THE EFFECT OF DIFFERENT CLOSURE TYPES, LIGHT, AND SUCROSE CONCENTRATIONS ON CARBON-ISOTOPE COMPOSITION AND GROWTH OF GARDENIA JASMINOIDES PLANTLETS DURING MICROPROPAGATION AND SUBSEQUENT ACCLIMATION EX-VITRO
Md. Serret et al., THE EFFECT OF DIFFERENT CLOSURE TYPES, LIGHT, AND SUCROSE CONCENTRATIONS ON CARBON-ISOTOPE COMPOSITION AND GROWTH OF GARDENIA JASMINOIDES PLANTLETS DURING MICROPROPAGATION AND SUBSEQUENT ACCLIMATION EX-VITRO, Plant cell, tissue and organ culture, 47(3), 1996, pp. 217-230
The growth of Gardenia jasminoides Ellis plantlets and the development
of photoautotrophy during two successive culture stages (shoot multip
lication and root induction) in vitro was analyzed. We examined the ef
fects of changes in growth conditions (type of tube closure, Light, an
d sugar levels) on the development of photoautotrophy and growth durin
g micropropagation and sought to establish whether they affected later
acclimation to conditions ex vitro. During the two stages in vitro, p
lantlets were grown in tubes under two different PPFD (50 and 110 mu m
ol m(-2)s(-1)), in media with three different sucrose concentrations (
0, 1.5, and 3.0%, w/v) and with two different CO2 levels inside the tu
bes (controlled by either tightly closed caps or loosely sealed caps,
and with an external CO2 concentration of 750 mu mol mol(-1)). The dev
elopment of photoautotrophy was assessed by determining the difference
between the stable carbon isotope composition (delta(13)C) of sugar c
ane sucrose used as a heterotrophic carbon source and that of leaflets
grown in vitro. Plantlets from the root-induction stage showed a more
highly developed photoautotrophy than those from the shoot- multiplic
ation stage. At both stages, utilization of closed caps was the treatm
ent which most stimulated development of photoautotrophy in plantlets.
Also, lowering PPFD or sucrose concentration induced a greater degree
of photoautotrophic development, the strongest effect being observed
in plantlets cultured inside loosely sealed tubes. During acclimation
ex vitro, plantlets taken from loosely sealed tubes in vitro performed
better than those cultured inside tightly sealed tubes. The former, a
s well as recording a larger increase in fresh weight during this stag
e, also showed more negative delta(13)C in the newly developed leaves,
which would seem to indicate a better water status during acclimation
. Present results validate the usefulness of delta(13)C analysis of le
aflets as a simple technique in assessing the development of photoauto
trophy during culture in vitro. In addition, delta(13)C analysis can b
e extended to evaluate growth conditions during acclimation to ex vitr
o conditions.