Apical dominance in long shoots of white pine (Pinus strobus)

1970 ◽  
Vol 48 (2) ◽  
pp. 239-253 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Compensatory Growth ◽  
Indoleacetic Acid ◽  
Nutrient Supply ◽  
Shoot Length ◽  
Growth Substances ◽  
White Pine ◽  
Hormone Synthesis ◽  
Auxin Production ◽  
Degree Of Dominance ◽  
Long Shoots

The roles of auxin and nutrition in determining the expression of dominance within a whorl of current shoots were investigated. It was demonstrated that the removal of shoots from a whorl induces compensatory growth in the remaining shoots. Treatments that block auxin movement (triiodobenzoic acid (TIBA), girdling) or decrease auxin production (defoliation, decapitation) also induce compensatory growth, at the same time inhibiting growth in the treated shoot. On the other hand, capping a decapitated and defoliated shoot with indoleacetic acid (IAA) in lanolin maintains diameter growth in the shoot stump and prevents the occurrence of compensatory growth. It is concluded that the shoots in a whorl compete for dominance by competing for a common supply of nutrients transported from the preceding internode. The quantity of nutrients diverted into a shoot, hence growth, is a function of the shoot's capacity to produce growth substances. Hormone synthesis, as well as shoot length, fascicle number, and number of buds in the current whorl are predetermined in the winter bud.The degree of dominance, expressed as the ratio of the sizes of the terminal and the longest lateral in the whorl, depends on the nutrient supply available during the period of winter bud development as well as during the period of shoot expansion.

Compensatory shoot growth in young black birch and red maple trees

1993 ◽  
Vol 23 (2) ◽  
pp. 302-306 ◽  
Author(s):  
Brayton F. Wilson
Keyword(s):  
Compensatory Growth ◽  
Shoot Growth ◽  
Shoot Length ◽  
Red Maple ◽  
Single Treatment ◽  
Frequency Distributions ◽  
Lateral Buds ◽  
Long Shoots ◽  
Short Shoots ◽  
Whole Tree

Black birch (Betulalenta L.) and red maple (Acerrubrum L.) trees 1.5–2 m tall responded by compensatory (increased) shoot growth following a single treatment where shoots on the whole tree were clipped. Total shoot length of clipped trees recovered to control levels after 1 year's growth. The remaining buds on clipped shoots grew more than they would have without clipping. Frequency distributions of shoot lengths shifted toward longer lengths in clipped trees in the 1st year, but were similar to controls 2 years after clipping. The longest shoots were as long, or longer, on clipped shoots as on unclipped shoots. The major compensatory growth mechanism was increased growth of lateral buds. Clipping induced a few preventi-tious buds to form shoots and a few unclipped short shoots to grow as long shoots.

The control of sucker growth in tobacco by growth substances and mineral oils.

1953 ◽  
Vol 4 (4) ◽  
pp. 390
Author(s):  
J Calvert
Keyword(s):  
Growth Regulator ◽  
Indoleacetic Acid ◽  
Maleic Hydrazide ◽  
Growth Substances ◽  
Mineral Oils ◽  
Highly Effective

Indoleacetic acid ranging in concentration from 50 to 10,000 p.p.m. significantly reduced the growth of suckers on plants which had had the apical leaves and inflorescence excised. Five mineral oils significantly reduced the suckering in tobacco grown in the glass-house. Twelve mineral oils tested in north Queensland under conditions similar to commercial growing were all highly effective in reducing sucker growth. As the concentration of indoleacetic acid increased, the epinastic effect on the leaves became more pronounced. The mineral oils did not produce epinasty. No pathological reactions were observed with any of the treatments. Maleic hydrazide was the only growth regulator used in the field that significantly reduced sucker growth.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: V. A PRELIMINARY EXAMINATION OF THE LEVEL OF FREE ENDOGENOUS INDOLEACETIC ACID IN RUSTED AND MILDEWED CEREAL LEAVES AND THEIR ABILITY TO DECARBOXYLATE EXOGENOUSLY SUPPLIED RADIOACTIVE INDOLEACETIC ACID

1958 ◽  
Vol 36 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Michael Shaw ◽  
A. R. Hawkins
Keyword(s):  
Oxidase Activity ◽  
Indoleacetic Acid ◽  
Sharp Decrease ◽  
Inhibiting Activity ◽  
Growth Substances ◽  
Fresh Weight ◽  
Avena Coleoptile ◽  
Preliminary Examination ◽  
Growth Promoting ◽  
Host Parasite

