Light intensity critically affects plant growth. Camptotheca acuminata is a light-demanding species, but its optimum light intensity is not known. To investigate the response of C. acuminata seedlings to different light intensities, specifically 100% irradiance (PAR, 1500 ± 30 μmol m(-2) s(-1)), 75% irradiance, 50% irradiance, and 25% irradiance, a pot experiment was conducted to analyze growth...

The pathways of energy dissipation of excessive absorbed energy in cyanobacteria in comparison with that in higher plants are discussed. Two mechanisms of non-photochemical quenching in cyanobacteria are described. In one case this quenching occurs as light-induced decrease of the fluorescence yield of long-wavelength chlorophylls of the photosystem I trimers induced by inactive reaction center...

Photochemical reactions of microcystin-LR, a toxic compound produced by some blue green algae, were investigated. Ultraviolet absorption of microcystin-LR was assessed. Time-dependent density functional theory (TDDFT) calculations indicated that absorption peak at 238 nm was mainly due to excitation of electrons from the linear chain structure Adda of microcystin-LR. Irradiation of microcystin-...

The photosensitivity of metal carbonyls has been known almost as long as the class of coordination compounds itself. Among no other group of inorganic compounds may one find so many light-sensitive materials. Hence photochemical reactions of metal carbonyls have found wide applications for synthetic purposes. However, whereas much research has been done to understand the thermal reactions," the...

The participation of sunlight in the natural chemistry of the earth is presented as a unique field of study, from historical observations to prospects for future inquiry. A compilation of known reactions shows the extent of light-driven interactions between naturally occurring components of land, air, and water, and provides the backdrop for an outline of the mechanisms of these phenomena. Cata...

Photochemical internalization (PCI) is a technique that uses the photochemical properties of photodynamic therapy (PDT) for the enhanced delivery of endolysosomal-trapped macromolecules into the cell cytoplasm. The released agent can therefore exert its full biological activity, in contrast to being degraded by lysosomal hydrolases. Activation of photosensitizers via ultrasound (US), called son...

Light-driven molecular motors convert light into mechanical energy through excited-state reactions. Unidirectional rotary molecular motors based on chiral overcrowded alkenes operate through consecutive photochemical and thermal steps. The thermal (helix inverting) step has been optimized successfully through variations in molecular structure, but much less is known about the photochemical step...

The photochemical liberation of functional groups is an attractive alternative to the traditional chemical approach. Several photolabile protecting groups have been developed in the past decades, but they were mainly designed to protect amines and carboxylic acids. In this account, we present some of our recent work on the photochemical release of other functions, such as silanols, aldehydes, a...

Plant photosynthesis is considered to consist of photochemical reactions originating from 2 separate pigment systems. Fractionation of the 2 photochemical systems has been demonstrated only recently by detergent treatment of spinach chloroplasts followed by di fferential centri ftugation ( 1, 9). This study shows that the light and heavy fractions obtained by either digitonin or Triton X-100 tr...