Timing of defoliation and its effect on bud development, starch reserves, and sap sugar concentration in sugar maple

1986 ◽  
Vol 16 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Robert A. Gregory ◽  
Philip M. Wargo
Keyword(s):  
Sugar Maple ◽  
Shoot Growth ◽  
Sugar Concentration ◽  
Starch Concentration ◽  
Bud Development ◽  
Late Season ◽  
Terminal Bud ◽  
Terminal Shoot ◽  
Terminal Buds ◽  
And Control

Sapling sugar maple (Acersaccharum Marsh.) trees were defoliated artificially at 10-day intervals beginning May 27 and ending August 5, 1981. Refoliation, terminal bud and shoot development, and xylem starch and sap sugar concentration were observed in defoliated and control trees. All defoliated trees refoliated, but decreasingly with later defoliation. Defoliation caused an acceleration in the rate of primordia initiation in terminal shoot apices. After early season defoliations, the developing buds in the axils of the removed leaves abscissed, but axillary and terminal buds on the refoliated terminal shoots survived through winter. In late season defoliation, most buds of refoliated shoots did not survive and the next year's growth depended on axillary buds formed prior to defoliation. Thus, when progressing from early to late defoliations, the next year's shoot growth depended decreasingly on the last-formed and increasingly on the first-formed portions of the previous year's shoot. Early October starch concentration in xylem decreased with later defoliation and was nearly absent in shoots and roots of trees defoliated in late July. There was not, however, a corresponding decrease in sap sugar concentration. Mortality occurred only in late defoliated trees and was associated with starch depletion.

Long shoot terminal bud development and the differentiation of pollen- and seed-cone buds in Pinuscaribaea var. hondurensis

1992 ◽  
Vol 22 (11) ◽  
pp. 1656-1668 ◽  
Author(s):  
Derek L.S. Harrison ◽  
Mike U. Slee
Keyword(s):  
Growth Pattern ◽  
Shoot Growth ◽  
Bud Development ◽  
Late Flowering ◽  
Seed Cone ◽  
Terminal Bud ◽  
Caribbean Pine ◽  
Terminal Buds

Bud type differentiation and development were investigated in early and late flowering grafted clones of Pinuscaribaea Morelet var. hondurensis Barr. & Golf. (Caribbean pine) growing at two sites in the tropical north of Australia. Regardless of the early and late flowering tendencies, pollen- and seed-cone buds began to differentiate in middle and late March, respectively. Unlike the cone buds of temperate pines, there was no apparent pause in development between pollination and differentiation. The long shoot terminal bud organogenic sequence resembled that described in temperate pines and led to an episodic, monocyclic shoot growth pattern. The formation of up to several long shoot terminal buds between the onset of seed-cone-bud differentiation and flowering frequently resulted in multiple sets of seed cones.

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.

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.

scholarly journals Effect of Rootstock on Shoot Preformation and Neoformation in Pistachio cv. Kerman

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 760C-760
Author(s):  
Timothy M. Spann* ◽  
Robert H. Beede ◽  
Steven A. Weinbaum ◽  
Theodore M. DeJong
Keyword(s):  
Water Stress ◽  
Genetic Control ◽  
Shoot Growth ◽  
Regulated Deficit Irrigation ◽  
Current Season ◽  
Carbohydrate Concentration ◽  
Dormant Bud ◽  
Terminal Bud ◽  
Dormant Season ◽  
Terminal Buds

Rootstock significantly alters the pattern of shoot growth of pistachio (Pistacia vera) cv. Kerman. Trees on P. atlantica typically produce a single flush of spring growth whereas trees on P. integerrima selection PGI and P. atlantica × P. integerrima selection UCB-1 can produce multiple flushes during the season. Terminal buds of shoots on all three rootstocks were dissected during the dormant season to determine the number of preformed nodes. Data indicate that there are 8-9 nodes preformed in the dormant terminal bud of shoots from Kerman trees and that this number is independent of rootstock, canopy location, crop load, and shoot carbohydrate concentration, suggesting genetic control. This number corresponds with the number of nodes typically found on a shoot at the end of the spring growth flush. Unlike the spring flush which is preformed in the dormant bud, later flushes are neoformed, that is, nodes are initiated and extended during the same season. Neoformed growth depends on current season photosynthates and may compete with fruit growth for available resources. Neoformed growth is sensitive to water stress and trees on all three rootstocks grown under two levels of regulated deficit irrigation showed a reduction in both the number and length of neoformed shoots. Preformed shoot growth did not appear to be reduced under water stress conditions, supporting the hypothesis that preformed shoots are more dependent on environmental conditions during the season they are initiated than during the season they are extended. Additionally, preformed shoots on well irrigated trees were similar in length for all rootstocks, further supporting the idea that preformed shoots are under genetic control and are not easily manipulated.

