scholarly journals THE EFFECT OF AUXINS ON PROTOPLASMIC STREAMING. II

1938 ◽  
Vol 21 (4) ◽  
pp. 439-461 ◽  
Author(s):  
Beatrice Marcy Sweeney ◽  
Kenneth V. Thimann
Keyword(s):  
Acetic Acid ◽  
Oxygen Deficiency ◽  
Pure Water ◽  
Time Of Day ◽  
Protoplasmic Streaming ◽  
Avena Coleoptile ◽  
Transient Nature ◽  
The Mean ◽  
Time Of Year ◽  
Indole 3 Acetic Acid

1. A further study has been made of the effect of indole-3-acetic acid (auxin) on protoplasmic streaming in the epidermal cells of the Avena coleoptile. 2. The transient nature of the effect of auxin, both in accelerating and retarding streaming, is due to the temporary exhaustion of carbohydrate from the tissues. In presence of 1 per cent fructose or some other sugars the acceleration or retardation of streaming by auxin is not transient, but is maintained for at least 2 hours. 3. The retardation of streaming brought about by concentrations of auxin above 0.5 mg. per liter is due to oxygen deficiency This has been confirmed in several ways. 4. It follows that the effect of auxin is to increase the respiration of the coleoptile tissue. 5. Younger coleoptiles, 3 cm. long, are sensitive to lower concentrations of auxin than those 5 cm. long, and more readily exhibit oxygen deficiency as a result of the action of auxin. However, after decapitation their response to auxin more closely resembles that of 5 cm. coleoptiles. 6. The retardation of streaming in such coleoptiles, resulting from oxygen deficiency, is delayed by very dilute solutions of histidine. On this basis an explanation is suggested for the results of Fitting on streaming in Vallisneria leaves. 7. The mean rate of streaming in control untreated coleoptiles in pure water varies with the time of year, but not with the time of day. 8. The results support the view that auxin accelerates an oxygen-consuming process which controls the rate of protoplasmic streaming, and that the latter controls growth. The substrate for this process is probably sugar. 9. It is suggested that auxin also accelerates another oxygen-consuming process, which may withdraw oxygen from the process which controls streaming rate and hence cause retardation of the latter.

scholarly journals THE EFFECT OF AUXINS UPON PROTOPLASMIC STREAMING

1937 ◽  
Vol 21 (2) ◽  
pp. 123-135 ◽  
Author(s):  
Kenneth V. Thimann ◽  
Beatrice Marcy Sweeney
Keyword(s):  
Acetic Acid ◽  
Indole Acetic Acid ◽  
Growth Promotion ◽  
Pure Water ◽  
Maximum Effect ◽  
Maximum Increase ◽  
Avena Coleoptile ◽  
High Auxin ◽  
Fitting In ◽  
Indole 3 Acetic Acid

