Floral development in three species of Acacia (Leguminosae, Mimosoideae)

2007 ◽  
Vol 55 (1) ◽  
pp. 30 ◽  
Author(s):  
Sandra Luz Gómez-Acevedo ◽  
Susana Magallón ◽  
Lourdes Rico-Arce
Keyword(s):  
Floral Development ◽  
Complete Sequence ◽  
Developmental Pathways ◽  
Flower Formation ◽  
Acacia Berlandieri ◽  
Postgenital Fusion

The complete sequence of floral development in three species of Acacia was analysed. These species were sampled from each of the three Acacia subgenera. The species were Acacia berlandieri Benth. (subg. Aculeiferum), A. pennatula (Schltdl. & Cham.) Benth. (subg. Acacia) and A. saligna (Labill.) H.L.Wendl. (subg. Phyllodineae). The aim of the study was to determine whether the different subgenera share developmental pathways during flower formation. This study showed that development in the genus Acacia is heterogeneous. Each species studied showed different inception patterns of the calyx and androecium, whereas the inception patterns of the corolla and gynoecium were similar. These differences of inception in the calyx are not necessarily constant within each subgenus. Nevertheless, each subgenus was differentiated on the basis of inception patterns of the androecium, and other features such as the presence or absence of congenital or postgenital fusion in the calyx and corolla, and the time of differentiation of calyx and corolla tubes and the style.

Floral development of Rosa setigera

1993 ◽  
Vol 71 (1) ◽  
pp. 74-86 ◽  
Author(s):  
James R. Kemp ◽  
Usher Posluszny ◽  
Jean M. Gerrath ◽  
Peter G. Kevan
Keyword(s):  
Key Words ◽  
Floral Development ◽  
Functional Approach ◽  
Floral Meristem ◽  
Cryptic Dioecy ◽  
Congenital Fusion ◽  
Postgenital Fusion

The development of the flower of Rosa setigera from initiation to the onset of anthesis is described. Rosa setigera is the only known member of the genus Rosa to exhibit dioecy. Flowers of functionally staminate (male) and functionally carpellate (female) plants appear identical, a condition referred to as cryptic dioecy. Discrete sepals and petals are formed on the floral meristem. As the hypanthium forms, stamens are initiated in alternating whorls on the wall of the hypanthium and continue to develop as the hypanthium extends. Carpel primordia arise individually on the remainder of the floral meristem and show neither adnation to the hypanthial wall nor coalescence to one another as they give rise to the styles and stigmas that are exserted above the hypanthium lip. The only observable fusion in this species appears to be the postgenital fusion of the margins of the carpel primordia to form the enclosed locule. Although historically the hypanthium has been variously interpreted as either axial and (or) appendicular in nature, resulting from congenital fusion of sepals, petals, and stamens, this paper uses a more realistic, testable and functional approach to the development of the hypanthium that is in keeping with current concepts such as process morphology. Key words: Rosa setigera, dioecy, floral development, fusion, hypanthium.

Flowering in Dactylis glomerata. II. Interaction of temperature and photoperiod

1973 ◽  
Vol 24 (5) ◽  
pp. 685 ◽  
Author(s):  
P Broue ◽  
GH Nicholls
Keyword(s):  
High Temperature ◽  
Floral Development ◽  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Controlled Environment ◽  
Flower Formation ◽  
Temperature Level ◽  
Dactylis Glomerata L ◽  
Dominant Influence

Controlled environment studies investigated the interaction between temperature and photoperiod in relation to floral initiation in seedling populations of the temperate perennial grass Dactylis glomerata L. High temperature inhibited flower formation, but this effect was confined to the early part of the terminal LD treatment, i.e, to the actual transition of the shoot apex from vegetative to floral development. During earlier stages of vegetative growth, including SD vernalization, high temperature was not inhibitory. Of the treatment parameters studied, two exerted a dominant influence on the level of flowering. These were (i) the duration of SD vernalization, and (ii) the temperature level during the terminal LD treatment. A model is presented to explain flowering response in terms of an interaction between these components.

scholarly journals Rootstock Effects on the Flowering of `Delicious' Apple. I. Bud Development

1995 ◽  
Vol 120 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
Peter M Hirst ◽  
David C Ferree
Keyword(s):  
Floral Development ◽  
Dry Weight ◽  
Growing Season ◽  
Flower Formation ◽  
Full Bloom ◽  
Floral Buds ◽  
One Year ◽  
Floral Bud ◽  
Leaf Dry Weight

