The concentration of the phenolic compounds exuded
into the culture solution ranged between 0.9 µg/L (FA for spiralis) and 29.7 µg/L (CA for H. verticillata), and in most
cases the concentration of the individual compound was not
beyond 10.0 µg/L (Table 3). The total amount of the four
phenolic compounds exuded from H. verticillata (52.1
µg/L) was approximately 10 times as high as that from spiralis (5.1 µg/L). The content of each compound except
A exuded from H. verticillata was higher than that in spiralis culture solution.
The percentage of the individual phenolic compounds
in the plant culture solution to those in the plant tissues
before release varied among plant species and different
compounds (Table 3). There was poor correlation between
the contents in the culture solution and the contents in the
plant tissues (p>0.05). In most cases, their contents in the
culture solution were lower than 10% of those in the plant
tissues.