Pathways for inflorescence and floral induction in Antirrhinum

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1535-1544 ◽  
Author(s):  
D. Bradley ◽  
C. Vincent ◽  
R. Carpenter ◽  
E. Coen
Keyword(s):  
Morphological Analysis ◽  
Floral Induction ◽  
Leaf Size ◽  
Axillary Meristem ◽  
The Third ◽  
Axillary Meristems ◽  
Meristem Identity ◽  
Short Internodes ◽  
Dependent Pathway ◽  
Subtending Leaves

The presentation of flowers on a modified stem, the inflorescence, requires the integration of several aspects of meristem behaviour. In Antirrhinum, the inflorescence can be distinguished by its flowers, hairy stem, modified leaves, short internodes and spiral phyllotaxy. We show, by a combination of physiological, genetical and morphological analysis, that the various aspects of the inflorescence are controlled by three pathways. The first pathway, depends on expression of the floricaula gene, and is rapidly and discretely induced by exposure to long daylength. Activation of this pathway occurs in very young axillary meristems, resulting in a floral identity. In addition, the length of subtending leaves and hairiness of the stem are partially modified. The second pathway affects leaf size, internode length, and stem hairiness, but does not confer floral meristem identity. This pathway is induced by long daylength, but not as rapidly or discretely as the floricaula-dependent pathway. The third pathway controls the switch in phyllotaxy from decussate to spiral and is activated independently of daylength. The coordination of these three programmes ensures that apical and axillary meristem behaviour is integrated.

Effect of the Stages of Floral Development and Postharvest Temperatures to Flowering of Eremurus in Israel

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 536d-536
Author(s):  
Rina Kamenetsky
Keyword(s):  
Morphological Analysis ◽  
Developmental Disorder ◽  
Floral Development ◽  
The Third ◽  
Initial Stage ◽  
Floral Differentiation ◽  
Soil Temperatures ◽  
Very High ◽  
Development Application ◽  
Flowering Process

The influence of postharvest temperature on the flowering response of Eremurus was studied. The plants were harvested at four different stages of development and were separated into three groups. The first group was immediately exposed to 2 °C, the second group to 20 °C followed by 2 °C, and the third group to 20 °C followed by 32 °C and, subsequently, 2 °C. Scanning electron microscopy (SEM) was used for concurrent morphological analysis of floral development. Application of 2 °C to the plants in the initial stage of floral development caused plant destruction and death, while the same treatment applied at the stage of full differentiation promoted normal flowering. Temperatures of 20 °C and, especially, 32 °C, significantly improved flowering of the plants harvested in the early stages of florogenesis, whereas the same treatment applied to the plants harvested at the end of flower differentiation did not affect the flowering process. A developmental disorder, which we term “Interrupted Floral Development” (IFD), was observed only in the plants harvested when the racemes were fully differentiated. This was probably caused by the very high air and soil temperatures that prevail in Israel during the summer. The extent of floral differentiation has a determinant role in subsequent scape elongation and flowering.

scholarly journals Establishment of a Rapid Plant Regeneration System in Physalis angulata L. through Axillary Meristems

2015 ◽  
Vol 7 (4) ◽  
pp. 471-474
Author(s):  
Owk ANIEL KUMAR ◽  
Songa RAMESH ◽  
Sape SUBBA TATA
Keyword(s):  
Shoot Culture ◽  
Shoot Multiplication ◽  
Multiple Shoot ◽  
Herbaceous Plant ◽  
Axillary Meristem ◽  
Regeneration System ◽  
Axillary Meristems ◽  
Meristem Explants ◽  
Physalis Angulata

An optimal plant propagation method of Physalis angulata L., a medicinally important herbaceous plant species has been developed using axillary meristem explants. Shoot bud proliferation was initiated from axillary meristem explants cultured on MS medium supplemented with various concentrations of 0.5-2.5mg/L/(BAP)/(Zeatin)/(KIN). The maximum in vitro response of shooting frequency of explants (88.1%) and shoots per explant (42) was achieved with medium containing 1.0mg/L BAP. Multiple shoot culture was established by repeated subculturing of the shoot buds of axillary meristems on shoot multiplication medium. Among the subculture media BAP in combination with 1.5mg/L (IAA)+0.25mg/L(GA3) produced maximum shoots per explant (128±0.29) after two weeks of culture. Effective in vitro shoot elongation and rooting was achieved on 1.0mg/L(GA3) and 1.0mg/L(IBA), respectively. Most of the generated shoots were successfully transferred to soil under field conditions. The survival percentage of the transferred plants on soil was found to be 90 per cent.  This protocol can be used for commercial propagation and for future genetic improvement studies.

