Leaf Abscission in Cotton. IV. Effects of a Natural Promoter and Amino Acids on Abscission in Cotyledonary Node Explants

Hall, Wayne C.; Herrero, Fay Alberto; Katterman, Frank R. H.

doi:10.1086/336125

Cited by 11 publications

(3 citation statements)

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“…Hall et al (5) reported that amino acids were poor promoters of abscission, but their tests did not include those amino acids which we have found to show greatest activity in the bean abscission test. Moreover, these workers tested the amino acids by incorporating them into lanolin and applying this to the cut ends of cotton cotyledon petioles.…”

Section: Discussionmentioning

confidence: 81%

“…Osborne (7) reported that besides auxins, diffusates from senescing leaves of various species were able to accelerate abscission of bean explants, while green leaf diffusates showed smaller effects. Since then, other workers (3,5) 2,000 ft-c, and a temperature of 24 ± 2 C. Approximately 13 days from seeding, the primary leaves were excised and the blades trimmed off. The petiole pieces were then cut by a 1 cm cutter so that the abscission zone was in the center of the explant with the pulvinus and about 1 mm of the midrib tissue on the distal side of the abscission zone and 5 mm of the petiole on the proximal side.…”

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confidence: 99%

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Effects of Amino Acids on Bean Leaf Abscission

Rubinstein

Leopold

1962

Plant Physiol.

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Stimulatory and inhibitory effects of auxin on leaf abscission were reported by Addicott and Lynch (1) using an abscission test with bean petiole explants. This test was modified by Gaur and Leopold (4), and then more extensively by Biggs and Leopold (2) in describing the range of auxin effects. Osborne (7) reported that besides auxins, diffusates from senescing leaves of various species were able to accelerate abscission of bean explants, while green leaf diffusates showed smaller effects. Since then, other workers (3,5) 2,000 ft-c, and a temperature of 24 ± 2 C. Approximately 13 days from seeding, the primary leaves were excised and the blades trimmed off. The petiole pieces were then cut by a 1 cm cutter so that the abscission zone was in the center of the explant with the pulvinus and about 1 mm of the midrib tissue on the distal side of the abscission zone and 5 mm of the petiole on the proximal side.Substances to be tested were dissolved in water and incorporated into a 1 % agar solution. The agar was poured into petri dishes to a depth of 4 mm and ten explants were imbedded into each dish with the proximal end in the agar. The dishes were subsequently returned to the same growth chamber except that they were now placed under a 400 ft-c light intensity. with a volume of water equal to the fresh weight of the leaves. 5 ml of this extract were poured onto a 6 cm AG 50W-X8 200 to 400 mesh cation exchange column (Calbiochem Corp.) and washed with 25 ml of water. The column was then eluted with 30 ml of 1 N ammonium hydroxide; this fraction contained onlv the amino acids and amides. After the amino acid and the neutral fractions were each flash evaporated to dryness, water was again added to the volume of original fresh weight. The pH was adjusted to 6 and the extracts were diluted 3.3 times with water before being incorporated into agar for the explant test. ResultsSince it had been suggested in various papers (12,13,14) that methyl donors might promote abscission through an incorporation into methylated pectins, several such compounds were checked using the bean abscission test. The compounds which were tested included those found to be most effective in plants for donating methyl groups to pectinic acid (9, 11), and each was tested over a concentration range of 10-7 to 5 X 10-3 Ai. Table I compares these methyl donors which are arranged in order of decreasing methylation efficiency with some non-methyl donors as modifiers of abscission in the bean abscission test. The most efficient methyl donors were, in general, far less effective in accelerating abscission than some other compounds, and the promotions were not proportional to the methyl donation abilities. Although formaldehyde is very effective in the promotion of abscission, the activity of this material was confined only to a concentration which probably does not oc-398 www.plantphysiol.org on May 7, 2018 -Published by Downloaded from

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Section: Discussionmentioning

confidence: 81%

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confidence: 99%

Effects of Amino Acids on Bean Leaf Abscission

Rubinstein

Leopold

1962

Plant Physiol.

