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...

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...

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...

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...

Jujube (Ziziphus jujuba Mill.) fruit is an important medicinal plant in Iran. The harvesting time is a crucial for jujube fruit quality. Several characteristics of jujube fruit when harvested at four development stages; white mature (light green), crisp mature (white-red), fully mature (red) and fully ripe (dehydrated brown) were evaluated. Fruit weight, diameter, volume, pulp to stone ratio, f...

Tonnage (T), Simmonds (S) avocado trees, and TxS crosses were evaluated for differences in chlorophyll content and maximal quantum yield of photosystem II in sun and shade-type leaves. Total chlorophyll content by area (Chl a+bar) ranged from 984 mg m in TxS240 to 4320 mg m in Simmonds. Chlorophyll a/b ratio (Chl a/b) ranged from 9.8 to 5.5 in TxS238 and TxS243, respectively. Tonnage and Simmon...

When the sub-core complex of photosystem II, D1/D2, is irradiated at 436 or 415 nm (absorption by chlorophyll and pheophytin and ß-carotene) or 540 nm (absorption primarily by pheophytin), the low temperature fluorescence spectrum has two maxima, at 685 and 674 nm. This shows the existence of at least two different fluorescent forms of chlorophyll (chlorophyll a and perhaps pheophytin a). When ...

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...