Regulation of cell reproduction in bud meristems of Tradescantia paludosa

1973 ◽  
Vol 51 (6) ◽  
pp. 1137-1145 ◽  
Author(s):  
Kyu-Byung Yun ◽  
J. M. Naylor
Keyword(s):  
Apical Dominance ◽  
Mitotic Cycle ◽  
Plant Cells ◽  
Central Zone ◽  
Apparent Absence ◽  
Cell Reproduction ◽  
Terminal Bud ◽  
Terminal Buds ◽  
Regulation Of Growth ◽  
Tradescantia Paludosa

The mitotic cycle can be arrested in the apical summit of vegetative terminal buds of Tradescantia paludosa by restricting the level of nitrogen or light available to the plant. Cells in this portion of the bud are much more sensitive to these stress conditions than those in the subjacent portion of the meristem. This differential response induced the establishment of a quiescent "central zone" which is distinguished from the rest of the meristem by the apparent absence of mitosis and DNA synthesis, larger nuclear volume, and a lower histone content of chromatin. These features are identical with those imposed by apical dominance in apices of inhibited lateral buds.The results support the view that competition for nutrients is an important causal factor in apical dominance. They suggest also that competition for nutrients within the terminal bud meristem is important in the regulation of growth in vegetative shoots in respones to conditions of the environment.

Studies on the sultana vine. III. Pruning experiments with constant number of buds per vine, number and length of cane varied inversely

1955 ◽  
Vol 6 (6) ◽  
pp. 823 ◽  
Author(s):  
AJ Antcliff ◽  
WJ Webster ◽  
P May
Keyword(s):  
Apical Dominance ◽  
Variable Length ◽  
Bud Burst ◽  
Constant Number ◽  
Terminal Bud ◽  
Bud Position

Pruning experiments are described in which the number of buds per vine was kept constant, and the number and length of canes was varied inversely. The position of the pruning cut affected per cent. bud burst at only the two terminal bud positions, and did not affect per cent. fruitful shoots a t any bud position. For any length of cane likely to be used in practice, per cent. bud burst in the most fruitful region would not be affected. For a constant pruning level there were no significant differences in yield when length of cane was varied from 11 to 18 buds, but in years of high fruitfulness yield was significantly depressed when the canes were 25 buds long. Apical dominance could also be demonstrated on vines with canes of variable length, and it was shown that the inhibiting agent did not move transversely.

Hormonal regulation of growth in cultured plant cells

In Vitro ◽  
1978 ◽  
Vol 14 (1) ◽  
pp. 63-75 ◽  
Author(s):  
D. E. Fosket ◽  
D. A. Tepfer
Keyword(s):  
Hormonal Regulation ◽  
Plant Cells ◽  
Regulation Of Growth

scholarly journals Exogenous Cytokinin Induces “Out of Season” Flowering in Protea cv. Carnival

2009 ◽  
Vol 134 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Eleanor W. Hoffman ◽  
Dirk U. Bellstedt ◽  
Gerard Jacobs
Keyword(s):  
Flowering Time ◽  
Southern Hemisphere ◽  
Shoot Growth ◽  
Xylem Sap ◽  
Development Stage ◽  
Green Point ◽  
Terminal Bud ◽  
Exogenous Cytokinin ◽  
Terminal Buds ◽  
Early Phases

The cytokinin concentration in the xylem sap of Protea L. cv. Carnival (Protea compacta R. Br. × Protea neriifolia R. Br.) shoots was determined at regular intervals from 11 weeks before until 10 weeks after spring budbreak. Cytokinin levels were high during the early phases of spring shoot growth. Benzyladenine (BA) at 50, 250, or 500 mg·L−1 was applied to entire shoots on 22 Feb., 12 Apr., and 22 May 2001 (fall in the southern hemisphere) or only to terminal buds on 22 May 2001 at 500 mg·L−1. Most of the terminal buds sprouted and initiated an inflorescence when BA application at 500 mg·L−1 in May was directed only to terminal buds, whereas lower flowering percentages (0%–35%) were achieved when the entire shoot was treated. After whole shoots were treated with BA in Apr. 2001, between 5% and 45% floral reversion was observed. High flowering percentages of 87% to 93% were recorded when BA was applied at 500 mg·L−1 to the terminal bud in the dormant state or up to the stage when sprouting buds reached the green point development stage. Later applications were less effective, inducing 42% to 43% inflorescence initiation. The flowering time of BA-induced inflorescences was advanced by more than 2 months compared with flowers that initiated naturally on the spring flush.

