Recent Posts

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…

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…

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…

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…

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…

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…

Cell wall properties in Oryza sativa influence mesophyll carbon dioxide conductance (New Phytol) $

Mesophyll CO2 conductance (gm) is an important factor in determining the concentration of CO2 at the site of fixation in the chloroplast stroma, and as such is crucial for determining photosynthetic capacity.  The mesophyll cell wall provides a major site of resistance to CO2 diffusion into the stroma…

Measurement of gross photosynthesis, respiration in the light, and mesophyll conductance using H218O labeling (Plant Physiol)

It is relatively simple to determine net O2 flux in leaves.  However, this data provides no information on the underlying processes responsible for this flux, namely gross oxygen production (GOP, water splitting), mitochondrial respiration in light, Rubisco oxygenation, and photorespiration.  In this…

Phosphorous Deficiency and Photosynthesis

Phosphorus (P) is an essential macronutrient, and P deficiency limits plant productivity. P influences many aspects of photosynthesis P-deficient plants typically remain green and do not develop leaf chlorosis and yet P starvation immediately affects CO2 assimilation. Specifically, P deficiency is believed…