Force Generation in the Coiling Tendrils of Passiflora caerulea

Abstract

Tendrils of climbing plants coil along their length, thus forming a striking helical spring and generating tensional forces. It is found that, for tendrils of the passion flower Passiflora caerulea, the generated force lies in the range of 6–140 mN, which is sufficient to lash the plant tightly to its substrate. Further, it is revealed that the generated force strongly correlates with the water status of the plant. Based on a combination of in situ force measurements with anatomical investigations and dehydration‐rehydration experiments on both entire tendril segments and isolated lignified tissues, a two‐phasic mechanism for spring formation is proposed. First, during the free coiling phase, the center of the tendril begins to lignify unilaterally. At this stage, both the generated tension and the stability of the form of the spring still depend on turgor pressure. The unilateral contraction of a bilayer as being the possible driving force for the tendril coiling motion is discussed. Second, in a stabilization phase, the entire center of the coiled tendril lignifies, stiffening the spring and securing its function irrespective of its hydration status.

Rhamnogalacturonan I with β-(1,4)-Galactan Side Chains as an Ever-Present Component of Tertiary Cell Wall of Plant Fibers

“…The peculiarities of the presentation of various RG-I epitopes at the tissue cross-sections may reflect, together with the specific details of the polymer structure, the peculiarities of the supramolecular organization of the polymer, the same as the differences in interactions of the RG-I backbone and side chains with other cell wall polymers. Further studies should be aimed to analyze the consequences of the differences in RG-I for the function of tertiary cell wall in planta, like the force generation in coiling tendrils [4,58] and for the properties of technical fibers obtained from fiber crops [18]. The structure and characteristics of tertiary cell wall constituents should be considered while discussing the prospects of artificial actuation systems inspired by the principles of plant fiber construction; such systems are becoming quite popular in robotic devices [2,59].…”

Helical close-packing of anisotropic tubes

“…ϵ → 0). Further, the 'tape-like' (α = 0) motif is often observed in lightly asymmetric coiling plant tendrils, including the species Celastrus orbiculatus shown in figure 1(F), which we estimate as having an anisotropy of 1 > ϵ ≳ 0.8 via [118]. Of course, the full coupling between differential growth, stimuli response, and mechanics in living systems are outside the scope of this current work.…”