scholarly journals Non-destructive measurement of chlorophyll b:a ratios and identification of photosynthetic pathways in grasses by reflectance spectroscopy

2009 ◽  
Vol 36 (11) ◽  
pp. 857 ◽  
Author(s):  
Katharina Siebke ◽  
Marilyn C. Ball
Keyword(s):  
Chlorophyll A ◽  
Reflectance Spectra ◽  
Grass Species ◽  
Chlorophyll B ◽  
Hordeum Vulgare L ◽  
Chlorophylls A And B ◽  
Fluorescence Characteristics ◽  
Destructive Measurement ◽  
Non Destructive

Equations for non-destructive determination of chlorophyll b : a ratios in grasses were developed from reflectance spectra of intact leaves of barley (Hordeum vulgare L.) and two barley mutants: clorina f2, which lacks chlorophyll b and clorina f104, which has a low chlorophyll b content. These plants enabled separation of effects of chlorophyll composition on reflectance spectra due to differential light absorption by chlorophylls a and b and to measure the effects of chlorophyll b on the contribution of fluorescence emitted by chlorophyll a to the reflectance spectra. Indices developed from these data were then tested on growth chamber-grown leaves from six C3 and 17 C4 grass species (7 NAD-ME and 10 NADP-ME subtypes). We used the chlorophyll b : a ratio because the data were less skewed than the chlorophyll a : b ratio. The best index for determination of the chlorophyll b : a ratio utilised wavelengths affected by chlorophyll absorbance: [R626 – 0.5 (R603 + R647)]/[R552– R626]. The chlorophyll b : a ratio was significantly lower in the C4 than C3 grasses, but was not sufficient in itself to separate these two functional groups. However, because of differences in fluorescence characteristics, C3 and C4 species could be distinguished by an index based on wavelengths affected by chlorophyll fluorescence: [R696 to 709/R545 to 567].

Interactions between Photosynthetic Pigments Bound to Lipid and Protein Particles. Spectroscopic Properties

1979 ◽  
Vol 34 (7-8) ◽  
pp. 582-587
Author(s):  
Framçoise Techy ◽  
Monique Dinant ◽  
Jacques Aghion
Keyword(s):  
Chlorophyll A ◽  
Photosynthetic Pigments ◽  
Relative Concentration ◽  
Spectroscopic Properties ◽  
Chlorophyll B ◽  
Pheophytin A ◽  
Chlorophylls A And B ◽  
Protein Particles ◽  
Β Carotene

Abstract The spectroscopic (visible) properties of pigment-bearing lipid and protein particles extract­ ed from milk show that: 1) chlorophylls a and b bound to separate particles can form aggregates provided their relative concentration is high enough. Neither pheophytin a nor β-carotene, in the same conditions, form observable aggregates. 2) Chlorophylls a and b can co-aggregate when they are bound to the same particles. Pheophytin a as well as β-carotene seem to prevent the aggregation of chlorophyll a. β-carotene has no effect on the aggregation of chlorophyll b.

Triplet-State Electron Spin Resonance of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF. I: Experimental Determination of Fine-Structure and Rate Constants

1978 ◽  
Vol 33 (1) ◽  
pp. 83-93 ◽  
Author(s):  
W. Hagele ◽  
D. Schmid ◽  
H. C. Wolf
Keyword(s):  
Triplet State ◽  
Chlorophyll A ◽  
Rate Constants ◽  
Resonance Field ◽  
Zero Field ◽  
Chlorophyll B ◽  
Low Concentrations ◽  
Spin Resonance ◽  
Chlorophyll A And B

The triplet state zero-field splittings and the rate constants for the population and depopulation of the triplet spin sublevels have been investigated for chlorophyll a and chlorophyll b in polymethylmethacrylate (PMMA) and methyltetrahydrofurane (MTHF) as a function of the concentration. In PMMA both chlorophyll a and chlorophyll b yielded only one ESR spectrum in the entire range of concentration which could be covered (1.5 × 10-5 - 1 × 10-3 mole/1). In MTHF the results were more complicated. At low concentrations (up to 103 mole/1) only one spectrum was observed, at higher concentrations additional spectra were detectable (all together two for chlorophyll a and five for chlorophyll b at 10-1 mole/1). The assignment of these spectra was facilitated by observing the "triplet resonance-field identity" which connects the resonancefield strengths for the canonical orientations of one particular species. Furthermore, the rate constants for some of these species could be determined.

scholarly journals Study of chlorophylls and carotenoids in Sansevieria hyacinthoides leaves

