THE EFFECTS OF INTRASPECIFIC AND INTERSPECIFIC

way with potting soil. Then seeds were placed inside each pot according to the
arrangement shown in Figure 1. 94 wheat seeds from a brown paper bag were used and
44 Alaskan pea seeds from a plastic bag full of seeds were used. The seeds were spaced
evenly within the pots. Then the pots were filled to the top with soil and watered. The
36 connected pots were covered with plastic and placed under one plant light inside a
classroom close to the windows, and the other 6 were placed under the adjacent plant
light and were covered, but air could still pass under the cover, for it was not a perfect fit
over the smaller number of pots. Every school day, around 12:40 PM, the plants were
watered, and extra water was given before a weekend, so the plants would not dry out.
Figure 1
2 W 2 W 2 W
2 W 2 W 2 W
2 W 2 W 2 W
2 P 2 P 2 P
2 P 2 P 2 P
2 P 2 P 2 P
2 W 2 W 2 W
2 W 4 W 4 W
4 W 6 W 6 W
8 W 10 W 1P, 1W
1P, 1W 1P, 1W 1P, 1W
1P, 1W 2P, 2W 2P, 2W
Once the plants were too tall and the wheat stalks were
2P, 2W 3P, 3W
3P, 3W 4P, 4W
5P, 5W EXTRA
hitting the cover, the covers were
removed. This was after about 11 days.
They continued to be watered. On
The arrangement of seeds planted.
W= wheat seed, P= pea seed, each cell=
one starting pot. 36 were all together in
one tray, and the other 5 were in the
neighboring tray. The top 9 are wheat
controls. The next 9 are pea controls.
The next 11 cells show wheat
intraspecific competition at different
densities, and the last 12 cells show pea
and wheat interspecific competition.
October 13,
the wheat
controls and
pea controls
were uprooted
and measured.
The individual plants were carefully pulled out of the pots,
and the soil was washed off in a beaker of water. Then,
using a metric ruler, the stalk length and root length of each plant was measured and
recorded. The number of leaves and the number of tendrils (on the peas) were also noted.
4