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

1959 ◽  
Vol 37 (1) ◽  
pp. 121-134 ◽  
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.

Ethylene, indoleacetic acid and apical dominance in peas: A reappraisal

1983 ◽  
Vol 59 (3) ◽  
pp. 481-487 ◽  
Author(s):  
Terence J. Blake ◽  
David M. Reid ◽  
Stewart B. Rood
Keyword(s):  
Apical Dominance ◽  
Indoleacetic Acid

Hormonal interaction in controlling apical dominance in soybeans

1971 ◽  
Vol 49 (9) ◽  
pp. 1727-1731 ◽  
Author(s):  
A. Ali ◽  
R. A. Fletcher
Keyword(s):  
Apical Dominance ◽  
Indoleacetic Acid ◽  
Inhibitory Effect ◽  
Benzyl Adenine ◽  
Intact Plants ◽  
Hormonal Interaction ◽  
Meristematic Activity ◽  
Bud Growth ◽  
Soybean Plants ◽  
Cut Surface

Growth of cotyledonary buds in soybean plants is controlled by an interaction between hormones and is dependent on age of the plant and meristematic activity of the buds. Indoleacetic acid (IAA) applied to the cut surface of decapitated 7-day-old plants does not inhibit the growth of buds which are actively undergoing mitosis. Growth is inhibited, however, when IAA is applied in combination with benzyl-adenine(BA) and this inhibitory effect is minimized by gibberellic acid (GA). In 16-day-old plants where mitosis in the buds has ceased IAA alone inhibits bud growth. In both 7- and 16-day-old decapitated plants, application of GA, alone or in combination with BA promotes growth of the buds. Inhibited buds have two peroxidase isoenzymes with pronounced activity. The activity of one of these decreases when the buds are released from dominance. Benzyladenine applied directly to inhibited buds initiates growth in 16-day-old intact plants and this growth is further enhanced when GA is applied 48 h after BA treatment. The enhanced growth by GA is prevented if 5-fluorouracil (5-FU) or 5-fluorodeoxyuridine (5-FDU) are applied before but not after the GA treatment. These results indicate that the hormones have a sequential role in releasing buds from apical dominance.

AXILLARY SHOOT STIMULATION AND PLANT DEVELOPMENT OF COLEUS TREATED WITH CERTAIN PLANT GROWTH REGULATORS

1978 ◽  
Vol 58 (4) ◽  
pp. 971-976 ◽  
Author(s):  
M. KHOSH-KHUI ◽  
I. ROUHANI ◽  
B. SHAYBANY
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Plant Development ◽  
Indoleacetic Acid ◽  
Leaf Size ◽  
The Other ◽  
Axillary Shoot ◽  
Coleus Blumei ◽  
Number Of Branches

N6-benzyladenine (BA), indoleacetic acid (IAA) and 2-choroethylphosphonic acid (ethephon) were applied to pinched and non-pinched plants of four cultivars of coleus (Coleus blumei Benth). All growth regulators increased the number of branches of treated plants, with 800 ppm BA having the most prominent effect. Ethephon treatments dwarfed the plants and decreased leaf size, while BA and IAA enhanced these characters. Plants treated with ethephon developed more leaves in most of the cultivars, as compared with the other two growth regulators. BA-treated plants had lower, and IAA-treated plants had higher, shoot fresh and dry weights than controls.

SOME RESPONSES OF ETIOLATED SEEDLINGS OF PISUM SATIVUM L. TO APPLIED 3-INDOLEACETIC ACID IN RELATION TO APICAL DOMINANCE

1965 ◽  
Vol 43 (1) ◽  
pp. 29-38 ◽  
Author(s):  
I. G. MacQuarrie
Keyword(s):  
Apical Dominance ◽  
Cell Expansion ◽  
Reducing Sugars ◽  
Indoleacetic Acid ◽  
Dry Weight ◽  
Pisum Sativum L ◽  
Pea Seedlings ◽  
Etiolated Seedlings ◽  
Bud Growth ◽  
The Relationship

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.

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

1998 ◽  
Vol 76 (7) ◽  
pp. 1227-1231 ◽  
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.

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

1993 ◽  
Vol 71 (4) ◽  
pp. 541-550 ◽  
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.

Apical Dominance in Marchantia: Correlative Inhibition of Neighbor Lobe Growth

1972 ◽  
Vol 133 (2) ◽  
pp. 177-184 ◽  
Author(s):  
G. H. Davidonis ◽  
M. H. Munroe
Keyword(s):  
Apical Dominance ◽  
Correlative Inhibition

Auxin–cytokinin interaction in the inhibition, release, and morphology of gametophore buds of Plagiomnium cuspidatum from apical dominance

1981 ◽  
Vol 59 (5) ◽  
pp. 750-762 ◽  
Author(s):  
L. P. Nyman ◽  
E. G. Cutter
Keyword(s):  
Apical Dominance ◽  
Nutrient Medium ◽  
Indoleacetic Acid ◽  
Inhibitory Influence ◽  
Intact Control ◽  
Triiodobenzoic Acid ◽  
Apical Bud ◽  
Lateral Buds ◽  
Activation Response ◽  
Bud Morphology

Observations were made on the effects of indoleacetic acid (IAA), kinetin (K), benzyladenine (BA), and triiodobenzoic acid (TIBA) on the lateral buds of decapitated and intact gametophores of Plagiomnium cuspidatum (Hedw.) Kop. Gametophores were cultured in both solid and liquid Parker's nutrient medium and treated with hormones either in solution or in lanolin paste. Based on numbers of activated buds counted from day 16 to 24, it appeared that IAA, K, and BA, when supplied to the decapitated stump, can to varying degrees replace the inhibitory influence of the apical bud. Closer study, however, of activated and inhibited lateral buds suggests that only IAA in the presence of a cytokinin can maintain inhibition in a morphological and anatomical state which is similar to that of intact control plants. Treatment of intact gametophores with TIBA increased bud activation below the treatment ring. Based on bud morphology and anatomical observations in conjunction with records of bud activation response, endogenous auxins and cytokinins appear to be at suboptimal concentrations for growth at inhibited bud sites.

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