Seasonal studies of vegetative buds of Helianthus tuberosus: concentration of nuclei in phase G1 during winter dormancy

1981 ◽  
Vol 59 (10) ◽  
pp. 1918-1927 ◽  
Author(s):  
S. S. Tepfer ◽  
Arlette Nougarède ◽  
Pierre Rondet
Keyword(s):  
Mitotic Activity ◽  
Mitotic Index ◽  
Developmental Stages ◽  
Central Zone ◽  
Winter Period ◽  
Helianthus Tuberosus ◽  
Winter Dormancy ◽  
Feulgen Staining ◽  
Vegetative Buds ◽  
Terminal Buds

The following vegetative buds were studied at several developmental stages during the course of the year: from November through February dormant terminal buds of subterranean tubers; in March, newly reactivated buds of young shoots; in June, terminal buds of horizontal underground stolons that will form tubers; and in July, the terminal buds of erect aerial shoots. Microdensitometric studies of DNA levels after Feulgen staining showed that during the winter period of dormancy, from November through February, the temporary arrest of growth and morphogenesis is accompanied by a concentration of nuclei in phase G1 (2C level) of a diploid cycle for all nuclei in the terminal meristems of the tubers. In March, reactivation occurs uniformly throughout the meristem without any zonal differences. The G1 phase remains predominant in the cycle and mitotic activity increases uniformly. In the meristems of young underground stolons, beginning in the month of June, signs of concentration at the 2C level again are perceptible. The nuclei of the apical meristems of erect shoots are also diploid at 2C and 4C. In the very large nuclei in the central zone of the tunica where the mitotic index is very low, the distribution of DNA levels shows that nuclei are present at all phases of the cycle. These results are discussed and compared with other species in temporary dormancy and in regard to the concept of nonpolysomatic species.

Efficiency of night interruption treatments with red and far-red light-emitting diodes (LEDs) in preventing bud set in Norway spruce seedlings

2018 ◽  
Vol 48 (9) ◽  
pp. 1001-1006 ◽  
Author(s):  
Johanna Riikonen
Keyword(s):  
Norway Spruce ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Growth Conditions ◽  
Early Spring ◽  
Light Emitting ◽  
Bud Set ◽  
Terminal Bud ◽  
Natural Photoperiod ◽  
Terminal Buds

Terminal bud set can be prevented by interrupting night with short pulses of light when the natural photoperiod is too short to maintain growth. Norway spruce (Picea abies Karst.) seedlings originating from 61°N and 64°N were grown in growth chambers under conditions that mimic growth conditions in a heated greenhouse in early spring in Finland (experiment 1) or under constant growth conditions (experiment 2). The seedlings were exposed to the following night interruption (NI) treatments using light-emitting diodes (LEDs) that generated red (R, peak at 660 nm) and far-red (FR, peak at 735 nm) wavelengths in 20 s pulses at 15 min intervals: (i) red light alone (R); (ii) R combined with FR (R + FR); and (iii) control (no NI treatment). The R + FR treatment was more effective in preventing terminal bud set than the R treatment. Seedling responses depended on the provenance and growth conditions. The R treatment reduced the proportion of seedlings with terminal buds in the 61°N seedlings and delayed bud set in the 64°N seedlings. The fluctuating growth conditions or longer dark period between the photoperiod and NI treatments reduced the efficiency of the R + FR treatment. A combination of R and FR LEDs with adequate light intensity and duration is suitable for intermittent NI treatment in Norway spruce seedlings.

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative processes in Douglas-fir. III. Effects on anatomy of shoot elongation and terminal bud development

1985 ◽  
Vol 15 (2) ◽  
pp. 354-364 ◽  
Author(s):  
J. N. Owens ◽  
J. E. Webber ◽  
S. D. Ross ◽  
R. P. Pharis
Keyword(s):  
Shoot Elongation ◽  
Douglas Fir ◽  
Apical Growth ◽  
Root Pruning ◽  
Bud Development ◽  
Leaf Initiation ◽  
Terminal Bud ◽  
Terminal Buds ◽  
Effective Cone ◽  
Vegetative Bud

The relative importance of cell division and cell elongation to shoot elongation and the anatomical changes in vegetative terminal apices were assessed for 9- and 10-year-old seedlings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in response to two effective cone-induction treatments, gibberellin A4/7 (GA4/7) and root-pruning (RP). Root-pruning was done in mid-April at the start of vegetative bud swelling and GA treatments were begun at vegetative bud flushing in mid-May and continued until early July. Shoot elongation before flushing resulted primarily from cell divisions and was not affected by the RP treatment. Shoot elongation after flushing resulted primarily from cell expansion which was reduced by RP treatments. Root-pruning significantly slowed mitotic activity, apical growth, and development of vegetative terminal buds from mid-June through mid-July. Apical growth then resumed during leaf initiation and the final number of leaf primordia initiated was not affected. This resulted in a delay of 2 to 4 weeks in the transition from bud-scale to leaf initiation. Retarded terminal vegetative apices anatomically resembled latent axillary apices but were never completely inhibited. GA + RP had the same effect as RP. GA4/7 alone had no effect on shoot or apical development. These results show that RP and GA + RP significantly retard shoot elongation and terminal bud development but still allow normal development of vegetative terminal buds. Retardation of bud development by a few weeks shifts the critical morphogenetic phase of transition from bud scale to leaf initiation to a later time when endogenous and environmental conditions may differ from the normal.

