lichens are composite organisms formed by a fungus and a green alga and / or a blue-green bacterium. they are recognized as being very sensitive to atmospheric pollution and respond to factors that influence human and environmental healths. since 1860, lichen has been identified as a biological indicator to detect air pollution in great britain and europe. lichens have the high sensitivityto ni...

An alternating light-dark system is described under which etiolated bean (Phaseolus vulgaris) leaves form selectively chlorophyll a.This system consists of cycles of 2 minutes of white light alternating with 98-minute dark periods.Etiolated tissue exposed to a series of such light-dark cycles accumulates chlorophyll a predominantly, with no lag phase in its biosynthesis. A very high ratio of ch...

We present here the first room-temperature 2D electronic spectroscopy study of energy transfer in the plant light-harvesting complex II, LHCII. Two-dimensional electronic spectroscopy has been used to study energy transfer dynamics in LHCII trimers from the chlorophyll b Qy band to the chlorophyll a Qy band. Observing cross-peak regions corresponding to couplings between different excitonic sta...

This study aims to determine the changes in quantities of chlorophyll a and chlorophyll b in various lead concentrations. The main parts of Elodea canadensis have been subjected to lead concentrations, such as 0.1, 0.5, 1, 5, 10, 20, 50 and 100 mg L, with periods of 24, 48, 72, 120, 168 and 216 hours. Chlorophyll a and b quantities were measured in control plants and lead concentrations of 5, 1...

Effect of gibberellic acid on marigold (Calendula Officinalis L.) was evaluated in a pot culture experiment. A factorial experiment based on completely randomized design including 12 treatments and four replications was carried out. Main factor was foliar application stages (first, second and third) and sub factor included different concentrations of GA3 (0, 50, 150 and 250 mg L...

using plant growth regulators at the stresses environment can improve plant growth and crop production. hence, in this research response of photosynthesis rate, chlorophyll, soluble sugar and flower dry weight of chamomile to methyl jasmonate under different salinity levels was studied. values of 0 (control), 75, 150, 225 and 300μm methyl jasmonate (meja) with salinity levels of 2, 6, 10 and 14...

Pigment-protein complexes separated from wheat (Triticum aestivum L. selection ND96-25 by two gel electrophoresis techniques were analyzed by high-performance liquid chromatography for chlorophylls and carotenoids. The two techniques are compared, and pigment analyses are given for the major reaction centers and light-harvesting complexes. Reaction centers contain mostly chlorophyll a, carotene...