The major reason for such low values is the fact that most crop plants display their maximal photosynthetic efficiency for relatively brief periods of time during the life cycle of the plant.
这样低值的主要原因是，大多数作物只能在整个生命周期中相对短的时期内表现出最大的光合效率。
2
There are C3 and C4 cycle in the wheat cycle system and the key enzyme activity affects the first step reactions directly in photosynthetic carbon cycle.