Isolation and identification of lateral bud growth inhibitor, indole-3-aldehyde, involved in apical dominance of pea seedlings

Effects of decapitation and treatment with indoleacetic acid (IAA) were studied in etiolated pea seedlings. The relationship between epicotyl swelling and bud growth inhibition was examined and found to be incomplete: concentrations of IAA which totally inhibit bud growth induce marked epicotyl swelling, but a lower concentration (5 p.p.m.) was shown to induce swelling without affecting bud growth. Swelling is a result of a change in polarity of cell expansion; the time of this change was unaffected by increasing the IAA concentration. Large increases in fresh and dry weight accompany the swelling.In mature (non-swelling) epicotyls treated with IAA, this substance tends to prevent the loss of reducing sugars brought about by decapitation. It is suggested that decapitation and IAA application affect the nutritional status of the epicotyl, and that this effect must be considered in constructing hypotheses dealing with apical dominance.

Download Full-text

Apical Dominance in Apple (Malus domestica Borkh): The Possible Role of Indole-3-Acetic Acid (IAA)

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.119.6.1215 ◽

1994 ◽

Vol 119 (6) ◽

pp. 1215-1221 ◽

Cited By ~ 11

Author(s):

Shiow Y. Wang ◽

Miklos Faust ◽

Michael J. Line

Keyword(s):

Lipid Composition ◽

Apical Dominance ◽

Saturated Fatty Acids ◽

Membrane Lipid ◽

Proton Density ◽

Membrane Lipid Composition ◽

Lateral Buds ◽

Terminal Bud ◽

Lateral Bud ◽

Bud Growth

The effect of IAA on apical dominance in apple buds was examined in relation to changes in proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral buds and maintained paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed; delaying application reduced the effect of IAA. An increase in proton density in lateral buds was observed 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Removing the terminal bud increased membrane galacto- and phospholipids and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also decreased the ratio of free sterols to phospholipids in lateral buds. Applying thidiazuron to lateral buds of decapitated shoots enhanced these effects, whereas applying IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in membrane lipid composition in lateral buds. These results suggest that change in water movement alters membrane lipid composition and then induces lateral bud growth. IAA, presumably produced by the terminal bud, restricts the movement of water to lateral buds and inhibits their growth in apple.

Download Full-text

Environmental control of lateral bud growth in the sunflower (Helianthus annuus)

Canadian Journal of Botany ◽

10.1139/b77-305 ◽

1977 ◽

Vol 55 (21) ◽

pp. 2673-2678 ◽

Cited By ~ 6

Author(s):

Gordon I. McIntyre

Keyword(s):

Water Stress ◽

Helianthus Annuus ◽

Apical Dominance ◽

Environmental Control ◽

High Light Intensity ◽

Nutrient Competition ◽

N Supply ◽

Lateral Bud ◽

Bud Growth ◽

Lateral Branches

A study of environmental effects on lateral bud growth in the sunflower, Helianthus annuus, showed that the provision of a high relative humidity (90 ± 5%) in conjunction with a high light intensity (about 30 000 lx) and an abundant N supply (420 ppm) permitted the buds at the basal nodes to escape from apical dominance and to develop as lateral branches. A reduction in any one of these three factors was sufficient to prevent the release of the buds from inhibition. The marked effect of humidity on bud growth suggested that the degree of water stress is the factor most likely to limit the growth of the lateral buds under field conditions. The mode of action of water stress and the N supply is discussed in relation to the genetic control of bud activity and to the role of nutrient competition in the mechanism of apical dominance.

Download Full-text

Genetics of Apical Dominance in Plantain (Musa spp., AAB Group) and Improvement of Suckering Behavior

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.119.5.1050 ◽

1994 ◽

Vol 119 (5) ◽

pp. 1050-1053 ◽

Cited By ~ 30

Author(s):

Rodomiro Ortiz ◽

Dirk R. Vuylsteke

Keyword(s):

Apical Dominance ◽

Recurrent Selection ◽

Recessive Gene ◽

Limiting Factor ◽

Incomplete Penetrance ◽

Vegetative Development ◽

Ratoon Crop ◽

Terminal Bud ◽

Lateral Bud ◽

Bud Growth

Apical dominance, i.e., the inhibition of lateral bud growth due to growth substances released by the terminal bud, has been considered as a limiting factor for the perennial productivity of plantains (Musa spp., AAB group). Segregation ratios in F1 and F2 plantain-banana hybrids suggest that inheritance of apical dominance is controlled by a major recessive gene, ad. The dominant Ad allele improved the suckering of plantain-banana hybrids, as measured by the height of the tallest sucker at flowering and harvest. At harvest, the ratoon crop of the diploid and tetraploid hybrids had completed 70% to 100% of its vegetative development, whereas the ratoon of the plantain parents, due to high apical dominance, was only at 50% of total pseudostem growth. Sucker growth rates are generally the result of gibberellic acid (GA3) levels, and it is suggested that the Ad gene regulates GA3 production. However, the Ad gene has incomplete penetrance, genetic specificity, and variable expressivity. Increased frequency of the Ad gene and a commensurate improvement in the suckering behavior of the diploid populations may be achieved by phenotypic recurrent selection.

Download Full-text

Penicillin inhibition of release of lateral buds of gram (Cicer arietinum) seedlings from apical dominance

Canadian Journal of Botany ◽

10.1139/b84-326 ◽

1984 ◽

Vol 62 (11) ◽

pp. 2391-2393

Author(s):

Monidipa Sen ◽

Subires Bhattacharya ◽

S. Mukherji

Keyword(s):

Cicer Arietinum ◽

Mode Of Action ◽

Apical Dominance ◽

Maleic Hydrazide ◽

Simultaneous Application ◽

Auxin Action ◽

Cicer Arietinum L ◽

Lateral Buds ◽

Lateral Bud ◽

Bud Growth

The effect of penicillin on apical dominance was investigated in gram (Cicer arietinum L.) seedlings. Application of penicillin to the decapitated stump was found to reestablish apical dominance in preventing the growth of lateral buds. Penicillin was seen to mimic auxin action in this system. Penicillin inhibition of lateral bud growth was relieved by the simultaneous application of antiauxins like 2,3,5-triiodobenzoic acid and maleic hydrazide. An increase in auxin-synthesizing capacity of the treated tissue has been suggested as the possible mode of action of penicillin in the regulation of lateral bud growth.

Download Full-text