The Photosynthetic Response to a Shift in the Chlorophyll a to Chlorophyll b Ratio of Chlorella

Abstract

The chlorophyll a:b ratio was shifted in Chlorella vannielii by varying the illuminance under which the cells were cultured-the ratio increased from 2.9, 3.0, 4.0, and 4

Disruption of the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) gene results in albino, dwarf and defects in trichome initiation and stomata closure in Arabidopsis

“…Like the other albino mutants of the enzymes involved in MEP-related biosynthetic pathways, the dxr mutants exhibited an arrest in plastid development at early stages [20,22,30,[46][47][48]. This is consistent with the increased chlorophyll a/ b ratio observed in the pale inflorescence tissues, which are more sensitive to light due to the undeveloped plastids [49]. In addition to the albino phenotype, we also found trichome initiation and stomata closure defects as a result of DXR disruption.…”

Phytobenthos and phytoplankton community changes upon exposure to a sunflower oil spill in a South African protected freshwater wetland

“…Thus, the accelerated respiration provides the required ATP for the dark reactions of photosynthesis. Therefore, the level of chl b appears to reflect a regulatory device in governing cyclic and noncyclic photophorylation (Reger and Krauss 1970). Such reports support our hypothesis that the energy demand for ATP and tempo of respiration which was much lower at the higher chl b to a concentrations could have had an affect on the cyclic and noncyclic photophorylation of the Selenastrum cells within the first 48 h of the algal bioassay.…”

“…Thus, the regulation of chl b synthesis is an important factor for the mechanisms of adaptation of algae to various light intensities which may have been affected by the presence of sunflower oil within the water column causing a change in light intensity. In a study conducted by Reger and Krauss (1970) on the green algal Chlorella vannielii, energy demand in the form of adenosine 5 0 -triphosphate (ATP) was strikingly greater when chl b concentrations were low (Reger and Krauss 1970). Thus, the accelerated respiration provides the required ATP for the dark reactions of photosynthesis.…”

The Photosynthetic Unit in Chlorella Measured by Repetitive Short Flashes

“…Variation in the chlorophyll a/b ratio is significant but smaller than that reported for another species of Chlorella (20). Dark respiration, measured before and immediately after the light-saturated photosynthesis also showed expected variation.…”

“…Pchl = moles 02/moles total chl-hr. 6 Actually measured rate under 20 rates were numerically added to the observed light rates to obtain the apparent rates of photosynthesis which are cited.…”