Entries by Mike Page

Diffusion of CO2 across the mesophyll-bundle sheath cell interface in a C4 plant with genetically reduced PEP carboxylase activity (Plant Physiol.)

C4 photosynthesis relies on the transport of carbon (in the form of C4 acids) from the mesophyll into bundle sheath cells (BSCs).  Subsequent decarboxylation of these C4 acids generates a high concentration of CO2 in the vicinity of Rubisco, helping to improve the catalytic efficiency of this enzyme.  However, carbon can also enter BSCs via […]

Review:  New insights into the cellular mechanisms of plant growth at elevated atmospheric carbon dioxide (Plant Cell Environ) $

Elevated CO2 (eCO2) encourages plant growth through increased photosynthetic rates and lower stomatal conductance.  However, eCO2 also has knock-on effects on plant secondary metabolism, which can also affect plant growth.  In this review, Gamage et al explore these ‘post-photosynthetic’ effects in detail.  Through analysis of the literature, the authors show that eCO2 modulates carbon metabolism, […]

Review:  C4-like photosynthesis has important functions in C3 plant vasculature (JXB)

In contrast to the much-studied photosynthetic processes in C4 plant vasculature, the processes in the cells surrounding C3 veins remain much less understood.  Here, there appears to be a partial and more spatially-separated C4 pathway, which has been observed in several species including rice, Arabidopsis, Scots pine and celery.  In this review, Gao et al […]

Dynamic feedback of the photosystem II reaction centre on photoprotection in plants (Nat Plants) $

The light reactions of photosynthesis are under constant regulation in order to continue operating efficiently and avoid photodamage in a fluctuating light environment.  One mechanism to avoid photodamage is the dissipation of excess excitation energy as heat, which can be determined by measuring non-photochemical quenching (NPQ) of chlorophyll fluorescence.  The various mechanisms responsible for NPQ […]

Unexpected reversal of C3 versus C4 grass response to elevated carbon dioxide during a 20-year field experiment (Science) $

It is widely accepted that the growth of C3 plants responds more to elevated CO2 (eCO2) than that of C4 plants, since photosynthesis in C3 plants is more limited by the current atmospheric CO2:O2 ratio due to the oxygenase activity of Rubisco.  This has been established empirically in short-term eCO2 experiments.  In this study, Reich […]

Natural variation within a species for traits underpinning C4 photosynthesis (Plant Physiol)

While C4 photosynthesis is relatively well understood, the research community is still some distance from converting a C3 crop to one that performs C4 photosynthesis.  There are many reasons for this, including the complex requirement to reconstitute Kranz leaf anatomy in a C3 species, and the elusive search for regulators of C4 gene expression.    The […]

Review:  Increasing metabolic potential: C-fixation (Essays Biochem) $

Increasing carbon fixation through the Calvin-Benson-Bassham (CBB) cycle is a viable strategy to boost crop yields, as has been demonstrated through both experimental and modelling approaches.  In this review, Andralojc et al outline the most recent advancements in this research field.  The authors firstly describe the reaction mechanism of the carbon-fixing enzyme Rubisco, and introduce […]

The amount of nitrogen used for photosynthesis modulates molecular evolution in plants (Mol Biol Evol)

Plant growth is often limited by the availability of nitrogen (N), which is required to synthesise monomers and macromolecules, and is especially important in the synthesis of the carbon assimilating enzymes of the Calvin-Benson-Bassham (CBB) cycle.  In this article, Kelly has demonstrated that photosynthetic efficiency is reflected in both genome and transcript nucleotide composition, due […]

Physiological performance of transplastomic tobacco plants overexpressing aquaporin AQP1 in chloroplast membranes (JXB)

A major factor in determining photosynthetic rate is the availability of CO2 at the site of fixation in the chloroplast stroma.  Classically, this has been thought to be mainly limited by stomatal conductance (diffusion from the air, through stomata, to sub-stomatal cavities).  However, more recently it has been demonstrated that mesophyll conductance (gm, diffusion from […]