Assessing photosynthesis rates with remote sensing is important for tracking the physiological state of plants. The photochemical reflectance index (PRI) is a good estimator of short-term light-use efficiency (LUE) at the leaf scale but its responses to environmental factors are poorly understood. In this study, we assessed changes in the responses of the PRI to ozone exposure and to an increas...

This study evaluated the tolerance of mango cultivars ‘Haden’, ‘Palmer’, ‘Tommy Atkins’ and ‘Uba’ grafted on rootstock ‘Imbú’ to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv’/Fm’, ΦPSII = [(Fm’-Fs)/(Fm’)], D = (1Fv’/Fm...

BACKGROUND AND AIMS Water is an increasingly scarce resource that limits crop productivity in many parts of the world, and the frequency and severity of drought are predicted to increase as a result of climate change. Improving tolerance to drought stress is therefore important for maximizing future crop yields. The aim of this study was to compare the effects of drought on soybean (Glycine max...

Amiloride-sensitive Na+/H+ exchange in plasma membrane vesicles prepared by sucrose density gradient centrifugation of mitochondria-rich posterior gill cells in two species of crabs (Callinectes sapidus and Carcinus maenas) was examined by acridine orange fluorescence quenching. Sodium-loaded vesicles injected into sodium-free incubation medium (pHout = pHin) caused a quench in fluorescence ind...

extended abstract background and objectives sugarcane (saccharum officinarum l.) is from poaceae trible and perennial native plant of asia continent warm areas. ratio fv/fm estimates the maximum quantum yield of photosystem ii. under conditions of stress fv/fm decreased, this decreasing is due to low activity of reaction of photosynthesis centers and reducing of proteins that are responsible fo...

During infection, hepatitis C virus (HCV) NS4B protein remodels host membranes to form HCV replication complexes (RC) which appear as foci under fluorescence microscopy (FM). To understand the role of Rab proteins in forming NS4B foci, cells expressing the HCV replicon were examined biochemically and via FM. First, we show that an isolated NS4B-bound subcellular fraction is competent for HCV RN...

Global warming is the leading cause of extreme meteorological events increase in last three decades. Increase annual average air temperature and values during winter early spring has been recorded comparison to (1961-1990) referent period Plovdiv region. The lettuce development was researched a greenhouse Agricultural University- Plovdiv. During growth six different variants were used: no ferti...

The recovery after photoinhibition in 20-day-old bean plants (Phaseolus vulgaris L.) induced by 4 h treatment with low (12°C), normal (24°C) and high (42°C) temperatures under high (1000 μmol.m–2.s–1) and low (100 μmol.m–2.s–1) photon flux density (PFD) was studied. The changes in the photosynthetic apparatus were analysed using chlorophyll fluorescence measurements. The ratios Fv/Fm measured b...

The presence of two spectral mechanisms, near-ultraviolet and green (lambda(max)=545nm), is strongly suggested by electroretinographic visual spectral sensitivity curves obtained under dark and red chromatic adaptation conditions in the compound eyes of the click beetle Pyrophorus punctatissimus. The bioluminescence emission of the dorsal prothoracic lanterns is deep green (lambda(max)=543nm) a...

The circadian system allows plants to coordinate metabolic and physiological functions with predictable environmental variables such as dusk and dawn. This endogenous oscillator is comprised of biochemical and transcriptional rhythms that are synchronized with a plant's surroundings via environmental signals, including light and temperature. We have used chlorophyll fluorescence techniques to d...