Determination of the site of CO₂ sensing in poplar: is the area-based N content and anatomy of new leaves determined by their immediate CO₂ environment or by the CO₂ environment of mature leaves?

Exposure to an elevated CO(2) concentration ([CO(2)]) generally decreases leaf N content per unit area (N(area)) and stomatal density, and increases leaf thickness. Mature leaves can 'sense' elevated [CO(2)] and this regulates stomatal development of expanding leaves (systemic regulation). It is unclear if systemic regulation is involved in determination of leaf thickness and N(area)-traits that are significantly correlated with photosynthetic capacity.

Stomatal development in new leaves is related to the stomatal conductance of mature leaves in poplar (Populus trichocarpaxP. deltoides).

In general, stomatal density (SD) decreases when plants are grown at high CO2 concentrations. Recent studies suggest that signals produced from mature leaves regulate the SD of expanding leaves. To determine the underlying driver of these signals in poplar (Populus trichocarpaxP.

Characterization of NADP-dependent malic enzyme from developing castor oil seed endosperm.

Metabolic pathways sequestered within the leucoplast of developing oilseeds ensure a balanced supply of substrates and cofactors for fatty acid biosynthesis. NADP-dependent malic enzyme (NADP-ME) may be important in supplying both carbon and NADPH for fatty acid biosynthesis in the developing endosperm of the oilseed Ricinus communis. NADP-ME was purified 5160-fold to a specific activity of 18.

In vitro phosphorylation of phosphoenolpyruvate carboxylase from the green alga Selenastrum minutum.

Previously, we described two distinct classes of phosphoenolpyruvate carboxylase (PEPC) isoforms in the green alga Selenastrum minutum. Class 1 PEPC (PEPC1) is a homotetramer composed of 102 kDa subunits (p102), whereas Class 2 PEPCs exist as three large protein complexes (PEPC2-PEPC4) containing varying proportions of structurally dissimilar p102 and 130 kDa (p130) PEPC catalytic subunits. In the current study, a p102 calcium-independent protein kinase was shown to co-purify with PEPC1, but not PEPC2.

A method for activity staining after native polyacrylamide gel electrophoresis using a coupled enzyme assay and fluorescence detection: application to the analysis of several glycolytic enzymes.

We describe a method for the detection of isoforms of several glycolytic enzymes by activity staining after native PAGE. The staining is based on coupled enzyme assays carried out on the gel after electrophoresis and is linked to the disappearance of NADH, which is visualized by fluorescence. This method offers reliable and sensitive detection for phosphoenolpyruvate carboxylase, PPi-dependent phosphofructokinase, and pyruvate kinase from plant tissues.