Organs of Gibberellin Synthesis in Light-Grown Sunflower Plants

Jones, Russell L.; Phillips, I. D. J.

doi:10.1104/pp.41.8.1381

Cited by 161 publications

(60 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experiments described here indicate that the root-synthesized GA has no direct controlling effect on pea stem growth (Table I). The mechanism controlling pea stem growth must be located in the stems, presumably near the apex, and the stem-synthesized GA (6,12,16) is presumed to be a factor in this mechanism (7,11). Based on our grafting experiments, the stem-synthesized GA must be the dominant controlling factor because dwarf pea stems grew the same amount whether they were grafted onto tall or dwarf rootstocks (Table I).…”

Section: Discussionmentioning

confidence: 87%

“…Since Went (17,18) (6,12,16). Lockhart (10) attempted to demonstrate the controlling aspect of shoot tip-syhthesized gibberellin by grafting a stem from a tall pea onto the root of a dwarf pea.…”

Section: Introductionmentioning

confidence: 99%

“…When similarly grafted plants were supplied with gibberellic acid, good graft unions did not inhibit its translocation. This evidence supports the thesis that the mechanism controlling stem growth in peas is located in the stem and that the roots have no direct control over this mechanism.Since Went (17,18) (6,12,16). Lockhart (10) attempted to demonstrate the controlling aspect of shoot tip-syhthesized gibberellin by grafting a stem from a tall pea onto the root of a dwarf pea.…”

mentioning

confidence: 99%

“…Bioassay experiments with extracts from root tips have also demonstrated the presence of gibberellin in this organ (1,6). Gibberellins have, however, been found in shoot tips of many plants, notably in peas; and diffusion and excision experiments have indicated that gibberellins are synthesized in the shoot tips as well as in the roots (6,12,16). Lockhart (10) attempted to demonstrate the controlling aspect of shoot tip-syhthesized gibberellin by grafting a stem from a tall pea onto the root of a dwarf pea.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Grafting and Gibberellin Effects on the Growth of Tall and Dwarf Peas

Lockard

Grünwald

1970

Plant Physiol.

View full text Add to dashboard Cite

Tall peas var. Alaska and dwarf peas var. Progress No. 9 were grafted onto their own roots or reciprocally grafted to determine the rootstock effect on the growth of the stem. In all cases the grafted stems grew the same as their ungrafted controls regardless of which rootstock they were grown on. When similarly grafted plants were supplied with gibberellic acid, good graft unions did not inhibit its translocation. This evidence supports the thesis that the mechanism controlling stem growth in peas is located in the stem and that the roots have no direct control over this mechanism.Since Went (17,18) (6,12,16). Lockhart (10) attempted to demonstrate the controlling aspect of shoot tip-syhthesized gibberellin by grafting a stem from a tall pea onto the root of a dwarf pea. No increased elongation occurred in the stem section of the dwarf rootstock, contrary to expectation, and he concluded that his experiments failed to provide evidence for or against the production of gibberellin in roots or cotyledons.Lockhart (9, 11) suggested that light regulates stem elongation in dwarf pea through some effect, or effects, on the metabolism of gibberellin. He considered three possible mechanisms: (a) light may inhibit the synthesis of endogenous gibberellin, (b) light may cause a destruction or diversion of endogenous gibberellin, or (c) light may make the tissue less responsive to a given amount of gibberellin; and he concluded that visible radiation probably inhibited stem elongation in pea through an effect ' The investigation reported in this paper is in connection with a project of the Kentucky Experiment Station and is published with approval of the Director. on the level of endogenous gibberellin (11). However, Kende and Lang (7) rejected the first two possibilities since they found equal amounts of gibberellin in dark-and light-grown dwarf peas. They favored the third mechanism, that light makes the tissue less responsive. Kohler and Lang (8) produced evidence for substances in higher plants (lima beans) which interfered with the response of dwarf peas to gibberellin, and they suggested that inhibitors may participate in the growth regulation of plants, particularly by an interplay with gibberellins.Our experiments were aimed at finding whether stem growth due to gibberellin is controlled by the root system or stem and/or if an inhibitor is produced in the roots which may be translocated to the stem of the pea plant and in this way regulate stem growth. MATERIALS AND METHODSTwo varieties of peas (Pisum salivum L.) were used: Alaska, a tall pea, and Progress No. 9, a dwarf pea. The Alaska seeds were obtained from a local seed house and the Progress No. 9 seeds from Northrup King, Minneapolis, Minnesota.The seeds were soaked for 5 hr in water and then planted in vermiculite in 3.8-cm pots. The plants were grown in a growth chamber at 20°under continuous illumination. For the first 3 days the plants were watered with distilled water, and after the 3rd day they were supplied daily with Hoagland's nutrient solut...

