Cultures of one and two percent (w/v) hairy roots were
grown in 50 ml of liquid B5 medium at 25 and 32 C on a
shaker, operated at 110 rpm, for 30 days. The hairy roots
were collected every 5 days until day 30, and the fresh
weight (FW) was measured; the samples were then dried at
60 C for 72 h, and the dry weights (DW) were measured.
In addition, the percentage of browning was recorded
(0 = no browning or browning50 % and 1 = browning
C 50 %). Each treatment was performed in triplicate.
The growth index was calculated from the dry weight using
the following equation: Growth index = (Final DW–Initial
DW)/Initial DW (Korsangruang et al. 2010