Plant and seed germination responses to global change, with a focus on CO2: A review

Earth atmospheric CO2 concentration has risen by over 35% since 1750 and is presently increasing by about 2 parts per million (ppm) every year. Due to contributions from human activity, CO2 is projected to keep rising in the predictable future and to double sometime during this century if fossil fuels burning remains. As a result, air temperature is projected to rise from 2 to 5 °C by 2100. Following this rise in CO2, some ecosystems will face challenges in the next few decades as plants will live in warmer temperatures, higher evaporating demand and widespread changes in drought lengths and severity. To yield healthy crops and forests in changing climate surroundings, it is vital to define whether elevated CO2 disturbs seed germination and plant formation, but even more, the physiological traits conferring drought tolerance. Here, we review the current understanding on the role that CO2 plays on plant growth and seed germination, as well as its impact during the exposure of abiotic stresses like drought and salinity.