Transpiration Lab

Question: Is the rate of transpiration in a plant, represented by the amount of water that escapes out through the stomata, affected by environmental factors? If so, which environmental factor will cause the greatest increase in the rate of transpiration? Will it be an increase in temperature, which will increase evaporation, an increase in light, which will increase photosynthesis, or an increase in wind, which will cause water to blow out of the leaves? This question is solvable through perfuming tests on a number of different plants. The environmental factors can be replicated through the use of a fan for the wind, a heater for the temperature increase, and a lamp for the light increase.

Hypothesis: If a number of plants are tested under different environmental factors, then the trials where heat is added will cause the greatest rate of transpiration for all of the plants, because if the temperature is raised, then more water will be evaporated out of the plant through the stomata, because the kinetic energy/molecular motion of the water molecules will increase, and the water molecules will vaporize. I also hypothesize that the tails with the fan will show the second highest transpiration rate in all the plants, because the wind will cause many of the water droplets hanging around the stomata to blow out of the plant, without the need of evaporation.

Plant Transpiration Data Table
	Normal	With Fan	With Heater	With Lamp
Arrowhead	3.6 mL	7.5 mL	6.6 mL	4.0 mL
Coleus	0.9 mL	6.0 mL	3.9 mL	3.0 mL
Devil’s Ivy	2.9 mL	4.6 mL	4.1 mL	3.0 mL
Dieffenbachia	4.1 mL	7.7 mL	6.0 mL	3.9 mL
English Ivy	1.8 mL	5.1 mL	3.2 mL	2.1 mL
Geranium	1.2 mL	4.7 mL	5.8 mL	2.4 mL
Rubber Plant	4.9 mL	8.4 mL	6.8 mL	4.3 mL
Weeping Fig	3.3 mL	6.1 mL	4.9 mL	2.5 mL
Zebra Plant	4.2 mL	7.6 mL	6.1 mL	3.2 mL

Question 1: Describe the process of transpiration in vascular plants.

Answer: Water is evaporated through the stomata in the leaves, which are usually on the underside of the leaves. Water in the plant is brought up from the roots to the leaves because water is pulled by the water molecules that are being evaporated (cohesion and adhesion). The water is let out when the stomata open to release oxygen and take in carbon dioxide.

Question 2: Describe any experimental controls used in the investigation.

Answer: The experimental control in this investigation is the normal experiment. It allows us to compare the environmental changes to normal environmental conditions. 

Question 3: What environmental factors that you tested increased the rate of transpiration? Was the rate of transpiration increased for all plants tested?

Answer: The introduction of wind, represented by the fan, and the introduction of heat, represented by the heater, both increased the rate of transpiration, with the fan causing the greatest increase. For those two factors, the rate of transpiration increased for all nine plants.

Question 4: Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?

Answer: The rate of transpiration was increased the most by introducing wind, with Geranium being the only plant who's rate of transpiration increase more with the introduction of heat than with the introduction of wind. This is because the wind causes the water molecules sitting at the stomata to be blown out of the leaves, without even evaporating. The reason the heat increased the rate of transpiration, though not as much as the wind, is because the increase in temperature meant that the molecular motion of the water molecules increased, and more were able to evaporate.

Question 5: Which species of plant that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates?

Answer: The Rubber Plant had the highest rate of transpiration in all four tests. This is because the Rubber Plant, pictured below, has the large leaves and probably has more, and larger, stomata than other plants. Different species of plants probably have different rates of transpiration because they have to survive different environments. The Rubber Plant probably lives in a wetter environment than the Coleus, and therefore will not die if it loses a lot of water through transpiration. Also, Coleus looks like its texture may make it harder for water to escape, compared to the Rubber Plant, which looks like water can slide right off of it.

http://redfoxbb.com.au/indoor-plants-which-clean-toxins/

Question 6: Suppose you coated the leaves of the plant with petroleum jelly. How would the plant's rate of transpiration be affected?

Answer: The rate of transpiration would decrease because the stomata would be covered, and water would not be able to escape.