The growth substances were extracted with cold alcohol from the first leaves of uninfected, rusted (wheat), and mildewed (barley) cereal seedlings. The acid ether fractions were chromatographed on paper and the chromatograms were cut into sections which were assayed for growth promoting or inhibiting activity in the Avena coleoptile straight growth test. The estimated, free, endogenous indoleacetic acid content of uninfected leaves ranged from 0.5 to 3.2 μg. per kilogram fresh weight. In the early stages of infection this decreased, but increased again to from 5 to about 10 μg. per kilogram fresh weight by the 10th day after the inoculation of susceptible hosts. Indoleacetic acid was not detected in ungerminated uredospores of stem rust (race 15B), but two other growth promoting substances appeared to be present.Leaf disks were incubated with radioactive indoleacetic acid (as —C14OOK) and the radioactivity released as C14O2 was measured. The ability of the tissue to decarboxylate the indoleacetate (‘oxidase’ activity) increased sharply, sometimes to as much as 1000%, in the first 3 days after inoculation. With susceptible hosts, this increase was followed by an almost equally sharp decrease to less than 50% of the values for uninfected tissue. With infected, resistant tissue, the secondary decrease in ‘oxidase’ activity was delayed and less pronounced.The results are discussed and a working hypothesis suggested with respect to the relation between susceptibility or resistance and the auxin balance.

Crown architecture of Larix laricina saplings: an analysis of higher order branching

1987 ◽  
Vol 65 (2) ◽  
pp. 268-279 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell
Keyword(s):  
Simulation Modelling ◽  
Shoot Length ◽  
Larix Laricina ◽  
Structural Development ◽  
Short Shoot ◽  
Lateral Buds ◽  
Architectural Patterns ◽  
Long Shoots ◽  
Short Shoots ◽  
Terminal Shoot

Quantitative analysis and simulation modelling of Larix laricina (Du Roi) K. Koch branches revealed a complex system of architectural patterns and correlations. Numbers of lateral buds and long shoots were positively correlated with parent-shoot length, but the relationships varied among shoot orders and for sylleptic shoots. For order 2 and sylleptic shoots, numbers of lateral long shoots were also correlated with associated terminal-shoot lengths. Sylleptic shoots produced more lateral long shoots than equivalent proleptic shoots. Lateral long-shoot lengths decreased basipetally and were correlated with terminal-shoot lengths. Lengths of order 2 lateral long shoots also varied independently with crown position. Generally, the degree of apical control decreased and the proportion of short shoots increased with positions of less vigour in the crown. Terminal long-shoot lengths varied with parent-shoot length, location, and to some extent parent-axis leader length. Terminal short-shoot production was associated with shorter parent shoots. Shorter order 2 shoots (<60 mm) and most order 3 shoots produced no lateral long shoots. The net result was that branch structural development ceased in less vigorous crown positions. The spatial disposition of shoots, as defined by elevation and divergence angles, varied with position of origin around and along parent shoots. Although variable, elevation angles decreased and divergence angles increased basipetally.

Long-shoot bud development, shoot growth, and foliage production in provenances of lodgepole pine

1987 ◽  
Vol 17 (11) ◽  
pp. 1421-1433 ◽  
Author(s):  
Conor O'Reilly ◽  
John N. Owens
Keyword(s):  
British Columbia ◽  
Mitotic Activity ◽  
Shoot Growth ◽  
Shoot Length ◽  
Apical Growth ◽  
Axillary Buds ◽  
Provenance Trial ◽  
Bud Development ◽  
Shoot Bud ◽  
Long Shoots

Long-shoot bud development, shoot growth, and foliage production were studied in seven provenances of Pinuscontorta Dougl. ssp. latifolia Engelm. from the major sites in British Columbia and one Yukon source growing in a provenance trial at Prince George, B.C. Branch terminal apical mitotic activity began in early March and continued until late September. Initiation of axillary buds began in May, about 2 weeks after the initiation of the subtending cataphyll. Differentiation of dwarf shoots began in early July to mid-August and continued until late October in some sources. Distal axillary buds had not always differentiated by late October in the southern sources. The duration of the period of apical growth and apical size during activity were related to final cataphyll numbers. Provenances with the widest, flattest, dormant apices produced the most cataphylls. The two northern provenances had more terminal sterile cataphylls but fewer sterile cataphylls lower in the long-shoot bud and shorter mean stem unit lengths than the others. Differences among provenances in shoot length were due mostly to variation in stem unit numbers. The large proportion of polycyclic long shoots in some provenances contributed to variation in dwarf shoot numbers.

scholarly journals Shoot-foliage relationships in deciduous, semideciduous, and evergreen cerrado tree species

2009 ◽  
Vol 21 (1) ◽  
pp. 76-86 ◽  
Author(s):  
João Paulo Souza ◽  
Carlos Henrique B. A. Prado ◽  
Ana Lúcia S. Albino ◽  
Maria A. Damascos
Keyword(s):  
Leaf Area ◽  
Biomass Allocation ◽  
Tree Species ◽  
Shoot Length ◽  
Leaf Number ◽  
Deciduous Tree ◽  
Structural Differentiation ◽  
Evergreen Species ◽  
Leaf Production ◽  
Long Shoots

