Concentrations of Abscisic Acid and Indoleacetic Acid in Cotton Fruits and Their Abscission Zones in Relation to Fruit Retention

Guinn, Gene; Brummett, Donald L.

doi:10.1104/pp.83.1.199

Cited by 30 publications

(22 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, from 8 to 15 DAA, concentrations of ABA increased in aborting and decreased in nonaborting kernels. Therefore, ABA may promote kernel abortion after it has been initiated just as it promotes boll abscission in cotton (10). The increase of ABA in aborting kernels was coincident with accumulation of reducing sugars in the cob of aborting kernels.…”

Section: Discussionmentioning

confidence: 92%

“…Therefore, IAA may promote continued growth of nonaborted kernels, but levels may be insufficient in aborted kernels to counteract growth inhibition. Similarly, it has been reported that IAA in the abscission zones of cotton bolls is positively correlated with boll retention (10).…”

Section: Discussionmentioning

confidence: 99%

“…The inhibitor was identified as ABA (2). Similarly, high levels of ABA have been correlated with abortion of developing cotton fruit (5,10) and wheat grain (16). In maize it was observed that aborting kernels contain higher levels of ABA and lower levels of IAA and cytokinins than nonaborting kernels during flowering (20).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Roles of Carbohydrate Supply and Phytohormones in Maize Kernel Abortion

Reed¹,

Singletary²

1989

Plant Physiol.

View full text Add to dashboard Cite

Kernels at the ear tip of field grown maize (Zea mays L.) often abort during flowering, resulting in significant yield loss. The objective of this study was to determine if abortion is initiated by an inadequate supply of carbohydrates for growth of ear tip kemels, and/or by a hormonal signal. Field grown maize plants were either unshaded or shaded during flowering to increase kernel abortion. Nonstructural carbohydrates, indoleacetic acid (IAA), abscisic acid (ABA), and cytokinins were measured in aborting and nonaborting kernels, before and after abortion occurred. Kemel abortion was initiated 8 days after anthesis (DAA) and was complete by 12 DAA, when kemels ceased dry weight accumulation. Concentrations of reducing sugars, sucrose, and starch in aborting kernels were not significantly different from those in nonaborting kemels up to 12 DAA. Also, total carbohydrate concentrations were higher in the cob of aborting than of nonaborting kernels from 8 to 26 DAA. These data suggest that kemel abortion is not initiated by an inadequate supply of carbohydrates. However, accumulation of reducing sugars in the cob of aborting kemels suggests that transfer of sugars from cob to kemels is impaired early in the abortion process. Differences in IAA, ABA, and cytokinin concentrations between aborting and nonaborting kemels were only observed after abortion was complete. Kemel abortion is apparently not initiated by a signal of these hormones. After completion of abortion, aborted kemels contained higher concentrations of ABA and lower concentrations of IAA than nonaborted kemels. There was also a trend toward higher concentrations of zeatin riboside in nonaborted kemels.Abscisic acid may promote kemel abortion after the process has been initiated. A mechanism for kemel abortion is discussed.

show abstract

Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Roles of Carbohydrate Supply and Phytohormones in Maize Kernel Abortion

Reed¹,

Singletary²

1989

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…The week immediately following anthesis appears to be a critical time in the development of each young boll because its IAA content is naturally low during this stage of development. Stresses, such as water deficit or an inadequate supply of photosynthate, were shown to decrease the free IAA content of young bolls and their abscission zones to even lower values and increase the percentage that abscised (17). Large flower buds and older bolls are much less likely than young bolls to abscise during periods of stress (12,16,22), probably at least in part because they contain much higher concentrations of IAA.…”

Section: Resultsmentioning

confidence: 99%

Changes in Amide-Linked and Ester Indole-3-Acetic Acid in Cotton Fruiting Forms during Their Development

Guinn¹,

Brummett²

1989

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

The concentration of free indoleacetic acid (IAA) is high in cotton (Gossypium hirsutum L.) fruiting forms before anthesis, but is low at and for a few days after anthesis. Amide-linked and ester IAA were measured in fruiting forms at 9, 6, and 3 days before anthesis; at anthesis; and at 2, 4, 7, and 9 days after anthesis to determine if free IAA decreased because it was converted to a conjugated form. Cotton (Gossypium hirsutum L.) fruiting forms rarely abscise during the week before anthesis (12, 22), but are most susceptible to abscission during the week after anthesis (16,22). Abscission rate then decreases with increasing fruit (boll) age until it is essentially zero at 18 d after anthesis (15,16).Because exogenous IAA delays or prevents abscission (2, 7), we measured the concentration of free IAA in fruiting forms from 9 d before until 9 d after anthesis (18). The concentration of free IAA decreased about 80% during the 6 d before anthesis, remained low for the next 4 d, and then increased rapidly between 7 and 9 d after anthesis. Abscission rate increased rapidly after anthesis to a maximum at 5 and 6 d postanthesis. it then decreased as free IAA increased. Because these changes in free IAA were inversely correlated with changes in fruiting-form abscission, we suggested that the high concentration of IAA in large flower buds inhibited abscission before anthesis, whereas the low concentration at and for 4 d after anthesis promoted abscission of young bolls (18).A decrease in the concentration of free IAA could result from decreased synthesis, increased destruction, export, conversion to another form, or a combination of these possible events. We measured the concentrations of ester and amidelinked IAA before, at, and after anthesis to see if the decrease in free IAA was associated with a similar increase in either of the conjugated forms. MATERIALS AND METHODS Plant MaterialCotton (Gossypium hirsutum L.), cv Deltapine 61,' was grown in a field at the Western Cotton Research Laboratory in Phoenix as reported earlier (18). Flower buds were harvested 9, 6, and 3 before anthesis; flowers were harvested at anthesis; and bolls were harvested 2, 4, 7, and 9 d after anthesis. All fruiting forms (buds, flowers, and bolls) were harvested the same day to minimize possible differences due to any change in environment. The fruiting forms were rinsed in cold water, quickly frozen at -80°C, and lyophilized. The dry tissue was ground to pass a 40-mesh screen and stored under N2 at -80°C.Analyses of Ester and Amide IAA Samples of 200 or 500 mg each were extracted overnight in 70% acetone that contained antioxidants (19). '4C-IAA was added as an internal standard. The samples plus three 10-mL rinses with 70% acetone were filtered and the volume reduced to about 9 mL by rotary evaporation at 45°C. Ester IAA was hydrolyzed by adding 1 ml of 10 N KOH, mixing, and incubating 1 h at room temperature (3). Amide-linked IAA was hydrolyzed in 7 N NaOH during 3 h at about 100°C (3). All samples were hydrolyzed in a nitrogen a...

show abstract

“…Water deficiency also changes the status of internal hormonal balance in the plant (Mcmichael et al, 1972;Guinn, 1976;Guinn and Brummett, 1988;Guinn et al, 1990). It enhances the rate of ethylene production (Guinn, 1976), increases abscisic acid (ABA) content in young cotton bolls and decreases the free indole-3-acetic acid (IAA) content (Guinn, 1982;Brummett, 1987 and1988). In sesame, abscission could be manipulated by altering the level of IAA and ethylene (Sexton and Roberts, 1982) .…”

mentioning

confidence: 99%