Articles
SOMATIC EMBRYOS AND BULBLET DEVELOPMENT FROM BIOREACTOR REGENERATED MERISTEMATIC CLUSTERS OF NERINE
Article number
393_24
Pages
203 – 212
Language
Abstract
The use of bioreactor cultures for the micropropagation of Nerine – a bulb forming Amaryllidaceae plant, depends on the manipulation of the liquid medium during specific developmental stages.
These manipulations are critical for enhanced proliferation, morphogenic expression and the control of hyperhydration.
Inflorescence-derived explants of Nerine were cultured on 2,4-dichlorophenoxy-acetic acid (2,4-D) and 6-benzyladenine (BA) supplemented Murashige & Skoog (MS) medium.
Meristematic tissue from differentiating peduncle explants subcultured to liquid media in flasks or bioreactors in the presence of NAA, BA and paclobutrazol (PAC) proliferated into nodular clusters, increased 4–5 times in biomass and were devoid of leaves.
The presence of PAC throughout the culture period decreased growth and proliferation, but was a promotive bioregulator for meristematic cluster formation.
The peripheral tissue of the clusters was induced into proembryogenic cluster by the removal of PAC. Clusters, 12–15 mm in diameter, made of rounded proembryogenic protrusions developed into elongated finger-like structures upon the substitution of BA by 2iP. This change allowed the expression of the proembryogenic clusters into somatic embryos.
Embryogenic clusters could be induced to form plants in the presence of low levels or in the absence of growth regulators, or to dedifferentiate again into meristematic clusters by PAC. Bulblet formation was enhanced in an auxin and elevated sucrose medium.
Embryonic tissue attached to the bulblets developed secondary embryos.
Scaled-up micropropagation used for other geophytes also resulted in storage organ formation.
These manipulations are critical for enhanced proliferation, morphogenic expression and the control of hyperhydration.
Inflorescence-derived explants of Nerine were cultured on 2,4-dichlorophenoxy-acetic acid (2,4-D) and 6-benzyladenine (BA) supplemented Murashige & Skoog (MS) medium.
Meristematic tissue from differentiating peduncle explants subcultured to liquid media in flasks or bioreactors in the presence of NAA, BA and paclobutrazol (PAC) proliferated into nodular clusters, increased 4–5 times in biomass and were devoid of leaves.
The presence of PAC throughout the culture period decreased growth and proliferation, but was a promotive bioregulator for meristematic cluster formation.
The peripheral tissue of the clusters was induced into proembryogenic cluster by the removal of PAC. Clusters, 12–15 mm in diameter, made of rounded proembryogenic protrusions developed into elongated finger-like structures upon the substitution of BA by 2iP. This change allowed the expression of the proembryogenic clusters into somatic embryos.
Embryogenic clusters could be induced to form plants in the presence of low levels or in the absence of growth regulators, or to dedifferentiate again into meristematic clusters by PAC. Bulblet formation was enhanced in an auxin and elevated sucrose medium.
Embryonic tissue attached to the bulblets developed secondary embryos.
Scaled-up micropropagation used for other geophytes also resulted in storage organ formation.
Authors
M. Ziv, S. Kahany, H. Lilien-Kipnis
Keywords
bioreactor, liquid cultures, paclobutrazol, proembryos, secondary embryogenesis
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