Abscission Processes in Cotton: Induction by Plant Water Deficit<sup>1</sup>

McMichael, B. L.; Jordan, W. R.; Powell, Robert D.

doi:10.2134/agronj1973.00021962006500020005x

Cited by 69 publications

(47 citation statements)

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“…Davenport (9) failed to find a promotion of ethylene release both with the petiole chamber technique and by comparing levels ofethylene vacuum extracted from control and droughttreated cotton seedlings. His samples were of cotyledonary blades and petioles of seedlings while McMichael et al (25,26) studied mature, fruited plants. Although cotton petioles have been shown to have higher ethylene production rates than leaf blades (23), an observation not confirmed in other species (4), there is no reason to anticipate that water deficit stress-mediated ethylene production would be limited to that tissue.…”

Section: Discussionmentioning

confidence: 99%

“…If a gradually imposed water deficit does not significantly increase ethylene production rates, why do leaves, flower buds, and fruits abscise extensively from stressed and rewatered plants (13,25,26)? It seems likely that changes in sensitivity to ethylene play a major role.…”

Section: Discussionmentioning

confidence: 99%

“…interest because the ethylene could be responsible for senescence and abscission induced by water deficits (13,25,26).…”

Section: Introductionmentioning

confidence: 99%

“…The data indicate that detached leaves react differently to rapid drying than intact plants react to drying of the soil with regard to ethylene production. This result suggests the need for additional attention to ethylene as a complicating factor in experiments employing excised plant parts and the need to verify the relevance of shock stresses in model systems.interest because the ethylene could be responsible for senescence and abscission induced by water deficits (13,25,26).Although the promotion of ethylene synthesis by water deficits appears firmly established, there are a number of concerns. First, to have a convenient experimental system, water deficits have often been imposed rapidly by drying detached leaves or fruits (3-6, 16, 18, 24, 31).…”

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Does Water Deficit Stress Promote Ethylene Synthesis by Intact Plants?

Morgan¹,

He²,

Greef³

et al. 1990

Plant Physiol.

120

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The effect of plant water deficit on ethylene production by intact plants was tested in three species, beans (Phaseolus vulgaris L.), cotton (Gossypium hirsutum L.) and miniature rose (Rosa hybrida L., cv Bluesette). Compressed air was passed through glass, plant-containing cuvettes, ethylene collected on chilled columns, and subsequently assayed by gas chromatography. The usual result was that low water potential did not promote ethylene production. When plants were subjected to cessation of irrigation, ethylene production decreased on a per plant or dry weight basis of calculation. No significant promotion of ethylene production above control levels was detected when water deficit-treated bean or cotton plants were rewatered. The one exception to this was for cotton subjected to a range of water deficits, plants subjected to deficits of -1.4 to -1.6 MPa exhibited a transient increase of ethylene production of 40 to 50% above control levels at 24 or 48 hours. Ethylene was collected from intact leaves while plants developed a water deficit stress of -2.9 megapascals after rewatering, and no significant promotion of ethylene production was detected. The shoots of fruited, flowering cotton plants produced less ethylene when subjected to cessation of irrigation. In contrast, the ability of bench drying of detached leaves to increase ethylene production several-fold was verified for both beans and cotton. The data indicate that detached leaves react differently to rapid drying than intact plants react to drying of the soil with regard to ethylene production. This result suggests the need for additional attention to ethylene as a complicating factor in experiments employing excised plant parts and the need to verify the relevance of shock stresses in model systems.interest because the ethylene could be responsible for senescence and abscission induced by water deficits (13,25,26).Although the promotion of ethylene synthesis by water deficits appears firmly established, there are a number of concerns. First, to have a convenient experimental system, water deficits have often been imposed rapidly by drying detached leaves or fruits (3-6, 16, 18, 24, 31). In contrast, under natural drought the soil water is depleted slowly and plants progress through a series of drying cycles during which #w3 falls during the day and rises at night as plants recover due to reduced evaporative demand (30). Second, the experimental measurement of ethylene has usually required that detached plant parts be concentrated in a sealed container from which air samples are withdrawn and analyzed for ethylene. The air supply in these containers has often been static which is of some concern because oxygen is needed for the conversion of ACC to ethylene (2) and CO2 can either promote or reduce the production of ethylene (33). Finally, there are a few reports in the literature where investigators failed to observe a promotion of ethylene release with water deficit treatment of intact plants (6,9,13,19).With the development of flowing air sys...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…interest because the ethylene could be responsible for senescence and abscission induced by water deficits (13,25,26).…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Does Water Deficit Stress Promote Ethylene Synthesis by Intact Plants?

