scholarly journals Synchrony of Inflorescence Initiation and Shoot Growth in Selected Protea Cultivars

2001 ◽  
Vol 126 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Audrey I. Gerber ◽  
Karen I. Theron ◽  
Gerard Jacobs
Keyword(s):  
Apical Meristem ◽  
Shoot Growth ◽  
Flower Initiation ◽  
Apical Bud ◽  
Meristematic Activity ◽  
Floral Primordia ◽  
Appendage Formation ◽  
Floral Bracts ◽  
Insight Into ◽  
Flowering Process

Protea L. sp. can be assigned to groups according to similar times of flower initiation and harvest. The stages occurring during flower initiation and their synchrony relative to shoot growth were investigated for three cultivars when flower initiation occurred on the spring growth flush. For all three cultivars, the spring flush was preformed and enclosed in the apical bud before spring budbreak. During elongation of the spring flush, the apical meristem produced floral primordia which differentiated into involucral bracts. After completion of the spring flush, meristematic activity continued and produced floral bracts with florets in their axils. The different cultivars were characterized by differences or similarities in the time of budbreak, and the rates of shoot growth, appendage formation, and flower development. Insight into the time of flower initiation relative to vegetative growth could be useful in making management decisions, as well as forming a basis for manipulation of the flowering process.

Localisation par autoradiographie de l'acide [5-3H]indole-3-acétique dans le bourgeon terminal du Lycopersicum esculentum

1984 ◽  
Vol 62 (6) ◽  
pp. 1149-1157 ◽  
Author(s):  
D. Driss-Ecole ◽  
G. Perbal ◽  
Y. Leroux
Keyword(s):  
Total Radioactivity ◽  
Lycopersicum Esculentum ◽  
Meristematic Cells ◽  
Differentiated Cells ◽  
Apical Bud ◽  
Ethylcarbodiimide Hydrochloride ◽  
Meristematic Activity ◽  
Sieve Tubes ◽  
Whole Plants ◽  
Label Distribution

[3H]indoleacetic acid (AIA) was applied to the shoot tip of intact young plants of Tomato (Lycopersicum esculentum Mill.) for 10, 60, or 120 min. Autoradiograms of whole plants were prepared and liquid scintillation counts of stem segments and principal root segments were performed. Chromatographic analysis showed that 66% of the radioactivity was associated with AIA after 120 min of contact with [3H]AIA. Autoradiographs of semithin and ultrathin sections were prepared after treatment by DCC (1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride). The quantity of label per cell and the density of label were determined for all tissues of the apical bud. The density of label was greater for meristematic cells than for differentiated cells. The observed homogeneity of label distribution in the apical meristem shows that auxin levels do not play a prominent role in distinguishing between its lateral and axial zones. The density of label was similar in the apical and in the axillary bud of leaf 4. The cells of the rib meristem, which elongate to produce pith, were more intensely labelled than the other meristematic cells. The percentage of label was calculated for each tissue in a transverse section of the stem just below the apex. The amount of auxin was greatest in the parenchyma (axial and cortical) with lesser amounts in the procambium, phloem parenchyma, and xylem parenchyma. Vessels, which had the greatest density of label, did not contain more than about 3% of total radioactivity of the stem section, while sieve tubes had only 0.5%. Pathways of auxin transport and the role of AIA in regulating meristematic activity in the apical bud are discussed.

scholarly journals RNA-seq analysis of an apical meristem time series reveals a critical point in Arabidopsis thaliana flower initiation

BMC Genomics ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Anna V. Klepikova ◽  
Maria D. Logacheva ◽  
Sergey E. Dmitriev ◽  
Aleksey A. Penin
Keyword(s):  
Time Series ◽  
Arabidopsis Thaliana ◽  
Critical Point ◽  
Apical Meristem ◽  
Flower Initiation ◽  
Rna Seq

scholarly journals Cone quality and seed efficiency in the clones from mutational witches brooms of Pinus sibirica

2018 ◽  
Vol 11 ◽  
pp. 00034
Author(s):  
Olga Polyakova ◽  
Evgeniya Zhuk ◽  
Sergei Goroshkevich
Keyword(s):  
Apical Meristem ◽  
Shoot Growth ◽  
Seed Quality ◽  
Pinus Sibirica ◽  
Normal Cones ◽  
Tree Crown ◽  
Normal Seed ◽  
Empty Seeds ◽  
Filled Seeds ◽  
Size And Structure

Mutational witches' broom is a fragment of the tree crown with abnormal morphogenesis including slow shoot growth, abundant branching and decreased apical dominance which caused by somatic mutation that presumably originates in the apical meristem bud. To study the variability in the cone quality and seed efficiency in witches' broom clones of Pinus sibirica, the cone size and structure were assessed in 21 mutant clones. The mutant clones were significantly differentiated both by the cone traits and seed quality. Their cone size varied from less than 3 to 4 cm. The clones had large number of sterile scales in proximal and distal cone parts, and from 16 to 39 fertile scales per cone. Cones from all mutant clones were inferior to average normal cones of the species. Six clones had large portion of filled seeds, more than 70%, and the other clones had less than 50% of filled seeds. The clones had 10-33% of empty seeds and 1-73% of seeds with collapsed megagametophyte per cone. In general, the seed quality in mutants was quite low, but individual clones had almost normal seed quality, and their seed efficiency was within the species norm.