Floral development was studied in buds of `Starkspur Supreme Delicious' apple trees growing on B.9, M.26 EMLA, M.7 EMLA, P.18, and seedling rootstocks. In each of 3 years, buds were sampled from the previous years growth at intervals throughout the growing season and dissected to determine whether the apex was domed, indicating the start of floral development. Number of bud scales and true leaves increased during the early part of the growing season, but remained fairly constant beyond 70 days after full bloom. The type of rootstock did not affect the number of bud scales or transition leaves, and effects on true leaf numbers were small and inconsistent. Final bract number per floral bud was similarly unaffected by rootstock. The proportion of buds in which flowers were formed was influenced by rootstock in only one year of the study, which was characterized by high temperatures and low rainfall over the period of flower formation. Bracts were observed only in floral buds, and became visible after doming of bud apices had occurred. Flowers were formed during the first 20 days in August, regardless of rootstock or year. The appendage number of vegetative buds was constant from 70 days after full bloom until the end of the growing season, but the number of appendages in floral buds increased due to the continued production of bracts. The critical bud appendage number for `Starkspur Supreme Delicious' before flower formation was 20, and was stable among rootstocks and years. Buds with diameters above 3.1 mm were generally floral, but on this basis only 65% of buds could be correctly classified. Spur leaf number, spur leaf area, and spur leaf dry weight were not good predictors of floral formation within the spur bud.

scholarly journals Morphological and Physiological Changes in Sedum spectabile during Flower Formation Induced by Photoperiod

2015 ◽  
Vol 43 (2) ◽  
pp. 426-431
Author(s):  
Cuiqin YANG ◽  
Xiyao WANG ◽  
Yaoguo QIN ◽  
Xin SUN ◽  
Qiang WANG ◽  
...  
Keyword(s):  
Floral Development ◽  
Morphological Changes ◽  
Floral Induction ◽  
Starch Content ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Flower Formation ◽  
Soluble Sugar Content ◽  
Apical Buds ◽  
Long Day

Sedum spectabile is an ornamental herbaceous perennial considered as a long-day plant. Varying levels of hormones and sugars possibly affect flower bud formation. This study aimed to determine the changes in endogenous hormones, sugars, and respiration levels in leaves and in apical buds. In addition, the current research was also conducted to observe the morphological changes during the induction, initiation and development of flower buds. Results showed that the periods of floral induction, initiation and development of S. spectabile were the period from 0 d to 1 d, 2 d to 10 d and after 11 d respectively under long day of 20 hours. High zeatin level in apical buds was conducive to floral induction; the increasing levels of gibberrelin and indole acetic acid favor floral initiation; floral development was regulated by mutually synergistic and antagonistic relationships of hormones. The total starch content in leaves remarkably decreased during floral induction. Moreover, soluble sugar content increased and reached the maximum level at 20 d of the treatment period. Afterward, soluble sugar content declined rapidly and was probably transported to the apical buds for rapid floral development. Furthermore, the total respiration of leaves maintained an upward trend; the cytochrome pathway also maintained an increasing trend after the plants were treated for 20 d. Such changes may favour the morphological differentiation of apical buds in floral development.

scholarly journals High crop load and low temperature delay the onset of bud initiation in apple

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Julian Kofler ◽  
Anton Milyaev ◽  
Filippo Capezzone ◽  
Slobodan Stojnić ◽  
Nikola Mićić ◽  
...  
Keyword(s):  
Floral Development ◽  
Morphological Changes ◽  
Flower Formation ◽  
Heat Accumulation ◽  
Flower Bud ◽  
Crop Load ◽  
Biennial Bearing ◽  
Growing Seasons ◽  
Growing Degree Hours ◽  
Bud Initiation

