A new scheme on test and control system for chlorophyll fluorescence is presented in this work, which uses light-emitting diode (LED) excitation by means of measuring the fluorescence parameter φpsII. The system takes programmable power supply as LEDs illumination drive power with high sensitivity and signal-tonoise ratio. MINIPAM is used to measure fluorescence parameter φpsII and keeps commun...

Precise measurements of the minimal fluorescence yield (F(o)) and maximal fluorescence yield (F(m)) of a dark-adapted sample are prerequisites for the quantification of other fluorescence parameters. The pulse amplitude-modulated chlorophyll fluorometer (PAM 101 Chlorophyll Fluorometer, Heinz Walz, Effeltrich, Germany) and saturating pulse technique have frequently been used in measuring F(o) a...

In this study, backward and forward fluorescence radiance within the emission spectrum of 640–850 nm were measured for leaves of soybean, cotton, peanut and wheat using a hyperspectral spectroradiometer coupled with an integration sphere. Fluorescence parameters of crop leaves were retrieved from the leaf hyperspectral measurements by inverting the FluorMODleaf model, a leaf-level fluorescence ...

The aim of this paper is to give a global insight into the behaviour of F0 and FM in a wide temperature range from -100 degreesC to 75 degreesC. We show that the F0 increases upon linear freezing, similarly to the widely published increase of the F0 upon linear heating. In contrast to this the FM decreases upon linear heating in the whole temperature range from -100 degreesC to 75 degreesC. A c...

Soil salinization requires developing genetically salt-tolerant and high-yielding genotypes, especially in semi-arid arid regions. In this study, two new Tunisian durum wheat cultivars, INRAT100 Dhahbi, were tested for the first time a semi-closed environment against salinity (0, 6 12 dS m-1). Dry weight of aerial root parts, plant height, number tillers per plant, spike awn length, grain yield...

We investigated how the presence of cadmium (Cd) at the emergence of Phragmites australis Trin. (Cav.) ex Steudel plants from rhizomes interacted with leaf and chloroplast physiological and biochemical processes. About 8.5 nmol Cd mg-1 chlorophyll was found in leaves, and 0.83 nmol Cd mg-1 chlorophyll was found in chloroplasts of plants treated with 50 microm Cd. As a result, a 30% loss of chlo...

1. The fluorescence spectra of the alga Porphyridium have been recorded as energy distribution curves for eleven different incident wave lengths of monochromatic incident light between wave lengths 405 and 546 mmicro. 2. In these spectra chlorophyll fluorescence predominates when the incident light is in the blue part of the spectrum which is strongly absorbed by chlorophyll. 3. For blue-green ...

Opuntia plants grow naturally in areas where temperatures are extreme and highly variable in the day during the entire year. These plants survive through different adaptations to respond to adverse environmental conditions. Despite this capability, it is unknown how CAM photosynthetic activity and growth in Opuntia plantlets is affected by constant heat or cold. Therefore, the main objective of...