The principles, equipment and procedures for measuring leaf and canopy gas exchange have been described previously as has chlorophyll fluorescence. Simultaneous measurement of the responses of leaf gas exchange and modulated chlorophyll fluorescence to light and CO2 concentration now provide a means to determine a wide range of key biochemical and biophysical limitations on photo synthesis in v...

Water deficiency is one of the most important environmental stresses that limit plant growth and crop production. Measurement of chlorophyll fluorescence parameters is considered as an important indicator to evaluate the photosynthetic apparatus. In the present study, the effects of regulated water deficit, investigated in four water-regimes in pistachio orchard with 12-year-old trees of Akbari...

The steady state absorption and fluorescence spectroscopic properties of the xanthophylls, violaxanthin, zeaxanthin, and lutein, and the efficiencies of singlet energy transfer from the individual xanthophylls to chlorophyll have been investigated in recombinant CP26 protein overexpressed in Escherichia coli and then refolded in vitro with purified pigments. Also, the effect of the different xa...

Measurements of chlorophyll fluorescence provide an elegant and non-invasive means of probing the dynamics of photosynthesis. Advances in video imaging of chlorophyll fluorescence have now made it possible to study photosynthesis at all levels from individual cells to entire crop populations. Since the technology delivers quantitative data, is easily scaled up and can be readily combined with o...

Chlorophyll fluorescence and hyperspectral reflectance were used to evaluate physiological responses to two common stressors in coastal environments. Chlorophyll content is one indicator of drought and salinity vegetation stress because of its direct role in the photosynthetic process and electron transport. Recent advances in fluorescence spectroscopy have led to the development of numerous re...

Frank Terjung Fachbereich Physik, Carl von Ossietzky-Universität Oldenburg, D-26111 Oldenburg, Germany Z. Naturforsch. 53c, 924-926 (1998); received May 18/June 9, 1998 Fluorescence Lifetimes, Photosystem II, Reabsorption of Fluorescence Effects of reabsorption of chlorophyll fluorescence were investigated in measurements on chloroplasts and higher plant leaves. The excitation was performed at ...

To explore the function of light-harvesting complex protein (LHCP) in Arabidopsis growth and development, the Leclere and Bartel seed collection was screened. In this collection randomly cloned cDNAs are expressed under the CaMV35S promoter. A pale green line has been identified and characterized in more details. Analysis of the inserted cDNA in the pale green line showed it encodes LHCB1 prote...

Seedlings of Citrus grandis (L.) Osbeck cv. Tuyou were irrigated daily for 5 months with nutrient solution containing 0 (control), 0.2, 0.6 or 1.6 mM aluminum (Al) from AlCl(3).6H(2)O. Shoot growth was more sensitive to Al toxicity than root growth, gas exchange, chlorophyll (Chl) concentration, polyphasic Chl a fluorescence (OJIP) induction and related parameters. Leaves of Al-treated plants s...

It has been suggested that some biological processes are equivalent to computation, but quantitative evidence for that view is weak. Plants must solve the problem of adjusting stomatal apertures to allow sufficient CO(2) uptake for photosynthesis while preventing excessive water loss. Under some conditions, stomatal apertures become synchronized into patches that exhibit richly complicated dyna...