Flowering in Pisum: Does Gibberellic Acid Directly Influence the Flowering Process?

1977 ◽  
Vol 4 (4) ◽  
pp. 479 ◽  
Author(s):  
JB Reid ◽  
PJ Dalton ◽  
IC Murfet
Keyword(s):  
Gibberellic Acid ◽  
Direct Effect ◽  
Continuous Light ◽  
Flower Initiation ◽  
Small Delay ◽  
Effect Of Age ◽  
Flowering Process

Gibberellic acid is shown to cause a substantial delay in the flowering node, time of flower initiation and leaf requirement for flowering in the late pea cultivar line 24, grown under an 8-h photoperiod. In continuous light, gibberellic acid caused only a small delay in the flowering node and leaf require- ment. As the plants became older the effect of applied gibberellic acid decreased. This was not due to initiation having already occurred or to the gibberellic acid not penetrating the plant. It is suggested that gibberellic acid has a direct effect on the flowering process in line 24 plants grown under an 8-h photoperiod and that it may act by reducing the effect of age on the gene Sn.

GROWTH AND DEVELOPMENT OF THE LOWBUSH BLUEBERRY: APICAL ABORTION

1963 ◽  
Vol 41 (9) ◽  
pp. 1319-1324 ◽  
Author(s):  
W. G. Barker ◽  
W. B. Collins
Keyword(s):  
Vegetative Growth ◽  
Growth And Development ◽  
Apical Meristem ◽  
Shoot Growth ◽  
Strong Indication ◽  
Vegetative Tissue ◽  
Aerial Shoot ◽  
Lowbush Blueberry ◽  
Below Ground ◽  
High Level

The semicultivated lowbush blueberry is fire-pruned on a 3- to 4-year cycle. In spring, vegetative growth is accomplished through the development of an axillary bud on an aerial shoot. In a fire-pruned area, the growth is delayed in both its initiation and termination by as much as a month and arises either from axillary buds on the unburned below-ground portions of the aerial stems, or from rhizome seated buds. Shoot growth is terminated by the abortion of the apical meristem and the death of the proximal portions of the axis. Evidence is presented suggesting that the death of the apex is not triggered by an appropriate photoperiod. Further, although it is inherently controlled, it does not follow the production of a specified quantity (relative to clone) of leaf nor vegetative tissue and is not related to the development of a specified (per clone) leaf photosynthetic area. Finally, there is a strong indication that the death of the shoot is speeded by the presence of a high level of auxin.

Low temperature effects on growth and physiology specific to a "grass-clump" dwarf wheat hybrid

1972 ◽  
Vol 50 (2) ◽  
pp. 253-261 ◽  
Author(s):  
J. D. Mahon ◽  
D. T. Canvin
Keyword(s):  
Low Temperature ◽  
Shoot Growth ◽  
Growth Habit ◽  
Temperature Response ◽  
Dry Weight ◽  
Growth Responses ◽  
Meristematic Region ◽  
Meristematic Activity ◽  
Dwarf Wheat ◽  
Induced Changes

The growth habit of "grass-clump" dwarf wheat plants can be affected by extremely short 16° treatments if given repeatedly. To localize the earliest growth responses in plants of one such hybrid (Mql × KF 1), the temperature sensitivity of plants of different ages, and the earliest temperature-induced changes in growth, development, and shoot physiology were investigated and compared with the responses of normal wheat plants.Mql × KF 1 plants growing at 26° responded to progressively shorter 16° treatments as they aged and plants exposed to 16° after 10 days growth at 26° were unable to recover from low temperature treatments of 3–5 days duration. Although shoot growth (as dry weight) of Mql × KF 1 stopped abruptly after 7 days at 16°, root growth (as dry weight) continued for at least 15 days. The rates of CO2 and water vapor exchange in individual leaves responded to low temperature similarly in both the dwarf and normal plants and did not markedly decrease until after 4 days at 16°. The most rapid low temperature response specific to Mql × KF 1 plants was cessation in primary tiller development immediately after the beginning of 16° exposure. It is proposed that the primary 16° effect is on the shoot meristematic region and that other changes in growth and physiology result from the lack of meristematic activity in the young growing region.

scholarly journals Applied aspects of pineapple flowering

Bragantia ◽  
2005 ◽  
Vol 64 (4) ◽  
pp. 499-516 ◽  
Author(s):  
Getúlio Augusto Pinto da Cunha
Keyword(s):  
Vegetative Growth ◽  
Apical Meristem ◽  
Crop Management ◽  
Chemical Substances ◽  
Complex Process ◽  
General Flowering ◽  
Flowering Initiation ◽  
Underlying Mechanisms ◽  
Flowering Process

