Apical Dominance in Marchantia: Correlative Inhibition of Neighbor Lobe Growth

G. H. Davidonis; M. H. Munroe

doi:10.1086/336631

CORRELATIONS AFFECTING REGENERATION AND REACTIVATION IN SPLACHNUM AMPULLACEUM (L.) HEDW.

Canadian Journal of Botany ◽

10.1139/b59-011 ◽

1959 ◽

Vol 37 (1) ◽

pp. 121-134 ◽

Cited By ~ 16

Author(s):

Ian G. MacQuarrie ◽

Kraft E. von Maltzahn

Keyword(s):

Apical Dominance ◽

Direct Relationship ◽

Indoleacetic Acid ◽

Leaf Size ◽

Primary Factor ◽

Reversible Inhibition ◽

Correlative Inhibition ◽

Stems And Leaves ◽

Phenylbutyric Acid ◽

Stem Segments

Correlations affecting restitutional behavior in the gametophore are examined. In short stem segments a direct relationship is found between the length of the segment and the number of regenerates; in longer segments this relationship disappears. No such correlation exists between leaf size and number of regenerates per leaf. The presence of leaves increases regeneration from the stem; the stem inhibits regeneration from the leaf.Isolation and not wounding is shown to be the most important factor in leaf regeneration.The apex of the gametophore inhibits both regeneration from the base of the gametophore and bud reactivation. These apical dominance effects can be replaced by the application of indoleacetic acid (IAA) to the tips of decapitated plants. Similar concentrations of IAA and γ-phenylbutyric acid (PBA) inhibit regeneration from both isolated stems and leaves; at lower concentrations some promotion is found with IAA, none with PBA. Shorter exposure of leaves to these compounds results in reversible inhibition, or even an increase in regeneration. IAA and PBA do not counteract each other in their effects.Leaves isolated from intact and decapitated plants show differences in regenerative behavior when treated with IAA. This indicates that IAA could be involved in the inhibition or regeneration from attached leaves.It is concluded that IAA is not the primary factor in the control of correlative inhibition of restitution in the gametophore.

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The role of specific plant organs and polar auxin transport in correlative inhibition of leafy spurge (Euphorbia esula) root buds

Canadian Journal of Botany ◽

10.1139/b98-138 ◽

1998 ◽

Vol 76 (7) ◽

pp. 1227-1231 ◽

Cited By ~ 5

Author(s):

David P Horvath

Keyword(s):

Apical Dominance ◽

Auxin Transport ◽

Leafy Spurge ◽

Polar Auxin Transport ◽

Euphorbia Esula ◽

Transport Inhibitor ◽

Correlative Inhibition ◽

Auxin Transport Inhibitor ◽

Bud Growth ◽

Root Buds

Localization of the source of the signal(s) controlling correlative inhibition of leafy spurge root buds (underground adventitious shoot buds located on the lateral roots) was studied by sequential removal of various plant organs. It was determined that full correlative inhibition of root buds was lost only after excision of all aerial tissue from the plant, or after excision of all aerial tissue except the stem. If mature leaves or growing axillary buds (or both) were left intact, no growth of root buds was observed. The synthetic auxin, alpha-NAA, prevented release of apical dominance and subsequent outgrowth of stem and crown buds when applied to the cut end of the stem or crown. Exogenous application of NAA to either the stem or the crown had little effect on root bud growth. Application of the auxin transport inhibitor NPA around the base of the crown had no effect on root bud quiescence. These data are not consistent with the previous studies (Weed Sci. 35: 155-159 (1987)) that indicate a role for auxin in maintenance of correlative inhibition of root bud growth in leafy spurge. The results of auxin transport inhibitor studies presented here suggest that correlative inhibition of root bud growth does not rely on the classic polar auxin transport system.Nomenclature: leafy spurge, Euphorbia esula L. #3 EPHES; NAA, naphthalene acetic acid; NPA, N-1-naphthylphthalamic acid; TIBA, 2,3,5-triiodobenzoic acid.Key words: root buds, apical dominance, auxin, NPA.