1. Evidence has accumulated that the action of auxins in promoting growth is exerted not upon the cell wall but upon the cell contents; i.e., the protoplasm. Following indications previously obtained, therefore, the effect of auxins on the rate of protoplasm streaming in the Avena coleoptile was studied. 2. Indole-3-acetic acid, the most active auxin available in pure form, was found to increase the rate of streaming in the epidermal cells of the Avena coleoptile at concentrations between 0.5 and 0.002 mg. per liter, the maximum increase being brought about at 0.01 mg. per liter. This concentration is approximately that which, applied in agar to one side of the decapitated coleoptile, would give a curvature of 1°; i.e., it is well within the range of concentrations active in growth promotion. It is, however, much less than that which produces maximum elongation in immersed sections of Avena coleoptiles. 3. This accelerating effect is readily determined quantitatively by comparison with the streaming in control coleoptiles in pure water, which, if thoroughly aerated, maintain a constant rate for over an hour. The accelerating effect takes place immediately and is over within about 30 minutes. 4. Concentrations of indole-3-acetic acid greater than 0.5 mg.per liter inhibit the streaming, the effect being also over in about 30 minutes, and its extent increasing with increasing auxin concentration. This parallels the effect of high auxin concentrations in inhibiting elongation, although the inhibition of streaming is obtained at much lower concentrations than inhibit elongation. 5. The effects of indole-3-acetic acid on streaming are not specific for that substance, but appear to be common to auxins in general. Thus coumaryl-3-acetic acid and allocinnamic acid, both of which bring about cell enlargement, root formation, and bud inhibition, i.e. are typical auxins, also cause an immediate acceleration of the rate of streaming, and as with indole-acetic add the effect is over in about 30 minutes. The concentrations of these two substances which produce the maximum effect are about ten times that of indole-acetic acid, which approximately corresponds with their relative auxin activities. The curves relating concentrations of these substances to their effects on streaming are very similar to that for indole-acetic acid. 6. On the other hand, certain substances which are known to affect streaming in other materials do not produce any effect comparable to that of auxin. Ethylene chlorhydrin, histidine, and urea in all concentrations were without effect on streaming in the Avena coleoptile within the first 30 minutes of treatment. 7. The effects produced by the auxins were not due to pH. 8. The action on streaming here studied is evidently quite different from the re-starting of streaming after its cessation, studied by Fitting in Vallisneria. Correspondingly histidine, which in Fitting's experiments showed activity down to 10–7 M, is inactive here. 9. Per contra, the effect of auxin here studied is on normal streaming. It takes place immediately and at concentrations in the same range as those which produce growth. The curve of effect against concentration parallels that for growth although the actual concentration values differ. It is therefore reasonable to suppose that the effect of auxin on streaming is closely connected with one of the first stages of its effect on the growth process.

scholarly journals Sulphur Analogues of Indoleacetic Acid: Synthesis and Biological Activity of some Thionaphthenacetic Acids

1957 ◽  
Vol 10 (1) ◽  
pp. 80 ◽  
Author(s):  
NP Kefford ◽  
Judith M Kelso
Keyword(s):  
Acetic Acid ◽  
Biological Activity ◽  
Plant Growth ◽  
Indoleacetic Acid ◽  
Acid Synthesis ◽  
Dichlorophenoxyacetic Acid ◽  
Protoplasmic Streaming ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Indole 3 Acetic Acid ◽  
Acetic Acids

The thionaphthen�2�, �3-, -5-, -6�, and -7-acetic acids have been synthesized from the chlorides of the corresponding carboxylic acids by the Arndt-Eistert reaction and their plant growth-regulating activities, as indicated by their effects upon protoplasmic streaming, have been compared with those of indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4�D). The thionaphthen-3- and -7- acetic acids and IAA have similar effects upon protoplasmic streaming, while the effects of the thionaphthen-2-, -5-, and �6-acetic acids differ from those of IAA and resemble in part those of 2, 4-D.

scholarly journals THE EFFECT OF AUXINS ON PROTOPLASMIC STREAMING. III

1942 ◽  
Vol 25 (6) ◽  
pp. 841-854 ◽  
Author(s):  
Beatrice Marcy Sweeney ◽  
Kenneth V. Thimann
Keyword(s):  
Sugar Solution ◽  
Protoplasmic Streaming ◽  
Acid System ◽  
Absolute Rate ◽  
Avena Coleoptile ◽  
Low Concentrations ◽  
Continuous Record ◽  
Streaming Velocity ◽  
Carbon Acid ◽  
Indole 3 Acetic Acid

1. A new method is described which gives a continuous record of the absolute rate of protoplasmic streaming in epidermal cells of the Avena coleoptile. 2. With this method a study was made of the influence of malate and iodoacetate on streaming velocity, in order to make correlations with the previously established effects of these substances on growth and respiration. 3. In the presence of optimum concentrations of indole-3-acetic acid in freshly cut sections, malate had no effect on streaming. In the presence of very low concentrations of the auxin, however, malate increased the range of response, so that the threshold of auxin sensitivity was lowered some ten times by the malate. Malate alone had no effect on streaming. 4. In coleoptile sections, soaked overnight in sugar solution or in water, the acceleration of streaming normally caused by auxin almost disappears, but the presence of malate causes large accelerations of streaming by the auxin. 5. Similarly, in sections from old coleoptiles, which no longer show acceleration of streaming by auxin, the acceleration is restored when malate is added together with the auxin. 6. Malate does not enter the cell as rapidly as does auxin, but easily detectable amounts penetrate within 30 minutes. 7. Iodoacetate in the concentration which inhibits growth (5 x 10–5 M) completely inhibits the acceleration of streaming by auxin. In still lower concentrations iodoacetate slightly accelerates streaming. Higher concentrations, up to 2 x 10–4 M, did not reduce the rate of streaming below that of controls without auxin. The effect of iodoacetate is therefore to inhibit the acceleration caused by auxin and not to affect the basal streaming rate. 8. It is concluded that, just as for growth and respiration, malate is necessary for the response to auxin shown by acceleration of streaming. This further strengthens the triple parallel between the effects of auxin on streaming, growth, and respiration, all of which are apparently mediated by the 4-carbon acid system.

