Induced apogamy in Tmesipteris (Psilotaceae)

2004 ◽  
Vol 82 (6) ◽  
pp. 721-725 ◽  
Author(s):  
Dean P Whittier
Keyword(s):  
Shoot Apical Meristem ◽  
Nutrient Medium ◽  
Apical Meristem ◽  
Vascular Tissue ◽  
Axenic Culture ◽  
Epidermal Cells ◽  
Direct Connection ◽  
Normal Anatomy ◽  
Induced Apogamy ◽  
Fern Gametophytes

Gametophytes of Tmesipteris lanceolata Dang., which are mycorrhizal in nature, were grown in axenic culture. If cultured in the light on a nutrient medium containing minerals and 0.5% glucose, they did not become photosynthetic; however, about 15% of them produced apogamous sporophytes with stems and microphylls. The gametophyte–sporophyte junction had a direct connection between the gametophyte and sporophyte tissues and lacked a foot, which is typical for apogamy. Gametangia were limited to the gametophyte portions of these gametophyte–sporophyte growths, and the vascular tissue was present only in the sporophyte regions. The apogamous aerial stems had the normal anatomy for a sporophyte, with vascular tissue, epidermal cells, stomata, and chlorenchyma. The origin of the apogamous sporophytes was different from the origin in fern gametophytes. The Tmesipteris sporophytes arose terminally from the gametophyte apices. It appears that the apical meristem of the gametophyte is converted to a shoot apical meristem to form the apogamous aerial shoot.Key words: Tmesipteris, Psilotaceae, apogamy, sporophyte, gametophyte.

In situ localization of storage protein mRNAs in developing meristems of Brassica napus embryos

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 299-313 ◽  
Author(s):  
D.E. Fernandez ◽  
F.R. Turner ◽  
M.L. Crouch
Keyword(s):  
Brassica Napus ◽  
Storage Protein ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Vascular Tissue ◽  
Leaf Primordia ◽  
Root Apical Meristem ◽  
Cdna Clones ◽  
Final Maturation

Probes derived from cDNA clones of napin and cruciferin, the major storage proteins of Brassica napus, and in situ hybridization techniques were used to examine changes in the spatial and temporal distribution of storage protein messages during the course of embryogeny, with a special emphasis on the developing apical meristems. Napin mRNAs begin to accumulate in the cortex of the axis during late heart stage, in the outer faces of the cotyledons during torpedo stage and in the inner faces of the cotyledons during cotyledon stage. Cruciferin mRNAs accumulate in a similar pattern but approximately 5 days later. Cells in the apical regions where root and shoot meristems develop do not accumulate storage protein messages during early stages of embryogeny. In the upper axis, the boundary between these apical cells and immediately adjacent cells that accumulate napin and cruciferin mRNAs is particularly distinct. Our analysis indicates that this boundary is not related to differences in tissue or cell type, but appears instead to be coincident with the site of a particular set of early cell divisions. A major change in the mRNA accumulation patterns occurs halfway through embryogeny, as the embryos enter maturation stage and start drying down. Final maturation of the shoot apical meristem is associated with the development of leaf primordia and the accumulation of napin mRNAs in the meristem, associated leaf primordia and vascular tissue. Cruciferin mRNAs accumulate only in certain zones of the shoot apical meristem and on the flanks of leaf primordia. Neither type of mRNA accumulates in the root apical meristem at any stage.

The shoot apical meristem and development of vascular architectureThis review is one of a selection of papers published on the Special Theme of Shoot Apical Meristems.

2006 ◽  
Vol 84 (11) ◽  
pp. 1660-1671 ◽  
Author(s):  
Nancy G. Dengler
Keyword(s):  
Arabidopsis Thaliana ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Leucine Zipper ◽  
Vascular Tissue ◽  
Vascular System ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Integrative Model ◽  
Class Iii

The shoot apical meristem (SAM) functions to generate external architecture and internal tissue pattern as well as to maintain a self-perpetuating population of stem-cell-like cells. The internal three-dimensional architecture of the vascular system corresponds closely to the external arrangement of lateral organs, or phyllotaxis. This paper reviews this correspondence for dicotyledonous plants in general and in Arabidopsis thaliana (L.) Heynh., specifically. Analysis is partly based on the expression patterns of the class III homeodomain-leucine zipper transcription factor ARABIDOPSIS THALIANA HOMEOBOX GENE 8 (ATHB8), a marker of the procambial and preprocambial stages of vascular development, and on the anatomical criteria for recognizing vascular tissue pattern. The close correspondence between phyllotaxis and vascular pattern present in mature tissues arises at early stages of development, at least by the first plastochron of leaf primordium outgrowth. Current literature provides an integrative model in which local variation in auxin concentration regulates both primordium formation on the SAM and the first indications of a procambial prepattern in the position of primordium leaf trace as well as in the elaboration of leaf vein pattern. The prospects for extending this model to the development of the complex three-dimensional vascular architecture of the shoot are promising.

