Ethylene in relation to the response of roots to physical impedance

Kays, Stanley J.; Nicklow, Clark W.; Simons, D. H.

doi:10.1007/bf00010513

Cited by 93 publications

(51 citation statements)

References 6 publications

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“…2) and those treated with eth>lene (Crossett & Campbell, 1975) reinforce this impression. Also, onl\' x'ery small concentrations of ethylene, near to the limits of detectable response by plants or gas chromatographs, are needed to retard elongation (Konings & Jackson, 1979) suggesting that increases in the rate of ethylene formation observed in mechanically impeded roots (Figs 3 and 6, and Kays et al, 1974) may be sufficient to slow elongation and promote lateral expansion. Veen (1982) has pointed out that the shape of a cell is probably determined by the orientation of cellulose micro-fibrils in the walls, ordinarily approximately perpendicular to the axis of the root.…”

Section: The Case For Involving Ethylenementioning

confidence: 99%

Ethylene and the responses of roots of maize (Zea mays L.) to physical impedance

Moss¹,

Hall

Jackson

1988

New Phytologist

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. SUMMARYThe response of the roots of maize seedlings to physical impedance was studied in glass chambers that enabled roots to be grown either unimpeded or in loosely packed small glass spheres (ballotini) and flushed with humidified air or other gas mixtures. Impedance decreased root length when measured after approxmiately 40 h by 30-60 "" and increased root diameter 10 cm behind the tip hy a similar percentage. Fresh weight was reduced by up to 28-40%, while ethylene evolution from roots was increased 2-to 2-S-fold. Supplying ethylene (5-13 //I 1 ') in the air flow to unimpeded roots simulated closely the effects of impedance.The volatile inhibitor of ethylene action, 2,5-norbornadiene (approx. 900//I 1 '), overcame the effects of ethylene (5 4//I 1 ') completely, but the growth of impeded roots was unchanged by norbornadiene. Smiilarly, aminoethoxyvinylglycinc (O-5-O-75 mmol m •') inhibited endogenous ethylene formation, but did not modify the growth responses of roots to impedance, even though ethylene production was suppressed to rates well below those of unimpeded roots. The concentration of ahscisic acid was not affected by impedance.It is concluded that despite a widespread view to the contrary, ethylene is not the cause of the morphological response of roots to physical impedance. Abscisic acid is also unlikely to be involved.

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Section: The Case For Involving Ethylenementioning

confidence: 99%

Ethylene and the responses of roots of maize (Zea mays L.) to physical impedance

Moss¹,

Hall

Jackson

1988

New Phytologist

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“…Increasing evidence suggests that the mechanisms by which the coleoptile or root senses an external mechanical impedance and transduces this stimulus into growth pressure involve hormonal regulation (6). A correlation between mechanically induced change in growth pattern and a higher than normal evolution of ethylene from the tissue led to the hypothesis that tissue response is mediated by ethylene (10,13,15). In support of this notion, applied concentrations of ethylene as low as 0.02 ,uL L' reduced pea epicotyl elongation rate within 5 to 10 min (1 1).…”

mentioning

confidence: 97%

“…One uses either beds of glass beads of small diameter as growth medium (10,20) or hollow containers in which tissue is brought in contact with a solid barrier (15,27). However, these systems do not simulate actual soil conditions.…”

mentioning

confidence: 99%

Ethylene Evolution from Maize (Zea mays L.) Seedling Roots and Shoots in Response to Mechanical Impedance

Sarquís

Jordan²,

Morgan³

1991

Plant Physiol.

109

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The effect of mechanical impedance on ethylene evolution and growth of preemergent maize (Zea mays L.) seedlings was investigated by pressurizing the growth medium in triaxial cells in a controlled environment. Pressure increased the bulk density of the medium and thus the resistance to growth. The elongation of maize primary roots and preemergent shoots was severely hindered by applied pressures as low as 10 kilopascals. Following a steep decline in elongation at low pressures, both shoots and roots responded to additional pressure in a linear manner, but shoots were more severely affected than roots at higher pressures. Radial expansion was promoted in both organs by mechanical impedance. Primary roots typically became thinner during the experimental period when grown unimpeded. In contrast, pressures as low as 25 kilopascals caused a 25% increase in root tip diameter. Shoots showed a slight enhancement of radial expansion; however, in contrast to roots, the shoots increased in diameter even when growing unimpeded. Such morphological changes were not evident until at least 3 hours after initiation of treatment. All levels of applied pressure promoted ethylene evolution as early as 1 hour after application of pressure. After 1 hour, ethylene evolution rates had increased 10, 32, 70, and 255% at 25, 50, 75, and 100 kilopascals respectively, and continued to increase linearly for at least 10 hours. When intact corn seedlings were subjected to a series of hourly cycles of pressure, followed by relaxation, ethylene production rates increased or decreased rapidly, illustrating tight coupling between mechanical impedance and tissue response. Seedlings exposed to 1 microliter of ethylene per liter showed symptoms similar to those shown by plants grown under mechanical impedance. Root diameter increased 5 times as much as the shoot diameter. Pretreatment with 10 micromolar aminoethoxyvinyl glycine plus I micromolar silver thiosulfate maintained ethylene production rates of impeded seedlings at basal levels and restored shoot and root extension to 84 and 90% of unimpeded values, respectively. Our results support the hypothesis that ethylene plays a pivotal role in the regulation of plant tissue response to mechanical impedance.

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“…Loss of EIN3/EIL1 function has been known to lead to complete insensitivity to ethylene (37,38). In early physiological experiments, pea seedlings and bean roots have been shown to produce an increased amount of ethylene in response to mechanical stress (39,40), whereas ethylene pathway mutants are found to exhibit defects in their soil emergence capabilities (41). Moreover, ethylene has also been shown to induce dramatic morphological changes known as "the triple response" on typical dark-grown seedlings (20,38,42).…”

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confidence: 99%

Ethylene-orchestrated circuitry coordinates a seedling’s response to soil cover and etiolated growth

Zhong

Shi

Xue

et al. 2014

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

149

151

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Significance Seedlings’ ability to both adapt to their soil environment and acquire photoautotrophic capacity under various buried conditions is a life-or-death issue for terrestrial flowering plants. By designing and utilizing a standardized real-soil assay, we identify the key features of germinating seedlings’ soil response and deduce that the gaseous phytohormone ethylene acts as the primary regulator of soil-induced plant morphogenetic changes. Moreover, our study illustrates that an EIN3/EIL1-conducted PIF3–ERF1 molecular circuitry enables seedlings to synchronize the rate of protochlorophyllide biosynthesis with upward growth, a mechanism critical to the prevention of photooxidative damage during seedlings’ initial transition from dark to light in natural conditions.

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Ethylene in relation to the response of roots to physical impedance

Cited by 93 publications

References 6 publications

Ethylene and the responses of roots of maize (Zea mays L.) to physical impedance

Ethylene and the responses of roots of maize (Zea mays L.) to physical impedance

Ethylene Evolution from Maize (Zea mays L.) Seedling Roots and Shoots in Response to Mechanical Impedance

Ethylene-orchestrated circuitry coordinates a seedling’s response to soil cover and etiolated growth

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