Question 7: Of what value to a plant is the ability to lose water through transpiration?

Answer: Just like people in sweating, plants use transpiration to cool themselves. As the water is evaporated, heat is lost with the water molecules. When evaporation occurs, water is pulled up to the leaves through cohesion and adhesion, carrying nutrients up to the leaves.

Plant Hormones

Ethylene

http://labs.bio.unc.edu/Kieber/ethylene.htm

Ethylene comes from the endoplasmic reticulum in a plant cell. It is not very soluble, and this causes it to diffuse out of the plant cell. So the concentration of ethylene in the plant depends upon the rate at which it is produced with comparison to the rate at which it diffuses out. It functions to inhibit growth and also for ripening. It is used by farmers to force ripening of fruits, since naturally there is a burst of ethylene production just before ripening. Ethylene converts starch and acid from unripe fruits to sugar in ripe fruit.

http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=998688536&topicorder=7&maxto=11

 It is a positive feedback loop, that stimulates its own production. When the first fruit begins to ripen, it emits ethylene, which is then absorbed by the surrounding fruit, causing all of them to ripen too. Ethylene suppresses auxin (and auxin suppresses ethylene).

http://www.pnas.org/content/103/36/13286/F6.expansion.html

http://www.hort.cornell.edu/mattson/leatherwood/

The flowers disappeared because they are too sensitive to the ethylene. The ethylene also causes the plant's leaves to become more curled. Ethylene is responsible for the aging process of plants

Auxin

http://www.nature.com/nrm/journal/v7/n11/fig_tab/nrm2020_F5.html

 Auxin is produced in immature parts of plants, such as the embryo, the young leaves, and buds, and it stimulates growth. It increases the activity of the protein pump, and causes the cell wall of the plant to become more acidic and become capable of elongating. It controls cell division and can regulate fruit development, helping the fruit grow bigger. Farmers inject auxin into fruits to make them bigger.

http://www.bio.miami.edu/dana/226/226F09_13.html

http://www.tutorvista.com/content/biology/biology-iv/plant-growth-movements/growth-regulators.php

Auxin is synthesized at the tip of the plant, and gets sent to the dark side of the plant. This causes cell division on the dark side, or stem elongation, and causes the plant to bend toward the light. Auxin is part of a process known as Positive Phototropism, where a plant moves toward light.


Abscisic Acid

http://www.pnas.org/content/105/11/4495.figures-only

Abscisic acid is responsible for the dormancy of plants, inhibiting plant growth. It is produced in the terminal buds. It reduces transpiration by closing the stomata, causing low levels of water to reach the leaves. It inhibits plant growth during stress to prevent the plant from dying.

Flowers

All of the flowers smelt good. This is most likely to attract insects to pollinate them.

     The flowers are not open very much, but enough for a bee to be able to go in and pollinate it. The reason that it is not open much may be that it is better protected than it would be if it completely opened up.

      The flower is pink and has many pedals. The plant that it is attached to has thorns, which are designed to protect the flower.

     You can see it very well in any of these pictures, but there is a moldy fungi on some of the flowers.   The fungi is living of the plant, and the plant may also be benefiting from this situation.

     You can see that the pedals are white in the middle, then become pinker and pinker the farther from the center they are.

      There are small pieces of pollen, the males, surrounding a thicker stem, which is the female.

      Above is some pollen that came off of the flower when I gave it a gentle shake. The pollen for this flower is yellow.

I found the Pincher Bug above inside of the flower. These, along with tiny beetles, pollinate the flowers by transferring the male pollen to the female part of the flower. 

     Though I did not see any insects, I would guess that small flies might pollinate these. The opening of the flower is too small for a bee, and its position on the tree would make it hard for beetles to climb up to pollinate it.

If i had to compare the smell of the flower to something, I would say it is a similar smell to shampoo.

     The little purple things on the right are male pollen, and the white stem on the left is the female part of the flower.