2021 ◽  
pp. 62-65
Author(s):  
V. Velma ◽  
V. Kyslychenko ◽  
S. Velma ◽  
А. Popyk
Keyword(s):  
Chlorophyll A ◽  
Spectrophotometric Method ◽  
Biologically Active ◽  
Raw Material ◽  
Chlorophyll B ◽  
African Countries ◽  
Quantitative Content ◽  
Chlorophylls A And B ◽  
Chlorophyll A And B ◽  
Separation Results

Topicality. Sansevieria hyacinthoides (L.) Druce belongs to the Asparagaceae family. The plant is native to African countries. It has been introduced and naturalized in some countries of America, Asia, Australia and Europe. This species is grown as an ornamental plant in many countries, and as a medicinal plant in Africa. Aim. To determine the quantitative content of chlorophylls a and b and the amount of carotenoids in Sansevieria hyacinthoides leaves freshly collected and dried. Materials and methods. The quantitative content was determined by the spectrophotometric method. This method allows determining the amount of chlorophyll a and b and carotenoids by the characteristics of the absorption spectra without their prior separation. Results and discussion. The amount of chlorophyll a and b in the dried leaves was almost 7 times higher than in the freshly collected ones (1.82 ± 0.036 mg/g vs. 0.25 ± 0.005 mg/g, and 2.08 ± 0.038 mg/g vs. 0.29 ± 0.006 mg/g, respectively). The quantitative content of the amount of carotenoids differed by 3.6 times (0.05 ± 0.001 mg/g in freshly collected leaves, and 0.18 ± 0.004 mg/g in the dried raw material). Conclusions. The quantitative content of the amount of carotenoids, chlorophyll a and chlorophyll b in freshly collected and dried leaves of Sansevieria hyacinthoides has been determined by the spectrophotometric method. The dried plant raw material of Sansevieria leaves has a higher content of biologically active substances: chlorophyll a – 1.82 ± 0.036 mg/g, chlorophyll b – 2.08 ± 0.038 mg/g, and the amount of carotenoids – 0.18 ± 0.004 mg/g.

scholarly journals Assessment of the effect of heavy metal salts on the photosynthetic activity of aquatic plants

2021 ◽  
pp. 310-318
Author(s):  
G. V. Lobkova ◽  
E. I. Tikhomirova ◽  
Z. A. Simonova
Keyword(s):  
Chlorophyll A ◽  
Fluorescence Intensity ◽  
Aquatic Plants ◽  
Lemna Minor ◽  
Control Level ◽  
Lead Salt ◽  
Chlorophyll B ◽  
Chlorophylls A And B ◽  
Chlorophyll A And B ◽  
Effect Of Copper

The status of the photosynthetic pigments in the aquatic plants Lemna minor L. and Elodea canadensis Michx. under the action of Ni2+, Co2+, Cu2+ and Pb2+ acetate in concentrations 5.00, 2.50, 1.25, 0.62, 0.31, 0.15, 0.07, and 0.03 mg/L was assessed by changes in the fluorescence intensity of chlorophyll a and b and their ratio. It was established that nickel acetate in original solutions in all the above concentrations caused an increase in the fluorescence intensity of chlorophylls a and b in L. minor in relation to the control while the lead salt suppressed it. Co2+ acetate inhibits the fluorescence of chlorophyll a with concentrations in the initial solutions of 0.03 to 0.15 and 2.50 mg/L and that of chlorophyll b at all concentrations, except 0.62, 1.25 and 2.50 mg/L. For E. canadensis it was found that the salts of all metals at all concentrations caused a reduction of the fluorescence intensity of chlorophyll a relative to the control and increased it in the case of chlorophyll b. The exception is the effect of copper and lead acetates with a concentration of 1.25 mg/L, when the fluorescence intensity of chlorophyll b is maintained at the control level. The presence of Ni2+, Co2+, Cu2+, and Pb2+ acetates in all concentrations in the culture medium influences the quantitative and qualitative characteristics of chlorophyll a and b, which indicates a violation of the photosynthesis process. Our data on the change in the chlorophyll a / b ratio leads to a conclusion about degradation of chlorophyll a relative to chlorophyll b after the effect of heavy metals.

