The Uptake Oe Indole‐3‐acetic Acid by Pea Epicotyl Segments and Carrot Disks

Reinhold, Leonora

doi:10.1111/j.1469-8137.1954.tb05237.x

Cited by 40 publications

(24 citation statements)

References 28 publications

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“…respectively, and considere(d IAA uptake a purely physical process. Reinhold (15) concluded from her studies with carrot root discs that t\o processes are involved, an initial physical uptake followed by a continued slow metabolic uptake which she attributed either to an active transport of IAA into the cells or else to its mietabolic remloval. Our results, as just shown, provide evidence for the latter alternative.…”

Section: Methodsmentioning

confidence: 99%

Studies on 3-Indoleacetic Acid Metabolism. VI. 3-Indoleacetic Acid Uptake and Metabolism by Pea Roots and Epicotyls

Andreae

Ysselstein²

1960

Plant Physiol.

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For several years we have studied the metabolism of applied indoleacetic acid (IAA) by plant tissues to determine whether growth stimulation or inhibition by IAA could be in any way related to its metabolism. So far we have been chiefly concerned with IAA metabolism by pea epicotyls, and in previous publications (2,3,4) have suggested that the toxic action of IAA might be related to the accumulation of free IAA in the tissues which appeared in turn to be related to the rate of indoleacetylaspartic acid (IAAspA) formation. Both IAAspA formation and growth became maximal at the same concentration of applied IAA (about 0.6 X 10-4 M). With lower concentrations almost all the IAA found in the tissues was present as IAAspA; only with the higher, growth inhibitory concentrations, did free IAA accumulate in the tissues to any extent.To study more fully this apparent relationship between growth inhibition and IAA accumulation in plant tissues, we have turned our attention to pea roots. For many years it has been known that roots are over a thousand times more sensitive than epicotyls to growth inhibition by IAA. We, therefore, have attempted to determine whether this sensitivity could be related to a greater accumulation of IAA due either to an increased uptake of IAA, as compared with epicotyls, or to a less active metabolism via degradation or conjugation. Uptake in these studies was equated with loss from solution; degradation was considered to be the amount of IAA lost from solution which could not be accounted for as Salkowski reactive indole compounds in the tissues. Other workers (18) have shown that in tissue breis IAA is oxidized by the IAA-oxidase system, and it is probable that in tissues, IAA undergoes oxidative decarboxylation by the same enzyme system (9, 10).The Salkowski reactive compounds found in the IAA treated roots are almost entirelv IAA and IAAspA (2, 5, 9) although, as in epicotyls (12) The present paper is concerned with the uptake, conjugation, and degradation of IAA in root tips. It also is concerned with a comparison between these findings and those of epicotyls. part of which has been published previously (5). A subsequent paper will deal with the relationship of these metabolic processes to the growth inhibitory action of applied IAA. METHODSDetails of the methods used for raising plants and for incubating the tissues have been described in previous papers (4, 5). In some experiments, the tissues, after incubation, were transferred to a moist chamber which consisted of a large Petri dish containing a layer of moist cellocotton and a small Petri dish as receptacle for the tissues. The methods of determining IAA and IAAspA in the incubating medium and tissues have also been described in these papers.The procedures used with roots differed in certain aspects from those used with epictoyls. These changes were necessary because roots are metabolically more active than epictoyls and more sensitive to their environment. These differences are as follows:A. The sample weight of root tips was only ...

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Section: Methodsmentioning

confidence: 99%

Studies on 3-Indoleacetic Acid Metabolism. VI. 3-Indoleacetic Acid Uptake and Metabolism by Pea Roots and Epicotyls

Andreae

Ysselstein²

1960

Plant Physiol.

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“…Most studies dealing with this subject fail to distinguish clearly between these two aspects of the problem, although some (10,11,16,17,18,19,20,25) have measured uptake by plants either directly or indirectly. MAore often, however, the study has involved the measurement of a response of the organism to externally applied base or acid (1,2,3,4,5,6,7,8,11,22,24,26,27,28).…”

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confidence: 99%

The Role of pH in the Permeability of Chlorella to 2,4-D.

Wedding

Erickson

1957

Plant Physiol.

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“…The failure of 3-MO to promote cell elongation in pea stem or corn coleoptile tissue is not due simply to failure of 3-MO to enter the tissue as shown by the uptake data of Figure 5. The time course of uptake of 3-MO by these tissues is very similar to the time course of uptake of labeled IAA by these and similar tissues (14,15). Basu and Tuli (4) have suggested that the lack of growthpromoting activity of 3-MO in some of their experiments with coleoptile tissue might be attributed to the inhibitory action of bromide ion formed during the synthesis of 3-MO.…”

Section: Methodsmentioning

confidence: 59%

Inactivity of 3-Methyleneoxindole as Mediator of Auxin Action on Cell Elongation

Evans

Ray

1973

Plant Physiol.

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The recently reported growth-promoting ability of 3-methyleneoxindole was examined in order to test the hypothesis that indole-3-acetic acid acts as a growth promoter only after oxidative conversion to 3-methyleneoxindole. Methyleneoxindole was synthesized from indole-3-acetic acid and N-bromosuccinimide, and its identity was confirmed by ultraviolet absorption, infrared absorption, mass spectrometry, and melting point. Methyleneoxindole was found to lack growth-promoting activity in coleoptile and pea (Pisum sativum) stem segments. Chlorogenic acid, an inhibitor of the oxidation of indole-3-acetic acid, was found to have no inhibitory effect on growth promotion by indole-3-acetic acid. It is concluded that 3-methyleneoxindole is inactive as a growth promoter and therefore does not mediate the action of auxin on cell elongation. For efforts to determine the mechanism of action of auxin in the promotion of cell elongation, such as recent attempts to study the binding of labeled auxins to receptor sites (9), it is I

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The Uptake Oe Indole‐3‐acetic Acid by Pea Epicotyl Segments and Carrot Disks

Cited by 40 publications

References 28 publications

Studies on 3-Indoleacetic Acid Metabolism. VI. 3-Indoleacetic Acid Uptake and Metabolism by Pea Roots and Epicotyls

Studies on 3-Indoleacetic Acid Metabolism. VI. 3-Indoleacetic Acid Uptake and Metabolism by Pea Roots and Epicotyls

The Role of pH in the Permeability of Chlorella to 2,4-D.

Inactivity of 3-Methyleneoxindole as Mediator of Auxin Action on Cell Elongation

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