The Botany of Desire: Coevolution Blog

After reading Michael Pollan's The Botany of Desire, my perspective on our relationship with nature has changed. Replacing my traditional belief that humans are in control of their garden is the new idea that all every species is in charge. I choose the plants, I pull the weeds, I harvest the crops. This is the traditional idea of a human in a garden, where he alone is the subject. However, in reality these plants are manipulating humans into increasing numbers. Pollan focuses on apples, tulips, cannabis, and potatoes, and explores sweetness, beauty, intoxication, and control.

http://mshallarvadahs.pbworks.com/w/page/38617351/Coevolution%20and%20Pollinators

One very important relationship that exists in nature is the relationship between flowers and bees. The flower has actually manipulated the bee into moving its pollen from place to place. This is known as coevolution, because the flower increases its number by having its pollen moved from flower to flower, and the bee increases its number by have an abundant amount of hector to feed on. So while both parties are only looking after their won individual interests, they end up both helping each other.

http://aggie-horticulture.tamu.edu/vegetable/guides/the-crops-of-texas/tree-fruit-crops/

The apple's sweetness is what attracts us, and bees, into eating it. Since we love the sweetness of the apple, we grow many apple trees. As a result, the number of apples increases, so the apple's plan succeeds.

http://en.wikipedia.org/wiki/Tulip

Tulips make us do things because of there beauty. We have a desire to plant more tulips because we like to look at them. This is the intention of the tulip, and an important method for the growth of its numbers.

http://guardianlv.com/2014/01/colorado-cannabis-the-good-the-bad-and-the-ugly/

Cannabis attracts humans through its intoxication. As a result of this intoxication, humans want to grow as much cannabis as possible. Once again we see a plant's plan to increase its numbers.

http://potatonewstoday.com

An important question that Pollan asks is "Did I choose to plant these potatoes, or did the potato make me do it?". This is a question that Pollan asks throughout the who chapter. He makes the claim that both statements are indeed true. That we choose the potato because we want to eat it, and the potato entices us to choose it because it wants to be grown in the highest numbers possible. So while we may be remaking the potato to make it as large and tasteful as possible, the potato is remaking us, changing our way of life in a way that will cause us to grow more potatoes. The potatoes have manipulated us into moving and thinking for them

http://www.differencebetween.net/science/nature/difference-between-wolf-and-dog/

One human mistake is thinking of domesticated animal as less impressive than wild animals. For example, people think of wolves as a more impressive animal than domesticated dogs. However, in reality the dogs are more impressive because they have developed something that allows them to increase their numbers, which is being man's best friend. By doing this, dog population is more than 5 times greater than that of the wolves.

http://science.howstuffworks.com/environmental/earth/geophysics/earth3.htm

Pollan makes the valid argument that plants are more evolved than humans, despite humans displaying consciousness. Plants have invented photosynthesis, making them able to use the sun as a source of food. Humans on the other hand must grow food and harvest food. Also, plants have developed defense mechanisms, such as thorns and poisons, as well as developed chemical compounds that heal, and make humans want to use them.

http://www.abc.net.au/news/2012-11-10/charles-darwin-gets-4000-votes-in-us-election/4364602

In Charles Darwin's The Origin of Species, he first starts by talking about artificial selection, in which the humans select the most fit species, or at least in their eyes, to survive. However, he said that human desire plays the exact same role as nature, and that nature chooses the best fit species to survive.

http://www.divorcesaloon.com/2010/01/01/new-york-is-global-warming-behind-the-increasing-divorce-rate-around-the-world/

Pollan talks about how in a sense, everything is now domesticated, because humans have effected everywhere on earth by affecting the weather. He also says that humans are a part of nature as much as any other animal, and the idea that we have separated from nature is false.