Non-Destructive and Semi-Destructive Test Methods for Strength Determination of Aged Wood

2013 ◽  
Vol 778 ◽  
pp. 385-392
Author(s):  
Anton Kraler ◽  
Wilfried Beikircher
Keyword(s):  
Testing Machine ◽  
Constant Load ◽  
Test Methods ◽  
Climatic Conditions ◽  
Measurement Methods ◽  
Compression Tests ◽  
Starting Point ◽  
Destructive Measurement ◽  
Non Destructive

To what extent is there a change in the strength of wood over the course of centuries, when installed under a constant load? Are there non-destructive measurement methods for the determination of strength that are suitable for this investigation? These two questions were the starting point of this research project. Through experience we have learned that the strength of wood is dependent on the growth regions and climatic conditions in which it originates. For example, over centuries, in a northern Italian valley, there were commonly known and clearly defined areas which provided the wood for the construction of the local buildings. Another decisive factor for selecting this research region was that the buildings concerned had already been dated by means of dendrochronology. This created a unique situation in that the strength of the timber in these buildings, which cover about nine centuries (1250 to present), could be compared and analyzed. Local spruce and larch used in the construction typical of this region were selected for the investigations. Starting with 1250AD (the oldest dated wood construction) and in consecutive steps of 100 years, two projects (of the entire 18 projects) are selected and explored. Three non-destructive and respectively semi-destructive measurement methods were used for the strength testing. The measurement devices are: for drill resistance measuring IML-RESI F400S, for the fractometer tests (bending and compression tests) IML-Instrumenta Mechanik Labor Gmbh. For ultrasonic testing the device Sylvatest duo is used. So the validity of the measurement systems used could be brought into relation with the actual strength. Some small, flawless samples (without knots) from selected projects were removed and then tested in a laboratory with the universal testing machine Shimadzu 100KN.

Chlorophyll b Interference in the Fluorometric Determination of Chlorophyll a and 'Phaeo-Pigments'

1979 ◽  
Vol 30 (5) ◽  
pp. 597 ◽  
Author(s):  
CF Gibbs
Keyword(s):  
Chlorophyll A ◽  
Quantitative Estimate ◽  
Aqueous Acetone ◽  
Chlorophyll B ◽  
Fluorometric Determination ◽  
Chlorophyll A Concentration ◽  
Marine Samples ◽  
Water Ratio

A quantitative estimate was made of the interference by chlorophyll b in the fluorometric determination of chlorophyll a using an Aminco-Bowman spectrofluorometer. The undegraded (or 'living') chlorophyll a concentration was underestimated by an amount equal to the concentration of chlorophyll b present. The value for chlorophyll a uncorrected for phaeophytin was increased by 30% of the chlorophyll b concentration. The acetone to water ratio was found to affect the acidification factor only at aqueous acetone concentrations above 90%. The need for standardization of solvent and wavelengths is discussed, and the implications of chlorophyll b occurring in marine samples are considered.

scholarly journals SPAD index and leaf pigments in cauliflower in different water conditions and silicon fertilization

2021 ◽  
Vol 29 ◽  
pp. 204-210
Author(s):  
Gustavo Soares Wenneck ◽  
Reni Saath ◽  
Roberto Rezende ◽  
Lucas Henrique Maldonado da Silva
Keyword(s):  
Chlorophyll A ◽  
Block Design ◽  
Chlorophyll B ◽  
Chlorophyll Contents ◽  
Randomized Block Design ◽  
Silicon Fertilization ◽  
Water Conditions ◽  
Water Recharge ◽  
Upper Third ◽  
Non Destructive

The measurement of leaf pigments using non-destructive methods can be influenced by water management conditions and the use of nutrients in cauliflower, not showing adequate correlations with chlorophyll contents. The objective of this study was to evaluate the correlation between the SPAD index and the pigment content in cauliflower leaves managed with different water conditions and the application of silicon (Si). The cultivation was carried out in a protected environment in the city of Maringá, Paraná State from October 2019 to March 2020. It was adopted a randomized block design, with treatments in a 3 x 4 factorial scheme, with three levels of water recharge (40; 70 and 100% of crop evapotranspiration (ETc)) and four doses of Si (0; 50; 100 and 150 kg ha-1), with four replications. Once plants showed developed inflorescence, the SPAD index was determined in the field and the levels of chlorophyll a, chlorophyll b, and carotenoids in the laboratory using leaves from the upper third. The correlation between water recharge and Si fertilization on the SPAD index was determined. The proportion of carotenoids in relation to total pigments was compared under different conditions. Correlation analysis was performed considering silicon fertilization, water recharge, leaf pigments, and the SPAD index. Silicon fertilization reduced the levels of carotenoids in addition to being related to chlorophyll a (100% of ETc) and chlorophyll b (70% of ETc). The correlation of the SPAD index with pigments is variable with the water condition of the crop, in a condition without water deficit, it is related to chlorophyll a and in a condition of 70% replacement of ETc, it is correlated with chlorophyll b.

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