H. verticillata and V. spiralis were collected from Moon
Lake (30º33’N, 114º15’E) in Wuhan, China, and then precultured
in the laboratory [15]. When
the experiment began,
the
plants were washed carefully with tap water and later
distilled
water.
One part of the plant materials was weighed
and
prepared for extraction from plant tissues. The
other
parts
of the plants were cultivated at a density of 10 g FW/L
in
MIII medium [16] for three days under the same conditions
as the pre-cultured (a light intensity of 3000 lux and
12:12
light: dark cycle at 25ºC), and then the allelochemicals
in the culture solution were extracted. MIII medium without plants was cultivated under the same conditions as
the control.