Transcript PowerPoint Presentation on Blackberry

Internode Morphology in
Common Blackberry
INTRODUCTION
Observations:
• Blackberry is common in the Jewel Moore Nature
Reserve
• Blackberry can be an invasive species, just like
Japanese Honeysuckle.
• It seemed to grow more prolifically in the sunlight.
Question:
Having already studied inter-node length
dependency on sunlight in invasive honeysuckle,
we wanted to know if this morphological
adaptation would be shown in another common
invasive species.
INVASIVE SPECIES
 Invasive species are especially problematic in areas
that have been disturbed by human activities.
 Natural disturbances, such as fires, floods, tornadoes,
landslides, and tree falls also provide avenues for invasive
species to get started.
 Some native plants display invasive growth tendencies
in their native ranges, often as a response to natural or
human-caused disturbances.
CHARACTERISTICS OF COMMON
BLACKBERRY

Favors moist to slightly dry prairie edges along
woodlands, open woodlands, areas along roadsides and
railroads, abandoned pastures, and disturbed, burned-over
areas in and around woodlands

Arching or trailing stems, to 3.4 m in height; stems red or
green; prickles or bristles usually present; leaves compound,
3-7 serrate leaflets; red or black 'raspberry' fruit; white flowers.
(source http://www.hort.cornell.edu/department/faculty/weston/weedfacts/wdfct4a.html and
http://www.shout.net/~jhilty/plantx/cm_blackberryx.htm)
 It prefers sunlight, and produces best in full sun, but can
tolerate partial shade. However, plants don't grow or produce
well in heavy shade.
HYPOTHESES
Alternative Hypothesis:
The internode length of Rubus allegheniensis will be shorter
in the direct sun and longer in the shade.
Null Hypothesis:
There will be no significant difference in internode length
due to varying sun light availability.
Shade
Sun
METHODS
Twenty shoots each were collected from both areas of
shade and areas of more prolific sunlight:
Starting at the North edge of the reserve, we
walked South (parallel to Ferris Road) three
times, moving 20 meters East each time.
Using hand clippers, we retrieved a sample
size of 20 individuals from sunny areas and 20
representing shady areas.
The internode lengths of sun and shade shoots were
measured and recorded in millimeters.
The results were run on Systat to determine the mean,
standard deviation, and variance between variables.
RESULTS
Internode Length (mm)
80
70
60
50
Shade
40
Sun
30
20
10
0
Shade vs. Sun
Figure 1. Comparative average internode lengths of
blackberry plants in the sun and shade.
RESULTS CONTINUED…
(at 95% conf.) MEAN STANDARD DEV. P-VALUE
SHADE PLANTS 70.05
SUN PLANTS
29.7
14.329
0
8.646
0
Table 1. Statistical results for T-test run on
internode length data.
DISCUSSION
 The data show a significant difference in the average
internode lengths of plants from shade and from sun.
 The plants grown in shadier areas had significantly
larger internode lengths.
 Therefore, the null hypothesis can be rejected – the
data supports our functional hypothesis.
Greater
Shade
Sun
DISCUSSION CONTINUED…
 The results are indicative of the Optimal Foraging
Theory’s presence in Rubus allegheniensis’s growth patterns:
 (The optimal foraging theory states that plants and
animals attempt to feed in ways that optimize
acquisition of energy and nutrients.
http://www.shout.net/~jhilty/plantx/cm_blackberryx.htm)
 In the sun, more leaves were grown to make use of the
excess sunlight, causing shorter internodes.
 However, in the shade, instead of growing leaves, the plant
extended its internode length in an attempt to reach the
sunlight that it prefers.
INTERNODE LENGTH AS A
MORPHOLOGICAL ADAPTATION
Shade
Sun
CONCLUSIONS
 The morphological variation within this species is similar to
that of the invasive Lonicera japonica (Honey Suckle). Both
species have the ability to be flexible in response to
environmental changes.
 This also reflects optimal foraging theory, and thus flexible
change in plants, by showing that plants utilize the resources
that are available to them by “changing growth form and
resource allocation in response to environmental cues.”
(sources: class notes, A Framework for Plant Behaviors: Jonathan Silvertown; Deborah M. Gordon.
Annual Review of Ecology and Systematics, Vol. 20. (1989), pp. 349-366. Stable URL:
http://links.jstor.org/sici?sici=00664162%281989%2920%3C349%3AAFFPB%3E2.0.CO%3B2-5, and text
book)
A stream bed that has been cleared of an
invasive blackberry species.