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...

Cadmium (Cd) is a highly toxic metal for plants, even at low concentrations in the soil. The annual production of world cocoa beans is approximately 4 million tons. Most of these fermented and dried beans are used in the manufacture of chocolate. Recent work has shown that the concentration of Cd in these beans has exceeded the critical level (0.6mgkg-1 DM). The objective of this study was to e...

The expression of many cyanobacterial genes is regulated by the redox state of the photosynthetic electron transport chain. However, factors involved in this regulation have not been identified. In this study, we demonstrate that a small LuxR-type regulator in Synechocystis sp. PCC 6803, PedR (Ssl0564), senses the activity of photosynthetic electron transport to achieve the photon flux density-...

The frequency of marine sponges that harbour photosynthetic organisms was examined in a tropical area of the Western Indian Ocean. Out of 77 species from five different habitats in Zanzibar, 55 (71.5%) were found to have photosynthetic activity, as assayed by in situ pulse amplitude modulated (PAM) fluorometry (and validated by measurements of chlorophyll content). A significantly higher percen...

We have investigated two approaches to enhance and extend H2 photoproduction yields in heterocystous, N2-fixing cyanobacteria entrapped in thin alginate films. In the first approach, periodic CO2 supplementation was provided to alginate-entrapped, N-deprived cells. N deprivation led to the inhibition of photosynthetic activity in vegetative cells and the attenuation of H2 production over time. ...

State transitions allow for the balancing of the light excitation energy between photosystem I and photosystem II and for optimal photosynthetic activity when photosynthetic organisms are subjected to changing light conditions. This process is regulated by the redox state of the plastoquinone pool through the Stt7/STN7 protein kinase required for phosphorylation of the light-harvesting complex ...

With average global temperatures predicted to increase over the next century, it is important to understand the extent and mechanisms of C4 photosynthetic acclimation to modest increases in growth temperature. To this end, we compared the photosynthetic responses of two C4 grasses (Panicum coloratum and Cenchrus ciliaris) and one C4 dicot (Flaveria bidentis) to growth at moderate (25/20 degrees...

Light was not essential for the development of ribulose-1,5-diphosphate carboxylase protein or catalytic activity in the photosynthetic cotyledons of germinating castor beans (Ricinus communis). Cotyledons developing in the dark showed higher activity than those in the light. Returning cotyledons developing in the light to darkness resulted in a significant increase in ribulose-1,5-diphosphate ...