Search results for "Chlorophyll"
showing 10 items of 453 documents
Physiological and molecular analysis of the maturation process in fruits of Clementine Mandarin and one of its late-ripening mutants
2009
Peel color is one of the main features affecting citrus quality. Clementine is a widespread citrus species with several mutants showing a delay in pigmentation and harvesting. This work characterizes the fruit development and ripening of two clementine clones, 'Comune', a widespread variety, and one of its natural mutations, 'Tardivo', which differ by a delayed color-break and extended harvest period. Morphological, chemical, and molecular analyses were carried out on fruits of both genotypes during the whole maturation process. Analysis showed that mutation did not affect ripening characteristics such as juice acidity and TSS. However, biochemical and molecular analysis revealed marked dif…
Abundance and Distribution Patterns of Thunnus albacares in Isla del Coco National Park through Predictive Habitat Suitability Models
2016
Information on the distribution and habitat preferences of ecologically and commercially important species is essential for their management and protection. This is especially important as climate change, pollution, and overfishing change the structure and functioning of pelagic ecosystems. In this study, we used Bayesian hierarchical spatial-temporal models to map the Essential Fish Habitats of the Yellowfin tuna (Thunnus albacares) in the waters around Isla del Coco National Park, Pacific Costa Rica, based on independent underwater observations from 1993 to 2013. We assessed if observed changes in the distribution and abundance of this species are related with habitat characteristics, fis…
Imaging and force transduction in correlative scanning force and confocal fluorescence microscopy
2018
Correlative scanning force and confocal fluorescence microscopy has been used to study individual molecules, nanoparticles and nanoparticle oligomers. By applying a compressive force via the AFM cantilever, spectral blue and red shifts in the range of several meV/GPa have been observed for single dye molecules and semiconductor quantum dots. Moreover, individual Au nanoparticle dimers linked by a chlorophyll binding protein have been imaged in both modes and plasmonic fluorescence enhancement of the chlorophyll emission of up to a factor of 15 has been found.
Nutrient removal by rice–wheat cropping system as influenced by crop establishment techniques and fertilization options in conjunction with microbial…
2020
AbstractNutrient uptake by the rice–wheat cropping system (RWCS) is an important indicator of soil fertility and plant nutrient status. The hypothesis of this investigation was that the rate and sources of nutrient application can differentially influence nutrient removal and soil nutrient status in different crop establishment techniques (CETs). Cropping system yield was on par in all the CETs evaluated, however, there were significant changes in soil nutrient availability and microbiological aspects. The system nitrogen (N), phosphorus (P), potassium (K) and zinc (Zn) uptake in aerobic rice system followed by zero tillage wheat (ARS-ZTW) was 15.7–17.6 kg ha−1, 0.7–0.9 kg ha−1, 7–9.8 kg ha…
Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence
2014
Guanter, Luis et al.
Exciton Interactions and Femtosecond Relaxation in Chlorophyll a−Water and Chlorophyll a−Dioxane Aggregates
1998
Chlorophyll a (Chl a) in hydrocarbon solution with a small amount of dioxane or water shows red-shifted absorption bands at 686 nm and at 700 nm (dioxane) and at 745 nm (water), indicative of self-organized aggregate structures in solution. To study the relationship between the structure and spectral properties of the aggregates, several one-dimensional model structures of Chl a−dioxane and Chl a−water aggregates were computed by the molecular mechanics method. Three overall structures ranging from stick to a ring shape were energetically favored for the dioxane system. All these structures contain structural heterogeneity that consists of repeating dimers that further form tetramer substru…
The effect of kinetin on the photosynthetic apparatus of Sinapis alba
1980
The influence of kinetin during the development of primary leaves of Sinapis alba was investigated. Kinetin treatment (6 ppm) induced an increase of dry weight, of soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; a higher ratio of chlorophyll a to chlorophyll b, higher rates of CO2 fixation per fresh weight and higher activity of nitrite reductase, were also found. These effects are comparable with strong and blue light adaptations. On the other hand, the Hill activity with ferricyanide as the electron acceptor, the rates of CO2 fixation per chlorophyll, the ratios of chlorophyll to cytochrome f and of protein to chlorophyll did not change. Therefore we …
The Effect of Vanadium on the Content of Chlorophyll, P-700 and Cytochrome f at Different Light Intensities in Chlorella fusca
1980
Summary Cells of Chlorella fusca, were grown in liquid medium supplemented ,vith O.2% glucose and varied concentrations of vanadium both at 5 different light intensities and in the dark. \Vith increasing concentrations of vanadium the content of chlorophyll, P-700 and cytochrome f increased as well, each, however, in a different way. At the saturating concentration of 20 µg vanadium per litre the pigment content per dry weight was double as high as that of the vanadium-free control; the ratio of chlorophyll a/chlorophyll b increased from 2.1 to 2.9. The content of P-700 at saturating vanadium concentration was four times higher than that of the control when based on dry weight and double as…
The effect of indole-3-acetic-acid on the photosynthetic apparatus of Sinapis alba
1980
The influence of indole-3-acetic-acid (IAA) during the development of primary leaves of Sinapis alba was studied. IAA treatment (4 ppm ≈ 22.8 μM) caused a decrease of dry weight, soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; it also caused a lower ratio of protein to chlorophyll, a lower ratio of chlorophyll a to chlorophyll b and a higher ratio of chlorophyll per cytochrome f. Furthermore, IAA treatment induced a significantly lower rate of CO2 fixation and a depressed nitrite reductase activity. Similar effects could also be observed in adaptation reactions brought about by red light and low-light (or shade) conditions.
Changes in the Constitution of Thylakoid Membranes in Spruce Needles During an Open‐top Chamber Experiment
1992
The goal of the presented paper was to study the emission effects of natural air pollutants on the protein complexes of the thylakoid membrane. The tests were carried out in the frame of a long-term experiment in which spruce trees kept in open-top chambers with unfiltered ambient-air were compared to spruce trees in chambers with purified-air. The reaction centres of photosystem I (P-700), cytochrome f, cytochrome b-563, cytochrome b-559, as well as the oxidation speed of the antennae chlorophylls were quantified. The concentrations of the cytochromes f and b-563 indicate a marked annual rhythm with decreased concentrations during the summer months. The spruce trees in chambers with ambien…