Apical dominance in the rhizome of Agropyron repens. Evidence of competition for carbohydrate as a factor in the mechanism of inhibition

1969 ◽  
Vol 47 (7) ◽  
pp. 1189-1197 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Sucrose Solution ◽  
Growth Potential ◽  
High Nitrogen ◽  
Experimental Conditions ◽  
Lateral Buds ◽  
Mechanism Of Inhibition ◽  
Lateral Bud ◽  
High Nitrogen Level ◽  
Agropyron Repens

When plants of Agropyron repens L. Beauv. are grown at a high nitrogen level (210 p.p.m. N) apical dominance in the rhizome is sufficiently reduced to permit the continued growth of the lateral buds. If, however, the rhizome is isolated from the parent shoot the dominance of the apex is markedly increased and lateral bud growth is strongly inhibited.Experiments with these isolated, high-nitrogen rhizomes showed that apical dominance could be significantly reduced either by increasing the length of the rhizome or by retarding the growth of the rhizome apex by exposing it to light. The growth potential of the lateral buds declined rapidly as the duration of their attachment to the rhizome apex was increased. This effect was associated with the translocation of carbohydrate to the rhizome apex and could be overcome by providing the isolated buds with a 2% sucrose solution. When buds were isolated from the rhizome apex before their growth potential was exhausted a marked increase in their carbohydrate content was apparent after 48 h. This increase was associated with their resumption of growth. Buds still attached to the apex could be released from inhibition by supplying sucrose solutions to the cut end of the rhizome.The results suggest that, under the experimental conditions, apical dominance was due primarily to competition for a limited carbohydrate supply.

Apical dominance in the rhizome of Agropyron repens. Some factors affecting the degree of dominance in isolated rhizomes

1971 ◽  
Vol 49 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Soluble Nitrogen ◽  
Small Reduction ◽  
High Nitrogen ◽  
Factors Affecting ◽  
Lateral Buds ◽  
Degree Of Dominance ◽  
High Nitrogen Level ◽  
Low Nitrogen ◽  
Agropyron Repens

A study of apical dominance in isolated rhizomes of Agropyron repens L. Beauv. showed that increasing the length of the rhizome significantly reduced the degree of dominance only in rhizomes from plants grown at a high nitrogen level (210 ppm). Exposing the rhizomes to light also reduced dominance more effectively in high-nitrogen rhizomes but the response of rhizomes from low-nitrogen plants was greatly increased by supplying water through the end of the rhizome. Further experiments with low-nitrogen rhizomes showed that buds could be released from apical dominance by treatment with kinetin. When isolated from the plant the buds showed a significant increase in length after 24 h and an associated increase in moisture and insoluble nitrogen content. Soluble nitrogen and carbohydrate increased concurrently during the next 24 h. Rhizomes kept in darkness showed a small reduction of bud inhibition when water was supplied through the cut end; NH4NO3 solution had a greater effect, while solutions in which both nitrogen and carbohydrate (as sucrose) were supplied resulted in the almost complete elimination of apical dominance.The results suggest that apical dominance in isolated, low-nitrogen rhizomes was due mainly to competition between the apex and the lateral buds for water, nitrogen, and carbohydrate.

Studies on the growth and development of Agropyron repens: interacting effects of humidity, calcium, and nitrogen on growth of the rhizome apex and lateral buds

1987 ◽  
Vol 65 (7) ◽  
pp. 1427-1432 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Water Status ◽  
Dry Weight ◽  
Apical Growth ◽  
High Humidity ◽  
N Supply ◽  
Lateral Buds ◽  
Low Humidity ◽  
Bud Growth ◽  
Agropyron Repens

A previous investigation of apical dominance in the rhizome of Agropyron repens showed that keeping the rhizome in a high humidity promoted the outgrowth of the lateral buds but strongly inhibited the growth of the rhizome apex. A study of these related responses demonstrated that the inhibition of apical growth was not prevented by excision of the lateral buds and was also induced when only the apex of the rhizome received the high humidity treatment. The necrotic lesions that developed in the arrested apices and the reduction of apical inhibition produced by various Ca treatments indicated that the inhibition of apical growth was caused by Ca deficiency. When the rhizome apex was exposed to low humidity, a localized high-humidity treatment of the lateral buds did not release the buds from apical dominance in low-N rhizomes but strongly promoted bud growth at a higher N level. When growth of the buds was induced at low humidity by increasing the N supply, the increase in bud weight was preceded by an increase in the water content of the bud when expressed on a dry weight basis. These results agree with those of previous investigations and suggest that the interacting effects of N and humidity on the water status of the buds may play a significant role in the mechanism of apical dominance.