Morgan¹,

He²,

Greef³

et al. 1990

Plant Physiol.

120

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“…Petioles contain levels of ethylene about 10 times higher than leaf blades (12). During water stress or following release from stress by watering, cotton plants defoliate (14).Finally, exogenous ethylene promotes the water stress-induced abscission of cotyledonary leaves (10). The evidence suggests that an increase in the synthesis of ethylene and interruption in the auxin flux serve to trigger the separation process.…”

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confidence: 99%

Abscission Responses to Moisture Stress, Auxin Transport Inhibitors, and Ethephon

Morgan¹,

Jordan

Davenport

et al. 1977

Plant Physiol.

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The three abscsion-inducing agents-water stress, Ethephon, and auxin transport inhibitors-acted synergtically to promote leaf fail in cotton (Gossypium hirsutum L.). However, the synergism was prmarily between stress and Ethephon. Auxin Several lines of evidence suggest that a relationship may exist between abscission-modifying effects of water stress, auxin transport inhibitors, and ethylene in cotton. First, there is growing evidence that endogenous ethylene regulates leaf abscission (9, 18). The action of ethylene in abscission appears to be due in part to inhibition of auxin transport (4-6). Auxin transport inhibitors increase or hasten leaf abscission induced by exogenous ethylene or Ethephon (15,16). There is some evidence that ethylene production in cotton petioles increases during water stress (13). Petioles contain levels of ethylene about 10 times higher than leaf blades (12). During water stress or following release from stress by watering, cotton plants defoliate (14).Finally, exogenous ethylene promotes the water stress-induced abscission of cotyledonary leaves (10). The evidence suggests that an increase in the synthesis of ethylene and interruption in the auxin flux serve to trigger the separation process.The series of interrelations suggested to us that water stress, MATERIALS AND METHODSCotton plants (Gossypium hirsutum, L., c.v. Stoneville 213)were grown in a greenhouse in sand-peat moss-vermiculite mixture watered with Hoagland solution modified as described previously (17). Plants were in flowering to heavily fruited stage of growth with 12 to 20 expanded true leaves when experiments were initiated by withholding water.Water stress was initiated by withholding water from the appropriate plants beginning on day zero. Growth regulators were applied when plants reached the desired level of stress; the time of application ranged between 16 and 24 hr before the pots were again watered. Aqueous solutions of the growth regulators were freshly prepared on the day of application to include 0.05% Tween 20 as a surfactant. Compressed air-activated glass atomizers were used to spray plants to a wet but not dripping stage. For dual treatments, plants were allowed to dry before the second growth regulator was applied. The auxin transport-inhibiting compounds applied were N-1-naphthyl phthalamate as the sodium salt (Uniroyal Chemical Co., Alanap) and 3,3a-dihydro-2-(p-methoxyphenyl)-8H-pyrazolo-(5, la) isoindol-8-one (E. I. du Pont de Nemours & Co., DPX-1840) (15). They were used interchangeably without apparent difference in our experiments. Ethylene treatment was accomplished by application of Ethephon:2-chloroethanphosphonic acid (Amchem Corp., Ethrel). Concentrations are indicated in the figures and table.Plant water potentials were determined before dawn on the day of rewatering on the eighth true leaf with a Scholander pressure bomb (10). Abscission of leaves greater than 5 cm in diameter in response to gentle pressure on each main stem leaf was observed daily. In some experiments, plants ...

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