Floral response of Piceaglauca to gibberellin A4/7, napthaleneacetic acid, root-pruning, and biennial treatment

1985 ◽  
Vol 15 (4) ◽  
pp. 743-746 ◽  
Author(s):  
Robert D. Marquard ◽  
James W. Hanover
Keyword(s):  
Water Potential ◽  
Shoot Growth ◽  
White Spruce ◽  
Root Pruning ◽  
Female Cone ◽  
Cone Production ◽  
Napthaleneacetic Acid ◽  
Terminal Shoot ◽  
And Control ◽  
Male Strobili

The floral response of 6-year-old seedling white spruce (Piceaglauca (Moench) Voss.) was evaluated after treatment in 1981 with the gibberellin mixture of A4 and A7 (GA4/7), napthaleneacetic acid (NAA), and root-pruning. To evaluate the effectiveness of biennial treatment, trees treated in 1981 were again treated in 1983 and compared with a second group of trees treated only in 1983. Trees treated in 1981 with 500 mg•L−1 GA4/7 plus 25 mg•L−1 NAA and root-pruning averaged 42 female strobili per tree and control trees remained vegetative. Root-pruning significantly reduced terminal shoot growth and shoot water potential. No male strobili were produced on study trees. Trees treated in 1981 and again in 1983 were as productive (based on female counts) as trees treated only in 1983. Two treatments in 1983 significantly enhanced female strobilus production over the control: (i) 500 mg•L−1 GA4/7 alone and (ii) 250 mg•L−1 GA4/7 plus root-pruning. These treatments averaged 150 and 192 female strobili per tree, respectively; control trees averaged 30. Biennial treatment with GA4/7 and root-pruning can effectively continue to increase female cone production of white spruce.

Accumulation and Utilization of Carbohydrate Reserves in Shoot Growth of Pinusresinosa

1973 ◽  
Vol 3 (3) ◽  
pp. 346-353 ◽  
Author(s):  
M. O. Olofinboba ◽  
T. T. Kozlowski
Keyword(s):  
Shoot Growth ◽  
Shoot Elongation ◽  
Bud Development ◽  
Carbohydrate Reserves ◽  
Late Season ◽  
Phloem Translocation ◽  
Food Reserves

Evidence is presented which emphasizes the importance of food reserves and conditions controlling late-season photosynthesis (e.g. during bud development) to subsequent-year shoot growth ofPinusresinosa. By the end of August, after shoot elongation ceased, current 14C-photosynthate was mobilized by roots, stems, and twigs. Much of the currently produced photosynthate accumulated as reserves in roots, stems, and twigs. When phloem blocks were applied in March behind the prior-year internode of defoliated shoots, thereby preventing phloem translocation of currently produced photosynthate from old needles to the buds, considerable shoot expansion still occurred, indicating utilization of reserve photosynthates of the prior-year internode.

Seedling Shoot and Bud Development in Provenances of Sitka Spruce, Piceasitchensis (Bong.) Carr.

1975 ◽  
Vol 5 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Douglas F. W. Pollard ◽  
Abraham H. Teich ◽  
Kenneth T. Logan
Keyword(s):  
Growth Rate ◽  
Induction Period ◽  
Growth And Development ◽  
Shoot Growth ◽  
Shoot Elongation ◽  
Sitka Spruce ◽  
Bud Development ◽  
The Third ◽  
Terminal Bud ◽  
Needle Primordia

Growth and development of seedlings of ten provenances were compared in three investigations. The provenances ranged from Oregon to south-east Alaska and were collected for the I.U.F.R.O. International Sitka Spruce Provenance Experiment. The potential for seedling growth was studied by measuring (a) the rate of shoot growth and (b) the duration of shoot elongation. Growth rate was rather uniform, being only slightly faster among northern provenances. The duration of shoot growth, under artificial declining photoperiods was strongly influenced by latitude of origin. The critical photoperiods necessary for sustained growth in southern provenances were up to 4 hours shorter than those in northern provenances. In the third investigation development of the terminal bud was followed during the first 8 weeks. After a 4-week induction period buds attained macroscopic sizes with ca. 100 needle primordia. Northern provenances had up to 65% more primordia than southern ones. At 8 weeks, a strong but reversed relationship was evident, with southern provenances having up to 35% more than northern provenances. These observations indicate that latitude-correlated variations will be an important feature of the I.U.F.R.O. Experiment, with southern provenances performing especially well in southern trials. Potential advantages of southern provenances will be protracted periods of shoot growth in young seedlings and protracted periods of development of the primordial shoot in overwintering buds. However, where summer seasons are short, such advantages may not be realized.

Annual cycle of shoot development in sugar maple

1980 ◽  
Vol 10 (3) ◽  
pp. 316-326 ◽  
Author(s):  
Robert A. Gregory
Keyword(s):  
Annual Cycle ◽  
Sugar Maple ◽  
Growing Season ◽  
Shoot Formation ◽  
Shoot Development ◽  
Bud Formation ◽  
Terminal Bud ◽  
Long Shoots ◽  
Short Shoots ◽  
Terminal Buds

Cytohistology and the development and morphogenesis of sugar maple (Acersaccharum Marsh.) shoots were studied. Three types were recognized: short shoots, long shoots entirely preformed in the bud (Epf long), and long shoots partially preformed in the bud (heterophyllous). The three shoot types varied not only in the size and number of internodes and leaves but also in the development of terminal buds. Terminal bud formation was delayed in heterophyllous shoots but because of a shorter plastochron, which extended later into the growing season, the terminal apices of these shoots were able to annually produce more primordia than in other shoot types. The beginning of embryonic shoot formation, however, began about the same time (late July) for all shoot types.

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.

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