AbstractThe reproductive cycle of apple (Malus × domestica Borkh.) starts with the induction of floral development, however, first morphological changes within the bud appear during the following period of bud initiation. This study identifies the onset and duration of bud initiation in the apple cultivars ‘Fuji’ and ‘Gala’, characterized by biennial and non-biennial bearing behaviour, respectively, and describes the effect of crop load and heat accumulation on the temporal pattern of floral development. The onset of flower bud initiation in heavy cropping ‘Gala’ trees was delayed for 20 days compared to trees with no crop load, but the rate of initiation was not affected by crop load. Bud initiation on heavy cropping ‘Fuji’ trees was minor, whereas trees with no crop load started initiating buds 19 days earlier than those of ‘Gala’ despite the same cropping status and growing degree hours in a given year. The onset of bud initiation in ‘Fuji’ ‘off’ trees was 5 and 20 days after summer solstice, respectively, in two consecutive growing seasons, suggesting that this process is driven by heat accumulation rather than by daylength. The results indicate, that the genetic make-up of the cultivar determines the onset of bud initiation. This can be delayed by increasing crop loads and low temperatures at the beginning of the flower formation process.

Comparative development of perianth and androecial primordia of the single flower and the homeotic double-flowered mutant in Hibiscus rosa-sinensis (Malvaceae)

1996 ◽  
Vol 74 (12) ◽  
pp. 1871-1882 ◽  
Author(s):  
Judith P. Maclntyre ◽  
Christian R. Lacroix
Keyword(s):  
Floral Development ◽  
Developmental Pathways ◽  
Partial Replacement ◽  
Double Flower ◽  
Flower Petal ◽  
Hibiscus Rosa Sinensis ◽  
Stamen Primordia ◽  
Staminal Tube ◽  
Mature Flower ◽  
Single Flower

The double-flowered variety of Hibiscus rosa-sinensis L. (Malvaceae) displays a divergent floral morphology that appears to fit the criteria for homeosis. A comprehensive definition defines homeosis as the complete or partial replacement of one part of an organism with another part. The corolla of the single flower is pentamerous. The mature flower has a staminal tube bearing 60 – 70 stamens that surrounds an exserted synstylous gynoecium with five fused stigmas. In double flowers, the outermost whorl of petals is similar in appearance to that of the single flower. The remaining floral appendages have a morphology that is intermediate between petals and stamens, to varying degrees. No two double flowers are exactly the same, even on the same plant. As with other members of the Malvaceae, floral development in both floral types is unusual: once the calyx has been initiated, a ring meristem is formed from which both petal and stamen primordia are initiated. In the single flower, petal primordia are initiated on the flank of the ring, and then stamen primordia arise in five distinct and orderly clusters. In the double flower, petal primordia are also initated on the abaxial flank, but the remainder of the ring initiates primordia that form a mixture of petals, petal – stamen intermediates, and stamens. A common ring meristem that has two different developmental pathways provides a novel opportunity to study homeosis from the perspective of comparative developmental morphology. Keywords: homeosis, Hibiscus rosa-sinensis, androecium, intermediates, ring meristem, floral development.

Flower development in Amelanchier alnifolia (Maloideae)

1991 ◽  
Vol 69 (4) ◽  
pp. 844-857 ◽  
Author(s):  
Taylor A. Steeves ◽  
Margaret W. Steeves ◽  
A. Randall Olson
Keyword(s):  
Key Words ◽  
Flower Development ◽  
Floral Development ◽  
Floral Meristem ◽  
Amelanchier Alnifolia ◽  
Inferior Ovary ◽  
Postgenital Fusion

The development of the flower of Amelanchier alnifolia from initiation to the onset of anthesis is described. Sepals are formed sequentially, but interprimordial zonal growth results in the initiation of the hypanthium. Petals and stamens arise in whorls around the floral meristem as the hypanthium extends. They show neither coalescence nor adnation and do not appear to contribute to the development of the hypanthium. Gynoecial primordia arise individually, give rise to the styles and stigmas, and are joined basally by zonal growth to produce the roof of the ovary. The wall of the inferior ovary is interpreted as a gynoecial hypanthium. It is difficult to determine the extent to which the gynoecial primordia contribute to the development of the ovary. They do not give rise to most of its structure but may be responsible for the initiation of the ovules. There is evidence of postgenital fusion of the septal margins as they converge in the centre of the ovary. The timing of events in floral development is recorded for the locality of the study. The observations are discussed in relation to current theories concerning the nature of the inferior ovary. Key words: Amelanchier, flower, development, inferior ovary, hypanthium.

scholarly journals INFLUENCE OF LOW TEMPERATURE ON FLORAL DEVELOPMENT IN CHRYSANTHEMUM

