Spinach leaf disks were cultured for 5 days in low-intensity green light and then were transferred to high-intensity white light. Harvests over the next 16 h established that cell area increased by about 80% and chloroplast number per cell increased by about 65%, while the percentage of dumbbell-shaped chloroplasts per cell decreased by 65%. Freeze-etch replicas of fixed and unfixed leaf disks,...

In photosynthesizing plant cells, chloroplasts change their arrangements and/or positions in response to light irradiation. These photo-orientation movements of chloroplasts are believed to play important roles in optimizing the photosynthetic activity of plant cells. We have been investigating the roles of the actin cytoskeleton in the intracellular movement and positioning of chloroplasts usi...

Several photochemical and spectral properties of maize (Zea mays) bundle sheath and mesophyll chloroplasts are reported that provide a better understanding of the photosynthetic apparatus of C(4) plants. The difference absorption spectrum at 298 K and the fluorescence excitation and emission spectra of chlorophyll at 298 K and 77 K provide new information on the different forms of chlorophyll a...

The presence of chloroplasts in guard cells from leaf epidermis, coleoptile, flowers, and albino portions of variegated leaves was established by incident fluorescence microscopy, thus confirming the notion that guard cell chloroplasts are remarkably conserved. Room temperature emission spectra from a few chloroplasts in a single guard cell of Vicia faba showed one major peak at around 683 nano...

Two immunological approaches were used to determine if ribulose bisphosphate carboxylase oxygenase (RuBisCo) is present in guard cell chloroplasts. Immunocytochemistry on thin plastic sections using tissue samples that were processed using traditional glutaraldehyde/osmium fixation and then restored to antigenicity with metaperiodate treatment, resulted in labeling over wild-type mesophyll and ...

The O(2) concentration in intact and osmotically disrupted isolated spinach (Spinacia oleracea, L.) chloroplasts during photosynthesis was estimated. The chloroplasts were allowed to reduce 3-phosphoglycerate, CO(2), or ferricyanide in light until the rate of O(2) production was linear. When the light was turned off O(2) evolution from the chloroplasts continued for a few seconds. This prolonge...

Intact mesophyll and bundle sheath chloroplasts wee isolated from the NADP-malic enzyme type C(4) plants maize, sorghum (monocots), and Flaveria trinervia (dicot) using enzymic digestion and mechanical isolation techniques. Bundle sheath chloroplasts of this C(4) subgroup tend to be agranal and were previously reported to be deficient in photosystem II activity. However, following injection of ...

Nitrite reduction in either whole, isolated spinach chloroplasts (Spinacia oleracea L.) or in reconstituted spinach chloroplasts is stimulated by a short period of photosynthetic CO(2) fixation in the light prior to nitrite addition. With reconstituted chloroplasts, a similar stimulation can be obtained in nitrite reduction without CO(2) fixation by the addition of dihydroxyacetone phosphate or...

Whole chloroplasts isolated from the leaves of spinach (Spinacia oleracea L.) exhibit 2 types of conformational change during electron transport. Amine-uncoupled chloroplasts swell and atebrin-uncoupled chloroplasts shrink. Chloroplasts uncoupled by carbonylcyanide phenylhydrazones and by treatment with ethylenediamine tetraacetic acid do not change their volumes or light-scattering properties ...

Chloroplasts can be obtained by gentle lysis or mild shear of spheroplasts of vitamin B(12)-deficient Euglena gracilis and then purified by isopycnic sedimentation on gradients of Ludox AM or Percoll. The chloroplasts appear compact and highly refractile by phase contrast or Hoffmann contrast microscopy. Upon incubation with [(3)H]leucine or [(35)S]methionine, the chloroplasts incorporate the a...