The localization of some key enzymes leading to sucrose synthesis in photosynthetic tissue of C(3) and C(4) species was investigated. These included UDP-glucose (UDPG) pyrophosphorylase, sucrose phosphate synthetase, and glycerate kinase. Whether glycerate kinase is localized exclusively in the chloroplast or partly outside the chloroplast could influence the fate of carbon flow to sucrose thro...

BACKGROUND AND AIMS Understanding the fate and dynamics of cells during callus formation is essential to understanding totipotency and the mechanisms of somatic embryogenesis. Here, the fate of leaf explant cells during the development of embryogenic callus was investigated in the model legume Medicago truncatula. METHODS Callus development was examined from cultured leaf explants of the high...

The anatomical structure of mesophyll tissue in the leaf is tightly connected with many physiological processes in plants. One of the most important mesophyll parameters related to photosynthesis is the internal leaf surface area, i.e. the surface area of mesophyll cell walls exposed to intercellular spaces. An efficient design-based stereological method can be applied for estimation of this pa...

CO(2) faces a series of resistances while diffusing between the substomatal cavities and the sites of carboxylation within chloroplasts. The absence of techniques to measure the resistance of individual steps makes it difficult to define their relative importance. Resistance to diffusion through intercellular airspace differs between leaves, but is usually of minor importance. Leaves with high ...

The tissue and subcellular distribution of prephenate aminotransferase, an enzyme of the shikimate pathway, was investigated in protoplasts from leaves of Sorghum bicolor. Activity was detected in purified epidermal and mesophyll protoplasts, and in bundle sheath strands. After fractionation of mesophyll and epidermal protoplasts by differential centrifugation, 92% of the total prephenate amino...

Pyruvate orthophosphate dikinase, phosphoenolpyruvate carboxylase, and NADP-malate dehydrogenase function in a series of reactions for fixing Con in mesophyll cells and NADP-malic enzyme (ME) catalyzes the production of CO, and NADPH in bundle sheath cells of maize which is a NADP-ME type C4 plant. Northern blot analyses with cDNA clones for pyruvate orthophosphate dikinase and phosphoenolpyr...

A nonaqueous fractionation method to obtain highly purified mesophyll chloroplasts from lyophilized leaves of Zea mays L. is described. The levels of several metabolites including pyruvate were determined in the purified mesophyll chloroplast fractions which were prepared from leaves exposed to different light intensities. The role of pyruvate in the regulation of pyruvate,Pi dikinase in these ...

MATERIALS AND METHODS A nonaqueous fractionation method to obtain highly purifled mesophyll chloroplasts from lyophilized leaves ofZea mays L. is described. The levels of several metabolites including pyruvate were determined in the purified mesophyll chloroplast fractions which were prepared from leaves exposed to different light intensities. The role of pyruvate in the regulation of pyruvate,...

Within the maize leaf primordium, coordinated cell division and differentiation patterns result in the development of two morphologically and biochemically distinct photosynthetic cell types, the bundle sheath and the mesophyll. The bundle sheath defective2-mutable1 (bsd2-m1) mutation specifically disrupts C4 differentiation in bundle sheath cells in that the levels of bundle sheath cell-specif...

Red (retro)-carotenoids accumulate in chloroplasts of Buxus sempervirens leaves during the process of winter leaf acclimation. As a result of their irregular presence, different leaf colour phenotypes can be found simultaneously in the same location. Five different colour phenotypes (green, brown, red, orange, and yellow), with a distinct pattern of pigment distribution and concentration, have ...