Proline Accumulation in Oil Palm Polyembryogenic Cultures Under Various Conditions
Low temperature of 15˚C to 20˚C was observed to suppress the growth and multiplication capacity of oil palm polyembryogenic cultures.This condition enabled the cultures to be maintained for at least six months duration without subculture and thus was suitable for minimal growth storage of invitr...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1992
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8567/1/FSAS_1992_3_A.pdf |
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| Summary: | Low temperature of 15˚C to 20˚C was observed to suppress
the growth and multiplication capacity of oil palm
polyembryogenic cultures.This condition enabled the cultures
to be maintained for at least six months duration without
subculture and thus was suitable for minimal growth storage of invitro cultures. Proline, a .universal stress indicator,was found to
accumulate in oil palm cultures under low temperature and
moisture stresses(sucrose treatment)but not under anaerobic
stress (non-agitated liquid media treatment). Sucrose treatment at 0.5 M caused moisture reduction and induced proline
accumulation. In addition, when combined with low temperature storage it extended the low temperature tolerance
and prolonged the subculture duration for at least nine months.
The application of exogenous proline and ornithine at 10
mM could also induce proline accumulation in the cultures.
However, only low level of proline accumulated with application
of glutamic acid, glutamine and arginine Inconsistent
pattern was observed with pyrroline-S-carboxylic acid (PSC).
PSC reductase (EC1.5.1.2) and ornithine aminotrans ferase ( EC2.6.1.13) were found to involve directly/indirectly with
proline biosynthes is in polyembryogenic cultures. The specific
activities of these enzymes and soluble protein were higher
under low temperature and moisture stresses. Since exogenous
ornithine could induce proline accumulation and there was an
active involvement of ornithine aminotransferase, ornithine
could be one of the preferred precursors for proline
biosynthes is in oil palm cultures.
Similarly, Thioproline (proline analog) increased
proline accumulation but produced some toxic effect which
eventually killed the cultures. Polyembryogenic cultures were
found to utilize the exogenous proline and ornithine more
efficiently in the liquid media than in the solid media. The
proline in accumulated cultures which were treated with
exogenous proline, ornithine and subjected to low temperature stress was observed to return to normal level on transferring to
the normal media and conditions. This suggested that the
proline accumulated was readily utilizable when re turned to
normal condition sand could be considered as a labile
metabolite in oil palm polyembryogenic cultures. |
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