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Involvement of auxin in the loss of apical dominance and plant growth potential accompanying aging of potato seed tubers

Canadian Journal of Botany ◽

10.1139/b93-060 ◽

1993 ◽

Vol 71 (4) ◽

pp. 541-550 ◽

Cited By ~ 19

Author(s):

G. N. M. Kumar ◽

N. Richard Knowles

Keyword(s):

Plant Growth ◽

Apical Dominance ◽

Specific Activity ◽

Tissue Concentration ◽

Growth Potential ◽

Potato Seed ◽

Naphthaleneacetic Acid ◽

Seed Tubers ◽

Correlative Inhibition ◽

Aged Seed

Studies were conducted to further characterize a role for auxin in the loss of apical dominance and plant growth potential that occurs during long-term storage of potato (Solanum tuberosum L.) seed tubers. Treatment of single-eye seed cores from 18-month-old seed tubers with 1-naphthaleneacetic acid (NAA) restored apical dominance and increased dry matter partitioning to roots, stems, and leaves, thus partially mitigating the deleterious effects of advanced seed-tuber age on growth potential. Conversely, NAA treatment of seed cores from 6-month-old tubers substantially inhibited plant growth. In contrast to NAA, IAA was totally ineffective at counteracting the deleterious effects of advanced tuber age on plant growth, whereas the effect of IAA on overall growth of plants from 6-month-old seed cores remained slightly inhibitory. The difference in efficacy of these two auxins appears to be related to age-induced differences in ability of tissues to transport and catabolize IAA. The specific activity of IAA oxidase (IAAox) was 4 times higher in tissue from 20-month-old seed tubers at planting and increased at a faster rate during sprouting compared with that from 8-month-old tubers. Hence, the higher potential for oxidation of IAA in tissue from older seed cores is well correlated with the inability of this auxin to alter growth. In translocation studies, etiolated sprouts from aged seed tubers showed a reduced ability to translocate [1-14C]IAA basipetally compared with those from younger tubers. Moreover, intact etiolated sprouts growing from older seed cores decarboxylated the radiolabeled IAA at a much faster rate on a dry weight basis than those from younger seed cores. The specific activities of IAAox and peroxidase in the sprout apex, sprout base, and tuber tissue from 18-month-old seed cores were substantially higher than in similar tissues from 6-month-old seed cores, and tissue concentration of the radiolabel was negatively correlated with IAAox activity. Hence, aging of potato seed tubers not only reduces the ability of sprouts to transport auxin basipetally, but it also increases the capacity for auxin catabolism during sprouting. The physiological consequence of this may be the release of lateral meristems from correlative inhibition, and in effect, reduced apical dominance and shoot growth potential during plant establishment from aged seed tubers. Key words: potato, age-reduced vigor, sprouting, apical dominance, auxin.

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Studies on the growth and development of the rhizome and lateral rhizome buds in Elytrigia repens: some effects of parent shoot excision

Canadian Journal of Botany ◽

10.1139/b98-049 ◽

1998 ◽

Vol 76 (5) ◽

pp. 769-776 ◽

Cited By ~ 2

Author(s):

G I McIntyre ◽

A J Cessna

Keyword(s):

