Date of Award
Kalanchoe pinnatum is able to asexually reproduce with the help of its leaves. In K. pinnatum, embryos are embedded in the notches of a leafs margin. Through the process of abscission, when the plant is disturbed a leaf with embryos falls to the ground and the embryos grow into new plants. Thus, as leaves mature, they face conflicting functional demands to stay on the plant and continue their role in photosynthesis or fall off the plant and asexually reproduce. To examine if there is a point in the leafs development where abscission occurs more readily, I examined breaking strength in leaves that varied in age and morphology. I hypothesized as leaves mature in both developmental phase and temporal age, it would take less breaking strength to remove them from the plant and that the leaves' tissues would reflect these mechanical changes. Results showed that temporal age and leaf morphology influenced breakage as well as the direction of force application. Though temporal age did not significantly affect mechanical properties beyond the first week, breaking strength varied most noticeably with phase development as compound leaves detached more easily than simple leaves. Additionally, leaf abscission in K. pinnatum will likely only easily occur when shear forces are exerted on the leaf compared to tensile forces.
Hodge, Jillian, "Biomechanical and morphological changes in leaf abscission zones during the ontogeny of Kalanchoe pinnatum" (2010). Undergraduate Honors Thesis Collection. Paper 66.