was not composed of a homogeneous mixture, but with less oxidised species at the surface which would limit the water adsorption onto particle. In addition, an apparent change of both mobility diameter and scattering coefficient with increasing RH from 0 to 30% was observed for SOA after 16 h reaction. We postulate that this change could be due to a change in the viscosity of the SOA from a predominantly glassy state to a predominantly liquid state.

scholarly journals Analysis of a lidar voxel-derived vertical profile at the plot and individual tree scales for the estimation of forest canopy layer characteristics

2016 ◽  
Vol 37 (11) ◽  
pp. 2653-2681 ◽  
Author(s):  
Matthew Sumnall ◽  
Alicia Peduzzi ◽  
Thomas R. Fox ◽  
Randolph H. Wynne ◽  
Valerie A. Thomas
Keyword(s):  
Vertical Profile ◽  
Forest Canopy ◽  
Canopy Layer ◽  
Individual Tree

The structure and bonding properties of tiopronin-protected silver nanoparticles as studied by X-ray absorption spectroscopy

2018 ◽  
Vol 96 (7) ◽  
pp. 749-754 ◽  
Author(s):  
J. Daniel Padmos ◽  
David J. Morris ◽  
Peng Zhang
Keyword(s):  
Optical Properties ◽  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Chemical Properties ◽  
Structure Property ◽  
Ag Nps ◽  
X Ray ◽  
Ligand Shell ◽  
Bonding Properties ◽  
X Ray Absorption

Thiolate-protected Ag nanoparticles (NPs) exhibit interesting physical and chemical properties which may lead to various sensing, diagnostic, and therapeutic applications. Further, understanding structure–property relationships of Ag NPs is of great interest to optimize their application. Herein, we used TEM, UV–vis, and a series of synchrotron X-ray spectroscopy techniques to probe the local structure and chemical bonding properties of thiolate-stabilized Ag NPs. Compared with other Ag nanostructures prepared under slightly modified conditions, the Ag NPs were found to have pronounced structural changes, which led to immensely different optical properties. Notably, the NPs were also found to have similar surface structure to recently elucidated Ag nanoclusters prepared with different thiolates. These findings suggest that the NP structure and optical properties can be sensitively tailored by controlling the synthetic conditions. The multi-element, multi-core excitation approach (i.e., Ag K-, Ag L3-, and S K-edges) employed in the X-ray absorption spectroscopy measurements was also demonstrated as an effective tool to uncover the NP structure from both the metal core and the ligand shell perspectives.

scholarly journals Alleviation of nickel toxicity in wheat (Triticum aestivum L.) seedlings by selenium supplementation

2013 ◽  
Vol 50 (2) ◽  
pp. 65-78 ◽  
Author(s):  
Ewa Gajewska ◽  
Daniel Drobik ◽  
Marzena Wielanek ◽  
Joanna Sekulska-Nalewajko ◽  
Jarosław Gocławski ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Electrolyte Leakage ◽  
Growth Parameters ◽  
Photosynthetic Pigment ◽  
Triticum Aestivum L ◽  
Photochemical Activity ◽  
Wheat Seedlings ◽  
Chlorophyll A And B ◽  
Hydroponically Grown

Abstract Hydroponically grown wheat seedlings were treated with 50 μM N i and/or 15 μM Se. After a 7-day culture period, their growth parameters, N i, Se, F e, and M g contents, electrolyte leakage, photosynthetic pigment concentrations, and photochemical activity of photosystem II were determined. Exposure of wheat seedlings to N i alone resulted in reduction in the total shoot and root lengths, by 22% and 50%, respectively. Addition of Se to the N i-containing medium significantly improved the growth of these organs, compared to the seedlings subjected to N i alone. Application of Se decreased the accumulation of N i in shoots and roots and partially alleviated the N i-induced decrease in F e and M g concentations in shoots. Electrolyte leakage increased in response to N i stress, but in shoots it was diminished by Se supplementation. Exposure to N i led to a decrease in chlorophyll a and b contents and enhancement of chlorophyll a/b ratio, but did not influence the concentration of carotenoids. Enrichment of the N i-containing medium with Se significantly increased chlorophyll b content, compared to the seedlings treated with N i alone. Photochemical activity, estimated in terms of the maximum quantum yield of photosystem II , decreased in response to N i treatment but was significantly improved by simultaneous addition of Se. Results of our study suggest that alleviation of N i toxicity in wheat seedlings by Se supplementation may be related to limitation of N i uptake.

scholarly journals Progesterone increases photochemical efficiency of photosystem II in wheat under heat stress by facilitating D1 protein phosphorylation

2017 ◽  
Vol 55 (4) ◽  
pp. 664-670 ◽  
Author(s):  
R. L. Xue ◽  
S. Q. Wang ◽  
H. L. Xu ◽  
P. J. Zhang ◽  
H. Li ◽  
...  
Keyword(s):  
Heat Stress ◽  
Photosystem Ii ◽  
Protein Phosphorylation ◽  
Photochemical Efficiency ◽  
D1 Protein

scholarly journals Quantification of black carbon mixing state from traffic: implications for aerosol optical properties

2016 ◽  
Vol 16 (7) ◽  
pp. 4693-4706 ◽  
Author(s):  
Megan D. Willis ◽  
Robert M. Healy ◽  
Nicole Riemer ◽  
Matthew West ◽  
Jon M. Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Black Carbon ◽  
Chemical Properties ◽  
Mixing State ◽  
Aerosol Optical Properties ◽  
Aerosol Composition ◽  
Average Mass ◽  
Measurement Capability ◽  
Aerosol Mass ◽  
Physical And Chemical

Abstract. The climatic impacts of black carbon (BC) aerosol, an important absorber of solar radiation in the atmosphere, remain poorly constrained and are intimately related to its particle-scale physical and chemical properties. Using particle-resolved modelling informed by quantitative measurements from a soot-particle aerosol mass spectrometer, we confirm that the mixing state (the distribution of co-emitted aerosol amongst fresh BC-containing particles) at the time of emission significantly affects BC-aerosol optical properties even after a day of atmospheric processing. Both single particle and ensemble aerosol mass spectrometry observations indicate that BC near the point of emission co-exists with hydrocarbon-like organic aerosol (HOA) in two distinct particle types: HOA-rich and BC-rich particles. The average mass fraction of black carbon in HOA-rich and BC-rich particle classes was  < 0.1 and 0.8, respectively. Notably, approximately 90 % of BC mass resides in BC-rich particles. This new measurement capability provides quantitative insight into the physical and chemical nature of BC-containing particles and is used to drive a particle-resolved aerosol box model. Significant differences in calculated single scattering albedo (an increase of 0.1) arise from accurate treatment of initial particle mixing state as compared to the assumption of uniform aerosol composition at the point of BC injection into the atmosphere.

Sign in / Sign up

Export Citation Format

Share Document