Predator & Prey Population vs. Time

     Our goal in this experiment was to see how predator and prey populations changed over a course of many generations in a few different environments. Unfortunately, we did not have enough time to do more than one environmental situation. However, we can still analyze the data that we did get, and make a prediction for the data that we most likely would have gotten for the other locations.

http://uppun.deviantart.com/art/Wolf-and-rabbit-75129696

http://blogs.cofc.edu/american-novel/2012/11/16/as-rabbits-of-the-world/

Predator & Prey Population Data Table

Generation	Wolves	Rabbits	White	Light Green	Dark Green
1	1	3	1	1	1
2	0	4	0	2	2
3	0	6	0	2	4
4	0	10	0	2	8
5	0	16	0	2	14
6	0	30	0	4	26
7	2	46	0	8	38
8	4	60	0	12	48
9	8	66	0	10	56
10	14	44	0	2	42
11	20	8	0	2	6
12	1	3	1	1	1
13	0	4	0	2	2
14	0	6	0	2	4
15	0	8	0	2	6
16	0	12	0	4	8
17	2	18	0	6	12
18	4	20	0	8	12

Predator & Prey Population Line Graph

Analysis



Meadow

     For the meadow environment, we see that the Dark Green Rabbits continually had the highest population in every generation but one. This makes sense since the Dark Green Rabbits would have blended in the best to its surroundings, which were a dark green meadow. The fact that the Dark Green Rabbits became the most populated over time is due to natural selection, which states that a beneficial biological trait will become more common in a population, and a negative biological trait will become less common. In our experiment, both of the White Rabbits that migrated in to the meadow died within the first generation in which is migrated (the white rabbits that migrated to the meadow during generation 1 and 12 both died right away). This is because their trait of having white fur causes them to stick out in the dark green meadow, be spotted by wolves, and eaten. To the contrary, the dark green fur on the Dark Green Rabbits blended with the dark green meadow, causing them to become hard to spot, and less likely to be eaten. The Light Green Rabbits population was less than that of the Dark Green Rabbits, but more than that of the White Green Rabbits, because their light green fur made it harder for the wolves to spot them than to spot white fur, but easier for wolves to spot them compared to spotting dark green fur.

     As mentioned earlier, their was one generation in which the population of the Dark Green Rabbits was not the highest. In this generation, the 11th generation, the number of Wolves exceeded the number of not just the Dark Green Rabbits, but rather exceeded more than double the population of all of the three different colored rabbits combined. This certainly does not prove to be a favorable situation for the wolves, who need to eat 3 rabbits to survive and produce offspring. In the 11th generation, we see that all of the remaining rabbits were eaten by the wolves. This in effect caused all the wolves to die as well, because their were no longer any rabbits for them to eat. With all of the predators and prey dead, we had to wait for a new wolf and three new different colored rabbits to migrate into the meadow in order to form a 12th generation, which is the first generation that has no descendants from generation 1.

     Now that a new wolf and 3 rabbits migrated into the meadow and formed the 12th generation, a new population cycle occurs. Though it is a different cycle, you can see that the results are typically the same. The population of the Dark Green Rabbits increased at the highest rate, the Light Green Rabbits' population grew at a much slower rate, and the White Rabbits once again died off right away.

Snowy Area

http://wolfdreams.wordpress.com/2012/07/03/adrenal-dump/

     Though we did not actually perform this experiment, and therefore have no data, it can be predicted that the population of White Rabbits would increase at the highest rate, because their white fur would blend in with the white snow, and they would have a less likely chance of being eaten by the wolves (though the picture above shows a white rabbit being chased by a wolf, this would be the least likely rabbit to be hunted first, but would be the most hunted later because there will be so many of them, and so little of the other rabbits).

     If I had to make a hypothesis, I would predict that the Light Green Rabbits would be the most likely to go extinct immediately, because I think that the light green fur will be more visible to wolves than a dark green fur.




Light Green Environment


     If we had performed another experiment in an environment that is light green, I hypothesize that the population of the Light Green Rabbits would increase at the highest rate, the Dark Green Rabbits will increase population at a slow rate, and the White Rabbits will go extinct.






Conclusion


     Through this experiment, we saw several aspects of the predator-prey relationship in nature. The one thing that caught my eye, and that I have never thought of before, is that if the population of prey is really high, the predator population will increase rapidly, and in effect will cause both populations to rapidly decrease. This is because there will be so many wolves that the rabbit population will be nearly wiped out, and after the rabbit population is depleted, the wolves will starve and their population will too be depleted.