The primary events in bacterial photosynthesis have been studied since it became possible [l] to isolate reaction centers of photosynthetic bacteria, e.g., of Rhodopseudomonas sphaeroides. Within <lO ps [2,3] after excitation of bacteriochlorophyll to its first excited singlet state, the radical pair state PF is formed consisting of a bacteriochlorophyll dimer cation (Bdhl); and a bacteriopheop...

Photosynthetic acclimation (photoacclimation) is the process whereby leaves alter their morphology and/or biochemistry to optimize photosynthetic efficiency and productivity according to long-term changes in the light environment. The three-dimensional architecture of plant canopies imposes complex light dynamics, but the drivers for photoacclimation in such fluctuating environments are poorly ...

Salinity is an important factor in reduced cucumber yield and quality. Grafting on the resistant rootstock could keep growth near to optimum condition. The aim of the present research is to investigate the characteristics of different rootstocks on physiology and fruit characteristics of cucumber. Treatments were rootstocks [Rn: Nongrafted (Cucumis sativus v. DAVOSII), Rt: Tanbal (Cucurbita max...

Comparative studies of photosynthetic physiology in rain forest trees have focused on differences related to successional status, with the general finding that earlysuccessional species tend to show physiological characteristics of sun plants, while latesuccessional species show shade-plant characteristics. The present study examines analogous evolutionary responses to vertical gradients in lig...

Plants have evolved complex mechanisms to balance the efficient use of absorbed light energy in photosynthesis with the capacity to use that energy in assimilation, so avoiding potential damage from excess light. This is particularly important under natural light, which can vary according to weather, solar movement and canopy movement. Photosynthetic acclimation is the means by which plants alt...

For almost 100 years now, ecotypic differentiation of plant species has been a major topic of research. In changing environments, the question needs to be answered as to how long it takes to adapt, and which parameters are subject to this fast adaptation. Short-living colonizing plant species are excellent examples, especially when they are selfing. Shepherd's Purse Capsella bursa-pastoris (Bra...

The major objective of the present study was to identify the relationship of physiologial parameters of the photosynthetic system with the elemental content of the lichen Ramalina lacera (With.) J.R. Laund. Thalli of R. lacera were collected in an unpolluted site and transplanted in a national park and an industrial region in Israel for 8 mo. Analyses of photosynthetic activity, chlorophyll int...

Chloroplasts contain 3000-4000 different proteins but only a small subset of them is encoded in the plastid genome while the majority is encoded in the nucleus. Expression of these genes therefore requires a high degree of co-ordination between nucleus and chloroplast. This is achieved by a bilateral information exchange between both compartments including nucleus-to-plastid (anterograde) and p...