canopy temperature (ct) is used as a selection tool to improve crop adaptation to drought. the aim of this work was to investigate association of some photosynthetic characters with ct during grain filling in three cereal species. for this objective, a two-year study (2009-2011) was carried out in kurdistan province in western iran. four genotypes of triticale, three cultivars of bread wheat, a...

in order to compare photosynthetic features of triticale, bread wheat, and barley under water deficit conditions, this experiment was carried out in kurdistan province in western iran. four genotypes of triticale, three cultivars of bread wheat, and a new variety of barley were compared under well watered (ψsoil= -3 bars) and soil water deficit (ψsoil= -12 bars) conditions in a randomized compl...

Chlorophyll in green plants is thought to reside in the internal membranes or lamellae of chloroplasts (1). These membranes are observable by electron microscopy and can be roughly grouped, on the basis of size and arrangement , into grana lamellae and stroma lamellae which exist as closed, flattened sacs, or thylakoids (2). Al though the chlorophyll molecule is not yet demonstrable by electron...

Vertical profiles of the in situ quantum yield of fluorescence of chlorophyll a, ff, were derived with an algorithm from spectral underwater radiometer measurements. Select inherent optical properties were obtained from an initial radiance reflectance inversion that was optimized by comparing retrieved estimates of phytoplankton absorption with independent measurements. The comparison of chloro...

Comparative studies of chlorophyll a fluorescence, measured with a pulse amplitude modulated fluorometer, and of the pigment composition of leaves, suggest a specific role of zeaxanthin, a carotenoid formed in the xanthophyll cycle, in protecting the photosynthetic apparatus against the adverse effects of excessive light. This conclusion is based on the following findings: (a) exposure of leave...

The viability of algae belonging to divisions Cyanophyta, Chlorophyta and Xantophyta has been assessed by chlorophyll autofluorescence and after staining with fluorescent dyes rodamin B, neutral rot, calcofluor white and fluorescein diacetate. For this purpose the fluorescence of algal cells from fresh and old cultures was scored. It was established that chlorophyll autofluorescence could be re...

Each quantum of light absorbed by a chlorophyll molecule rises an electron from the ground state to an excited state. Upon de-excitation from a chlorophyll a molecule from excited state 1 to ground state, a small proportion (3-5% in vivo) of the excitation energy is dissipated as red fluorescence. The indicator function of chlorophyll fluorescence arises from the fact that fluorescence emission...

From the absorption spectra and the excitation spectra of chlorophyll a fluorescence measured (4-77 °K) at different wavelengths (685-760 nm) and their comparison with the emission spectra published elsewhere 23, we confirm that both the Pigment Systems (I and II) contain chlorophyll b, chlorophyll a 670 and chlorophyll a 678. But System II is relatively enriched in chlorophyll b and System I i...