scholarly journals New bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu islands revealed by molecular and morphological analysis

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Gustavo Sanchez ◽  
Jeffrey Jolly ◽  
Amanda Reid ◽  
Chikatoshi Sugimoto ◽  
Chika Azama ◽  
...  
Keyword(s):  
Morphological Analysis ◽  
East Timor ◽  
Ryukyu Islands ◽  
Morphological Investigation ◽  
Ryukyu Archipelago ◽  
The Third ◽  
The Ryukyu Islands ◽  
Close Relationship ◽  
Microbe Interactions ◽  
Host Microbe Interactions

AbstractBobtail squid are emerging models for host–microbe interactions, behavior, and development, yet their species diversity and distribution remain poorly characterized. Here, we combine mitochondrial and transcriptome sequences with morphological analysis to describe three species of bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu archipelago, and compare them with related taxa. One Ryukyuan type was previously unknown, and is described here as Euprymna brenneri sp. nov. Another Ryukyuan type is morphologically indistinguishable from Sepiola parva Sasaki, 1913. Molecular analyses, however, place this taxon within the genus Euprymna Steenstrup, 1887, and additional morphological investigation led to formal rediagnosis of Euprymna and reassignment of this species as Euprymna parva comb. nov. While no adults from the third Ryukyuan type were found, sequences from hatchlings suggest a close relationship with E. pardalota Reid, 2011, known from Australia and East Timor. The broadly sampled transcriptomes reported here provide a foundation for future phylogenetic and comparative studies.

scholarly journals Populus CEN/TFL1 regulates first onset of flowering, axillary meristem identity and dormancy release in Populus

2010 ◽  
Vol 62 (4) ◽  
pp. 674-688 ◽  
Author(s):  
Rozi Mohamed ◽  
Chieh-Ting Wang ◽  
Cathleen Ma ◽  
Olga Shevchenko ◽  
Sarah J. Dye ◽  
...  
Keyword(s):  
Dormancy Release ◽  
Axillary Meristem ◽  
First Onset ◽  
Meristem Identity

scholarly journals A Terminal Flower1-Like Gene from Perennial Ryegrass Involved in Floral Transition and Axillary Meristem Identity

2001 ◽  
Vol 125 (3) ◽  
pp. 1517-1528 ◽  
Author(s):  
Christian S. Jensen ◽  
Klaus Salchert ◽  
Klaus K. Nielsen
Keyword(s):  
Perennial Ryegrass ◽  
Floral Transition ◽  
Axillary Meristem ◽  
Meristem Identity

Ecological advantage of leaf heteroblasty in Costus pulverulentus (Costaceae)

Botany ◽  
2015 ◽  
Vol 93 (3) ◽  
pp. 151-158 ◽  
Author(s):  
J. Antonio Guzmán Q.
Keyword(s):  
Leaf Area ◽  
Morphological Analysis ◽  
Leaf Size ◽  
Efficiency Index ◽  
Basal Leaf ◽  
Adaptive Value ◽  
Crown Density ◽  
Size And Morphology ◽  
Light Capture ◽  
Light Acquisition

Leaf heteroblasty is a plant phenomenon related to leaf development that describes substantial differences between temporally separated plant stages. This study explores the ecological advantage of leaf heteroblasty in the herb Costus pulverulentus C.Presl and analyzes its possible adaptive value. Heteroblasty was studied using leaf morphology analysis and characterizations of leaf area, specific leaf area (SLA), and leaf divergence angles along the crown. A light capture efficiency index (STAR) was also used by simulating plants with only top- or basal-leaf forms to test its adaptive value. Morphological analysis indicated that C. pulverulentus develop two leaf forms: basal leaves with an obovate form, and top leaves with an oblanceolate form. Mid-crown leaves showed a reduced SLA and angles of divergence, and an increased area compared with top and lower leaves, which may indicate greater space utilization for light acquisition. Plants with top-leaf forms showed greater STAR than plants with basal-leaf forms, likely due to lower self-shading and lower crown density produced by leaf arrangements. Results of this study suggests that changes in leaf size and morphology occur in later stages of plant development as an adaptation to reduce self-shading and crown density which promotes an adaptive advantage by increasing the STAR.

scholarly journals Expression Pattern of Homologues of Floral Meristem Identity Genes LFY and AP1 during Flower Development in Apple

2000 ◽  
Vol 125 (4) ◽  
pp. 398-403 ◽  
Author(s):  
Nobuhiro Kotoda ◽  
Masato Wada ◽  
Sadao Komori ◽  
Shin-ichiro Kidou ◽  
Kazuyuki Abe ◽  
...  
Keyword(s):  
Flower Development ◽  
Woody Plants ◽  
Floral Induction ◽  
Fruit Trees ◽  
Vegetative Organs ◽  
Meristem Identity ◽  
Floral Gene ◽  
Floral Bud ◽  
The Relationship