Lateral bud growth on excised stem segments: effect of the stem

1975 ◽  
Vol 53 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Carol A. Peterson ◽  
R. A. Fletcher
Keyword(s):  
Sucrose Solution ◽  
Apical Part ◽  
Endogenous Auxin ◽  
Cell Divisions ◽  
Cotyledonary Nodes ◽  
Lateral Buds ◽  
Lateral Bud ◽  
Bud Growth ◽  
Soybean Plants ◽  
Stem Segments

Lateral buds at the cotyledonary nodes of soybean plants grown under the conditions used in this study usually remain inhibited. These buds grow when the apical part of the plant is removed. They will grow, but less strongly, when the roots as well as the apex of the plant are removed and the basal end of the cut stem is placed in a mineral salt solution. Bud growth is further diminished by decreasing the length of stem left attached to the bud. The cotyledon is essential for bud growth on plant segments maintained in nutrient solution, but it can be replaced by a 1% sucrose solution during the early days of bud growth. Buds which are completely detached from the stem and placed in 1% sucrose do not elongate, but a small number of cell divisions are detectable, indicating that the early events of the release from inhibition have occurred. Buds elongate when they are apically or centrally located on stem segments. Increasing the length of the attached stem segments increases the growth of the buds. Additions of the cytokinin benzyladenine to plants causes a dramatic increase in bud growth when buds are attached to stem segments but does not stimulate growth of buds without stem segments. It is concluded that benzyladenine alone will not substitute for a factor(s) present in the stem which is necessary for bud growth. Increasing stem lengths above buds located at the basal ends of segments inhibits bud growth. It is suggested that this may be due to an accumulation of endogenous auxin at the site of the buds.

scholarly journals 760 PB 184 INDOLE-3-ACETIC ACID REGULATES APICAL DOMINANCE BY CONTROLLING THE STATE OF WATER AND MEMBRANE LIPID COMPOSITION IN BUDS OF MALUS DOMESTICA BORKH

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 541h-542
Author(s):  
Shiow Y. Wang ◽  
Miklos Faust ◽  
Michael J. Line
Keyword(s):  
Acetic Acid ◽  
Lipid Composition ◽  
Apical Dominance ◽  
Membrane Lipid ◽  
Proton Density ◽  
Membrane Lipid Composition ◽  
Lateral Buds ◽  
Terminal Bud ◽  
Lateral Bud ◽  
Indole 3 Acetic Acid

The effect of Indole-3-acetic acid (IAA) on apical dominance in apple (Malus domestica Borkh.) buds was examined by studying 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 bud paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed. Delaying this application weakens the effect of IAA. An increase in proton density in lateral buds was observable 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Decapitating the terminal bud induced an increase in membrane galacto- and phospholipids. and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also induced a decrease in the ratio of free sterols to phospholipids in lateral buds. Application of IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in the membrane lipid composition of lateral buds.

scholarly journals Molecular mechanism of lateral bud differentiation of Pinus massoniana based on high-throughput sequencing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hu Chen ◽  
Jianhui Tan ◽  
Xingxing Liang ◽  
Shengsen Tang ◽  
Jie Jia ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Apical Dominance ◽  
High Throughput Sequencing ◽  
Pinus Massoniana ◽  
Side Branch ◽  
Gene Set Enrichment Analysis ◽  
Molecular Characteristics ◽  
Bud Development ◽  
Lateral Buds ◽  
Lateral Bud

