Light is one of most important factors to plants because it is necessary for photosynthesis. In this study, physiological and gene expression analyses under different light intensities were performed in the seedlings of rubber tree (Hevea brasiliensis) clone GT1. When light intensity increased from 20 to 1000 µmol m(-2) s(-1), there was no effect on the maximal quantum yield of photosystem II (...

In photosynthetic chains, the kinetics of fluorescence yield depends on the photochemical rates at the level of both Photosystem I and II and thus on the absorption cross section of the photosynthetic units as well as on the coupling between light harvesting complexes and photosynthetic traps. A new set-up is described which, at variance with the commonly used set-ups, uses of a weakly absorbed...

As climate change progresses, the breeding of drought-tolerant forest trees is necessary. Breeding requires screening for drought stress using a large number individuals and high-throughput phenotyping method. The aim this study was therefore to establish methods evaluating clonal responses infrared thermography chlorophyll fluorescence in Cryptomeria japonica. stomatal conductance index (Ig), ...

O2-evolution activity and the Mn complex can be reconstituted in photosystem II by a process called photoactivation. We have studied the elementary steps in photoactivation by using electron paramagnetic resonance spectroscopy to probe electron transport in Mn-depleted photosystem II membranes. The electron donation reactions in Mn-depleted photosystem II were found to be identical with those i...

A mild tryptic digestion of chloroplast membranes eliminates the effects of saturating concentrations of cations (3 to 5 millimolar MgCl(2)) on chlorophyll fluorescence yield, membrane stacking, and photosystem II photochemical efficiency in spinach. At the same time, the negative surface potential of the membranes is increased (by trypsin) as revealed by studies with 9-aminoacridine. High conc...

• The staygreen (SGR) gene encodes a chloroplast-targeted protein which promotes chlorophyll degradation via disruption of light-harvesting complexes (LHCs). • Over-expression of SGR in Arabidopsis (SGR-OX) in a Columbia-0 (Col-0) background caused spontaneous necrotic flecking. To relate this to the hypersensitive response (HR), Col-0, SGR-OX and RNAi SGR (SGRi) lines were challenged with Pseu...

Photosystem I of the cyanobacterium Synechococcus elongatus contains two spectral pools of chlorophylls called C-708 and C-719 that absorb at longer wavelengths than the primary electron donor P700. We investigated the relative quantum yields of photochemical charge separation and fluorescence as a function of excitation wavelength and temperature in trimeric and monomeric photosystem I complex...

Radix Isatidis (Isatis indigotica Fort.) is one of the most important traditional Chinese medicine plants. However, there is no suitable herbicide used for weed control in Radix Isatidis field during postemergence stage. To explore the safety of sulfonylurea herbicide nicosulfuron on Radix Isatidis (Isatis indigotica Fort.) seedlings and the photosynthetic physiological response of the plant to...

In arid and semi-arid areas of the world, excessive mineral aerosol carried by air parcels is a common climatic incident with well-known environmental side effects. In this study, the role of sand-dust accumulation was investigated on various aspects of photosynthetic yield of Plantago lanceolata including chlorophyll (Chl) a, b, effective quantum yield of PSII photosystem (ФPSII), maximal quan...

Plant biotypes that are resistant to S-triazines under most conditions often grow less vigorously and have lower quantum yields and lower maximum rates of photosynthesis. The photosynthetic reactions responsible for these effects were identified in whole leaves and thylakoids of nearly isonuclear lines of oilseed rape (Brassica napus L.). The lower quantum yield was a result of poor efficiency ...