Abscisic Acid Accumulates at Positive Turgor Potential in Excised Soybean Seedling Growing Zones

Creelman, Robert A.; Mullet, John E.

doi:10.1104/pp.95.4.1209

Cited by 29 publications

(18 citation statements)

References 23 publications

(44 reference statements)

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“…These increases in ABA level are similar to the increases in ABA levels observed during VPD transitions . This observation is consistent with the subtle but continuous increases in foliar ABA levels observed in desiccation experiments prior to C tlp (Pierce and Raschke, 1980;Henson, 1982;Creelman and Mullet, 1991;Dingkuhn et al, 1991), and we propose that these increases are due to a reduction in leaf turgor in the same manner as the major increases in foliar ABA levels during desiccation are due to a loss of leaf turgor (Pierce and Raschke, 1980;Davies et al, 1981;Creelman and Zeevaart, 1985). While our method of applying external pressure results in both a decrease in leaf turgor and cell solute potential, we can attribute the increase in foliar ABA levels solely to a decrease in cell turgor, as variation in cell osmotic potential in the absence of changes to cell turgor does not affect ABA levels (Creelman and Zeevaart, 1985).…”

Section: Resultssupporting

confidence: 75%

“…Given that ABA is critical for the effective closure of seed plant stomata during drought (Iuchi et al, 2001;Wilkinson and Davies, 2002), and stomatal closure during drought stress largely coincides with C tlp , it is reasonable to assume that turgor loss in leaf cells provides the endogenous signal for increasing ABA biosynthesis at C tlp leading to stomatal closure during water stress. Intriguingly, a number of early studies investigating the triggers for ABA accumulation in excised leaves or droughtstressed plants also observed up to, or greater than, a 20% increase in ABA levels before C tlp was reached (Pierce and Raschke, 1980;Henson, 1982;Creelman and Mullet, 1991;Dingkuhn et al, 1991). Very few studies have commented on the trigger for this more subtle increase in ABA level that occurs in dehydrated leaves at positive turgor pressures, yet these increases may be very important for the regulation of stomatal aperture in well-watered plants.…”

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confidence: 99%

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Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants

2016

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Stomatal responses to changes in vapor pressure deficit (VPD) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD. Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD. We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD. In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability.

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Section: Resultssupporting

confidence: 75%

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confidence: 99%

Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants

2016

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“…24) are mediators of wound responses in plants. ABA has been reported to modulate the expression of a tomato proteinase inhibitor gene (24), but in the soybean seedling system this plant hormone had no effect on the expression of two wound-inducible genes (25). ABA levels increased in excised unwounded elongating tissue but did not cause changes in either extensin or sbPRPI gene expression (25).…”

mentioning

confidence: 92%

Jasmonic acid/methyl jasmonate accumulate in wounded soybean hypocotyls and modulate wound gene expression.

Creelman

Tierney

Mullet

1992

Proc. Natl. Acad. Sci. U.S.A.

491

277

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“…We have also noted similarities between the effects of auxins on the mechanosensitive channels from these protoplasts and their already known effects on responses to osmotic shifts in the epidermal tissue, suggesting that these similarities support putative participation of the channels in osmoregulation. EPC and Gd3+ as well as auxin could be used to further study the possibilities that admission of Ca2' through the channels during turgor changes (whether subtle or conspicuous) might directly or indirectly regulate not only turgor perse but also functions that are putatively dependent on turgor level, such as sugar transport (Taiz and Zeiger, 1991) or the synthesis of ABA (Creelman and Mullet, 1991 ;Lahr, 1990).…”

Section: Is the Mechanosensitive Channel Mechanosensory?mentioning

confidence: 99%

Mechanosensory calcium‐selective cation channels in epidermal cells

1993

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SummaryThis paper explores the properties and likely functions of an epidermal Ca2+-selective cation channel complex activated by tension. As many as eight or nine linked or linkable equivalent conductance units or co-channels can open together. Open time for co-channel quadruplets and quintuplets tends to be relatively long with millimolar Mg2+ (but not millimolar Ca2+) at the cytosolic face of excised plasma membrane. Sensitivity to tension is regulated by transmembrane voltage and temperature. Under some circumstances channel activity is synchronized in rhythmic pulses. Certain lanthanides and a cytoskeleton-disturbing herbicide that inhibit gravitropic reception act on the channel system at low concentrations. Specifically, ethyl-hlphenylcarbamate promotes tension-dependent activity at micromolar levels. With moderate suction, Gd3+ provided at about 0.5 pM at the extracellular face of the membrane promotes for several seconds but may then become inhibitory. Provision at 1-2 p M promotes and subsequently inhibits more vigorously (often abruptly and totally), and at high levels inhibits immediately. La3+, a poor gravitropic inhibitor, acts similarly but much more gradually and only at much higher concentrations. These properties, particularly these susceptibilities to modulation, indicate that in vivo the mechanosensitive channel must be mechanosensory and mechanoregulatory. It could serve to transduce the shear forces generated in the integrated walknernbrane-cytoskeleton system during turgor changes and cell expansion as well as transducing the stresses induced by gravity, touch and flexure. In so far as such transduction is modulated by voltage and temperature, the channels would also be sensors for these modalities as long as the wall-membranecytoskeleton system experiences mechanical stress.

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Abscisic Acid Accumulates at Positive Turgor Potential in Excised Soybean Seedling Growing Zones

Cited by 29 publications

References 23 publications

Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants

Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants

Jasmonic acid/methyl jasmonate accumulate in wounded soybean hypocotyls and modulate wound gene expression.

Mechanosensory calcium‐selective cation channels in epidermal cells

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