Roles of Hormones, Protons and Calcium in Geotropism

Pickard, Barbara G.

doi:10.1007/978-3-642-67734-2_8

Cited by 37 publications

(49 citation statements)

References 243 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, GAs are not the only hormone thought to be involved in gravitropism. The differential movement and metabolism of IAA with gravistimulation has also been well-documented for grass shoots, including maize (1,2,20). Gravistimulation also results in the differential movement gravitropic upturning (9,17) and the general theory that GA, controls shoot elongation in maize (19) are consistent with a regulatory role for GAs in elongation growth following gravistimulation.…”

mentioning

confidence: 62%

“…While the involvement of IAA in the response of maize and other plants is now well established (1,2,9,20), the possible involvement of GAs3 is less well documented. It is known, however, that the application of GA3 or GA4/7 will accelerate shoot upturning in grasses (9,17), and upturning of lateral branches of decapitated or intact conifers (see references cited in Pickard [20]), and further, that differential localization of GAlike substances occurs between the upper and lower halves of gravistimulated shoots of oats, sunflower and maize (17,18,21).…”

mentioning

confidence: 99%

“…Although studies are usually conducted under greenhouse or growth chamber conditions where temperature gradients are minimized, the presentation of light is still directional. Consequently, phototropic responses may confound the study of gravitropism (20). Further, the presence of a bench below the plant, as well as the pot in which the plant is growing, introduce additional physical differences experienced by the upper and lower halves of the shoot.…”

mentioning

confidence: 99%

“…4). Upper halves contained a large peak of GA-like activity at the Rt of GA20 (SiC)2 partition column fractions 3-8) and relatively small peaks of GA1-and GA19-like activity (SiC)2 partition column fractions [15][16][17][18][19][20][21][22]. In contrast, lower halves contained much lower levels of bioactivity at the Rt of GA20 and higher levels of activity in the more polar regions (Table IV, Fig.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Gibberellins and Gravitropism in Maize Shoots

Rood

Kaufman²,

Abe³

et al. 1987

Plant Physiol.

View full text Add to dashboard Cite

PHjGibberellin A20 (GA2o) of high specific radioactivity (49.9 gigabecquerel per millimole) was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old gravistimulated and vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la PHIGA2o feed, there was a significantly higher proportion of total radioactivity in lower than in upper halves of internode and leaf sheath pulvini in gravistimulated normal maize. Further, there was a significantly higher proportion of putative free GA metabolites of [HJGA2., especially 1H1 GA1, in the lower halves of normal maize relative to upper halves. The differential localization of the metabolites between upper and lower halves was not apparent in the pleiogravitropic mutant, la. Endogenous GA-like substances were also examined in gravistimulated maize shoots. Fortyeight hours after gravistimulation of 3-week-old maize seedlings, endogenous free GA-like substances in upper and lower leaf sheath and internode pulvini halves were extracted, chromatographed, and bioassayed using the 'Tanginbozu' dwarf rice microdrop assay. Lower halves contained consistently higher total levels of GA-like activity. The qualitative elution profile of GA-like substances differed consistently, upper halves containing principally a GA2o-like substance and lower halves containing mainly GA,-like and GA,9-like substances. Gibberellins A, (10 nanograms per gram) and A2. (5 nanograms per gram) were identified from these lower leaf sheath pulvini by capillary gas chromatographyselected ion monitoring. Results from all of these experiments are consistent with a role for GAs in the differential shoot growth that follows gravitropism, although the results do not eliminate the possibility that the redistribution of GAs results from the gravitropic response.

show abstract

mentioning

confidence: 62%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Gibberellins and Gravitropism in Maize Shoots

Rood

Kaufman²,

Abe³

et al. 1987

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Most studies deal with herbaceous species, and even for them experimental work and reviews have generally been confined to geotropism of the seedling radicle. The direction sensing apparatus lies in the root cap (Wilkins, 1975 (Raper and Barber, 1970), possibly in response to drought or high temperature (Mitchell and Russell, 1971 (Juniper, 1976;Firn and Digby, 1980;Jackson and Barlow, 1981;Pickard, 1985) and the mechanism will not be discussed further here.…”

Section: Introductionmentioning

confidence: 99%