• Title/Summary/Keyword: exotesta

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Taxonomic Implications of Seed Coat in the Subtribe Calthinae (Ranunculaceae) (미나리아재비과 동의나물아족의 종피형태와 분류학적 검토)

  • Heo, Kweon;Suh, Youngbae
    • Korean Journal of Plant Taxonomy
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    • v.38 no.1
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    • pp.1-16
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    • 2008
  • Anatomical features of seed coat were examined on Trollius, Calathodes, and Caltha of Ranunculaceae to evaluate the taxonomic circumscription of Megaleranthis saniculifolia, which is monotypic and endemic in Korea. Megaleranthis saniculifolia showed the exotestal type of seed coat exhibiting a well-developed palisade structure in exotesta and its external surface of exotesta cells was concave. On the other hand, the shape of exotesta cells in Caltha was cuboidal and the outer surface was smooth. The exotesta of Calathodes seeds was formed of the palisade structure like M. saniculifolia, but the outer surface of exotesta cells was smooth. The palisade structure was much better developed in the exotesta of Calathodes as well as Megaleranthis seeds than in the exotesta of Trollius seeds. The outer surface of exotesta cells in Trollius was either convex or concave according to the species examined. Since the genera of the subtribe Calthinae of the family display differences in seed sculpturing and the anaotmy of seed coat, these characteristics are useful to access taxonomic relationships among them. The morphological and anatomical features of seed coat suggest that Megaleranthis be possibly allied with Trollius rather than Caltha or Calathodes. Concave surface of seed coat cells and well-developed palisade structure of exotesta are shared by M. saniculifolia and some species of Trollius in common.

Seed characteristics of Withania somnifera (Solanaceae) (가지과 Withania somnifera 의 종자 형질)

  • Ghimire, Balkrishna;Ghimire, Bimal Kumar;Heo, Kweon
    • Korean Journal of Plant Taxonomy
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    • v.41 no.2
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    • pp.103-107
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    • 2011
  • The seed characteristics of Withania somnifera were studied using light and scanning electron microscopy in order to determine the specific features of this species. The seed color is yellow, and the seed shape is reniform measuring between two to three millimeters. The seed of W. somnifera is exarillate and albuminous. The seed coat type is exotestal. The seed coat develops from a single integument. The young seed coat consists of single-layered exotesta, multi-layered mesotesta and single-layered endotesta. However, parenchymatous mesotesta layers are completely compressed at maturity. Therefore, the seed coat was represented by sclerenchymatous exotesta. The primary sculpture on the seed surface is reticulate, and cells are irregular in shape with undulating anticlinal walls. In addition, the seed surface has several characteristic holes between the anticlinal walls.

Morphological Study of Storage Granules of Cotyledon Cells in Cannabis sativa cv. Chungsam (헴프종자 자엽세포의 저장과립에 관한 형태학적 연구)

  • Lee, Na-Young;Kim, Dong-Min;Kim, Eun-Soo
    • Applied Microscopy
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    • v.41 no.1
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    • pp.61-67
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    • 2011
  • The purpose of this study is to investigate the hemp (Cannabis sativa cv. Chungsam) seed structure and ultrastructure of food reserves by scanning and transmission electron microscopy. We examined the seed coat and embryo consisting of a hypocotyl-radicle axis and two cotyledons. The seed coat consisted of exotesta and endotesta. The exotesta was a mechanical layer with lignified and elongated cells, while endotesta of the underlying layers of the exotesta was consisted of two separated cell layers. The collapsed outer layer of endotesta showed the unique reticulate structures. In cotyledon cells, protein and lipid bodies occupied most of cytoplasm. Protein bodies varied in diameter from 1.8 to $5.0{\mu}m$ and possessed a protein matrix containing electron-dense globoid crystals. Numerous lipid bodies ranged from 0.8 to $3.0{\mu}m$ in diameter were distributed around the protein bodies. During the early stages of breakdown, protein bodies rapidly changed their shape into the granular feature, however, lipid bodies were gradually degradated and fused each other. The degeneration process of protein bodies and lipid bodies of cotyledon cells might be correlated with the reports which hemp seeds rapidly lose their ability to germinate.

Systematic application of seed morphology In Korean Orobanchaceae (한국산 열당과 종자 형태의 분류학적 적용)

  • An, Beom-Cheol;Hong, Suk-Pyo
    • Korean Journal of Plant Taxonomy
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    • v.33 no.4
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    • pp.411-420
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    • 2003
  • To examine the seed morphology in Korean Orobanchaceae, seeds of 5 species including 1 variety in five genera and one related taxon, Boschniakia himalaica Hook. f. & Thomson in Hook. f. from the Himalaya (7 taxa in total) were investigated by scanning electron microscopy (SEM). Two different seed types are recognized depending on three characters (e.g, .the seed size, seed coat structure and seed number per fruit). - Type I: size less than 1mm, seed coat structure reticulate and seed number per fruit more than ca. 1,000; Type II: size more than 1 mm, exotesta irregularly crested and seed number per fruit less than 1,000 (Lathraea japonicu Miq.). In Type I, three subtypes of exotesta internal surface pattern can also be classified; (1) Subtype Ia: reticulate - include irregularly striate (Ia') and deeply reticulate (Ia"), (2) Subtype Ib: foveolate, (3) Subtype Ic: smooth. Systematics application of the seed morphological data for the Korean Orobanchaceae is also briefly discussed.