scholarly journals Sample preparation for laser-microdissection of soybean shoot apical meristem

2012 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Chui E. Wong ◽  
Mohan B. Singh ◽  
Prem L. Bhalla
Keyword(s):  
Sample Preparation ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Laser Microdissection ◽  
Specific Cell ◽  
Legume Crop ◽  
Continuous Formation ◽  
Molecular Events ◽  
Depth Analysis ◽  
Specialized Equipment

The shoot apical meristem houses stem cells responsible for the continuous formation of aerial plant organs including leaves and stems throughout the life of plants. Laser-microdissection in combination with high-throughput technology such as next generation sequencing permits an in-depth analysis of molecular events associated with specific cell type of interest. Sample preparation is the most critical step in ensuring good quality RNA to be extracted from samples following laser-microdissection. Here, we optimized the sample preparation for a major legume crop, soybean. We used Farmer’s solution as a fixative and paraffin as the embedding medium for soybean shoot apical meristem tissue without the use of any specialized equipment. Shorter time for tissue fixation (two days) was found to be critical for the preservation of RNA in soybean shoot apical meristem. We further demonstrated the utility of this method for different tissues derived from soybean and rice. The method outlined here shall facilitate studies on crop plants involving laser-microdissection.

Somatic embryogenesis from Arabidopsis shoot apical meristem mutants

Planta ◽  
2002 ◽  
Vol 214 (6) ◽  
pp. 829-836 ◽  
Author(s):  
Andreas Mordhorst ◽  
Marijke Hartog ◽  
Mazen El Tamer ◽  
Thomas Laux ◽  
Sacco de Vries
Keyword(s):  
Somatic Embryogenesis ◽  
Shoot Apical Meristem ◽  
Apical Meristem

scholarly journals Arabidopsis Argonaute10 Specifically Sequesters miR166/165 to Regulate Shoot Apical Meristem Development

Cell ◽  
2011 ◽  
Vol 145 (2) ◽  
pp. 242-256 ◽  
Author(s):  
Hongliang Zhu ◽  
Fuqu Hu ◽  
Ronghui Wang ◽  
Xin Zhou ◽  
Sing-Hoi Sze ◽  
...  
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Meristem Development

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

scholarly journals Spatiotemporal Sequestration of miR165/166 by Arabidopsis Argonaute10 Promotes Shoot Apical Meristem Maintenance

Cell Reports ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. 1819-1827 ◽  
Author(s):  
Yuyi Zhou ◽  
Minami Honda ◽  
Hongliang Zhu ◽  
Zhonghui Zhang ◽  
Xinwei Guo ◽  
...  
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Meristem Maintenance

Phyllotaxis of the palm Euterpe oleracea Mart. at the level of the shoot apical meristem

Botany ◽  
2010 ◽  
Vol 88 (5) ◽  
pp. 528-536 ◽  
Author(s):  
Denis Barabé ◽  
Laura Bourque ◽  
Xiaofeng Yin ◽  
Christian Lacroix
Keyword(s):  
Shoot Apical Meristem ◽  
Fundamental Theorem ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Divergence Angle ◽  
Euterpe Oleracea ◽  
The Mean ◽  
The Relationship ◽  
Euterpe Oleracea Mart

Previous studies on palm phyllotaxis deal mainly with the mature trunk. The goals of this study are (i) to determine the relationship between the number of parastichies, the divergence angle, and the plastochrone ratio at the level of the shoot apical meristem; (ii) to examine whether there are fluctuations in the divergence angle; (iii) to interpret the significance of phyllotactic parameters with respect to the mode of growth of the apex. The tubular base of the leaf primordium is more or less asymmetrical, and completely surrounds the shoot apical meristem. The phyllotactic system corresponds to a (2, 3) conspicuous parastichy pair. The mean divergence angle per apex varies between 126.9° ± 9.3° (mean ± SD) and 135. 8° ± 8.0°. Divergence angles for all apices fluctuate within a range of 115.89° to 157.33°. The mean plastochrone ratios between apices varies from 1.35 ± 0.18 to 1.58 ± 0.12. The plastochrone ratio at each plastochrone for all apices ranges from 1.09 to 2.00. There is no correlation between the angle of divergence and the plastochrone ratio. There is a fluctuation in the value of the divergence angle that falls within the range predicted by the fundamental theorem of phyllotaxis. The high value of the ratio of the diameter of leaf primordia over the diameter of the apex, and the long plastochrone might explain the lack of correlation between certain phyllotactic parameters.

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