Determination of the Origin of Vigorous Shoots Generated from Particle-bombarded Chrysanthemum Shoot Tips
0
Citation
22
Reference
10
Related Paper
Abstract:
Vigorous shoots in chrysanthemums (Chrysanthemum morifolium) often develop from shoot tips (apical meristems with two leaf primordia) cultured in vitro following particle bombardment. The average fresh weight of regenerated shoots from a bombarded shoot tip of chrysanthemum ‘Jinba’ was 10 times more than that regenerated from unbombarded shoot tips. The average number of leaves per bombarded shoot tip was also more than that from an unbombarded shoot tip. The average number of leaves developing from a shoot tip increased with an increase in the amount of gold particles shot into the shoot tips. In addition, when the area destroyed in a shoot apical meristem (SAM) was varied by bombardment through nylon mesh with different pore sizes, the total number of leaves produced from each shoot tip increased with the size of the destroyed SAM area. Knowing the origin of these vigorous shoots, which may be from the bombarded meristem or from the lateral meristems, is important for the screening of transgenic plants. When the entire surface of a SAM was destroyed by bombardment, it was unable to rebuild itself; instead, lateral meristems were initiated at the base of the leaf primordia. Furthermore, the initiation of lateral meristems at the base of the leaf primordia was also observed in instances of restoration of the area of a partially destroyed SAM. This result indicates that vigorous lateral shoots initiate and develop from the bases of leaf primordia when SAMs are damaged to varying degrees. When leaf primordia-free shoot apical meristems (LP-free SAMs) were cultured after bombardment, vigorous shoots failed to develop from the wounded SAM; instead, the wounded LP-free SAMs regenerated a SAM by repairing the wounded areas and developed a non-vigorous single shoot. It was concluded the vigorous shoots do not participate in transgenic plant production because vigorous shoots arise from unbombarded lateral meristems. Finally, an effective and versatile method for transgenic plant production was established by combining micro-wound treatment on a SAM by bombardment and LP-free SAM culture to suppress the growth of vigorous lateral shoots after wounding.Keywords:
Primordium
Lateral shoot
Vigorous shoots in chrysanthemums (Chrysanthemum morifolium) often develop from shoot tips (apical meristems with two leaf primordia) cultured in vitro following particle bombardment. The average fresh weight of regenerated shoots from a bombarded shoot tip of chrysanthemum ‘Jinba’ was 10 times more than that regenerated from unbombarded shoot tips. The average number of leaves per bombarded shoot tip was also more than that from an unbombarded shoot tip. The average number of leaves developing from a shoot tip increased with an increase in the amount of gold particles shot into the shoot tips. In addition, when the area destroyed in a shoot apical meristem (SAM) was varied by bombardment through nylon mesh with different pore sizes, the total number of leaves produced from each shoot tip increased with the size of the destroyed SAM area. Knowing the origin of these vigorous shoots, which may be from the bombarded meristem or from the lateral meristems, is important for the screening of transgenic plants. When the entire surface of a SAM was destroyed by bombardment, it was unable to rebuild itself; instead, lateral meristems were initiated at the base of the leaf primordia. Furthermore, the initiation of lateral meristems at the base of the leaf primordia was also observed in instances of restoration of the area of a partially destroyed SAM. This result indicates that vigorous lateral shoots initiate and develop from the bases of leaf primordia when SAMs are damaged to varying degrees. When leaf primordia-free shoot apical meristems (LP-free SAMs) were cultured after bombardment, vigorous shoots failed to develop from the wounded SAM; instead, the wounded LP-free SAMs regenerated a SAM by repairing the wounded areas and developed a non-vigorous single shoot. It was concluded the vigorous shoots do not participate in transgenic plant production because vigorous shoots arise from unbombarded lateral meristems. Finally, an effective and versatile method for transgenic plant production was established by combining micro-wound treatment on a SAM by bombardment and LP-free SAM culture to suppress the growth of vigorous lateral shoots after wounding.
Primordium
Lateral shoot
Cite
Citations (0)
Rhizome-tips of Cymbidium goeringii REICHB. F. cultured on the basal medium (KNUDSON′s C with NITSCH′s microelement), developed into rhizomes without the shoot formation. However, the addition of 10mg/l kinetin to the medium induced shoot formation. Histological studies were carried out with the shoot formation in order to analyze the rhizome-shoot differentiation. Results of the observation were summarized as follows:During the growth of the rhizome, the apical meristem remained to a primitive appearance. A few mitotic figure was observed within the apical meristem from which small leaf primordia were porduced and developed into scale-like leaves. The cells in the leaf primordia appeared to be less meristematic and considerably vacuolated. A remarkable expansion of the cells in the subapical region could be responsible for elongation of the rhizome.In the course of the shoot formation, on the contrary, leaf primordia were produced with a short plastochron then developed into leaves with vascular tissues. Relatively abundant mitotic figures were observed not only within the apical meristem but also in the lower part and the leaf primordia. The cells in the leaf primordia and the subapical region were smaller and less vacuolated than those of the rhizome.
Primordium
Organogenesis
Lateral shoot
Elongation
Cite
Citations (9)
Sumary: Higher plants develop species-specific architectures by continuously generating lateral structures such as leaves and flowers from the shoot apical meristem post-embryonically. Their primordia are generated with phyllotactic patterns of species-specific manner and develop autonomously from the shoot apical meristem. In addition, axillary shoots, which form in the axils of leaves develop autonomously from the main axis and affect the final architecture of a plant. The variations of different developmental patterns in these lateral structures give rise to a variety of plant morphology. In this review, we focus on molecular mechanisms that regulate development of lateral structures.
