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241.
An efficient in vitro regeneration system in kumquats (Fortunella crassifolia Swingle) was established. Explant types and orientations, concentrations and combinations of plant growth regulators were
evaluated for their influences on efficiency of plant regeneration. It was found that the optimum explant and its orientation
was epicotyl planted vertically with upper part upward, and a shoot regeneration frequency of 1.48 shoots per explant was
obtained on Murashige and Skoog (1962; MS) medium supplemented with 22.19 μM 6-benzyladenine (BA). A rooting percentage as
high as 74 % was obtained on 1/2 MS supplemented with 0.54 μM 1-naphthaleneacetic acid (NAA), 9.29 μM kinetin (KN), and 0.5
g dm−3 activated charcoal. 相似文献
242.
Martine Avella Jocelyne Berhaut Patrick Payan 《In vitro cellular & developmental biology. Animal》1994,30(1):41-49
Summary We have developed the first explant technique that allows the in vitro study of gill physiology and biochemistry in marine
species. Gill fragments were cultured at 17° C, in atmospheric Pco2, with nutrient medium (Leibovitz L15), pH 7.8, supplemented with 10% fetal bovine serum and adjusted to the osmolarity of
fish plasma (350 mOsm/liter). Coating plates with collagen, gelatin, or polylysin did not improve our results. Decrease in osmotic pressure, removal
of bovine serum, or its replacement by fish serum inhibited growth from the explants. Approximately 50% of the explants produced
cell growth, and after 4 days of culture a monolayer of contiguous cells was formed. This technique is rapid and does not
require the use of enzymes. The cells appeared flat and thin with an epithelioid shape. They looked polygonal with a maximum
length of 10 to 50 μm. Evidence that they are unique gill cells is the presence of polymorphic surface crenelations (microplicae),
prominent Golgi apparatus, tight junctions and desmosomes. Comparison with in vivo tissue showed them to be epithelial cells
having differentiated in a homogeneous population of respiratorylike (pavement) cells. They are polarized with their apical
surface facing the culture medium. The development of this culture system represents a new tool for cellular approaches to
determine precisely the functions and transport mechanism of gill cells. 相似文献
243.
An improved method for sterilization of explants was tested and found to be suitable for plants with elongated internodes,
such as bamboos. Final cutting of the explants into single nodal segments for inoculation was done only after surface sterilization
of multi-nodal explants in a stoppered glass measuring cylinder. This minimized penetration of the contaminants and the sterilizing
agents into the exposed intercellular spaces and vascular cavities at the cut ends, thereby minimizing their harmful effects.
The method was experimented upon three different plants, viz., bamboo, tea and rose. Through this method the number of cultures
getting contaminated was substantially reduced as compared to the conventional means where single nodal explants were used,
employing identical treatments. Moreover, in this method, the number of cultures showing bud-break also showed a marked increase
thereby resulting in a tremendous increase in the percentage of successfully established proliferating cultures. 相似文献
244.
Bennici Andrea Grifoni Tiziana Schiff Silvia Bovelli Ruggero 《Plant Cell, Tissue and Organ Culture》1997,49(1):29-33
A study has been carried out on several Amaranthus L species and breeding lines (A. caudatus, A. cruentus, A. hybridus, A.
hypochondriacus), some of which have previously shown poor or no plant regeneration from callusing primary explants. Callus
formation occurred from explants from almost all the lines tested. Significant differences in callus growth were observed
among the lines depending on the growth regulator combinations used. Cultural conditions such as type and growth regulator
combination, as well as age-dependent competence of the explant tissues, also influenced the frequency of shoot (and/or root)
regeneration in Amaranthus species that had been shown difficult to regenerate in the past. The results obtained demonstrate
that in Amaranthus the genotype, growth regulator dose and combination, the type and the physiological stage of explant are
factors of great importance for in vitro plant regeneration.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
245.
Jameel M. Al-Khayri Christine E. Shamblin Edwin J. Anderson 《In vitro cellular & developmental biology. Plant》1996,32(4):227-232
Summary This study was conducted to establish and optimize a regeneration system for adapted U.S. rice genotypes including three commercial
rice cultivars (LaGrue, Katy, and Alan) and two Arkansas breeding lines. Factors evaluated in the study were genotype, sugar
type, and phytohormone concentration. The system consisted of two phases, callus induction and plant regeneration. In the
callus induction phase, mature caryopses were cultured on MS medium containing either 1% sucrose combined with 3% sorbitol
or 4% sucrose alone, and 0.5 to 4 mg·L−1 (2.26 to 18.10 μM) 2,4-D with or without 0.5mg·L−1) (2.32 μM) kinetin. In the plant regeneration phase, callus was transferred to 2,4-D-free MS medium containing 0 or 2 mg·L−1 (9.29 μM) kinetin combined with 0 or 0.1 mg·L−1 (0.54 μM) NAA. Callus induction commenced within a week, independent of the treatments. Callus growth and plant regeneration, however,
were significantly influenced by interactions among experimental factors. Generally, the greatest callus growth and plant
regeneration were obtained with 0.5 mg·L−1 (2.26 μM) 2,4-D and decreased with increasing 2,4-D concentrations. Kinetin enhanced callus growth only when combined with 0.5 mg·L−1 (2.26 μM) 2,4-D, and 4% sucrose. Inducing callus on kinetin-containing medium generally enhanced regeneration capacity in the presence
of sucrose but not with a sucrose/sorbitol combination. Media containing sucrose alone generally supported more callus proliferation,
but the sucrose/sorbitol combination improved regeneration of some cultivars. NAA and kinetin had little effect on regeneration. 相似文献
246.
