Compression induced intercellular shaping for some geometric cellular lattices

Calbo, Adonai Gimenez; Nery, Amauri Alves

doi:10.1590/s1516-89132001000100006

Cited by 6 publications

(5 citation statements)

References 13 publications

(7 reference statements)

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“…4), it can be observed that readings by these two methods were proportional with slopes of 1.16 for lettuce, 1.13 for kale, and 1.04 for chicory. These values are consistent with the fact that the flattening method conceptually should generate pressure readings smaller than the cell turgor pressure measured with the pressure probe, except for limiting tissues in which the cell wall thickness and the intercellular air volumes could be considered vanishingly small (Calbo and Nery, 2001). The percentage of intercellular air volume (v/v) in the leaf is expressive and for most crops it is in the range between 20% and 30% (Spector, 1956).…”

Section: Resultssupporting

confidence: 80%

“…Using a more general plant physiology reasoning, the flattening procedure was extended to estimate cell turgor pressure of other convex fruits and vegetables covered by soft dermal tissues composed of thin-walled poliedric cells that cover the internal plant cellular structure made out of parenchymatous cells having deformable intercellular air volumes. Accordingly, for some regular cellular lattices, it was demonstrated that there is a simple mathematical relation between the flattening pressure and cell turgor (Calbo and Nery, 2001). In these lattice models, the flattening pressure and the cell turgor pressure are related by a cell compression ratio, whose magnitude ranges from zero to one depending on remaining intercellular air volume fraction during mechanical axial compression assays.…”

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confidence: 99%

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A Leaf Lamina Compression Method for Estimating Turgor Pressure

Calbo¹,

Ferreira²,

Pessoa³

2010

horts

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A portable wiltmeter instrument to estimate leaf turgor pressure according to an adaptation of the flattening method was developed. In the instrument, a flexible inflating membrane presses the leaf against a flattening plate having small orifices surrounded by a finely engraved network of obtuse indentations through which air flow is delivered. During a measurement, as the compression builds up, the leaf is progressively molded against the flattening plate, and as a consequence, the air flow (x) crossing the plate is reduced toward zero. The smallest leaf compression (p0) that blocks the air passage is an estimate of the leaf turgor. Wiltmeter measurements were compared with pressure probe measurements of cell turgor pressure in detached leaves of lettuce (Lactuca sativa L.), kale (Brassica oleracea L. var. Acephala), and chicory (Chichorium endivia L.), which were allowed to suffer diverse levels of wilting caused by transpiration. Such observed wiltmeter readings were a little lower than the cell turgor pressure measured with a pressure probe; the regression coefficients between these methods were: 1.156 for lettuce, 1.13 for kale, and 1.036 for chicory. This portable quantitative procedure to measure leaf firmness has potentially valuable applications related to postharvest and field plant physiology studies.

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Section: Resultssupporting

confidence: 80%

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confidence: 99%

A Leaf Lamina Compression Method for Estimating Turgor Pressure

Calbo¹,

Ferreira²,

Pessoa³

2010

horts

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“…In this regard, it is important to mention that theoretical estimations (as in Calbo & nery, 2001) of such phenomena (Calbo et al, 2010) that use flattening pressure, as in older articles, are always slightly smaller than the average cell turgor pressure measured with a cell pressure probe. Therefore, a Wiltmeter instrument measures an average pressure of a leaf as a whole organ.…”

Section: Resultsmentioning

confidence: 98%

“…Such density error may not be too high if water loss is below 25% and if the intercellular air volume fraction can be considered stable. According to Calbo and nery (2001) with pressure probe measurements, Calbo et al (2010) observed linear relationships, with a decline close to one, when these methods were applied to detached leaves of lettuce (Lactuca sativa L.), kale (Brassica oleracea L. var. acephala), and chicory (Chichorium endivia L.) subjected to air dehydration.…”

Section: *R = (M -M S )/(M I -M W -M S )mentioning

confidence: 99%

Evaluation of hydration indexes in kale leaves

Calbo¹,

Ferreira²

2011

Braz. J. Plant Physiol.

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Hydration indexes are practical variables for quantifying plant water stress and can be useful for agronomic purposes. Three adapted hydration indexes based on relative water content, volumetric hydration, and leaf turgor pressure were evaluated in kale (Brassica oleracea var. acephala) leaf segments. Relative water content and volumetric hydration were measured in leaf segments after a water infiltration procedure with the aim of filling its large intercellular volumes (@18%v/v). The infiltration was done using a hydrostatic weighing procedure and with the aid of vacuum to fully hydrate the leaf segments. These two relative indexes were proportional to the transpiration-induced leaf water loss. The third index, turgor pressure, was measured with a Wiltmeter ® instrument. Similarly, the turgor pressure was proportional to the leaf water loss, and it decreased from @310kPa in recently harvested leaves to zero in dehydrated leaves, after a total water loss of @23%. Turgor pressure was correlated with the other two hydration indexes using approximations of leaf volumetric elastic modules. Similar estimates were obtained because the decline between turgor pressure and the natural logarithm of these relative leaf hydration indexes was numerically similar (@900kPa). However, the volumetric hydration index seemed to be more suitable as a model, not only for being more concise but also because it showed a clearer biomechanical representation of the leaf water deficit effects.

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“…After placing the applanating plate on the top of a fruit, the user waits 1 or 2 minutes to read flattened area at presumed constant cell pressure. Alternatively, these systems allow immediate flattened area readings at presumed constant cell volume [70] to calculate firmness as a ratio between the applied external force and the fruit flattened area.…”

Section: Related Workmentioning

confidence: 99%

A Wearable Mobile Sensor Platform to Assist Fruit Grading

Aroca

Gomes

Dantas

et al. 2013

Sensors

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Wearable computing is a form of ubiquitous computing that offers flexible and useful tools for users. Specifically, glove-based systems have been used in the last 30 years in a variety of applications, but mostly focusing on sensing people's attributes, such as finger bending and heart rate. In contrast, we propose in this work a novel flexible and reconfigurable instrumentation platform in the form of a glove, which can be used to analyze and measure attributes of fruits by just pointing or touching them with the proposed glove. An architecture for such a platform is designed and its application for intuitive fruit grading is also presented, including experimental results for several fruits.

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Compression induced intercellular shaping for some geometric cellular lattices

Abstract: The wall perimeter fraction, which contact neighboring cells, was named compression ratio (α). A zero compression ratio indicates maximum intercellular (air) volume (v G , v/v)

Cited by 6 publications

References 13 publications

A Leaf Lamina Compression Method for Estimating Turgor Pressure

A Leaf Lamina Compression Method for Estimating Turgor Pressure

Evaluation of hydration indexes in kale leaves

A Wearable Mobile Sensor Platform to Assist Fruit Grading

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