The Opening Mechanism of Pine Cone Scales

Harlow, W. M.; Côté, W. A.; Day, Arnaud

doi:10.1093/jof/62.8.538

Cited by 71 publications

(62 citation statements)

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“…In figure 1b, we show that the deformation is localized to a small region close to where the scale is attached to the midrib of the cone while the rest of the scale simply amplifies this motion geometrically. In this active outer layer of tissue, closely packed long parallel thick-walled cells respond by expanding longitudinally when exposed to humidity (Harlow et al 1964;Dawson et al 1997), and shrinking when dried, while the inner passive layer does not respond as strongly. Consequently, the tissue behaves like a thermally actuated bimetallic strip that curves in response to temperature changes because of the differential expansion of the constituent strips that are glued together.…”

Section: Pine Conesmentioning

confidence: 99%

Hygromorphs: from pine cones to biomimetic bilayers

Reyssat

Mahadevan

2009

J. R. Soc. Interface.

415

360

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We consider natural and artificial hygromorphs, objects that respond to environmental humidity by changing their shape. Using the pine cone as an example that opens when dried and closes when wet, we quantify the geometry, mechanics and dynamics of closure and opening at the cell, tissue and organ levels, building on our prior structural knowledge. A simple scaling theory allows us to quantify the hysteretic dynamics of opening and closing. We also show how simple bilayer hygromorphs of paper and polymer show similar behaviour that can be quantified via a theory which couples fluid transport in a porous medium and evaporative flux to mechanics and geometry. Our work unifies varied observations of natural hygromorphs and suggests interesting biomimetic analogues, which we illustrate using an artificial flower with a controllable blooming and closing response.

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Section: Pine Conesmentioning

confidence: 99%

Hygromorphs: from pine cones to biomimetic bilayers

Reyssat

Mahadevan

2009

J. R. Soc. Interface.

415

360

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“…Fast and robust responsiveness coupled with large-scale displacement are eagerly sought after 18 , which have been the defining feature of biological actuators but missing from synthetic counterparts [19][20][21][22][23][24] . For example, sea cucumbers can alter the stiffness of their dermis within seconds to obtain survival advantages 19 ; the Venus flytrap can close their leaves in a second for efficient prey capture 20 .…”

mentioning

confidence: 99%

“…For example, sea cucumbers can alter the stiffness of their dermis within seconds to obtain survival advantages 19 ; the Venus flytrap can close their leaves in a second for efficient prey capture 20 . On the other hand, the hygroscopic movements of pine cones 24 and ice plant seed capsules 22 , although slower, can function even when the host organisms are dead. Recently, enormous efforts have been paid to these bio-prototypes, with progress being made on responsive nanocomposites and surfaces 3 , energy generators and transducers 25,26 , programmable origami 27 , soft robotics [28][29][30] , smart gels [31][32][33] and artificial muscles [34][35][36] .…”

mentioning

confidence: 99%

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

et al. 2014

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Fast actuation speed, large-shape deformation and robust responsiveness are critical to synthetic soft actuators. A simultaneous optimization of all these aspects without trade-offs remains unresolved. Here we describe porous polymer actuators that bend in response to acetone vapour (24 kPa, 20°C) at a speed of an order of magnitude faster than the state-ofthe-art, coupled with a large-scale locomotion. They are meanwhile multi-responsive towards a variety of organic vapours in both the dry and wet states, thus distinctive from the traditional gel actuation systems that become inactive when dried. The actuator is easy-tomake and survives even after hydrothermal processing (200°C, 24 h) and pressing-pressure (100 MPa) treatments. In addition, the beneficial responsiveness is transferable, being able to turn 'inert' objects into actuators through surface coating. This advanced actuator arises from the unique combination of porous morphology, gradient structure and the interaction between solvent molecules and actuator materials.

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“…Cone moisture content is an important factor determining cone opening time (Harlow et al 1964, Hellum and Barker 1980, Johnson and Gutsell 1993 and may potentially affect seed viability (Beaufait 1960). However, it has not been examined whether cone moisture content is determined by internal factors (e.g., the health condition of the tree; cone age) or by external factors (e.g., precipitation).…”

Section: Soung Ryoul Ryumentioning

confidence: 99%

The moisture content and opening of serotinous cones from lodgepole pine killed by the mountain pine beetle

SharpeMaria

Ryoul

2015

The Forestry Chronicle

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The aging lodgepole pine forests of Western Canada have become increasingly susceptible to insect and disease outbreaks. This is evident by the rise of mountain beetle (MPB) populations in British Columbia and Alberta. Serotinous cones of lodgepole pine require heat to open and the moisture content (MC) of cones is considered to influence the opening process. However, little is known about how tree conditions (live and dead) may affect this process. We evaluated the effects of MPB-killed trees and cone age on (1) cone MC, (2) moisture exchange, and (3) time required to open a cone after exposure to heat. The results showed active moisture exchange into and out of closed cones from both live and dead trees. Cone MC was not a main driving factor determining the time for opening the cones. Cones from dead trees had higher mean moisture content (MC), higher MC variation and took a longer time to open than those from live trees, presumably decreasing the potential for scorching of seed supply. This indicates that seeds in cones of MPB-killed stands may be better able to survive a fire than those of live trees.Key words: serotinous cones, mountain pine beetle, forest fire, cone moisture, cone opening, forest management. RÉSUMÉLes forêts vieillissantes de pin lodgepole de l' ouest du Canada sont de plus en plus susceptibles aux épidémies d'insectes et aux ravages des maladies. La preuve en est l'augmentation des populations de dendroctone du pin en Colombie-Britannique et en Alberta. Les cônes sérotineux du pin lodgepole requièrent de la chaleur pour pouvoir s' ouvrir et le taux d'humidité (TH) des cônes est considéré comme ayant une influence sur le processus d' ouverture. Cependant, peu de choses sont connues sur l' état des arbres (vivants et morts) qui pourrait influencer le processus. Nous avons évalué les effets réper-toriés sur des arbres ravagés par le dendroctone du pin et l'âge des cônes au niveau (1) du TH des cônes, (2) des échanges d'humidité et (3) du temps requis pour que s' ouvre le cône après une exposition à la chaleur. Les résultats ont démontré des échanges actifs d'humidité vers l'intérieur et vers l' extérieur dans les cônes fermés tant chez les arbres vivants que morts. Le TH des cônes n'a pas été un facteur déterminant du moment de l' ouverture des cônes. Les cônes d'arbres morts affichaient un taux d'humidité (TH) moyen supérieur, une plus grande variation du TH et ont pris plus de temps à s' ouvrir par rapport aux arbres vivants, permettant probablement de réduire la possibilité que les graines soient brûlées. Cela démontre que les graines des cônes issus de peuplements ravagés par le dendroctone du pin pourraient être en meilleur position pour survivre à un feu de forêts que celles provenant d'arbres vivants.

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The Opening Mechanism of Pine Cone Scales

Cited by 71 publications

References 0 publications

Hygromorphs: from pine cones to biomimetic bilayers

Hygromorphs: from pine cones to biomimetic bilayers

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

The moisture content and opening of serotinous cones from lodgepole pine killed by the mountain pine beetle

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