Primordium
Lateral shoot
Apical dominance
Apical cell
Phyllotaxis
Cite
Citations (0)
Primordium
Lateral shoot
Organogenesis
Apical dominance
Apical cell
Cite
Citations (0)
Axillary and floral meristems are shoot meristems that initiate postembryonically. In Arabidopsis, axillary meristems give rise to branches during vegetative development while floral meristems give rise to flowers during reproductive development. This review compares the development of these meristems from their initiation at the shoot apical meristem up to the establishment of their specific developmental fates. Axillary and floral meristems originate from lateral primordia that form at flanks of the shoot apical meristem. Initial development of vegetative and reproductive primordia are similar, resulting in the formation of a morphologically defined primordium partitioned into adaxial and abaxial domains. The adaxial primordial domain is competent to form a meristem, while the abaxial domain correlates with the formation of a leaf. This review proposes that all primordia partition into domains competent to form the meristem and the leaf. According to this model, a vegetative primordium develops as leaf-bias while a reproductive primordium develops as meristem-bias.Key words: SHOOTMERISTEMLESS, LATERAL SUPPRESSOR, AINTEGUMENTA, adaxial primordial domain, abaxial primordial domain, shoot morphogenesis.
Primordium
Lateral shoot
Cite
Citations (13)
The terms "meristem" and "shoot tip" culture have often been indiscriminately interchanged. According to Cutter ), the apical meristem refers to only that portion of the shoot apex lying distal to the youngest leaf primordium. The shoot apex, or shoot tip, consists of the apical meristem and one to three subjacent leaf primordia. True apical meristem culture of higher plants was first demonstrated by Smith and Murashige ). The isolated tissues of the apical domes develop directly into plants, demonstrating the developmental automony of the angiosperm shoot apical meristem.
Primordium
Apex (geometry)
Lateral shoot
Phyllotaxis
Apical cell
Cite
Citations (0)
In order to obtain more microstructure information on development of soybean,the methods for apical meristem sections were studied in the paper.Based on the process of fixation,dehydration,transparency,saturated paraffin,embedding,section and dye,straight-sections of the shoot apical meristem of soybean were obtained.The results from this study indicated that the regions splitting actively,such as the top of apical meristem,leaf primordia and flower primordia,were dyed deeply.At the same time,pith meristem zone was dyed lightly.At vegetative growth stage,leaf primordia were found at the basal part of apical meristem,and they became bigger gradually.At reproductive growth stage,the dome-liked apical meristem became longer slightly,then each of floral primordia began to appear in turn.The results could provide the base for further investigation on anatomical structure and developmental biology of shoot apical meristem in soybean.
Primordium
Lateral shoot
Apical cell
Apical dominance
Phyllotaxis
Cite
Citations (1)
Within wild‐type Arabidopsis populations, a subset of the plants were found to have a single chimeric shoot on their primary shoot axes. The chimeric shoots were located below the lowest primary‐axis flower; and they exhibited features of both flowers and paraclades (lateral flowering shoots). Morphological analyses of chimeric shoots indicated that they developed from single primordia. In each chimeric shoot, the side furthest from the apical meristem was specified as ‘flower’—while the side closest to the meristem was specified as ‘paraclade’—suggesting that a stimulus from outside the apical meristem can directly induce primordia to develop as flowers. It is concluded that the development of the teratological chimeric shoots resulted from the overlap of the vegetative and floral specification processes within single primordia.
Primordium
Lateral shoot
Organogenesis
Cite
Citations (44)
Preface: the shoot apex: what it is and what it does 1. A source of cells: the apical cell 2. A source of cells: the meristem 3. Growth rates within the shoot apex 4. Cell cycles 5. The subcellular and biochemical structure of the meristem 6. The mechanism of primordium initiation 7. Positioning the primordia 8. Partitioning the apex: the size of the apical meristem and the primordia 9. The transition to flowering 10. The new floral meristem Index.
Primordium
Apex (geometry)
Lateral shoot
Apical cell
Cite
Citations (131)
Vegetative development in the Arabidopsis shoot apex follows both sequential and repetitive steps. Early in development, the young vegetative meristem is flat and has a rectangular shape with bilateral symmetry. The first pair of leaf primordia is radially symmetrical and is initiated on opposite sides of the meristem. As development proceeds, the meristem changes first to a bilaterally symmetrical trapezoid and then to a radially symmetrical dome. Vegetative development from the domed meristem continues as leaves are initiated in a repetitive manner. Abnormal development of the vegetative shoot apex is described for a number of mutants. The mutants we describe fall into at least three classes: (1) lesions in the shoot apex that do not show an apparent alteration in the shoot apical meristem, (2) lesions in the apical meristem that also (directly or indirectly) alter leaf primordia, and (3) lesions in the apical meristem that alter meristem size and leaf number but not leaf morphology. These mutations provide tools both to genetically analyze vegetative development of the shoot apex and to learn how vegetative development influences floral development.
Primordium
Apex (geometry)
Lateral shoot
Vegetative reproduction
Phyllotaxis
Cite
Citations (141)