In vitro conditions
All media were supplemented with 3% sucrose and 7 gl-1
agar. The
pH of all media was adjusted to 5.7 with 1 N NaOH or 1 N HCl prior
to autoclaving at 1.05 kgcm-2
, 121°C for 20 min. Cultures were
maintained at 25±1°C air temperatures in a culture room with a 16 h
photoperiod under an illumination of 20 mmolm-
2
s-
1
photosynthetic
photon flux density provided by cool-white fluorescent light. Plant
materials were stored in glass-capped culture jars (125 ml capacity)
each containing 20 ml of medium.