“…Such a mechanism results in advantages in A n and WUE under non-or mild-water-deficit conditions [9,66,69,73,77,78]. However, these advantages cannot be maintained when the drought gets severe, especially for maize and C 4 grass species [66,69,73,77,78,86], which is in agreement with our observation for maize B73 at SWC below 27%. The differences can also translate to the field level, where maize has been found to be more sensitive to drought than wheat (C 3 ), with yield reductions of 39.3% compared to 20.6%, respectively, at approximately 40% water reduction [88].…”