Inflorescence development in Amelanchier alnifolia

1990 ◽  
Vol 68 (8) ◽  
pp. 1680-1688 ◽  
Author(s):  
Margaret W. Steeves ◽  
Taylor A. Steeves
Keyword(s):  
Shoot Growth ◽  
Early Stage ◽  
Axillary Buds ◽  
Vegetative Shoot ◽  
Inflorescence Development ◽  
Amelanchier Alnifolia ◽  
Inflorescence Size ◽  
Fruit Crop ◽  
Terminal Flower ◽  
Foliage Leaf

The morphology and development of the inflorescence of Amelanchier alnifolia, a potential fruit crop, are described. Although racemelike in appearance, the 8- to 12-flowered inflorescence is determinate, and the occasional branching of the basal member indicates its compound nature. This basal member in the axil of a foliage leaf frequently bears three to four bracteoles instead of the two characteristic of the remaining lateral flowers, and an arrested bud may be found in the axil of one or more of the bracteoles. The inflorescence is thus interpreted as a much reduced panicle. The phenology of inflorescence development in relation to seasonal shoot growth has been documented. Transformation of vegetative shoot apices to the flowering condition begins after the differentiation of a set of cataphylls and as the current fruit crop is ripening. It is marked by the accelerated formation of bract primordia with precocious axillary buds, culminating after about 2 weeks with the initiation of a terminal flower. Although the last to be formed, the terminal flower at all subsequent stages is equivalent in development to those at the base of the inflorescence. The buds in the axils of three to five bracts immediately below the terminal flower are arrested at an early stage and variation in inflorescence size may in part be due to variability in their development.

Studies in the Alismataceae. I. Developmental morphology of Echinodorus tenellus

1968 ◽  
Vol 46 (11) ◽  
pp. 1345-1360 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Regular Sequence ◽  
Axillary Buds ◽  
Developmental Morphology ◽  
Vegetative Development ◽  
Reproductive Shoot ◽  
Terminal Flower ◽  
Stage Of Development ◽  
Foliage Leaf ◽  
Unlimited Growth ◽  
Regular Alternation

Development of each shoot of Echinodorus tenellus proceeds through a vegetative phase when foliage leaves are formed and enters an abruptly initiated reproductive phase, when only scale leaves are formed, by conversion of the meristem into a different form, while a large and precocious bud in the axil of the last foliage leaf continues vegetative development. The reproductive meristem may, according to conditions, form an inflorescence or a “pseudostolon” with vegetative axillary buds in place of flowers. Both inflorescence and pseudostolon show a regular sequence of long and short internodes and a regular alternation of scale leaves with and without axillary buds, though the pattern of the inflorescence is less regular than that of the pseudostolon and the inflorescence has a terminal flower while the pseudostolon has unlimited growth. Phyllotaxis varies according to the stage of development of the plant and in the reproductive shoot is largely determined by the patterns of internode elongation and bud distribution. The significance of the developmental pattern is discussed.

scholarly journals Use of GA3 to Manipulate Flowering and Yield of `Hass' Avocado

2000 ◽  
Vol 125 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Samuel Salazar-García ◽  
Carol J. Lovatt
Keyword(s):  
Early Stage ◽  
Persea Americana ◽  
Yield Reduction ◽  
Alternate Bearing ◽  
Concomitant Increase ◽  
Vegetative Shoot ◽  
Inflorescence Development ◽  
Initial Development ◽  
Shoot Number ◽  
Hass Avocado

Avocado trees (Persea americana Mill.) bearing a heavy crop produce a light “off” bloom the next spring. This results in a light crop and a subsequent intense “on” bloom the year after. The objective of the study was to quantify the effects of GA3 canopy sprays applied to `Hass' avocado trees during the months preceding an “off” or “on” bloom on inflorescence and vegetative shoot number and yield. The experiment was initiated approximately seven months before an anticipated “off” bloom in an attempt to increase flowering intensity and yield. GA3 (25 or 100 mg·L-1) was applied to separate sets of trees in September (early stage of inflorescence initiation), November (early stage of inflorescence development), January (initial development of the perianth of terminal flowers), March (cauliflower stage of inflorescence development; only 25 mg·L-1), or monthly from September through January (only 25 mg·L-1). Control trees did not receive any treatment. GA3 (100 mg·L-1) applied in September reduced inflorescence number in both years, but not yield. GA3 (25 or 100 mg·L-1) applied in November before the “on” bloom reduced inflorescence number with a concomitant increase in vegetative shoot number and 47% yield reduction compared to control trees. This treatment might provide avocado growers with a tool to break the alternate bearing cycle by reducing yield in an expected “on” crop year to achieve a higher yield the following year. GA3 (25 mg·L-1) applied in November or January stimulated early development of the vegetative shoot of indeterminate inflorescences. January and March applications did not affect the number of flowering or vegetative shoots produced either year. GA3 (25 mg·L-1) applied in March at the start of an “off” bloom increased 2-fold the production of commercially valuable fruit (213 to 269 g per fruit) compared to the control.

