Relative Elemental Elongation Rates in the Etiolated Hypocotyl of Sunflower (Helianthus annuus L.)-A Comparison of Straight Growth and Gravitropic Growth

Berg, Arthur R.; MacDonald, Ian R.; Hart, J. W.; Gordon, D. C.

doi:10.1086/337604

Cited by 20 publications

(16 citation statements)

References 30 publications

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“…The shortest seedlings gave the highest EC values, PE and EC variations could be due to the histological and physiological variations occurring during plant development and to the location of tissue responsible for growth. For example, the explant tissue used in this work corresponds to the elongation zone which is apical in sunflower hypocotyl [20]. Following the conclusions of Sharp & Evans [21], Kolenbach et al [22] and Gosh et al [23], it might be probable that along the hypocotyl, some cells of peculiar origin were predetermined to give, in the appropriate culture conditions, embryogenic protoplasts.…”

Section: Mode Of Incubationmentioning

confidence: 92%

Plant donor tissue and isolation procedure effect on early formation of embryoids from protoplasts of Helianthus annuus L.

Dupuis¹,

Péan²,

Chagvardieff

1990

Plant Cell Tiss Organ Cult

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The effects of factors influencing sunflower protoplast isolation yield, plating efficiency (PE) and the early differentiation into embryoids (embryogenic capacity, EC) have been studied. Only hypocotyl-derived protoplasts divided. The variations of PE and EC in the various treatments did not seem to be linked to the protoplast yields. From statistical analysis of the data, we concluded that, the sunflower genotype, the age and height of seedlings, the part of hypocotyl used, the incubation time (from 6 to 16 hours) in enzymes of explants or of protoplasts alone, influenced PE but large variations were detected for EC. A comparison of the factors effecting EC suggested an origin, inside the hypocotyl, of cells able to give rise, after induction, to embryogenic protoplasts.

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Section: Mode Of Incubationmentioning

confidence: 92%

Plant donor tissue and isolation procedure effect on early formation of embryoids from protoplasts of Helianthus annuus L.

Dupuis¹,

Péan²,

Chagvardieff

1990

Plant Cell Tiss Organ Cult

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“…In the experiment of Figure 2 Figure 1 unequivocally shows that auxin has become laterally asymmetric within 5 initiation of gravitropic stimulation. This is as early as a macroscopic curvature response is seen in most dicot seedling stems; although stems may possibly begin bending at a very slow rate within a minute or two after horizontal placement (24), in general, bending is not rapid for at least 5 to 20 min (cf 3). Assuming that the elongation response to gravitationally developing auxin asymmetries may sometimes begin after a lag of a minute or so and is well underway in perhaps 10 min (for review see Ref.…”

Section: Time-course Of Curvaturementioning

confidence: 99%

Auxin Asymmetry during Gravitropism by Tomato Hypocotyls

Harrison

Pickard²

1989

Plant Physiol.

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Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA collected from the lower sides to that from the upper sides was about 1.4 between 5 and 10 minutes. This was adequately early to account for the beginning of curvature. The auxin asymmetry ratio rose to about 2.5 between 20 and 25 minutes, and to 3.5 during the main phase of curvature. This compares reasonably well with the roughly 3.9 ratio for elongation on the lower side to elongation on the upper side that is the basis for the curvature. These data extend evidence that the Went-Cholodny theory for the mediation of tropisms is valid for dicot stems. Also consistent with the theory, an auxin asymmetry ratio of 2.5 was observed when wrong-way gravitropic curvature developed following application of a high level of auxin. In addition to reversing the asymmetry of elongation, the large supplement of auxin resulted in lower net elongation. Previous data established that ethylene is not involved in this decrease of growth as a function of increasing level of auxin.A large body of evidence has accumulated in support of the Went-Cholodny theory that phototropism and gravitropism are mediated by lateral migration of auxin (22,23

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“…It is not known if the fate of the dividing protoplasts is related only to the culture conditions, or whether it is conditioned by the tissue from which the protoplasts are issued. Hypocotyls are formed from several tissues presenting different sectors of growth and elongation of cells (Berg et al 1986) and this gives rise to a very heterogeneous population of protoplasts. Centrifugation of the crude preparation on a ficoll gradient (Chanabe et al 1989) allows the selection of a sub population bearing the highest capacity of division but, unfortunately, nothing is known concerning the origin of the protoplasts which constitute this selected population.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of protoplasts from hypocotyls of Helianthus annuus in relation to their tissue origin

Brière

Borin

Kallerhoff

et al. 1995

Plant Cell Tiss Organ Cult

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Cells and protoplasts isolated from three different tissues of sunflower hypocotyls and cultured either in liquid or agarose medium were compared in terms of their volume, DNA content, division potential and embryoid formation. Epidermal and external cortical cells differ from other tissue cells by their small size, their weak response to plasmolysis and their low DNA content (around 1C). They contribute only very weakly to the dividing protoplast population. In contrast, protoplasts from cortical and medullar cells both have similar division potential, reaching 50%. The nuclear DNA content of these two cell types, as well as their corresponding protoplasts, has a 2C value, taking root tip cells in GO phase as standard. The culture conditions induce the same specific response in protoplasts isolated from both tissues: exclusively loose colony formation in liquid medium, and mainly production of embryoids in agarose medium.

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Relative Elemental Elongation Rates in the Etiolated Hypocotyl of Sunflower (Helianthus annuus L.)-A Comparison of Straight Growth and Gravitropic Growth

Cited by 20 publications

References 30 publications

Plant donor tissue and isolation procedure effect on early formation of embryoids from protoplasts of Helianthus annuus L.

Plant donor tissue and isolation procedure effect on early formation of embryoids from protoplasts of Helianthus annuus L.

Auxin Asymmetry during Gravitropism by Tomato Hypocotyls

Characterisation of protoplasts from hypocotyls of Helianthus annuus in relation to their tissue origin

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