Jaime A. Teixeira da Silva Nisha Singh Michio Tanaka 《Plant Cell, Tissue and Organ Culture》2006,84(2):100119-100128
Protocorm-like bodies (PLBs) and callus were induced in epiphytic hybrid Cymbidium Twilight Moon ‘Day Light’, where induction capacity was strongly explant dependent. Following the use of various explant
sources (PLB, leaf tip or base, root tip or base, cell and tissue ‘suspension’), highest PLB formation and callus induction
occurred when we used whole PLBs, PLB segments or PLB transverse thin cell layers (tTCLs) or longitudinal TCLs (lTCLs). Plantlet
growth and photosynthetic state from whole or bisected PLBs, as well as from tTCLs were not significantly different, after
analysis of chlorophyll content. However plantlets generated from lTCLs showed lower values for growth and photosynthetic
parameters. All resultant plants were shown to be cytogenetically identical using RAPD and mtDNA analysis despite cytological
variation and endopolyploidy occuring between different plant parts. Acclimatization and survival rate was shown to be 100%
in the generated plants. 相似文献
247.
Summary Two stocks of shoots growingin vitro, obtained from either seedlings or adult plants, were used to study the effects of material origin, the number of previous
subcultures on the establishment medium, the explant type, and the macronutrients on shoot multiplication and elongation inMyrtus communis L., always in the presence of 4.4. μM benzyladenine (BA). Shoot proliferation was influenced mainly by stock origin, with higher responses from the adult material
than from the seedling material, and by the number of subcultures, with the largest rates of multiplication and elongation
in the first subculture. In the first subculture, the adult material was characterized by high rates of shoot multiplication
and shoot elongation, and some shoots were hyperhydric. On the other hand, in the first subculture the seedling material was
characterized by lower rates of shoot multiplication and elongation, and some shoots were affected by apical necrosis. In
the third and the fifth subcultures, shoot multiplication and elongation declined in both materials, and hyperhydricity or
apical necrosis were never found, although higher multiplication and elongation were consistently found for the adult material.
The influence of the studied sources of variation is discussed in relation to shoot multiplication and elongation. 相似文献
248.
Rajbir S. Sangwan Yvan Bourgeois Spencer Brown Gérard Vasseur Brigitte Sangwan-Norreel 《Planta》1992,188(3):439-456
The insertion of foreign DNA in plants occurs through a complex interaction between Agrobacteria and host plant cells. The marker gene β-glucuronidase of Escherichia coli and cytological methods were used to characterize competent cells for Agrobacterium-mediated transformation, to study early cellular events of transformation, and to identify the potential host-cell barriers that limit transformation in Arabidopsis thaliana L. Heynh. In cotyledon and leaf explants, competent cells were mesophyll cells that were dedifferentiating, a process induced by wounding and-or phytohormones. The cells were located either at the cut surface or within the explant after phytohormone pretreatment. In root explants, competent cells were present in dedifferentiating pericycle, and were produced only after phytohormone pretreatment. Irrespective of their origin, the competent cells were small, isodiametric with thin primary cell walls, small and multiple vacuoles, prominent nuclei and dense cytoplasm. In both cotyledon and root explants, histological enumeration and β-glucuronidase assays showed that the number of putatively competent cells was increased by preculture treatment, indicating that cell activation and cell division following wounding were insufficient for transformation without phytohormone treatment. Exposure of explants for 48 h to A. tumefaciens produced no characteristic stress response nor any gradual loss of viability nor cell death. However, in the competent cell, association between the polysaccharide of the host cell wall and that of the bacterial filament was frequently observed, indicating that transformation required polysaccharide-to-polysaccharide contact. Flow cytofluorometry and histological analysis showed that abundant transformation required not only cell activation (an early state exhibiting an increase in nuclear protein) but also cell proliferation (which in cotyledon tissue occurred at many ploidy levels). Noncompetent cells could be made competent with the appropriate phytohormone treatments before bacterial infection: this should aid analysis of critical steps in transformation procedures and should facilitate developing new strategies to transform recalcitrant plants. 相似文献
249.
K. M. Volkmar 《Journal of nematology》1991,23(4):425-431
The relationship between root stunting caused by the cereal cyst nematode and levels of two root growth inhibiting hormones, abscisic acid and ethylene, was investigated in aseptically cultured root segments and in intact roots of two oat cultivars differing in tolerance to the nematode. Cultured root segments of oat cultivars New Zealand Cape (tolerant) and Sual (intolerant) were inoculated with sterilized Heterodera avenae second-stage juveniles. Suppressed growth of root axes and emerged laterals following nematode penetration corresponded to an increase in abscisic acid and ethylene in roots of both intolerant and tolerant cultivars. When the experiment was repeated on intact root systems, nematodes retarded root growth of Sual more than New Zealand Cape despite an increase in ABA and ethylene in both cultivars. Abscisic acid and (or) ethylene may be involved in growth inhibition of H. avenae-infected roots but appear to play no direct role in determining tolerance. 相似文献