Transport properties of the mung bean (<i>Vigna radiata</i>
) non-aerial hypocotyl membrane: permselectivity to hydrophilic compounds

Aponte, John; Baur, Peter

doi:10.1002/ps.3540

Cited by 4 publications

(6 citation statements)

References 38 publications

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“…The hypocotyl underground surface was more hydrophilic and permeable to water and solutes than a cuticle, being also less size-limiting and maybe closer to a primary cell wall. The limiting size threshold for the diffusion of molecules was found to be 1.5 nm (Aponte and Baur, 2014), which is within the range reported for plant cuticles, as described above.…”

Section: Cuticular Absorption Pathways For Water and Solutessupporting

confidence: 87%

“…The existence of these cuticular pores has never been microscopically observed and has been questioned by various authors (e.g. Riederer, 2006;Aponte and Baur, 2014;Fern andez et al, 2016). An alternative hypothesis could be that water and solute cuticular transport may be associated with polar functional groups of cuticular chemical constituents (chiefly hydrophilic polysaccharides; Chamel et al, 1991;Reina et al, 2001;Riederer, 2006;Fern andez et al, 2016).…”

Section: Cuticular Absorption Pathways For Water and Solutesmentioning

confidence: 99%

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Foliar water and solute absorption: an update

2020

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The absorption of water and solutes by plant leaves has been recognised since more than two centuries. Given the polar nature of water and solutes, the mechanisms of foliar uptake have been proposed to be similar for water and electrolytes, including nutrient solutions. Research efforts since the 19th century focussed on characterising the properties of cuticles and applying foliar sprays to crop plants as a tool for improving crop nutrition. This was accompanied by the development of hundreds of studies aimed at characterising the chemical and structural nature of plant cuticles from different species and the mechanisms of cuticular and, to a lower extent, stomatal penetration of water and solutes. The processes involved are complex and will be affected by multiple environmental, physico-chemical and physiological factors which are only partially clear to date. During the last decades, the body of evidence that water transport across leaf surfaces of native species may contribute to water balances (absorption and loss) at an ecosystem level has grown. Given the potential importance of foliar water absorption for many plant species and ecosystems as shown in recent studies, the aim of this review is to first integrate current knowledge on plant surface composition, structure, wettability and physico-chemical interactions with surface-deposited matter. The different mechanisms of foliar absorption of water and electrolytes and experimental procedures for tracing the uptake process are discussed before posing several outstanding questions which should be tackled in future studies.

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Section: Cuticular Absorption Pathways For Water and Solutessupporting

confidence: 87%

Section: Cuticular Absorption Pathways For Water and Solutesmentioning

confidence: 99%

Foliar water and solute absorption: an update

2020

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“…As essentially the same pore size (0.3 to 2.4nm in the literature, 1.5nm in our studies) exists the decreased selectivity is obviously linked to lower viscosity (of a thinner barrier). This difference does not need diffusion in channels but may exist simply due to these openings and it might be speculated that the very thin barrier itself is the reason.The interested reader is referred to Aponte and Baur (35) for more details on permselectivity of the hypocotyl and a discussion of the transport mechanisms.…”

Section: Different Pathways For Different Plant Organs: Coleoptile Anmentioning

confidence: 99%

“…Besides the radiolabelled diffusion studies and the osmotic experiments (35) we also used staining techniques with a hydrophilic cationic dye, methylene blue, that stains hydrophilic and particularly anionic surfaces and indicates also the particular surface characteristics of the hypocotyl. The non-aerial hypocotyl and a bit less so the aerial, stained intensively blue, similar to the primary root surface while the mature leaf is not stained at all.…”

Section: Different Pathways For Different Plant Organs: Coleoptile Anmentioning

confidence: 99%

Co-penetration of Actives and Adjuvants and Its Significance for the Matched Pair Liaison

Baur

Aponte

2014

ACS Symposium Series

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Most formulants and adjuvants are low molecular weight solutes and can principally be sorbed in the surface lipids and deeper layers of the cuticle. This can have huge impact on the sorption potential of actives and their mobility in the rate limiting barrier of the cuticle. Factors like volatility, photostability, plant compatibility, selectivity, salt compatibility, rainfastness, speed of action, weed control, residual efficacy, the possibility of product combinations etc. depend often primarily on the relative absorption and penetration of active and adjuvant and their interaction. However, many factors affect the manifestation of these effects in practice like separation of active and adjuvant from the respective dispersion during evaporation, unmatched speed of penetration, or precipitation of active or adjuvant, respectively. Typically, adjuvants have several functions and -ignoring wetting effects in this contribution -they can act in the dry spray deposit as much as in the cuticle, for example they can solubilize actives in the former and mobilize them in the latter. For best results a timely and rate fit is needed, robust enough to withstand practical variability. Important commercial formulations show a perfect match of active(s) and adjuvant penetration or non-penetration, respectively. Examples on interactions among formulation or spray ingredients will be shown for a model compound and leaf cuticle system. On the

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“…Different methods were employed to understand the uptake process including osmotic measurements, studies on the impact of pH, staining with cationic and anionic dyes, radiolabeled tracer studies and here also measurement of the size selectivity of penetration 3,29,30,32,33 . Independent of the method, the ‘cut‐off’ size of these pores is below 1.5 nm.…”

Section: Plant Uptakementioning

confidence: 99%

What makes a molecule a pre‐ or a post‐herbicide – how valuable are physicochemical parameters for their design?

Krähmer¹,

Walter²,

Jeschke

et al. 2021

Pest Management Science

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Pre‐emergence herbicides are taken up by seeds before germination and by roots, hypocotyls, cotyledons, coleoptiles or leaves before emergence, whereas post‐emergence herbicides are taken up primarily by foliage and stems. Most modern pre‐emergence herbicides are lipophilic, but post‐emergence herbicides may be lipophilic or hydrophilic. The metabolic conversion of herbicides to inactive or active metabolites after plant uptake is of major importance for some compound classes. Several herbicides are proherbicides as for example some acetyl‐coenzyme A carboxylase (ACCase)‐inhibitors. The physicochemical characteristics of proherbicides and herbicides are usually unrelated. A major role can be attributed to the site of action at a cellular level. A great number of herbicides such as photosystem II (PS II)‐inhibitors, protoporphyrinogen oxidase (PPO)‐inhibitors or carotenoid biosynthesis inhibitors require light for activity. Others, such as cellulose‐biosynthesis and mitotic inhibitors seem to be primarily active in belowground organs. Several lipophilic barriers against the uptake of xenobiotics exist in aboveground and belowground plant parts. The relevance of these barriers needs, however, further clarification. Uptake and translocation models are valuable tools for the explanation of the potential movement of compounds. Many factors other than uptake and translocation have, however, to be considered for the design of herbicides. For post‐emergence herbicides, ultraviolet (UV) light stability, stability in formulations, and mixability with other agrochemicals have to be kept in mind while, in addition to the aforementioned factors soil interaction plays a major role for pre‐emergence herbicides. In our opinion, general physicochemical characteristics of pre‐ or post‐emergence herbicides do, unfortunately not exist yet. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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Transport properties of the mung bean (Vigna radiata ) non-aerial hypocotyl membrane: permselectivity to hydrophilic compounds

Cited by 4 publications

References 38 publications

Foliar water and solute absorption: an update

Foliar water and solute absorption: an update

Co-penetration of Actives and Adjuvants and Its Significance for the Matched Pair Liaison

What makes a molecule a pre‐ or a post‐herbicide – how valuable are physicochemical parameters for their design?

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