Studies in the Alismataceae. IV. Developmental morphology of Ranalisma humile and comparisons with two members of the Butomaceae, Hydrocleis nymphoides and Butomus umbellatus

1973 ◽  
Vol 51 (5) ◽  
pp. 899-910 ◽  
Author(s):  
W. A. Charlton ◽  
A. Ahmed
Keyword(s):  
Early Stage ◽  
Reduced Form ◽  
Developmental Morphology ◽  
Inflorescence Development ◽  
Developmental Patterns ◽  
Inflorescence Branch ◽  
Foliage Leaf ◽  
Lateral Bud ◽  
Floral Meristems ◽  
Vegetative Bud

The development of the foliage leaf bearing axes in Ranalisma humile (Kunth.) Hutch. and Hydrocleis nymphoides Buch. is similar in that both show sympodial development, each branch of the sympodium terminating in an inflorescence; in Butomus umbellatus L. the inflorescence is lateral and the vegetative axis is monopodial.Inflorescences of Ranalisma can adopt a horizontally growing pseudostolon form in which floral meristems are formed but abort at an early stage; there is no basic difference between the organ complements of the pseudostolon and the erect inflorescence.Inflorescences of Hydrocleis and Ranalisma have similar developmental patterns. In both, the main axis terminates in a floral primordium while a large bud is developed in the axil of the first of two bracts below the flower. The lateral bud in Hydrocleis develops into a sympodial bud complex consisting of flowers, a vegetative bud, and an inflorescence branch which repeats the pattern of development; in Ranalisma the lateral bud gives rise only to a vegetative bud and an inflorescence branch. Ranalisma appears to possess a reduced form of the kind of inflorescence development found in Hydrocleis.The inflorescence of Butomus also terminates in a flower. It has three bracts, each subtending a set of multiple axillary buds. Each individual bud develops into a sympodially arranged set of flowers.Previously proposed isolation of Butomus from other Butomaceae and Alismataceae is further emphasized by developmental data. Ranalisma provides a connecting link between Alismataceae and the Butomaceae excluding Butomus (i.e. the Limnocharitaceae of some authors).

scholarly journals Mechanism and Underlying Physiology Perpetuating Alternate Bearing in Citrus

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1117C-1117
Author(s):  
Johannes S. Verreynne ◽  
Carol J. Lovatt
Keyword(s):  
Phase Transition ◽  
Shoot Growth ◽  
Indoleacetic Acid ◽  
Alternate Bearing ◽  
Vegetative Shoot ◽  
Fruit Removal ◽  
Inflorescence Development ◽  
Shoot Initiation ◽  
Shoot Production ◽  
Return Bloom

Alternate-bearing trees produce a heavy on-crop followed by a light off-crop. Whereas climatic events initiate alternate bearing, it is perpetuated by endogenous tree factors. For citrus, the mechanism and underlying physiology by which fruit influence floral intensity the next spring was unresolved. To determine whether reduced return bloom of on-crop trees was due to inhibition of vegetative shoot production and, thus, a lack of “wood” on which to bear next spring's inflorescences or, alternatively, to inhibition of phase transition and inflorescence development on an adequate number of vegetative shoots, fruit were removed from individual shoots monthly or from entire on-crop `Pixie' mandarin trees during periods critical to shoot initiation (summer) and phase transition (winter). Fruit removal provided clear evidence that the on-crop exerted a significant effect on return bloom during the summer by reducing summer–fall shoot growth and, hence, the number of flowers borne on these shoots as well as on old wood of fruit-bearing shoots. The on-crop had less effect in winter on phase transition and return bloom. Buds collected during the summer from on-crop `Pixie' mandarin trees were characterized by high indoleacetic acid and low isopentenyladenosine concentrations compared to buds from off-crop trees. The starch level of the buds was not affected. No differences in hormone concentrations were detected for buds collected during winter from on- and off-crop trees, but buds of on-crop trees had less starch. The results demonstrate that the on-crop reduces return bloom predominantly by inhibiting summer-fall vegetative shoot growth by a mechanism similar to apical dominance, not a lack of available carbohydrate.

