The Reproductive Shoot in Grasses: Compression and Sterilisation

The Gramineae ◽  
2011 ◽  
pp. 164-206
Author(s):  
Agnes Arber
Keyword(s):  
Reproductive Shoot

Anatomical characterisation of the foliar colleters in Myrtoideae (Myrtaceae)

2012 ◽  
Vol 60 (8) ◽  
pp. 707 ◽  
Author(s):  
Cleber J. da Silva ◽  
Luiz Cláudio de A. Barbosa ◽  
Ana E. Marques ◽  
Maria Cristina Baracat-Pereira ◽  
Antônio L. Pinheiro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Relationships ◽  
External Morphology ◽  
Secretory Structures ◽  
Reproductive Shoot ◽  
Sds Page ◽  
Histochemical Tests ◽  
Five Tribes ◽  
Scanning Electron

Colleters are secretory structures that occur in vegetative or reproductive shoot apices of many botanical families. However, in the order Myrtales, reports of colleters have considered only external morphology. We therefore evaluated apical meristems of 52 species belonging to 17 genera from seven tribes of subfamily Myrtoideae (Myrtaceae), so as to analyse the incidence and morphological types of colleters. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on fresh and methacrylate-embedded material. Proteins of the colleter secretions were analysed by SDS-PAGE. We have classified and described the following three new colleter types: petaloid, conic and euryform. None of the species contained all three colleter types. The petaloid colleters were present in three tribes (Syzygieae, Melaleuceae and Lophostemoneae). The conic colleters were observed in three tribes (Leptospermeae, Myrteae and Melaleuceae) and the euryform type occurred in five tribes (Leptospermeae, Syncarpieae, Myrteae, Syzygieae and Melaleuceae). In the tribe Eucalypteae, we found no evidence of colleters. The presence of mucilaginous secretion that defines colleters was confirmed by histochemical tests, and no proteins were found in the secretion. The colleters in Myrtoideae may help clarify the phylogenetic relationships of the Myrtaceae family.

Austrosequoia wintonensis, a new taxodiaceous cone from Queensland, Australia

1978 ◽  
Vol 56 (24) ◽  
pp. 3119-3128 ◽  
Author(s):  
M. D. Peters ◽  
D. C. Christophel
Keyword(s):  
Upper Cretaceous ◽  
Sequoia Sempervirens ◽  
Reproductive Shoot ◽  
Single Row ◽  
Strong Similarity ◽  
Sequoiadendron Giganteum ◽  
To Come

Anew taxodiaceous ovulate cone, Austrosequoia wintonensis gen. et sp. nov., is described from the area of Winton, Queensland. Australia. The material is believed to come from the Upper Cretaceous but may be younger. The cones have 29–49 cone scales arranged helically around the axis. Each scale has four to seven ovules arranged in a single row. Reproductive shoot leaves are rhomboidal with an incurved apex and a distinct keel. Comparison with extant taxodiaceous genera indicate a strong similarity to Sequoia sempervirens (D.Don) Endl. and Sequoiadendron giganteum (Lindl.) Buchholz. Only limited similarities are observed with species of the Australian endemic Athrotaxis. The deposit also contains conifer pollen cones, ferns, and angiosperm remains which are yet to be described.

scholarly journals Effect of depth gradient and temperature on Zostera marina vegetative and reproductive phenology in the first year of the 1997–1998 El Niño

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Alf Enrique Meling-López ◽  
Silvia Emilia Ibarra-Obando ◽  
Horacio De la Cueva ◽  
Pedro Ortega-Romero ◽  
Adriana Leticia Navarro-Verdugo
Keyword(s):  
El Niño ◽  
Zostera Marina ◽  
El Nino ◽  
Southern Oscillation ◽  
Reproductive Phenology ◽  
Intertidal Environment ◽  
Reproductive Shoot ◽  
Stressful Environment ◽  
Subtidal Environment ◽  
Reproductive Biomass

Does Zostera marina exhibit phenotypic plasticity, maximizing fitness in traits responding to environmental factors, i.e., depth and temperature? We compared the vegetative and sexual phenology and reproductive effort of Z. marina by analyzing vegetative and reproductive shoot density, biomass, and reproductive stages to determine structural features of vegetative and reproductive shoots from subtidal and intertidal environments in San Quintín Bay, Baja California, a year before and after the 1997–1998 El Niño/Southern Oscillation (ENSO). We found significant differences in vegetative and reproductive biomass between intertidal and subtidal environments driven by temperature differences between ENSO and non-ENSO years. Subtidal plants had lower density of long reproductive shoots and a shorter reproductive cycle. Seed release occurred from May to October in the subtidal environment, and from May to November in the intertidal environment. Maximal recorded values were 219.5 (±45.8) seeds per reproductive shoot in the subtidal environment and 151.3 (±21.5) in the intertidal environment. We observed higher sexual activity and lower vegetative biomass in the intertidal environment, the most stressful environment. Both vegetative and reproductive biomass were affected by the increase in temperature during ENSO, but vegetative and reproductive shoot densities were not affected.

scholarly journals THIDIAZURON EFFECTS ON GROWTH INITIATION AND EXPRESSION IN MANGO (MANGIFERA INDICA L.)

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1167F-1168
Author(s):  
R. Nunez-Elisea ◽  
M. L. Caldeira ◽  
T. L. Davenport
Keyword(s):  
Mangifera Indica ◽  
Central Axis ◽  
Bud Break ◽  
Reproductive Shoot ◽  
Horticultural Crops ◽  
Shoot Initiation ◽  
Growth Initiation ◽  
Bud Growth ◽  
Axillary Bud Break ◽  
Mango Malformation

Thidiazuron (TDZ; N-phenyl-N-1,2,3-thiadiazol-5-ylurea) stimulates axillary bud break in some horticultural crops. We are exploring its ability to initiate bud growth in mango trees in order to manipulate vegetative and reproductive shoot initiation. Axillary buds on defoliated, decapitated shoots were treated in late October, 1989 (about two months before normal floral initiation), with 0, 125, or 1000 ppm TDZ. Although timing or percent of bud-break was unaffected by TDZ, the compound influenced growth expression. TDZ (125 ppm) produced morphologically typical panicles (mixed or purely floral), while at 1000 ppm purely floral panicles were produced which were abnormally compact (similar to panicles affected by mango malformation). Non-treated buds produced only vegetative shoots. Sprays of TDZ (25 to 200 ppm) on developing panicles produced morphological anomalies in panicles such as thickening of the central axis and secondary branches, increase in flower size, and sprouting of the most basal buds on the central axis. Effect during the vegetative flushing period will be discussed.

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