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 649f-649 ◽  
Author(s):  
Meriam G. Karlsson ◽  
Janice T. Hanscom
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Flower Development ◽  
Floral Development ◽  
Day Length ◽  
Flower Formation ◽  
Flower Initiation ◽  
Rooted Cuttings ◽  
Scanning Electron

The progression of flower initiation was documented in Dendranthema X grandiflorum (Ramat) Kitamura `Bright Golden Anne'. Rooted cuttings were planted and grown under 16 hours photoperiod (360 μmol·s-1m-2) and a constant 20C. After 7 days, the plants were pinched, the temperature reduced to 5, 10 or 15C and the day length shortened to 10 hours (13 mol·day-1m-2). Scanning electron microscopy was used to determine the transition from vegetative to reproductive meristem and to document the flower formation process. Shoot apices from three randomly selected plants were dissected weekly from each temperature until plants had developed floret primordia to completely cover the apical dome. Delayed floral development in the low temperature grown plants was a combination of a later flower initiation event and a slower progression of flower development. Required time for formation of 3-4 rows with floret primordia was about 21 days at 15C, 32 days at 10C and 70 days at 5C.

scholarly journals The HK5 and HK6 cytokinin receptors mediate diverse developmental pathways in rice

Development ◽  
2020 ◽  
Vol 147 (20) ◽  
pp. dev191734
Author(s):  
Christian A. Burr ◽  
Jinjing Sun ◽  
Maria V. Yamburenko ◽  
Andrew Willoughby ◽  
Charles Hodgens ◽  
...  
Keyword(s):  
Growth And Development ◽  
Apical Meristem ◽  
Shoot Growth ◽  
Floral Development ◽  
Developmental Pathways ◽  
Cytokinin Signaling ◽  
Cytokinin Receptors ◽  
Root And Shoot Growth ◽  
Cytokinin Response

ABSTRACTThe phytohormone cytokinin regulates diverse aspects of plant growth and development. Our understanding of the metabolism and perception of cytokinin has made great strides in recent years, mostly from studies of the model dicot Arabidopsis. Here, we employed a CRISPR/Cas9-based approach to disrupt a subset of cytokinin histidine kinase (HK) receptors in rice (Oryza sativa) in order to explore the role of cytokinin in a monocot species. In hk5 and hk6 single mutants, the root growth, leaf width, inflorescence architecture and/or floral development were affected. The double hk5 hk6 mutant showed more substantial defects, including severely reduced root and shoot growth, a smaller shoot apical meristem, and an enlarged root cap. Flowering was delayed in the hk5 hk6 mutant and the panicle was significantly reduced in size and infertile due to multiple defects in floral development. The hk5 hk6 mutant also exhibited a severely reduced cytokinin response, consistent with the developmental phenotypes arising from a defect in cytokinin signaling. These results indicate that HK5 and HK6 act as cytokinin receptors, with overlapping functions to regulate diverse aspects of rice growth and development.

The role of floral development in studies of legume evolution

1992 ◽  
Vol 70 (4) ◽  
pp. 692-700 ◽  
Author(s):  
Shirley C. Tucker
Keyword(s):  
Key Words ◽  
Floral Development ◽  
Developmental Pathways ◽  
Ceratonia Siliqua ◽  
Unique Type ◽  
Varied Structure ◽  
Interspecific Differences ◽  
Naturally Occurring ◽  
Key Words Development

Comparative floral development is useful to test hypotheses of phylogeny and taxonomic relationships among legumes because it provides a greater understanding of character states. It can reveal homologies, as in the cupule, an anomalous and varied structure among species of Psoralea that originates by fusion of two or more small bracts. Convergence is demonstrated by comparing differing developmental pathways of specialized floral features such as dorsiventral heterostameny, eccentric corolla, porate stamens, and enantiostyly, among species of Cassia, Senna, and Chamaecrista. Naturally occurring homeosis can be identified, as in the example of stamens developing from uncommitted primordia in petal sites in Saraca declinata. Floral development among species in a genus is generally very similar, with any differences usually occurring only terminally. In contrast, ontogenies among related genera show more differences, and those differences may be accelerated, appearing earlier in ontogeny than interspecific differences. Floral development in Ceratonia siliqua, in the same tribe as the Cassia group, diverges strongly from the latter, lacking petals and having a unique type of inception of stamens. Developmental evidence supports removing Ceratonia from Cassieae. Key words: development, evolution, flower, legumes, ontogeny, phylogeny.

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