Timing and rate of bud formation in Pinus resinosa

1971 ◽  
Vol 49 (10) ◽  
pp. 1821-1832 ◽  
Author(s):  
Edward Sucoff
Keyword(s):  
Quantitative Data ◽  
Shoot Growth ◽  
Pinus Resinosa ◽  
Growing Season ◽  
Axillary Buds ◽  
Growing Degree Days ◽  
Degree Days ◽  
Bud Formation ◽  
Late Season ◽  
Apical Dome

During the 1969 and 1970 growing season buds were collected almost weekly from matched trees in northeastern Minnesota. Cataphyll primordia for the year n + 1 shoot began forming at the time that internodes in the year n shoot started elongating (late April) and continued forming until early September. Primordia for axillary buds started forming about 2 months later and stopped forming at the same time as cataphylls. The size and deposition activity of the apical dome simultaneously increased during the early growing season and decreased during the late season. The maximum rates in July were over nine cataphylls per day.Rate of cataphyll deposition paralleled elongation of the needles on subtending shoots. Forty to fifty percent of the cataphylls had been formed when shoot growth was 95% complete. Although the bulk of the depositions occurred earlier in 1970, when growing degree days were used as the clock, the 2 years were similar.The results provide quantitative data to complement the histologic emphasis of previous studies.

Pollen development in relation to phenological stages of inflorescence expansion in Amelanchier alnifolia (saskatoon), with a comparison with buds forced out of dormancy

1999 ◽  
Vol 77 (2) ◽  
pp. 262-268
Author(s):  
Michael J Sumner ◽  
William R Remphrey ◽  
Richard Martin
Keyword(s):  
Time Frame ◽  
Early Spring ◽  
Flower Buds ◽  
Flower Bud ◽  
Phenological Stages ◽  
Inflorescence Development ◽  
Amelanchier Alnifolia ◽  
Bud Development ◽  
Internal Development ◽  
Flower Bud Development

A relationship was developed between phenological stages of inflorescence expansion and the internal development of pollen within the anther of Amelanchier alnifolia Nutt. flowers. The major microscopic events associated with microsporogenesis and microgametogenesis were correlated with seven stages of external inflorescence development in both natural buds and those forced from dormancy in different concentrations of gibberellin at various times of the year. In fall and early spring, it was found that gibberellin at a concentration of 2.5 mg/L forced buds to produce inflorescences that most resembled those from natural field populations. However, it was not possible to force flower buds to develop all the way to anthesis. Flower bud development stopped when the pollen was at the binucleate stage. Despite this limitation, the ability to force buds increases the time frame for the study of many aspects of the reproductive biology of A. alnifolia.Key words: microsporogenesis, microgametogenesis, gibberellin, GA, flowering.

The rotated-lamina syndrome. I. Ulmaceae

1993 ◽  
Vol 71 (2) ◽  
pp. 211-221 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Leaf Blade ◽  
Early Stage ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Foliage Leaf ◽  
Normal Orientation ◽  
Ulmus Glabra ◽  
Young Leaves ◽  
Final Orientation ◽  
Zelkova Serrata

In a number of plants, mostly woody, the components of the buds are arranged so that the laminae of the young leaves all face towards the same (upper) side of the bud, rather than towards the bud apex; in axillary buds they usually face towards the parent axis. This situation has been known for many years. For convenience, the general case is here called the rotated-lamina syndrome. There have been very few developmental investigations of how the laminae attain their unusual orientation, and these have come to different conclusions about cases in the Ulmaceae. This paper reports a detailed investigation of the syndrome in Ulmus glabra and Zelkova serrata, with comparative observations on other Ulmaceae, including cases in Celtis that do not exhibit the syndrome. The syndrome arises by different means in Ulmus and Zelkova. In Ulmus the leaf primordium is asymmetrical from the outset, the leaf blade region is obliquely dorsiventral from an early stage, and further asymmetrical growth of the leaf buttress rotates the whole leaf blade region into its final orientation as it develops. Individual shoots show heteroblastic development in progressing from bud scale to foliage leaf initiation, in increasing accentuation of the rotated-lamina syndrome, and in an increasing degree of dorsiventrality. In Zelkova, as previously described, the leaf blade region appears first as a radially symmetrical upgrowth, and it acquires dorsiventral symmetry directly in the rotated position. In Celtis spp. the lamina arises in a quite normal orientation, but reorients as it emerges from the bud. The leaf primordia of all species studied show asymmetry in other aspects, particularly in respect of stipule development, and these seem to be general features of the organisation of dorsiventral shoots. Key words: Ulmus, Zelkova, Celtis, leaf, development, dorsiventrality, lamina rotation.

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.

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