• Title/Summary/Keyword: cotyledon expansion

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Cotylodon Development and Seeding Growth of Lotus corniculantus , Lotus tenuis and Their Reciprocal Hybrids (Lotus corniculantus , Lotus tenuis 및 이들 상호 교잡종의 자엽과 유식물의 생장발육)

  • S. N. Hur;P. R. Beuselinck;C. J. Nelson
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.15 no.1
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    • pp.13-18
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    • 1995
  • Seedling development among reciprocal FI hybrids and their parents, Lotus comiculatus and L renuis, were studies using a simple method of measuring cotyledon area. Cotyledon area attached to the plant could be measured with simple rapid method. Cotyledons expanded very rapidly during the first week, then slightly expanded until maximum size was reached around 3 weeks after emergence. Cotyledon area upon emergence was correlated with seed size (P=0.05), but after emergence there was a divergence in cotyledon expansion rate. Rapidity of photosynthetic area development was determinant factor for seedling growth of trefoil species. 2 $\times$ m2 and 1 $\times$ m2 among the hybrids promised the possibility increasing seedling vigor of birdsfoot trefoil.

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Growth and Critical Light Intensity at Cotyledon Stage of Cornus controversa Hemsl. Seedling (층층나무 자엽단계(子葉段階) 유묘(幼苗)의 생장(生長)과 한계광도(限界光度)에 관(關)한 연구(硏究))

  • Cho, Jae Hyoung;Hong, Sung Gak;Kim, Jong Jin
    • Journal of Korean Society of Forest Science
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    • v.87 no.3
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    • pp.493-500
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    • 1998
  • To investigate the effects of light intensity on the growth, and the critical minimum light intensity for growing of Cornus controversa seedlings at the stage of cotyledon, hypocotyl elongation, cotyledon expansion, the times of leaves appearance, dry weights of each organ, and specific leaf area(SLA) were measured on a growth chamber with several light intensity gradients(385, 32, 17, 8, and $5{\mu}mol\;m^{-2}s^{-1}$). There was a positive correlationship between the size of cotyledon and the biomass of cotyledon and total seedling. Hypocotyl was more elongated under relatively low light intensities, such as 32, 17, 8, and $5{\mu}mol\;m^{-2}s^{-1}$ than under $385{\mu}mol\;m^{-2}s^{-1}$ light intensity, however, dry weight of the hypocotyl was adverse. As the light intensities decreased, the leaf appearance was delayed and the number of leaves decresed. In addition, leaves did not appear under $8{\mu}mol\;m^{-2}s^{-1}$ and $5{\mu}mol\;m^{-2}s^{-1}$ light intensity. Although cotyledons were more fully expanded under 32 and $17{\mu}mol\;m^{-2}s^{-1}$ light intensities than $385{\mu}mol\;m^{-2}s^{-1}$ light intensity, the dry weights of cotyledons were greater under the high light intensity. The dry weight of cotyledon, hypocotyl, root and leaves showed a decreased pattern with decreasing light intensities, but root to shoot(hypocotyl+leaves) ratio rapidly increased. Roots did not develop below $8{\mu}mol\;m^{-2}s^{-1}$ light intensity. In conclusion, the results showed that the critical minimum light intensity for growing of Cornus controversa seedlings was above $17{\mu}mol\;m^{-2}s^{-1}$ light intensity.

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Cotyledon and Leaf Development Associated with Seeding Vigor of Six Forage Lerumes (여섯가지 두과목초의 유식물 활력과 관련된 자엽과 엽의 발달)

  • Hur, S.N.;Nelson, C.J.
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.15 no.1
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    • pp.19-23
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    • 1995
  • Cotyledon and leaf development of six important forage legums were compared to study their contribution to the seedling growth, Cotyledons of forage legumes expanded their size rapidly during one week maximum size was reached and entered senescence. Larger seeds produced greater colyledon area, and speed of colyledon expansion was closely associated with seedling growth. Earlier onset leaf production and earlier leaf development were major determinant factor initial seedling growth. Alfalfa and red clover which have larger seeds were good in seedling vigor with larger photosynthetic area. Alsike clover and white clover with small seeds showed also good seedling vigor, as they developed leaves early with relatively high photosynthetic rate. On the other hand, though lespedeza has heavy seeds, its seedling vigor was very poor with slow photosynthetic area development and low photosynthetic rate.

