Additional components allow more newly developed photosynthetic systems and car engines to outperform conventional ones under specific conditions.

<p>(a) Supercharged engines outperform conventional ICEs with increasing altitude (decreasing O₂ concentration). (b) Likewise, “supercharged” C4 crops (corn and sorghum combined data) outperform “conventional” C3 crops (soybeans (o) and wheat (x)) with decreasing CO₂ concentration. (c) Hybrid cars strongly outperform their traditional counterparts under conditions of high variability in driving speed, while they perform similarly under conditions of low variability. (d) In a similar fashion, CAM plants strongly outperform their C3 counterparts in conditions of high variability in vapor pressure deficit, while they are less efficient in the absence of variability.</p

Comparative evolution of plants and cars.

<p>(a) In 1885, Karl Benz was among the automobile’s first producers, and in 1908, the Ford Motor Company pioneered the first mass produced automobile, the Model T [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref005" target="_blank">5</a>]. The turbocharger gained popularity during World War II, when it was used in military aircraft, which had to cope with low-pressure, high-altitude air [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref003" target="_blank">3</a>], and the first turbocharged passenger car, the Chevrolet Corvair Monza, debuted in 1962 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref010" target="_blank">10</a>]. Serious interest in hybrid technology arose in the 1960s when it was recognized as a means for harnessing variability in driving conditions to lower fuel use and emissions, and the Toyota Prius was introduced in 1997 as the first mass produced hybrid car [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref005" target="_blank">5</a>]. (b) The first C3 plants developed around 1 Ga ago as aquatic lifeforms [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref006" target="_blank">6</a>]. CAM photosynthesis evolved during the Paleozoic era and likely experienced a significant expansion in terrestrial plants in the Cenozoic era, which was accompanied by increasing seasonality of water availability [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref004" target="_blank">4</a>]. C4 photosynthesis is thought to have first evolved in the mid-Tertiary period and experienced a large increase in the late Miocene, 4-7 Ma, which brought decreasing CO₂ levels [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198044#pone.0198044.ref004" target="_blank">4</a>].</p

A comparison of plant photosynthesis and car engine functioning illustrates how the core processes interact with the additional components.

<p>The core processes in each system are the Calvin cycle and the ICE (middle row). A concentrating mechanism in C4 plants and turbocharged cars provides concentrated CO₂ and oxygen, respectively, to the core cycle (upper row). A storage mechanism in CAM plants allows carbon dioxide to be stored as malic acid at night and then passed to the Calvin cycle during the day, while a storage mechanism in HEVs allows energy to be stored in the battery during braking and then passed to the motor to power the drivetrain in parallel with the engine (bottom row).</p

Appendix A. Tables and figures reporting correlations between nutrient concentrations and resorption efficiencies and climatic variables (altitude, mean annual temperature, and mean annual precipitation).

Tables and figures reporting correlations between nutrient concentrations and resorption efficiencies and climatic variables (altitude, mean annual temperature, and mean annual precipitation)