scholarly journals Uptake of Indole-3-acetic Acid and Indole-3-acetonitrile by Avena Coleoptile Sections

1964 ◽  
Vol 39 (1) ◽  
pp. 98-103 ◽  
Author(s):  
Ronald J. Poole ◽  
Kenneth V. Thimann
Keyword(s):  
Acetic Acid ◽  
Avena Coleoptile ◽  
Indole 3 Acetic Acid

Die Anfangsphasen des durch Steringlucoside und Indol-3-essigsäure stimulierten Wachstums bei Avenakoleoptilen / Initial Phases of Growth Induced by Sterylglucosides and Indole-3-acetic Acid in Avena Coleoptiles

1981 ◽  
Vol 36 (9-10) ◽  
pp. 900-901 ◽  
Author(s):  
Amo Tietz
Keyword(s):  
Growth Rate ◽  
Acetic Acid ◽  
Sharp Increase ◽  
Growth Response ◽  
Avena Coleoptile ◽  
Recording Technique ◽  
First Response ◽  
Indole 3 Acetic Acid ◽  
Primary Action ◽  
Membrane Level

AbstractThe initial phases of growth induced by sterylglucosides were investigated by means of a high resolution recording technique. Avena coleoptile segments were preincubated with 10-6 M IAA in buffered solution, then the β-vglucosides of sitosterol, stigmasterol, campesterol, and cholesterol respectively were added in the concentration range from 10-7 –10-6 m . It could be demonstrated that the first response to the applied sterylglucosides is a reduction of the growth rate lasting about 15 min, followed by a sharp increase of the growth rate. As the growth response of the coleoptiles after treatment with sterylglucosides is very similar to that observed after application o f IAA alone, it is concluded from the results that sterylglucosides or sterols may also exhibit their primary action at the membrane level, perhaps by influencing microviscosity of the membrane and/or H +-secretion.

Meiotic behaviour of the pollen mother cells in cultured anthers of rye excised at early meiotic prophase

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 161-165
Author(s):  
J. Rueda ◽  
A. M. Vázquez
Keyword(s):  
Acetic Acid ◽  
Chiasma Formation ◽  
Free Medium ◽  
Pollen Mother Cells ◽  
The Mean ◽  
Mother Cells ◽  
Pollen Sacs ◽  
Indole 3 Acetic Acid

Anthers of rye were excised during leptotene and zygotene and cultured in vitro on media with and without indole-3-acetic acid to study the behaviour of pollen mother cells during meiosis. Percentages of pollen sacs in which pollen mother cells continued meiosis increased from approximately 20% to 60–70% when anthers were excised at early and late leptotene. The highest values were about 90% when the excision was during zygotene. The results were similar on both media. The timing of pollen mother cells through meiosis on the hormone-free medium was similar to that described in vivo. The mean numbers of chiasmata per cell at metaphase I from the cultured pollen sacs were compared with those from a random population of pollen sacs grown in the field. A significant decrease was observed when anthers were excised during leptotene and cultured on both media, as well as when anthers were excised at early zygotene and cultured on the hormone-supplemented medium. We concluded that at early zygotene there are processes related to chiasma formation that seem to be influenced by hormone balance.Key words: Secale cereale, anther culture, meiosis development, chiasma formation, indole-3-acetic acid.

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