抽象的

Vertical-Lift Potential of the Trapped Hypochaeris radicata (Catsear), a Phototropic Sub-Pavement Plant

Peter R Greene

The remarkable vertical lifting power of sub-surface driveway plants has been measured. The Taraxacum officinalae plants, working in buckling mode, can bend, lift, crack, and penetrate a 3 inch [6 cm to 8 cm] asphalt-macadam driveway surface (N=20 plants). The maximum vertical-lift capability of the 2-stem Taraxacum officinale was measured at 3-lbf (1.4 Kg). By comparison, the considerably stronger 3-stem Hypochaeris radicata (Catsear) was measured at 18 lbf (8.2 Kg) (N=1 plant). The remarkable ability of these plants to respond to extreme vertical loading conditions, is potentially an important laboratory model of mechanosensing. A 12-stem Hypochaeris radicata (Catsear) (N=1 plant) is observed, having penetrated a similar macadam sidewalk surface. Only the multi-stem Catsear is powerful enough to break through 3” to 4” (7 cm to 10 cm) of asphalt-macadam sidewalk. The driveway Catsear demonstrates Fcrit=18- lbf. (8 Kg, N=3 stems) whereas the considerably stronger sidewalk catsear is estimated at Fcrit=70-lbf. (32 Kg, N=12 stems) maximum vertical lifting force. This does not include the extra vertical force available from the leaf stems (N>24 leaves). These values approach feasibility, in terms of the integrated load-deflection work, required to bend and crack the pavement, deflecting the surface upwards 2.5 cm. Also reported are the phototropic behavior of the Hypochaeris plant throughout the day, and stem re-growth at the rate of 0.3 m/ wk. (N=200 plants).