AbstractKnot-free timber cultivation is an important goal of forest breeding, and lateral shoots affect yield and stem shape of tree. The purpose of this study was to analyze the molecular mechanism of lateral bud development by removing the apical dominance of Pinus massoniana young seedlings through transcriptome sequencing and identify key genes involved in lateral bud development. We analyzed hormone contents and transcriptome data for removal of apical dominant of lateral buds as well as apical and lateral buds of normal development ones. Data were analyzed using an comprehensive approach of pathway- and gene-set enrichment analysis, Mapman visualization tool, and gene expression analysis. Our results showed that the contents of auxin (IAA), Zea and strigolactone (SL) in lateral buds significantly increased after removal of apical dominance, while abscisic acid (ABA) decreased. Gibberellin (GA) metabolism, cytokinin (CK), jasmonic acid, zeatin pathway-related genes positively regulated lateral bud development, ABA metabolism-related genes basically negatively regulated lateral bud differentiation, auxin, ethylene, SLs were positive and negative regulation, while only A small number of genes of SA and BRASSINOSTEROID, such as TGA and TCH4, were involved in lateral bud development. In addition, it was speculated that transcription factors such as WRKY, TCP, MYB, HSP, AuxIAA, and AP2 played important roles in the development of lateral buds. In summary, our results provided a better understanding of lateral bud differentiation and lateral shoot formation of P. massoniana from transcriptome level. It provided a basis for molecular characteristics of side branch formation of other timber forests, and contributed to knot-free breeding of forest trees.

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

1994 ◽  
Vol 119 (6) ◽  
pp. 1215-1221 ◽  
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.

ENVIRONMENTAL CONTROL OF BUD AND RHIZOME DEVELOPMENT IN THE SEEDLING OF AGROPYRON REPENS L. BEAUV.

1967 ◽  
Vol 45 (8) ◽  
pp. 1315-1326 ◽  
Author(s):  
G. I. McIntyre
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Environmental Control ◽  
Nitrogen Supply ◽  
High Nitrogen ◽  
Bud Development ◽  
High Nitrogen Level ◽  
Terminal Shoot ◽  
Rhizome Development ◽  
Agropyron Repens

The effects of various environmental conditions on bud development in seedlings of Agropyron repens L. Beauv. were investigated. The bud in the axil of leaf 1 was the most responsive. At a high nitrogen level (315 p.p.m.) most of the buds at this position developed as tillers, and at a low level (2.1 p.p.m.) as rhizomes. A transition from rhizome to shoot development was induced by increasing the nitrogen supply after the rhizomes were initiated. Temperature had a similar effect, tillers being produced at a high (day) temperature (27 °C) and rhizomes at a low temperature (10 °C). Reducing the daylength from 18 to 9 h strongly promoted tillering and almost completely prevented rhizome development. A reduction of light intensity from 4000 to 2000 ft-c did not affect bud development but appeared to increase the tendency for rhizomes to form a terminal shoot. Similar effects were shown by the buds at the coleoptile and leaf 2 positions but the inherent tendency for the former to develop as rhizomes and the latter as tillers limited their response.There was some evidence from these results that bud and rhizome development is controlled by a similar mechanism and that the carbohydrate level may be an important factor in determining the inherent pattern of bud development.

Apical dominance in the rhizome of Agropyron repens: the influence of water stress on bud activity

1976 ◽  
Vol 54 (23) ◽  
pp. 2747-2754 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Apical Dominance ◽  
High Humidity ◽  
Apparent Increase ◽  
N Level ◽  
Lateral Buds ◽  
Influence Of Water ◽  
N Requirement ◽  
Agropyron Repens

Experiments conducted under both field and growth-chamber conditions showed that buds on the rhizome of Agropyron repens L. Beauv. could be released from inhibition by a localized reduction of water stress, e.g. by enclosing the rhizomes in moist vermiculite. This response was obtained even at low N levels, a fact which may be due partly to the relatively low N requirement of buds developing as rhizomes as compared with those developing as shoots. The induced growth of the lateral buds was correlated with a reduction or complete inhibition of apical growth of the parent rhizome or with its transition from rhizome to shoot development. Continuous root removal reduced the bud response to high humidity in N-deficient plants but had relatively little effect at a higher N level. In water-stressed rhizomes the apparent increase of bud inhibition with distance from the apex, a characteristic feature of apical dominance, was correlated with the water content of the rhizome, which was greatest at the apex and decreased basipetally. It is postulated that this gradient of decreasing rhizome water content may be causally related to the increasing inhibition of bud activity.

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

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.

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