Meristematic Activity during Adventitious Root Primordium Development

Haissig, Bruce E.

doi:10.1104/pp.49.6.886

Cited by 78 publications

(37 citation statements)

References 23 publications

(30 reference statements)

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“…However, it appears that sugar content was higher in IBA treatment than in other treatments throughout the process, suggesting that free sugar content might be associated with root formation. This is consistent with the findings of many researchers (see review by Haissig 1974).…”

Section: Fresh Weight and Soluble Sugar Changessupporting

confidence: 93%

Starch Accumulation Is Associated with Adventitious Root Formation in Hypocotyl Cuttings of Pinus radiata

Leung

2000

J Plant Growth Regul

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This study of the internal physiology of adventitious root formation in Pinus radiata was performed without the potential complications from microbial contamination and nutritional stress. Hypocotyl cuttings of radiata pine were cultured in half strength MS nutrient medium supplemented with IBA (indole-3-butyric acid), IBA + kinetin, kinetin, or without phytohormones (control). Averages of 8.35 and 0.08 roots per cutting were formed in IBA and in growth regulator-free treatments, respectively. No roots were formed in IBA + kinetin, kinetin, or sucrose-free treatments at day 30 after excision of hypocotyls. Changes in fresh weight, sugar, and starch content were measured at established developmental stages associated with adventitious root formation. Sucrose-supplemented medium was required for higher levels of sugar, starch, and root formation in rooting region of IBA-treated hypocotyls. Starch accumulation, in particular, seems to have potential as a biochemical marker before root primordium emergence in light of the following observations in the IBA treatment. Starch began to build up preferentially in cells involved in or in close proximity to potential sites of new root primordium formation (that is, the cells on the inside of the cortex and the pith) before any visible organized root primordia and then began to disappear during root primordium formation. The substantial starch accumulation associated with IBA treatment was not observed in the IBA + kinetin, kinetin alone, growth regulator-free, sucrose-free treatments (nonrooting treatments) or in the nonrooting region of hypocotyls treated with IBA.

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Section: Fresh Weight and Soluble Sugar Changessupporting

confidence: 93%

Starch Accumulation Is Associated with Adventitious Root Formation in Hypocotyl Cuttings of Pinus radiata

Leung

2000

J Plant Growth Regul

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“…It has been demonstrated here that a localized application of either of these chemicals to the epicotyl can inhibit root formation in the hypocotyl below, as well as inhibiting transport of [^^C]IAA from leaves to hypocotyl. These observations are consistent with the proposition that the natural regeneration of roots is dependent on an uninterrupted flow of auxin until primordia have formed (Haissig, 1970(Haissig, , 1972Mohammed & Eriksen, 1974).…”

Section: Resultssupporting

confidence: 80%

Adventitious Root Formation in Relation to the Uptake and Distribution of Supplied Auxin

Jarvis

Shaheed

1986

New Phytologist

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SUMMARYTriiodobenzoic acid (TIBA) or morphactin (chlorfluorenol), applied to the base of the epicotyl of mung bean cuttings, inhibit root formation in the hypocotyl. Such inhibition occurs even when cuttings are supplied with auxin at the same time. Both treatments reduce the accumulation of radioactivity in the hypocotyl when [i*C]IAA is supplied to the primary leaves. Morphactin does not influence the uptake of [i^CJIAA supplied basally to cuttings, nor does it have any apparent influence on the distribution of radioactivity within the cutting. However, the extent to which [i*C]IAA moves from leaves to hypocotyl is influenced by the basal supply of auxin in which cuttings are placed. These observations are discussed in terms of the role of the leaves in auxin-induced adventitious root formation.

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“…There are secondary root development mutants that have either elevated levels of auxin (Boerjan et al, 1995;King et al, 1995) or can be rescued by an exogenous supply of auxin (Celenza et al, 1995). Haissig (1972) demonstrated that both the level of endogenous auxin and applied GA 3 influence the number of cells in developing nodal root primordia of brittle willow. However, the lack of a response to the addition of IAA or indole to nodal explants suggests that the Mortal mutation is not due to a defect in auxin biosynthesis.…”

Section: Discussionmentioning

confidence: 99%

Mortal: A Mutant of White Clover Defective in Nodal Root Development

1998

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A monogenic dominant mutant of white clover (Trifolium repens L.), designated Mortal, which is defective in the formation of adventitious nodal roots, is described. Mortal plants grown at temperatures ranging from 10 to 25°C do not initiate nodal root primordium development. However, all other aspects of plant development are normal, including the formation of lateral roots and wound-induced adventitious roots. In some genetic backgrounds, the Mortal mutation has a temperature-sensitive conditional phenotype. Mortal plants shifted from growing conditions of 20 to 30°C for 2 to 3 d form nodal root meristems. However, new nodes that develop after plants are returned to 20°C exhibit the mutant phenotype. The capacity to form nodal roots on cuttings placed in water is also influenced by the genetic background of the Mortal mutation. Genetic analysis established that the physiological reversion of Mortal to nodal root formation is controlled by at least two separate dominant genetic loci, one for Nodal water response (Now) and one for Nodal temperature response (Not); the Now locus has a dominant epistatic interaction with the Not locus. The conditional nature of Mortal should provide opportunities for the identification of genetic and physiological mechanisms that influence the development of nodal roots.Whereas the basic structure of angiosperms is established during embryogenesis, most organs are formed by postembryonic development (Esau, 1977). Generally, all of the shoot structures (leaves, nodes, internodes, axillary shoot meristems, and flowers) are derived from the primary shoot apical meristem. However, adventitious shootborne roots are an exception because they develop endogenously from differentiated parenchyma cells close to the vascular tissues (Lovell and White, 1986).Little is known about the genes that control adventitious shoot-borne root morphogenesis, despite their importance for anchorage, nutrient acquisition, and water uptake from the soil in a wide range of plant species. One approach to understanding the genetic mechanisms that underlie adventitious root initiation and development is to identify and characterize mutants altered in the process. At present, few mutants with defects in adventitious root development are known (Schiefelbein and Benfey, 1991). There are mutants of tomato that produce few or no adventitious roots (Butler, 1954;Zobel, 1991) and mutants of maize that are defective in the formation of lateral seminal roots, crown roots, or both lateral seminal and crown roots (Jenkins, 1930; de Miranda, 1980;Hetz et al., 1996).The general unpredictability in the formation of secondary roots on shoots complicates the analysis of the genetic and molecular mechanisms controlling adventitious root development. This can be minimized by characterizing the genetic control of the formation of adventitious nodal root primordia. In some plant species, adventitious root primordia arise in a precise and ordered manner during node development. One such example is the nodal roots that form on the pro...

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Meristematic Activity during Adventitious Root Primordium Development

Cited by 78 publications

References 23 publications

Starch Accumulation Is Associated with Adventitious Root Formation in Hypocotyl Cuttings of Pinus radiata

Starch Accumulation Is Associated with Adventitious Root Formation in Hypocotyl Cuttings of Pinus radiata

Adventitious Root Formation in Relation to the Uptake and Distribution of Supplied Auxin

Mortal: A Mutant of White Clover Defective in Nodal Root Development

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