Flowering is an amazing, integrated and complex process of multifatorial control, which due to its great importance for agriculture has been extensively studied worldwide. Pineapple is one of the main crops on which many research works about this subject have been carried out, and it was the first one to have artificially induced flowering. However, even with all those studies, pineapple flowering is not yet characterized in many aspects. The main point for the comprehension of the physiologic aspects of flowering initiation is the identification of the factors involved in the differentiation of the apical meristem into floral primordium, as well as how these factors exert their action. This work aimed to describe the flowering process of pineapple plants, including notions about general flowering physiology, pineapple inflorescence, natural and artificial flowering. Flowering relation to several chemical substances which are involved with the vegetative growth of the plant are also discussed, in order to bring out more light on its underlying mechanisms, and also to help in crop management.

scholarly journals 295 The Effect of Cultivar, GA4+7, and Number of Fruit per Spur on Flower Initiation in Apple

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 493C-493
Author(s):  
Emily Hoover ◽  
S. McArtney ◽  
S. Tustin ◽  
M. White ◽  
P. Hirst
Keyword(s):  
Flower Initiation ◽  
Leaf Fall ◽  
Full Bloom ◽  
Flower Bud ◽  
Biennial Bearing ◽  
Appendage Formation ◽  
Commercial Crop ◽  
Bud Initiation ◽  
Number Of Seeds

Experiments were initiated to document the effect of cultivar, GA4+7, and number of fruit/spur on appendage number and flower bud initiation in apple. `Pacific Rose' is strongly biennial, `Braeburn' and `Fuji' are moderately biennial, and `Royal Gala' is not biennial. In the cultivar study, buds were sampled every 18 days starting at 50 days after full bloom and continuing through until leaf fall to determine the rate of appendage formation and appendage number in relation to doming. Because of the tendency for `Pacific Rose' to exhibit biennial bearing, the rate of appendage formation and the timing of doming were compared on nonfruiting trees, trees carrying a commercial crop, and trees sprayed with 300 PPM GA4+7 applied 14 days after full bloom. Number of appendages for the treatments were similar up to 100 days after full bloom. Presence of fruit on a spur has been demonstrated to inhibit flowering of apple. Spurs of `Pacific Rose', `Splendor', and `Royal Gala' were labeled with zero, one, two, and three fruit per spur and sampled three times during the season. As buds were harvested to count appendage number, the number of fruit per spur and the number of total seeds per spur were recorded. Correlation between number of seeds per spur and rate of appendage formation were done.

scholarly journals Cytological Examination of Scilla peruviana L. during a 20-month Cycle of Growth and Development

HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1175-1179 ◽  
Author(s):  
Naza Sh. Azizbekova ◽  
Stefanie L. Butland ◽  
Brian E. Ellis ◽  
Christia M. Roberts
Keyword(s):  
Growth And Development ◽  
Apical Meristem ◽  
Cytological Study ◽  
Growth Cycle ◽  
Flower Initiation ◽  
Cytological Examination ◽  
Complete Cycle ◽  
Meristematic Cells ◽  
Two Generations ◽  
Floral Differentiation

The growth cycle of Scilla peruviana L. involved the development of two generations of daughter bulbs enclosed within each mother bulb. Flower initiation of the primary daughter bulb took place in June as the mother bulb apparently entered dormancy. Floral differentiation was complete by late October, by which time the apical meristem of the secondary daughter bulb had developed for 3 months inside the primary daughter bulb. The complete cycle of ontogenesis, from meristem initiation to flowering, occurred without interruption and required 20 months. Small zones of meristematic cells detected at the bases of bulb scales may be the origin of adventitious bulblets in this species. This detailed cytological study enabled the development of an effective commercial forcing program for S. peruviana.

Regrowth response of young black spruce (Picea mariana) trees to meristem removal and resource addition

2003 ◽  
Vol 81 (9) ◽  
pp. 956-963 ◽  
Author(s):  
Marcy Bast ◽  
R J Reader
Keyword(s):  
Picea Mariana ◽  
Apical Dominance ◽  
Apical Meristem ◽  
Compensatory Growth ◽  
Shoot Growth ◽  
Black Spruce ◽  
Mineral Nutrients ◽  
Mineral Nutrient ◽  
Supply Condition ◽  
K Fertilizer

Regrowth of an injured plant may exceed the growth of a noninjured plant (i.e., overcompensation) when (i) dormant meristems are available to replace injured meristems, (ii) the injury level is sufficient to release dormant meristems from apical dominance, and (iii) the supply of mineral nutrient and light is sufficient to support the outgrowth of previously dormant meristems. A field experiment was conducted with 5-year-old black spruce trees to determine whether these three conditions were met when 25%, 50%, or 75% of a tree's uppermost buds were removed. Subsequent shoot growth on treated and nontreated trees (0% meristem removal) was compared for each of two levels of resource supply (natural and enhanced). Enhanced levels of light and mineral nutrients were created by removing neighbouring plants within a 2-m radius of a target tree and adding 10 grams of N–P–K fertilizer per tree. After 5 and 17 months, shoot growth did not differ significantly among trees in the four meristem removal treatments (condition ii above), regardless of resource supply (condition iii above). The absence of overcompensation most likely reflects the relatively small supply of dormant meristems on treated trees (condition i above).Key words: apical meristem, black spruce, compensatory growth, injury.

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