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


Variation in a Microhabitat


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.


Focussing on Variation in

Leaves


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


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


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


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


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


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.


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)


Measurement


Trees Surveyed


Analysis of leaf for colour

intensity


Other Leaves analysed


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


Determination of Chlorophyll

content Spectroscopically


Leaf Length and Plant Height


Leaf Width and Plant Height


Colour Contrast and Plant

Height


Chlorophyll Content and Plant

Height


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.


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


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


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.


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.


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


mailto:[email protected]





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


http://photo-dictionary.com/phrase/3414/lilac-leaf.html





http://www.hkherbarium.net/herbarium/topics/fsw/FSW_6_e.html

http://www.hkherbarium.net/herbarium/topics/fsw/FSW_6_e.html

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



Thank You

Plant Diversity across various Microhabitats...Plant Diversity across various Microhabitats...

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