Abscisic acid and the response of the roots of Zea mays L. seedlings to gravity

Wilkins, H. D.; Wain, R. L.

doi:10.1007/bf00389356

Cited by 45 publications

(17 citation statements)

References 25 publications

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“…The ability of added ABA to substitute for the red light (15), combined with the evidence that red light results in an increase in ABA in the roots (3) suggests that these two factors may influence similar components of the gravitropic system. Calcium has been found to be an important factor in orthogravitropism (10,12), although its elution from the root has little or no effect on diagravitropism (6).…”

mentioning

confidence: 99%

Interactions between Red Light, Abscisic Acid, and Calcium in Gravitropism

Leopold¹,

LaFavre²

1989

Plant Physiol.

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The effect of red light on orthogravitropism of Merit com (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of com which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.

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confidence: 99%

Interactions between Red Light, Abscisic Acid, and Calcium in Gravitropism

Leopold¹,

LaFavre²

1989

Plant Physiol.

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“…For horizontally placed roots, downward transport of these inhibiting substances occurs inside the apex (33,36) and their level is greater in the lower than the upper half of the cap (56", 37,41,47). These findings indicate clearly that the cap inhibitors control root geotropism (37,45,48,49).…”

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confidence: 89%

Abscisic acid effect on the DNA microgradients of decapped maize roots

1978

Plant and Cell Physiology

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Longitudinal and transversal total DNA gradients were analysed in 42-/*m thin sections of maize root tips. The optimum DNA concentration was found in the apex (quiescent centre and meristem). It significantly increased after removal of the root cap, which can be considered an essential source of abscisic acid (ABA). When the caps were taken off and agar blocks containing ABA were immediately placed on the apical cut sections, the total DNA level in the root apex decreased gready. ABA regulation of cellular and nuclear behaviour is discussed. Key words: ABA -Apex -Cap -DNA -Maize -Meristem -Nuclear behaviour -Nucleic acid -Root.Geosensitivity in roots is lost after removal of the cap (9,17,18,27,28), but is regained after a few hours, which is considered the georecovery time (17,27, 31). It has been assumed that the georecovery time is directly related to the formation of a new root cap (2,12,17). Decapping does indeed stimulate the cells of the quiescent centre to divide to form a new cap (3,13). However, it has been clearly demonstrated that georecovery precedes cap reformation by many hours (3, 4). Consequently, georecovery is not related to regeneration of the cap. During the ageotropic period of the decapped roots, some ultrastructural changes in the cells of the apex have been reported (5-7) and the formation of some amyloplasts has been observed (7). It is quite clear now that the cap imposes quiescence on cells at the pole of the root. As expected, removing the cap stimulates the cells of the quiescent centre and the meristem to grow and divide (3,5). This was also clearly demonstrated by Clowes (11): he cut off the distal half of the cap and, 5 hr later, observed that the average rate of cell division had declined in the cap initials but increased in the quiescent centre and the apex cells.On the other hand, the cap is the source of growth inhibitors (15, 29) which move basipetally (30,41). For horizontally placed roots, downward transport of these inhibiting substances occurs inside the apex (33, 36) and their level is greater in the lower than the upper half of the cap (56", 37, 41, 47). These findings indicate clearly that the cap inhibitors control root geotropism (37,45,48,49). One of these growth regulators could be abscisic acid (ABA), which strongly inhibits root elongation (23,24,26) and seems to have the same effects on root growth as the capinhibiting substances (32)(33)(34)46). Kundu and Audus (19,20) detected the presence of a cap inhibitor, the chromatographic properties of which were similar to those of 1475

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“…When applied to maize roots, ABA usually inhibits elongation (15,23,25). However, recent results show that ABA should not be considered only as a growth inhibitor, at some concentrations it may induce a significant stimulation of maize root elongation (6,9,14,16).…”

Section: Mean Growth Rate and Light Treatmentmentioning

confidence: 99%

“…It is in root caps (4, 21) and in root tips of several maize varieties (18,23). White light seems to increase the ABA level (17,23,25,26) while it inhibits root elongation (3). Coupling the GC-MS and a highly specific and sensitive, negative-chemical ionization method of quantification of ABA (20), it was possible to show the relation between ABA level in maize roots and their growth rate, indicating that the higher the ABA level the lower the growth rate.…”

Section: Mean Growth Rate and Light Treatmentmentioning

confidence: 99%

Endogenous ABA in Growing Maize Roots: Light Effects

Saugy

Mayor²,

Pilet³

1989

Plant Physiol.

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The growth of intact maize (Zea mays L.) roots and the abscisic acid (ABA) content (measured by gas chromatography-mass spectrometry of the root tip were analyzed after a white-light treatment. The decrease of the elongation rate due to the illumination corresponded to a concomitant increase in the ABA found in the root. When selecting roots, on the basis of their growth rate, it was possible to show that the relation between growth and ABA content, previously reported in darkness was conserved after light treatments. Therefore, light decreased the root growth rate while it simultaneously increased the ABA content in the roots. This increase was higher than expected, demonstrating the complexity of the involvement of ABA on root growth.

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Abscisic acid and the response of the roots of Zea mays L. seedlings to gravity

Cited by 45 publications

References 25 publications

Interactions between Red Light, Abscisic Acid, and Calcium in Gravitropism

Interactions between Red Light, Abscisic Acid, and Calcium in Gravitropism

Abscisic acid effect on the DNA microgradients of decapped maize roots

Endogenous ABA in Growing Maize Roots: Light Effects

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