Water is one of the most important substances for plants. Limited water
supplies directly influence crop yield, which eventually leads to food
scarcity to humans. In this present study, we quantify the dynamics of a
fluttering leaf as a function of the days without water. The deformation
and vibration of a plant leaf can be induced by dropping an object or
tapping with a finger. Using multiple cameras, the 3D motion of a leaf
can be measured. We found that the frequency of a leaf increases with
water stress. In terms of natural frequency, it tends to increase when
moisture stress is applied to leaves. These results suggest that the
stiffness of leaves according to moisture stress is related, so it can
be used as an indicator of the overall performance of plants. This would
lead to a nondestructive way to measure water stress through leaf
stiffness.