Plant Diversity across various Microhabitats...Plant Diversity across various Microhabitats...
Transcript of Plant Diversity across various Microhabitats...Plant Diversity across various Microhabitats...
Plant Diversity
across various
Microhabitats Variation of Plant Leaf Characteristics with Plant Height Presented by
Arindam Saha (10MS02)
Sandipan Dasgupta (10MS12)
IISER Kolkata, Evolutionary Biology Lab
Diversity in Plant Kingdom
Across various geographical regions
Within a geographic location
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Variation in a Microhabitat
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Microhabitat: the smallest part of the environment that supports a distinct flora and fauna
Example of variation within a microhabitat Negative correlation
between the height of the plant and its distance from a bunch of plants
Motivation: Inferences from
the Lab experiments
There is a correlation between the height of the plant and its immediate environment i.e. the central plants in a bunch were taller than peripheral plants to maximize its insolation.
Various plant having various leaf structures were differentially capable to capture the sunlight .
This two observations led us to the quest to find the correlation (if any) between plant height and its leaf physiology.
IISER Kolkata, Evolutionary Biology Lab
Focussing on Variation in
Leaves
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Questions to be addressed
What is the correlation between plant
height and
Length of the leaves
Width of the leaves
Chlorophyll content of the leaves
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Why such Variation?
Physiology highly adaptive to the
microhabitat of the plant concerned
Plants aim to maximize the insolation
Some plants have greater heights and
hence better exposure
Others with smaller heights have greater
leaf area and higher chlorophyll content to
maximise efficiency
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Expected Observation
On logical grounds we expect shorter
plants to have
Larger leaf span
Higher chlorophyll content
An their counterparts to have
Smaller leaf size
Relatively lower chlorophyll content
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Null Hypothesis
Since shorter plants in a landscape has less availability of sunlight vertically, therefore they must possess greater leaf surface area and more chlorophyll to capture whatever sunlight that seeps in below
Whereas taller plants having abundant quantity of sunlight can afford to have smaller leaves with less chlorophyll to carry out photosynthesis
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Area of Survey
Plants in the vicinity of
APC Roy Hostel of IISER
CV Raman & JC Bose Hall of BCKV
Rationale for selection
Dense plant cover
Wide variation in plant height
Ease of Accessibility
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Methodology
The height of the plant was measured by
following means:
Direct Measurement (using meter scale of
Least Count 0.5 cm)
Using the length of the shadow casted.
Perspective measurement.
The leaf length and breadth was
measured with a scale of LC = 1 mm.
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Methodology
The leaf was placed in a white paper and
a vertical photograph was taken .
The photo was analysed for intensity of
green light using GNU Image
Manipulation Program (GIMP).
Also, the absorbance maxima of the leaf
extract in 80 % acetone is measured at
665 nm (Maxima of Chlorophyll a)
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Measurement
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Trees Surveyed
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Analysis of leaf for colour
intensity
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Other Leaves analysed
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Range of Variation Studied Plants of Various were observed namely;
herbs, shrubs, trees
The leaf height varied from about 2 feet (small herbs) to 15 m (large trees)
Correspondingly the leaf size varied from about 2.5 cm to 10.5 cm
Also, the leaf width varied from 0.5 cm to 5 cm
The concentration of chlorophyll varied from 100 to 800 mg/m2
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Determination of Chlorophyll
content Spectroscopically
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Leaf Length and Plant Height
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Leaf Width and Plant Height
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Colour Contrast and Plant
Height
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Chlorophyll Content and Plant
Height
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Inferences
All the graphs show a negative slope which
imply that:
Leaf size (length) go on decreasing
progressively as the height of plant increases.
Similarly Leaf width also follow a similar pattern.
The variation of chlorophyll content as
determined by intensity of green colour by
GIMP is consistent with the finding determined
spectroscopically. The chlorophyll concentration also decreases with height.
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Conclusions
The null hypothesis that we began with
was shown to be correct
There is a negative correlation between
the plant leaf length, height, chlorophyll
content with the height.
The correlation between concentration of
chlorophyll and plant height was stronger
than the other two correlations
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Plausible Explanations
The reason for this observation can be the
adaptation to the different microhabitats
which have differential availability of sun-
light
This feature enables the plants to
enhance their productivity which is a
direct consequence of Natural Selection
that operated on these plants
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Limitations The sample size was taken to be 30 which is
statistically quite significant but a greater sample size would have more firmly grounded our conclusion.
Efforts were there to maintain homogeneity in the sample size, but very high trees were inaccessible and very small herbs were deemed insignificant.
Creepers, runners and offsets were not considered.
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Limitations Plants like banana were not considered as
they have other factors that govern their leaf physiology.
Plants with thick leaves were not considered as they have significant cross sectional variation of chlorophyll.
Though intensity of green color was used as a measure of Chlorophyll content, some leaves might have thick cuticle over its surface that might influence its color.
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References
Photosynthesis Research Protocols – Robert
Carpentier.
Extiction Coefficient of Chl a and b in N,N
DMF and 80% acetone –Inskeep et al,
PlantPhysiol.(1985)77,483-485
Peter v. Sengbusch - [email protected]
hamburg.de
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Photo Courtesy
Photo Dictionary Archive (http://photo-
dictionary.com/phrase/3414/lilac-leaf.html)
National Herbarium of Hong Kong.
(http://www.hkherbarium.net/herbarium/topi
cs/fsw/FSW_6_e.html)
The Oxford Dictionary Archive
GNU Image Manipulation program output
graphics.
QtiPlot plotting software for plots
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Acknowledgement Cordial Thanks to Our Professors
Dr. Annagiri Sumanna
Dr. Anuradha Bhat
Dr. Anindita Bhadra
Dr. Partho Sarathi Ray
Dr. Punyasloke Bhadury
Lab Technicians Mr. Sudip
Mr. Sudhansu Maity
Our Friends Gaurav Kr. Baruah
Uditendu Mukhopadhay
IISER Kolkata, Evolutionary Biology Lab
IISER Kolkata, Evolutionary Biology Lab
Thank You