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, for example by increasing the levels of sucrose biosynthetic enzymes.  They also highlight the importance of the foliar starch:sucrose ratio in determining levels of feedback inhibition on photosynthesis.  The authors then introduce the observation that plants grown in eCO₂ have a lower leaf nitrogen content.  The possible causes of this phenomenon are outlined, since a simple dilution effect caused by increased carbohydrates appears not to be responsible.  The authors further describe how growth at eCO₂ has been shown to lead to an accelerated cell cycle, as-well-as increased cell wall loosening.  The effect of eCO₂ on the levels of phytohormones and the activity of their signalling pathways is also discussed.  The authors conclude this review by stating the challenges to crop researchers and breeders in developing successful crops for a CO₂ enriched atmosphere.  (Summary by Mike Page) Plant Cell Environ 10.1111/pce.13206