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P.E. Kriedemann

Bio: P.E. Kriedemann is an academic researcher from Commonwealth Scientific and Industrial Research Organisation. The author has contributed to research in topics: Chlorophyll & Chlorophyll a. The author has an hindex of 1, co-authored 1 publications receiving 4878 citations.

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Journal ArticleDOI
TL;DR: In this paper, the extinction coefficients for chlorophylls a and b in diethylether (Smith, J.H. and Benitez, A.V., eds.), used in this paper as primary standards, were verified by magnesium determination using atomic absorbance spectrophotometry.

5,326 citations


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Journal ArticleDOI
TL;DR: In this paper, specific absorption coefficients for individual carotenoids and chlorophylls a and b, as well as the E 1% 1cm values for combined carotensoids, have been (re)estimated using 6 solvents (80 % acetone, chloroform, diethyl ether, dimethyl formamide and methanol) using two different types of spectrophotometer (0.1-0.5 nm and 1-4 nm band pass resolution).

4,156 citations

Journal ArticleDOI
17 Feb 1994-Nature
TL;DR: The structure of the light-harvesting chlorophyll a/b–protein complex, an integral membrane protein, has been determined at 3.4 Å resolution by electron crystallography of two-dimensional crystals.
Abstract: The structure of the light-harvesting chlorophyll a/b-protein complex, an integral membrane protein, has been determined at 3.4 A resolution by electron crystallography of two-dimensional crystals. Two of the three membrane-spanning alpha-helices are held together by ion pairs formed by charged residues that also serve as chlorophyll ligands. In the centre of the complex, chlorophyll a is in close contact with chlorophyll b for rapid energy transfer, and with two carotenoids that prevent the formation of toxic singlet oxygen.

1,801 citations

Journal ArticleDOI
TL;DR: In this paper, a combined modeling and indices-based approach is presented to predict the crop chlorophyll content from remote sensing data while minimizing LAI (vegetation parameter) influence and underlying soil background effects.

1,516 citations

Journal ArticleDOI
TL;DR: How the ratios are increasingly and alarmingly low as the proportion of chlorophyll a increases is described, which is always low.
Abstract: Over the last half century, the most frequently used assay for chlorophylls in higher plants and green algae, the Arnon assay [Arnon DI (1949) Plant Physiol 24: 1–15], employed simultaneous equations for determining the concentrations of chlorophylls a and b in aqueous 80% acetone extracts of chlorophyllous plant and algal materials. These equations, however, were developed using extinction coefficients for chlorophylls a and b derived from early inaccurate spectrophotometric data. Thus, Arnon’s equations give inaccurate chlorophyll a and b determinations and, therefore, inaccurate chlorophyll a/b ratios, which are always low. This paper describes how the ratios are increasingly and alarmingly low as the proportion of chlorophyll a increases. Accurate extinction coefficients for chlorophylls a and b, and the more reliable simultaneous equations derived from them, have been published subsequently by many research groups; these new post-Arnon equations, however, have been ignored by many researchers. This Minireview records the history of the development of accurate simultaneous equations and some difficulties and anomalies arising from the retention of Arnon’s seriously flawed equations.

1,176 citations

Journal ArticleDOI
TL;DR: Changes in specific leaf area (SLA, projected leaf area per unit leaf dry mass) and nitrogen partitioning between proteins within leaves occur during the acclimation of plants to their growth irradiance, and the relative importance of both of these changes in maximizing carbon gain is quantified.
Abstract: Changes in specific leaf area (SLA, projected leaf area per unit leaf dry mass) and nitrogen partitioning between proteins within leaves occur during the acclimation of plants to their growth irradiance. In this paper, the relative importance of both of these changes in maximizing carbon gain is quantified. Photosynthesis, SLA and nitrogen partitioning within leaves was determined from 10 dicotyledonous C 3 species grown in photon irradiances of 200 and 1000 μ mol m - 2 s - 1 . Photosynthetic rate per unit leaf area measured under the growth irradiance was, on average, three times higher for high-light-grown plants than for those grown under low light, and two times higher when measured near light saturation. However, light-saturated photosynthetic rate per unit leaf dry mass was unaltered by growth irradiance because low-light plants had double the SLA. Nitrogen concentrations per unit leaf mass were constant between the two light treatments, but plants grown in low light partitioned a larger fraction of leaf nitrogen into light harvesting. Leaf absorptance was curvilinearly related to chlorophyll content and independent of SLA. Daily photosynthesis per unit leaf dry mass under low-light conditions was much more responsive to changes in SLA than to nitrogen partitioning. Under high light, sensitivity to nitrogen partitioning increased, but changes in SLA were still more important.

1,055 citations