Responses of Norway spruce seedlings to different night interruption treatments in autumn

2016 ◽  
Vol 46 (4) ◽  
pp. 478-484 ◽  
Author(s):  
Johanna Riikonen ◽  
Juha Lappi
Keyword(s):  
Norway Spruce ◽  
Light Emitting Diode ◽  
Late Summer ◽  
Forest Tree ◽  
Additional Increase ◽  
Growth Cessation ◽  
Terminal Bud ◽  
Container Nurseries ◽  
Terminal Buds ◽  
Growth Formation

Photoperiodic lighting can be used in late summer to prevent height growth cessation and terminal bud formation in nurseries growing forest tree species in Nordic countries. To create guidelines for using the method in container nurseries growing Norway spruce (Picea abies (L.) Karst.) and to test the use of light-emitting diode (LED) technology, we exposed first-year, nursery grown seedlings to the following night interruption (NI) treatments from 10 July 2014 onwards (00:00–03:00): (i) no lighting, (ii) 1 min lighting at intervals of 30 min, (iii) 1 min lighting at intervals of 15 min, and (iv) 3 h continuous lighting. Light intensities (LI) of 10, 25, and 70 μmol photosynthetically active radiation (PAR) m−2·s−1 were used. Growth, formation of terminal buds, and winter damage of the seedlings were measured. All NI treatments prevented growth cessation at LI of 25 and 70 μmol PAR·m−2·s−1, but the intermittent treatments were less effective at a LI of 10 μmol PAR·m−2·s−1. The treatments of duration longer than 1 min at intervals of 30 min did not provide any additional increase in shoot growth but predisposed the seedlings to frost injury during autumn and winter. Both seed origins used in this experiment responded similarly to the NI treatments.

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 Investigations on the dormancy of Fraxinus excelsior L. buds. I. Sequence of growth period, correlated inhibition and rest of shoot apex in the annual cycle

2015 ◽  
Vol 42 (4) ◽  
pp. 627-636 ◽  
Author(s):  
L. Witkowska-Żuk ◽  
W. Kozłowska
Keyword(s):  
Growth Period ◽  
Fraxinus Excelsior ◽  
Main Shoot ◽  
Subsequent Period ◽  
Tree Population ◽  
Terminal Bud ◽  
The Mean ◽  
Bud Opening ◽  
Terminal Buds ◽  
The Given

The relation between the period of growth and the subsequent period of correlated inhibition and rest of the terminal bud on the main shoot of the 6-year-old <i>Fraxinus excelsior</i> trees was investigated. From July 21 to August 31, 1971, at ten-day intervals groups of 12 trees, each similar as regards the mean date of bud setting on the main shoot, were defoliated. The data of bud opening after defoliation was considered as index of the depth of dormancy. Statistical analysis demonstrated a rather strong correlation between the number of days after bud setting and the date of their opening after defoliation. The calculated regression curve reached its limit 65.4 days after bud setting, this empirically determining the duration of the period of correlated inhibition of buds of the given tree population. Rest of the terminal buds occurred, therefore, in particular trees at various. times in dependence on the date of bud setting.

Freezing temperatures and exposure times during bud break and shoot elongation influence survival and growth of containerized black spruce (Piceamariana) seedlings

1996 ◽  
Vol 26 (8) ◽  
pp. 1481-1489 ◽  
Author(s):  
Francine J. Bigras ◽  
Carole Hébert
Keyword(s):  
Black Spruce ◽  
Seedling Survival ◽  
Shoot Elongation ◽  
Bud Break ◽  
Significant Damage ◽  
Terminal Bud ◽  
Survival And Growth ◽  
Freezing Temperatures ◽  
Terminal Buds ◽  
Spring Frosts

Spring frosts frequently cause significant damage to conifer seedlings during bud flushing and shoot elongation in forestry nurseries. To insure adequate protection, levels of frost sensitivity must be known during these stages of development. Eight- or 9-month-old containerized black spruce seedlings (Piceamariana (Mill.) BSP) were submitted to freezing temperatures of 0° to −10 °C for 1–6 h at the following stages: (1) nonswollen terminal buds, (2) swollen terminal buds, (3) terminal bud scales bursting, needle tips emerging, and (4) shoots elongating, 1−5 cm. After freezing, seedlings were grown for 130 days in a greenhouse. Seedling survival was estimated; dead seedlings discarded; and damage to buds, needles, and roots as well as diameter and shoot increment were measured on the remaining seedlings. Frost sensitivity increased as buds flushed and new shoots elongated. Decreased seedling and bud survival was noted with increasing time of freezing exposure and decreasing temperature in stages 2, 3, and 4. Damage to needles and roots increases, while diameter decreases, with decreasing temperatures at all stages; however, shoot increment was influenced by decreasing temperatures only at stages 2 and 3.

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