show abstract

Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Grafting and Gibberellin Effects on the Growth of Tall and Dwarf Peas

Lockard

Grünwald

1970

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Several workers have shown that root exudates contain kinetin-like activity (8,13,14) as well as gibberellin activity (25,28). The root tips are production sites for both cytokinins (30) and gibberellins (9,10). Rootless plants have not been extensively used to study the effect of hormones produced by the roots on shoot growth.…”

mentioning

confidence: 99%

Hormonal Regulation of Cell Elongation in the Hypocotyl of Rootless Soybean: An Evaluation of the Role of DNA Synthesis

Holm

Key

1969

Plant Physiol.

View full text Add to dashboard Cite

Abstract. A method was developed where soybean seedlings were grown without roots to study the influence of hormones of root origin on shoot growth. Excision of the root resulted in inhibition of apical section growth and DNA synthesis and inhibited elongating section growth. A synthetic cytokinin restored DNA synthesis in the apical seotion, but did not influence growth in either the apical or elongating sections. Low concentrations of gibberellin with the cytokinin restored growth in the apical section. Gibberellin alone was sufficient to restore grow-th in the elongating section.An inhibitor of DNA synthesis, 5-fluorodeoxyuridine, inhibited the increase in apical section DNA without inhibiting control or gibberellin-induced growth in the elongating section. Experiments with 14C-thymidine resulted in no DNA labeling differences in the elongating section under conditions where gibberellin-induced elongation varied from 50 % to 73 % above controls. It was concluded that gibberellin-induced elongation in soybean hypocotyl occurred in the absence of DNA synthesis. Gibberellin does stimulate DNA synthesis in the apical tissue apart from its effect on cell elongation.Excised soybean hypocotyl elongated maximally at 10-8 M auxin. At higher auxin concentrations, fresh weight and ethylene production increased, but elongation was reduced. Addition of GA to the higher auxin concentations resulted in a 50 % inhibition in auxin-induced ethylene production and resumption in maximal elongation. Added ethylene inhibited elongation 30% at 2 A/l. Addition of up to 100 ll/ ethylene did not inhibit elongation with GA present in the incubation medium. Thus GA may counteract ethylene inhibition of cell elongation in addition to inhibiting othylene production in auxin-treated tissues.Thirty years ago Went (31) proposed the existence of-hormones produced by the roots that were necessary for stem growth. Chibnall (2), studying protein loss in detached leaves, suggested that the root system exerted an influence on leaf protein metabolism. He found that development of adventitious roots on the petioles of detached leaves caused a reduction in the rate of protein breakdown (3). Richmond and Lang (26) discovered a chemical basis -for senescence retardation when they showed that kinetin delayed yellowing of detached Xanthium

show abstract

The Grape Root System

Richards¹

1983

Horticultural Reviews

View full text Add to dashboard Cite

Organs of Gibberellin Synthesis in Light-Grown Sunflower Plants

Cited by 161 publications

References 11 publications

Grafting and Gibberellin Effects on the Growth of Tall and Dwarf Peas

Grafting and Gibberellin Effects on the Growth of Tall and Dwarf Peas

Hormonal Regulation of Cell Elongation in the Hypocotyl of Rootless Soybean: An Evaluation of the Role of DNA Synthesis

The Grape Root System

Contact Info

Product

Resources

About