Two apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] homologous fragments of FLO/LFY and SQUA/AP1 (AFL and MdAP1, respectively) were analyzed to determine the relationship between floral bud formation and floral gene expression in `Jonathan' apple. The AFL gene was expressed in reproductive and vegetative organs. By contrast, the MdAP1 gene, identified as MdMADS5, which is classified into the AP1 group, was expressed specifically in sepals concurrent with sepal formation. Based on these results, AFL may be involved in floral induction to a greater degree than MdAP1 since AFL transcription increased ≈2 months earlier than MdAP1. Characterization of AFL and MdAP1 should advance the understanding of the processes of floral initiation and flower development in woody plants, especially in fruit trees like apple.

Morphology and development of the primary and accessory buds of Eucalyptus regnans

1972 ◽  
Vol 20 (2) ◽  
pp. 175 ◽  
Author(s):  
KW Cremer
Keyword(s):  
Axillary Meristem ◽  
Serial Sections ◽  
Meristematic Tissue ◽  
Eucalyptus Regnans ◽  
Apical Bud ◽  
Direct Observations ◽  
Continuous Sequence ◽  
Shoot System ◽  
Axillary Meristems ◽  
Thin Walled

The vegetative axillary buds of Eucalyptus regnans F. Muell. at various ages were studied by light microscopy in serial sections and by direct observations in the field and glasshouse. All buds (except the very first apical bud) originated from axillary meristems, i.e. from generative tissue which arose in the axils of primordial leaves and survived in a meristematic condition for many years. Each axillary meristem normally produced one emergent primary bud and then an indefinite sequence of concealed accessory buds. The extensive dynamic shoot-system condensed within a primary bud comprised secondary as well as tertiary axes and their respective appendages. All parts were present throughout the year in a continuous sequence of maturation which extended also to the expanding shoot. During winter, development appeared to be merely slowed down or suspended. Primary buds which did not grow into shoots were shed after only a few weeks. The accessory buds were formed in a uniserial descending series at the base of and abaxial to each primary axillary bud. The first of the accessory buds was initiated within the primary bud, and the second within the expanding shoot. The first accessory bud resembled young primary buds in structure, but subsequent accessory buds were less and less complex. Keeping pace with the cambium, the axillary meristem formed a radial trace of thick-walled parenchyma in the wood and accessory buds embedded in a strand of thin-walled parenchyma in the bark. The distal portions of the bud strand and the buds embedded in it were shed progressively with the decorticating bark. Each of the bud strands which traversed the bark of 20-year-old E. viminalis Labill. was found to contain six to 12 radial strips of meristematic tissue. When epicormic growth was stimulated, several of these strips produced files of separate, new, condensed shoots. Of the scores of shoots thus initiated throughout the length of the bud strand, up to 10 or 20 of the distal ones emerged from the bark and grew into epicormic shoots. The buds of 20 other eucalypt species were examined by dissecting microscope only. It appeared that their bud systems were essentially similar to that of E. regnans. The widened concept of the axillary meristem shifts attention from individual buds to the continuous generative powers of the axillary meristem and helps to explain the outstanding capacity of the eucalypts to produce new shoots.

scholarly journals A suppressor of axillary meristem maturation promotes longevity in flowering plants

2020 ◽  
Author(s):  
Omid Karami ◽  
Arezoo Rahimi ◽  
Majid Khan ◽  
Marian Bemer ◽  
Rashmi R. Hazarika ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Development ◽  
Ectopic Expression ◽  
Flowering Plants ◽  
Axillary Meristem ◽  
Flowering Genes ◽  
Axillary Meristems ◽  
Maturation State ◽  
Stem Cell Niches ◽  
Ga Biosynthesis

AbstractPost embryonic development and growth of flowering plants are for a large part determined by the activity and maturation state of stem cell niches formed in the axils of leaves, the so-called axillary meristems (AMs)1,2. Here we identify a new role for the Arabidopsis AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED 15 (AHL15) gene as a suppressor of AM maturation. Loss of AHL15 function accelerates AM maturation, whereas ectopic expression of AHL15 suppresses AM maturation and promotes longevity in Arabidopsis and tobacco. Together our results indicate that AHL15 expression acts as a key molecular switch, directly downstream of flowering genes (SOC1, FUL) and upstream of GA biosynthesis, in extending the plant’s lifespan by suppressing AM maturation.

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