Changes in leaf growth, photosynthetic efficiency, and incorporation pattern of photosynthetically fixed 14CO2 in leaves 1 and 2 from plant apex, in roots, and rhizome induced in Curcuma by growing in a solution culture at Fe concentration of 0 and 5.6 g m-3 were studied. 14C was incorporated into primary metabolites (sugars, amino acids, and organic acids) and secondary metabolites (essential oil and curcumin). Fe deficiency resulted in a decrease in leaf area, its fresh and dry mass, chlorophyll (Chl) content, and CO2 exchange rate at all leaf positions. The rate of 14CO2 fixation declined with leaf position, maximum being in the youngest leaf. Fe deficiency resulted in higher accumulation of sugars, amino acids, and organic acids in leaves at both positions. This is due to poor translocation of metabolites. Roots and rhizomes of Fe-deficient plants had lower concentrations of total photosynthate, sugars, and amino acids whereas organic acid concentration was higher in rhizomes. 14CO2 incorporation in essential oil was lower in the youngest leaf, as well as incorporation in curcumin content in rhizome. Fe deficiency influenced leaf area, its fresh and dry masses, CO2 exchange rate, and oil and curcumin accumulation by affecting translocation of assimilated photosynthates. and Deeksha Dixit, N. K. Srivastava.
Absorption , fluorescence, delayed emission and photoacoustic spectra were obtained for the green photosynthetic bacterium. Whole cells incorporated in fluid (culture medium, viscous solution of polyvinyl alcohol, glycol) and rigid (isotropic and stretched polyvinyl alcohol film) media were investigated. The polarized absorption spectra of the stretched polyvinyl alcohol sample showed that the Qy transition moments of chlorosomal bacteriochlorophyll с was almost parallel to the film axis. Bacteriochlorophyll (BChl) с degradation occurred in some of the samples during prolonged storage and as a result a pigment absorbing at 670 nm, which was disaggregated BChl с or/and bacteriopheophytin c, was formed. This pigment was unoriented in stretched polyvinyl alcohol. The fluorescence spectrum of native cells can be analyzed using three Gaussian components at 754, 781 and 813 pm. The first component seems to be related to BChl с aggregates and the others to BChl a complexes. The time-resolved delayed luminescence spectra showed that practically all the complexes of green bacteria exhibited delayed emission but the decay times and intensities were different for the different complexes. In the photoacoustic spectra two maxima of the chlorosomal BChl с forms were well resolved and located at 748 and 765 nm. The photoacoustic maximum at 830 nm was probably related to the reaction centre (RC). In the Soret band the largest peak of the photoacoustic spectra was observed at 473 nm which showed that carotenoids absorbing in this range were losing more excitation by heat. The BChl с aggregates attached to chlorosome rods exhibited a peak at 446 nm. The efficient thermal deactivation also showed a BChl a located in RC (peak at 846 nm) and long-wavelength BChl a antenna complexes with a deactivation peak at 884 nm.
Patterns of fluorescence and colony tissue, colour were studied (field observations and epifluorescence microscopy) in six species of the coral genus Madracis over depth from 10 to 60 m at a reef slope in Curaçao. Two functions showed up: (1) Decrease in number of colourmorphs (n = 25) with depth suggests a photo-protective function where short wavelengths (e.g. UV) are transformed to long wavelengths, (2) Green fluorescence, observed in four species over their entire depth range, transforms radiation to wavelengths useful for photosynthesis. The observed patterns in fluorescence between species did not correspond to the current taxonomic classification. Our results do not support the usefulness of fluorescence as a taxonomic tool in corals. and M. J. A. Vermeij ... [et al.].
Life and research results of Pavel Siffel, a talented but untimely deceased Czech scientist in photosynthesis, are reviewed. He studied biophysics and physiology of chlorophyll, its complexes with proteins, their absorption and fluorescence spectra, activities in mutants and transformants, dealt with chlorophyll biosynthesis and protochlorophyllide photoreduction, pigments in plants grown at CO2 deficiency and under simulated acid rain, with changes accompanying leaf and plant development, photobleaching, etc. He participated in construction of specialised spectrofluorometers, finally he built the kinetic spectrophotometer SpeKin. and J. Květoň ... [et al.].