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STUDIES ON THE TISSUE CULTURE OF PANAX GINSENG

  • Harn C
    • Proceedings of the Ginseng society Conference
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    • 1974.09a
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    • pp.9-22
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    • 1974
  • Unlike the tissue culture in animals and human being, in higher plants various parts of the plant are cultured for varied purposes, and they are named variously depending on which parts are used as explants or what purposes they are cultured for. Followings are some of the names of culture used frequently: organ culture, tissue culture, callus culture, single cell culture, meristem culture, mericlone culture, ovary culture, ovule culture, embryo culture, endosperm culture, anther culture, pollen culture, protoplast culture, etc.. As the names of the culture indicate, in some kinds of culture the explants used for culture are actually not tissues, but organs, single cells, or protoplasts. It seems, however, convenient to call all of the above-mentioned cultures grossly as tissue culture. Several kinds of tissue culture were attempted using Panax ginseng as material and some of the results were summarized below. 1. Callus culture After dormancy of the sed was broken, whole embryo or parts (hypocotyl, cotyledon and epicotyl) of partly grown embryo were cultured in the media supplemented with growth regulators. Rapid swelling occurred in a few weeks, but most of the swelling was observed only in the basal part of epicotyl, changes in the other parts of embryo appearing in much later stages. The swelling or increase in size, however, was resulted not from the divisions of cells, but from the mere expansion of cell. Real calli were formed about two months after inoculation of explants. Callus tissues developed from cortex, pith, and vascular bundle in the cases of hypo- and epicotyl, from mesophyl tissue in the case of cotyledon. Shoots developed more easily from cotyledons regardless of whether they are detached from or attached to the embryo proper. 2. Culture in the Knudson C medium When cotyledons, detached from or attached to the embryo proper, were cultured in the growth regulator-free Knudson C medium comprision only several kinds of mineral compounds and sucrose, shoot primordium or callus developed profusely and finally plantlets were produced directly from shoot primordium or indirectly through callus. In this medium epidermal cells as well as mesophyl cells of the cotyledon became meristematic and divided, changing into multinucleate cells or multicellular bodies, developing eventually into either shoot primordia or calli. 3. Anther culture Anthers were cultured in the media supplemented with various growth regulators applied singly or in combinations. Callus was formed mostly in the connective tissue of anther. Cells of anther wall layers changed in appearance, but no division occurred. Microspores of all stages in development were not changed, ruling out the possibility that microspore-originated callus might be formed. 4. Isolation of protoplast Protoplasts were isolated from young root, leaf, and epicotyl, using 0.7M D-mannitols as osmoticum and using macerozyme and cellulase respectively for maceration and digestion of the cell wall. Production in large number of naked intact protoplast was rather difficult as compared with other plant species. Fusion of protoplasts occurred infrequently mainly due to the fewer number of naked protoplasts in the solution.

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Bioassays of Plant Hormones and Plant Growth Regulating Substances I . Auxins, Gibberellins, and Cytokinins (식물홀몬 및 생장조절물질의 생물검정기술 I. 옥신, 지베렐린 및 싸이토키닌)

  • 이정명
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.s01
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    • pp.4-15
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    • 1989
  • The objective of this paper is to compare and summarize the procedure and effectiveness of some bioassay systems and to point out ways to obtain reliable results from each bioassay. Detailed C:escriptions were given for those widely-adapted bioassay methods, such as mungbean rooting (auxin), Avena first internode straight growth (auxin), dwarf rice growth (gibberellin), dwarf pea epicotyl elongation (gibberellin), radish cotyledon expansion test (cytokinin), and tobacco stem pith callus growth (cytokinin), and the effects of various plant growth regulators including some recently introduced growth retardants (Paclobutrazol, Uniconazol, etc.) were also summarized.

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Identification and Changes of Physiologically Active Substances During Chilling Storage of Dehisced Ginseng Seeds (저온저장중 개갑인삼종자내의 생리활성물질 동정 및 변화)

  • Kwon, Woo-Saeng;Baek, Nam-In;Lee, Jung-Myung
    • Journal of Ginseng Research
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    • v.21 no.1
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    • pp.13-18
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    • 1997
  • Identification and changes of physiologically active substances during chilling storage of dehisced ginseng (Panax ginseng C. A. Meyer) seeds were analyzed using various preparatory separation methods and purification columns; Dowex 50W and silica gel columns. Seven components with Rf values of 0.20, 0.40, 0.58, 0.66, and 0.70 In solvent system, $CHCl_3$:MeOH=3:1 (v/v), Rf values of 0. 63 and 0.74 in solvent system, $CHCl_3$:MeOH:$H_2O$:=7:3:1 (v/v) were obtained through Dowex 50W and silica gel column chromatographies. Two components with Rf values of 0.20 and 0.63 in the all chilling treatments were detected in the extract obtained through both chromatographies, and only the former component was gradually increased till 4 weeks of chilling storage and then rapidly decreased from 8 to 16 weeks. UV spectra of Rf values of 0.66 and 0.56 were similar to that of cytokinin, but their physiological activities were not found. Rf values of 0.20 showed activity by radish cotyledon expansion bioassay. The component with Rf value of 0.20 was revealed to have a naphthalene in the proposed chemical structure by various NMR techniques.

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