2644 - CSUN ScholarWorks - California State University, Northridge

62 · Journal of Student Research Abstracts
2778
THE EFFECTS OF CARROT JUICE ON E. COLI BACTERIA.
Stanley Wong and Stephen DeGusta (teacher). John F. Kennedy High School, 6715 Gloria Drive,
Sacramento, CA 95831.
The purpose of this experiment was to test if carrot juice can be a growth inhibitor for a non-pathogenic
strain Escherichia coli. Carrots contain complex sugars which interferes with the binding of pathogenic bacteria
to the intestinal lining. Carrots have been used for centuries in the treatment and prevention of diarrhea.
Pathogenic strains of E. coli have been known to cause severe diarrhea. Non-pathogenic strains of E. coli aids
the intestines in digestion. In my experiment, 1 isolated carrot juice in filter disks and placed these disks into
a nutrient agar media containing E. coli. I attempted to see if there were any difference between the disks containing
the carrot juice and the control, disks containing ordinary filter paper. To my surprise, the carrot juice
seems to aid the growth of non-pathogenic E. coli although it affects the binding of pathogenic E. coli to the
intestinal lining. When observing the dishes, I found more colonies of E. coli surrounding the disks containing
the carrot juice than the control. This method of testing led me to conclude that carrot juice not only aids
treating pathogenic bacteria in the intestines, but also encourages the growth of non-pathogenic E. coli.
2779
VARIANCE OF ROOTS GROWN IN DIFFERENT FIELD CAPACITIES.
Lisa Ann Gregory, Steve DeGusta (teacher). John F. Kennedy High School, 6715 Gloria Drive, Sacramento,
CA 95813.
The primary purpose of this experiment was to see if the field capacity of a soil has a direct effect on the
root growth of bean plants. The field capacity is defined as the ability of a soil to retain water (Schultz, 1960).
The conditions set to test my problem were to grow 10 bean plants in potting soil and 10 bean plants in sand.
I chose these soils I because potting soil has an almost four times higher field capacity than sand (Gregory,
1998). Both groups were given the same amount of water over a period of 11 days. After four days I didn't
water the plants for three days so that the plants would have to survive on the water retained by the soils.
After 11 days I took the plants out of their pots and measured the lengths of the primary roots of each plant,
their heights, and counted the number of roots of each plant. The mean of the lengths of the primary roots of
each plant grown in potting soil was 13.8 em, and for the plants grown in sand was 5.3 em. The mean of the
heights of the bean plants grown in potting soil was 7.85 em, and in sand was 3.86 em. The mean of the number
of roots of each plant grown in potting soil was 39, and in sand was 18.7.
I conclude that the bean plants grown in potting soil adapted much better to their environment than those
grown in sand. This was due to the lack of water due to the low field capacity of sand. Also, sand is inoraganic
so nutrients were scarce to those bean plants. The bean plants grown in potting soil were taller (p