Fruit and seed morphology of Korean Ranunculaceae (한국산 미나리아재비과의 열매 및 종자 형태)

  • Jung, Woo-Chul;Heo, Kweon
    • Korean Journal of Plant Taxonomy
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    • v.47 no.2
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    • pp.137-153
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    • 2017
  • Fruit and seed morphological characteristics were investigated in 36 taxa of 20 genera of Korean Ranunculaceae. As a result, fruits were classified as the achene, berry, or follicle type. In the taxa with achene, the presence of trichomes and stoma on the surface of the fruit and a feature in which the endocarp distinctively develops into a one-layer sclereid were considered as useful characteristics. Moreover, in the taxa with follicles, the composition of the seed coat (bitegmic vs. unitegmic), the cell shape of the seed coat, the presence of trichomes, and the type of seed coat were useful for taxonomic characteristics in Korean Ranunculaceae. Based on the fruit and seed characteristics, Adonis is likely to be classified into Helleboroideae rather than Ranunculoideae, as it has bitegmic ovules. In addition, Enemion is similar to Eranthis in unitegmic ovule and the seed coat structure which has non-sclereid exotesta; therefore, it is reasonable to be placed in Helleboroideae. According to the results of this study, more in-depth research is needed regarding the taxonomic positions of Callianthemum and Actaea, which has the only berry fruit type.

Embryo, Seed coat and Pericarp Development in Abeliophyllum distichum Nakai (Oleaceae): A Rare and Endemic Plant of Korea

  • Ghimire, Balkrishna;Jeong, Mi Jin;Choi, Go Eun;Lee, Hayan;Lee, Kyung Mee;Lee, Cheul Ho;Suh, Gang Uk
    • Korean Journal of Plant Resources
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    • v.28 no.3
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    • pp.350-356
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    • 2015
  • Abeliophyllum distichum is a monotypic taxon of Oleaceae and endemic to Korea. A comprehensive study on embryogeny and fruit and seed coat ontogeny in Abeliophyllum was carried out via microtome and light microscopy. The fertilization occurs during mid– to late April and embryo matures by early July. The embryo development follows the general fashion from globular embryo – transition embryo – heart shaped embryo – torpedo embryo – walking-stick embryo to mature embryo. The pericarp clearly differentiates into three histological zones: exocarp, mesocarp, and endocarp. The young seed comprises 10-12 cells thick seed coat and the mature seed coat comprises an exotesta, 6-8 mesotesta and an endotesta. Any crystals, phenolic-like compounds, idioblasts, and the sclereids are not found in pericarp as well as seed coat. An overall development confirms Solanade type of embryogenesis in Abeliophyllum. The endocarp becomes more prominent in mature fruit and all the layers of endocarp are highly lignified. On the basis of mechanical layer the seed coat is of exotestal type.

Embryology of Jeffersonia dubia Baker et S. Moore (Berberidaceae) and comparison with allied genera (깽깽이풀의 발생과 근연속간 비교)

  • Ghimire, Balkrishna;Heo, Kweon
    • Korean Journal of Plant Taxonomy
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    • v.42 no.4
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    • pp.260-266
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    • 2012
  • Because the embryological features of Jeffersonia dubia are poorly understood, we conducted the first embryological study comparing it to other related genera of Berberidaceae. Important embryological features of J. dubia are as follows: the anther is tetrasporangiate, anther wall formation confirms basic type, glandular tapetum cells are two nucleate, the epidermis persistent, and the endothecium develops fibrous thickenings, anther dehiscence by two valves, meiosis in a microspore mother cell is accompanied by simultaneous cytokinesis, microspore tetrads are usually tetrahedral, pollen grains two cells at the time of anthesis. The ovule is bitegmic, anatropous and crassinucellate, archesporium single celled, development of the embryo sac Polygonum type, a mature embryo sac is ellipsoidal in shape. Endosperm formation is of Nuclear type and embryogeny Onagrad type. Seeds are arillate and seed coat exotestal type. Embryological comparisons showed that Jeffersonia resemble to Epimedium and Vancouveria rather than Berberis and Mahonia in some features, like as number of tapetal cells, cytokinesis in meiosis, and thickness of exotesta. It also resembles to Gymnospermium in mode of anther wall formation, number of tapetal cells, formation of nucellar cap, and nature of antipodal cells. Nevertheless, Jeffersonia and Gymnospermium differ from several other embryological features and molecular data too. Therefore, embryological evidences support that Jeffersonia is closely related with Epimedium and Vancouveria.