Adaptation to shear stress by leaf variation within an aquatic plant species: Sparganium and Potamogeton pectinatus.

Abstract

The following experiment examines the variation in leaf shape and size within two species of aquatic plants, Sparganium and Potamogeton pectinatus, across different values of shear force. I hypothesized that Sparganium and Potamogeton pectinatus under relatively great shear stress possessed leaves with less length and width than leaves under less shear stress. I predicted these characteristics were more streamlined and less hydraulically resistant to the movement of water, reducing the potential of shear force in damaging plant tissue and uprooting. However, Sparganium leaf surface area, length, width, and thickness was not found to be significantly different across various values of shear stress. Likewise in this experiment, shear stress did not influence Potamogeton pectinatus leaf surface area and length. The effect of depth on these variables on these two plant species were examined as well, and again, data statistics proved inconclusive. This data reveals perhaps other various factors in affecting leaf variation within species in different shear stress values.