Apical Dominance ◽

Water Pressure ◽

C:N Ratio ◽

Dry Weight ◽

Nitrate Content ◽

Total N ◽

Lateral Buds ◽

Elytrigia Repens ◽

Correlative Inhibition ◽

Rhizome Buds

In experiments conducted under controlled conditions, excision of the shoot of Elytrigia repens (L.) Nevski increased the rate of rhizome elongation and promoted the growth of the lateral rhizome buds. Measurements with a transducer showed that the long-term growth response of the rhizome to shoot excision (4-6 days) was preceded by an immediate but transient (10 min) increase in growth rate. These various responses were associated with the occurrence of guttation from the rhizome apex, increases in the water content of the rhizome apex and lateral buds, and a 62% increase in rhizome water (pressure) potential. Parent shoot excision also induced a transition from rhizome to shoot development at the rhizome apex and caused lateral buds to develop as shoots instead of rhizomes when released from apical dominance. These developmental responses were associated with reductions in the dry weight of the rhizome apex and lateral buds and increases in the total N, amino-N, and nitrate content of the rhizome apex when expressed on a dry weight basis. These results provide evidence that, in E. repens, competition for water by the parent shoot may limit rhizome growth and contribute to the correlative inhibition of the lateral buds. They are also consistent with previous evidence that the C:N ratio may be an important morphogenetic factor in the mechanism controlling the path of bud and rhizome development.Key words: Elytrigia repens, water, nitrogen, rhizome, apical dominance.

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Developmental studies on Euphorbia esula. The influence of the nitrogen supply on the correlative inhibition of root bud activity

Canadian Journal of Botany ◽

10.1139/b72-115 ◽

1972 ◽

Vol 50 (5) ◽

pp. 949-956 ◽

Cited By ~ 16

Author(s):

Gordon I. McIntyre

Keyword(s):

Apical Dominance ◽

Nitrogen Supply ◽

Euphorbia Esula ◽

Nitrogen Level ◽

Developmental Studies ◽

Subsequent Increase ◽

Lateral Buds ◽

Lateral Shoots ◽

Correlative Inhibition ◽

Low Nitrogen

When seedlings of leafy spurge (Euphorbia esula L.) were grown at a low nitrogen level (10.5 ppm) the growth of the lateral buds on the shoot was completely arrested by apical dominance while the buds on the roots, although also inhibited, showed considerably greater activity. At a higher nitrogen level (210 ppm) apical dominance was markedly reduced but the resulting outgrowth of the lateral buds increased the inhibiting capacity of the shoot, limiting root bud response. When the main shoot was decapitated the degree to which root bud growth was suppressed by a given number of lateral shoots was inversely related to the nitrogen supply. Inhibition of the root buds by the lateral shoots could be significantly reduced by growing the plants initially at a low nitrogen level so that growth of the lateral buds was arrested. A subsequent increase in the nitrogen supply strongly promoted the growth of the roots buds, some of which were sufficiently released from inhibition to emerge as leafy shoots.

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The correlative inhibition of bud and shoot growth in flax. Anatomical changes associated with the release of lateral buds from inhibition

Canadian Journal of Botany ◽

10.1139/b74-294 ◽

1974 ◽

Vol 52 (11) ◽

pp. 2269-2275 ◽

Cited By ~ 2

Author(s):

Gordon I. McIntyre ◽

Shirley D. Larmour

Keyword(s):

Apical Dominance ◽

Shoot Growth ◽

Vascular Tissue ◽

Sand Culture ◽

Quiescent Center ◽

Staining Reaction ◽

Linum Usitatissimum L ◽

N Supply ◽

Lateral Buds ◽

Correlative Inhibition

Seedlings of flax (Linum usitatissimum L.) were grown in sand culture under controlled conditions and the bud at node 3 was released from apical dominance by increasing the concentration of N in the nutrient solution. Within 24 h of increasing the N supply the number of mitoses per bud had markedly increased and within 48 h the length of the bud was significantly greater than the controls. A distinctive group of cells (the "quiescent center"), characterized by enlarged nuclei with a reduced Feulgen staining reaction, was present at the apex of all inhibited low-N buds but rapidly disappeared when the buds were released from inhibition. Of the buds examined 48 h after the N supply was increased, about 50% had no xylem in the bud trace; the rest had only a single xylem strand and none had established a connection with the stele of the parent stem. Buds examined after 72 h showed a marked increase in the number of xylem strands, but more than 75% of these buds still lacked a complete xylem connection with the vascular tissue of the parent shoot.These results support the hypothesis that the release of lateral buds from apical dominance is not dependent on the prior strengthening of the xylem connections and that associated changes in vascular tissue development are the consequence rather than the cause of the release of the bud from inhibition.

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