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“…The biofilms were quantified after adding 200 µL of 95% ethanol, followed by slight manual shaking. The absorbance was measured at 585 nm wavelength (λ), as reported in previous studies [34][35][36][37].…”

Section: Pcp and Surfactant Effects On Biofilm Formationmentioning

confidence: 99%

Pentachlorophenol Effect on Auxin Production by Pseudomonas fluorescens GU059580 and Its Application in Wastewater Bioremediation

Ammeri¹,

Hassen²,

Mehri³

et al. 2022

Recent Prog Mater

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Bioaugmentation by Pseudomonas strains is widely used for the removal of pollutants in wastewater. In this study, we aimed to determine the removal of pentachlorophenol (PCP, 800 mg·L–1) in secondary wastewater by the bioaugmentation process. We determined the effects of using three surfactants, namely sodium dodecyl sulfate (SDS), cetyl-tri-methyl-ammonium bromide (CTAB), and Tween 80 for PCP removal. We determined the effect of the role of PCP surfactant for the biofilm and auxin production of the selected bacterial strain of P. fluorescens GU059580. High-performance liquid chromatography and spectroscopic analysis were used to determine PCP removal and bacterial growth, respectively. Biofilm production was determined using 96-well polystyrene plates, and auxin production was determined using spectrophotometric measurement at 535 nm. The results showed the removal of PCP from wastewater by P. fluorescens GU059580 is about 90.12%. The PCP removal from wastewater showed an improvement of about 96.5% after the addition of Tween 80, whereas significant biofilm formation was found in the mineral liquid medium supplemented with PCP and Tween 80, with a value of 3.78. The highest concentration of auxin was found in the presence of PCP without surfactants, showing a value of 1.7 mg·L–1. To conclude, P. fluorescens GU059580 can be used in bioreactors or some specific wastewater treatment processes for bioremediation.

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Shoot Tip Abortion in Ulmus Americana

Millington

1963

American J of Botany

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Millington, W. F. (Marquette U., Milwaukee, Wis.) Shoot tip abortion in Ulmus americana. Amor. Jour. Bot. 50(4): 371–378. Illus. 1963.—Phenological observations of American elm have shown that the phenomenon of shoot tip abortion in which the distal several plastochrons of each shoot turn yellow and abort, inducing sympodial growth, occurs over a period of several weeks starting at the time fruits are shed from older trees. Time of abortion varies among plants of different age, among individuals of the same age, and among shoots on the same individual. In the latter case, time of abortion is inversely correlated with the vigor of the shoot, the most vigorous shoots on a branch being the last to abort. Abortion is first evident in the yellowing of the entire shoot tip. Cytohistological studies show that necrosis commences at the sixth to eighth node back of the apex, where it is apparent in autolysis of internal cells of the stipules. Necrosis progresses acropetally in the stipules and young leaves and ultimately involves the leaf primordia at the shoot apex. Mitosis ceases in the shoot apex and its meristematic appearance is lost. These changes follow in basipetal sequence in the axillary buds down to the bud below the abscission site. This bud remains active and will resume growth the following season. The abscission site is evident externally as a green‐yellow boundary in the basal part of the internode. No protective layer is present at the time of abscission, but it develops after the shoot tip abscises. There is no indication of blocking of vascular tissues before shoot tip abortion and limitation of water supply probably is not a causal factor. Photoperiod studies show that shoot tip abortion is accelerated in short days and delayed but not prevented in long days. Greenhouse experiments show that abortion is delayed also in seedlings, in plants supplied with organic fertilizer, or grown with the roots unconfined. Plants grown in a nutrient solution deficient in nitrogen aborted ahead of controls and plants deficient in calcium. Although shoot tip abortion occurs coincident with fruit drop, there is no indication of a causal relationship. The literature relating to shoot tip abortion is discussed in relation to the above observations.

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Leaf Abscission in Cotton. IV. Effects of a Natural Promoter and Amino Acids on Abscission in Cotyledonary Node Explants

Cited by 11 publications

References 20 publications

Effects of Amino Acids on Bean Leaf Abscission

Effects of Amino Acids on Bean Leaf Abscission

Pentachlorophenol Effect on Auxin Production by <i>Pseudomonas fluorescens</i> GU059580 and Its Application in Wastewater Bioremediation

Shoot Tip Abortion in Ulmus Americana

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