The morphology and the biomass allocation in shoots and leaves were investigated in 15 cerrado tree species with distinct leaf phenology growing under natural conditions. Higher values of leaf/shoot ratio on mass base, individual leaf area, leaf area per shoot, leaf display index, and leaf number per shoot length were found in deciduous than in evergreen species. The differences about shoot-foliage relationship across leaf phenological groups could be explained by plagiotropic shoots on deciduous and by erect shoots in semideciduous and evergreen species. Plagiotropic shoots allow similar irradiance along shoots and high biomass allocation in favor of leaves without foliage self-shading in deciduous tree species. The structural differentiation between short and long shoots was indicated by an exponential relationship between leaf display index and shoot length in all deciduous, in three semideciduous, and in two evergreen species. Therefore, especially in deciduous, the short shoots had higher leaf area per unit of length than the long shoots. The differentiation between short and long shoots depends on the shoot length in deciduous because of the leaf number on shoot is predetermined in buds. Contrastingly, the leaf neo-formation in semideciduous and in evergreen tree species keeps the shoot-leaf relationship per shoot length more constant, because of the foliage being produced according to the shoot growth during the year. In conclusion, the foliage persistence, the shoot inclination, the type of leaf production and the resources allocation between autotrophic and heterotrophic vegetative canopy parts are interdependent in cerrado tree species across different leaf phenological groups.

Crown architecture of Larix laricina saplings: sylleptic branching on the main stem

1985 ◽  
Vol 63 (7) ◽  
pp. 1296-1302 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell
Keyword(s):  
Growth Increment ◽  
Height Growth ◽  
Shoot Length ◽  
Larix Laricina ◽  
Crown Architecture ◽  
Branching Patterns ◽  
Architectural Model ◽  
Long Shoots ◽  
Lateral Branches ◽  
Architectural Characteristics

Sylleptic branching occurred on the current (1983) height-growth increment in 44% of Larix laricina (Du Roi) K. Koch (tamarack) saplings sampled from a natural population near Fredericton, N.B. Although variable, the occurrence and amount of syllepsis tended to increase with parental shoot length. Sylleptic shoots were generally located on the proximal halves of parental shoots. In most cases, the proximally and distally situated sylleptic shoots were somewhat shorter than those in between. The lengths of terminal shoots arising from sylleptic shoots were significantly correlated with parental shoot length, current tree leader length, and location of the branch on its parental shoot. The lengths and elevation angles of terminal extensions from sylleptic shoots tended to be greater than those from nonsylleptic (proleptic) lateral long shoots borne in the same region of the height-growth increment. Architectural characteristics of the extensions resembled those of the more distal proleptic shoots, which develop into major branches. Thus, an additional complement of major lateral branches appeared to be developing where syllepsis occurred. Quantitative relationships depicting sylleptic branching patterns were incorporated into a previous architectural model and simulations of crown architecture which included syllepsis were obtained.

scholarly journals Willow tree shoot module length and the attack and survival pattern of a shoot-galling sawfly, Euura atra (Hymenoptera: Tenthredinidae)

1997 ◽  
Vol 8 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Peter Price ◽  
Heikki Roininen ◽  
Jorma Tahvanainen
Keyword(s):  
Explanatory Power ◽  
Small Population ◽  
Pattern Generation ◽  
Shoot Length ◽  
Length Class ◽  
Salix Alba ◽  
Ovipositional Preference ◽  
Long Shoots ◽  
Survival Pattern ◽  
The Mean

A small population of the shoot-galling sawfly , Euura atra (Jurine), attacking the willow, Salix alba L. (Salicaceae) in Joensuu, Finland, showed strong preference-performance linkage between female ovipositional choices and survival of progeny. Although shoot lengths on trees were most common in the classes 200-400 mm, the probability of attack increased with shoot length until rare long shoots over 400 mm had a 50-80% probability of attack. The regression of attack probability on shoot length class accounted for 91% of the variance in attack. Attack was significantly greater on longer shoot length classes than that predicted by random attack based on total shoot length available per class, or total number of shoots per class. As shoot length increased the mean number of galls per shoot increased from 0 to 3 per shoot, and establishment and survival of progeny increased from 0 to over 60%. Shoot length class accounted for 70% and 50% of the variance in larval establishment and ultimate survival respectively, while attack by carnivores showed no pattern and had no explanatory power. The results are consistent with those from studies on seven other Euura species showing attack on rapidly growing plants, an ovipositional preference for longer shoots, higher survival on longer shoots, and no detectable effects of carnivores on pattern generation. The study aids in the development of a strong comparative ecology of galling sawflies and the eventual development of empirically based factual theory on their population dynamics.

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