Stomata density denzel,breana

Stomata Density

By:By:Breana HullBreana Hull

Denzel DrennonDenzel Drennon

http://mrskingsbioweb.com/images/stomata.jpg

What Are Stomata?1

A microscopic spore in the epidermis of plantsA microscopic spore in the epidermis of plants

surrounded by guard cells surrounded by guard cells

In leaves and stems of a plantIn leaves and stems of a plant

allows gas exchange between the environment allows gas exchange between the environment

and the interior of the plantand the interior of the plant

Surrounded by guard cells which control the Surrounded by guard cells which control the

opening and closing of the stomataopening and closing of the stomata

What Are Stomata Cont.What Are Stomata Cont.11

There are three cues for There are three cues for Stomatal opening:Stomatal opening:

1.1.Depletion of carbon dioxide Depletion of carbon dioxide within the plantwithin the plant

2.2.Light at dawn triggers the guard Light at dawn triggers the guard cellscells

3.3.The internal clock of the guard The internal clock of the guard cells cells

Guard CellsGuard Cells11 Guard cells become turgid Guard cells become turgid

when swollen with water when swollen with water causing an opening in the causing an opening in the stomastoma

When they lose water they When they lose water they become flaccid causing the become flaccid causing the stoma to closestoma to close

Water is stabilized in and out Water is stabilized in and out of the guard cells as of the guard cells as potassium ions are potassium ions are transported across the transported across the plasma membrane, plasma membrane, regulating the amount of regulating the amount of water and ions taken in.water and ions taken in.

http://leavingbio.net/TRANSPORT%20OF%20MATERIALS%20IN%20A%20FLOWERING%20PLANT_files/image011.jpg

What do Stomata do?1

Main avenues of Main avenues of TRANSPIRATION:TRANSPIRATION:Transpiration is the evaporative loss of water through a Transpiration is the evaporative loss of water through a

plants leaves. plants leaves. Balance the requirement for water conservation for Balance the requirement for water conservation for

photosynthesisphotosynthesis Open during the day and close at night to prevent water Open during the day and close at night to prevent water

losslossEspecially in low water and high temperature Especially in low water and high temperature

conditionsconditions Regulate the carbon dioxide intake and oxygen output for Regulate the carbon dioxide intake and oxygen output for

photosynthesis.photosynthesis. Provides gas exchange for the plantProvides gas exchange for the plant

Why is it interesting to Why is it interesting to study stomata?study stomata?11

95% of a plant’s water loss is through 95% of a plant’s water loss is through these small pores.these small pores.

An internal clock in the guard cells open An internal clock in the guard cells open the stomata at dawn even if plant is in the stomata at dawn even if plant is in the dark. the dark.

HypothesisHypothesis

stomata density in leaves directly exposed to the sun will be greater then

those in the shade

In this environment the southern faced leaves are directly exposed to sunlight, where the northern faced leaves are low to the ground

with less sunlight exposure.

We believe this has an We believe this has an effect becauseeffect because44::

Increase gas exchange

therefore more water released

lowering plant temperature in times of

high sunlit conditions.

On the other hand…On the other hand…

If these plants were put under If these plants were put under conditions with limited water, there conditions with limited water, there would be hypothesized to have less would be hypothesized to have less

stomata in leaves of the sun.stomata in leaves of the sun.44

HollyHolly

NORTH (shaded)NORTH (shaded)Found closest to Found closest to

the ground, under the ground, under the bushthe bush

Smaller leavesSmaller leavesLighter Lighter

yellow/greenyellow/green

HollyHolly

SOUTH (sun)SOUTH (sun)Found on top of Found on top of

bush, fully bush, fully exposedexposed

Bigger leavesBigger leavesDark greenDark green

MethodsMethodsGather leaf samples from site; 12 leaves from Gather leaf samples from site; 12 leaves from

shaded, north facing shaded, north facing ANDAND 12 leaves from direct 12 leaves from direct sun, south facingsun, south facing

Paint underside of leaves with clear nail polishPaint underside of leaves with clear nail polishPlace clear scotch tape on underside of leaf once Place clear scotch tape on underside of leaf once

drydryPlace tape on slide and labelPlace tape on slide and labelUnder microscope, count number of stomata for 3 Under microscope, count number of stomata for 3

fields of view on all 24 leavesfields of view on all 24 leavesMeasure field of view in millimeters under 400 xMeasure field of view in millimeters under 400 x

ResultsResults

The stomata density in leaves of the sun are greater than

those in the shade

YES!YES!

We accept our hypothesisWe accept our hypothesis

251.92

ConclusionConclusion

Looking at the t Critical and t Stat, we confirm that there is a significant difference between stomata density in leaves of the shade and sun areas

Sun Shade

Mean 251.92 186.50

Variance 1202.34 452.27

Standard Deviation 34.67 21.27

t Stat 5.57108

t Critical one-tail 1.73406

P(T<=t) one-tail 1.372 x 10-5

Looking at the Probability we can assure that we are 100% sure of our conclusion

StatisticsStatistics

Future StudyFuture Study

The shade of the leaf compared to the The shade of the leaf compared to the stomata densitystomata density

Hypothesis:Hypothesis:

Darker leaves have more stomata then Darker leaves have more stomata then lighterlighter

Because:Because:

The darker color of leaves attracts sunlightThe darker color of leaves attracts sunlight

References:References:

1.1. Campbell, Neil. 2010. Biology. Edition 8. Pearson Education, Inc.Campbell, Neil. 2010. Biology. Edition 8. Pearson Education, Inc.

2. http://mrskingsbioweb.com/images/stomata.jpg. mrskingsbioweb.com/images/stomata.jpg. “February 16, “February 16, 2011”2011”

3.3. http://leavingbio.net/TRANSPORT%20OF%20MATERIALS%20INhttp://leavingbio.net/TRANSPORT%20OF%20MATERIALS%20IN%20A%20FLOWERING%20PLANT_files/image011.jpg. %20A%20FLOWERING%20PLANT_files/image011.jpg. “February “February 16, 2011”16, 2011”

4.4. Bruce W. Grant, Itzick Vatnick, and the Ecological Society of Bruce W. Grant, Itzick Vatnick, and the Ecological Society of America. 2004.Environmental Correlates of Stomata Density. TIEE. America. 2004.Environmental Correlates of Stomata Density. TIEE. http://tiee.ecoed.net/vol/v1/experiments/stomata/stomata_descriptiohttp://tiee.ecoed.net/vol/v1/experiments/stomata/stomata_description.html. “n.html. “February16, 2011February16, 2011””