HEAT PRODUCED DURING RESPIRATION

INTRODUCTION

Background of the Study

Respiration is a process where glucose is converted into energy in series of reaction. The energy released is called ATP and heat energy is also lost to the environment. Two types of respiration are aerobic and anaerobic. Aerobic occurs under conditions where oxygen is available while anaerobic reaction occurs without oxygen. In this experiment, the type of respiration observed is aerobic, obviously because we are dealing with heat, which is more abundant in aerobic reactions. Respiration retrieves the energy from sugars. The summary equation of the chemical reaction during respiration is as follows.

Glucose + Oxygen Carbon Dioxide + Water + Energy

The generation of heat during respiration can be observed using germinating seeds of Mung Bean or Mongo (Vigna radiata) since seed germination is a period of rapid cell division and high respiration rates.

Objective of the Study

The objective of this study is to demonstrate how heat energy is released during respiration from germinating mongo (Vigna radiata) seeds and to understand how and why heat energy is released in respiration.

Definition of Terms

ATP – adenosine triphosphate, supplies energy for many biochemical cellular processes by undergoing enzymatic hydrolysis

Germination – to cause to sprout or develop

Respiration – the enzymatic breakdown of organic compounds leading to a controlled release of energy.

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WATER TRANSPORT IN THE STEM AND LATERAL WATER MOVEMENT

INTRODUCTIONBackground of the Study

Water is very essential for plant growth, metabolism, and transport. As plants evolved, they have developed functional organs that would effectively suffice their daily requirements, especially water and minerals. Plants have conducting vessels that transport water and minerals. For water conduction, xylem is present. It is the only vascular tissue capable of upward water translocation from the roots up to the leaves. Water transport is impaired when xylem is seriously blocked.

Objective of the Study

This experiment aims to familiarize with the physiological processes involved in the transport of water in the stem and the water’s lateral movement. Also, it aims to learn the path of water transport in plants and determining its rate of transport.

Definition of Terms

Apoplast- is the free diffusional space outside the plasma membrane Casparian strip- is a band of cell wall material deposited on the radial and transverse walls of the

endodermis, and is chemically different from the rest of the cell wall, being made of suberin and lignin.

Cortex- a layer of cells in the epidermis that is used by the plants for the storage of foods such as resin, tannins and oils

Xylem- a complex tissue in the vascular system of higher plants that consists of vessels,

tracheids, or both usually together with wood fibers and parenchyma cells, functions chiefly in conduction of water

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TRANSPIRATION IN PLANTS

INTRODUCTION

Background of the Study

Transpiration is common among plants which means to perspire. It is the process of water movement through a plant and its evaporation from aerial parts, such as from leaves but also from stems and flowers. Leaf surfaces are dotted with pores which are called stomata, and in most plants they are more numerous on the undersides of the foliage. The stomata are bordered by guard cells and their stomatal accessory cells (together known as stomatal complex) that open and close the pore. Transpiration occurs through the stomatal apertures, and can be thought of as a necessary "cost" associated with the opening of the stomata to allow the diffusion of carbon dioxide gas from the air for photosynthesis. Transpiration also changes osmotic pressure of cells, enables mass flow of mineral nutrients and water from roots to shoots, and cools the plant.

Objective of the Study

The purpose of this exercise is to demonstrate water transport in plant due to transpiration.

Definition of Terms

Photosynthesis – synthesis of chemical compounds with the aid of radiant energy and especially light; formation of carbohydrates from carbon dioxide and a source of hydrogen (as water) in the chlorophyll-containing cells (as of green plants) exposed to light

Stomata – one of the minute openings in the epidermis of a plant organ (as a leaf) through which gaseous interchange takes place

Transpiration – the passage of watery vapor from a living body (as of a plant) through a membrane or pores

HEAT PRODUCED DURING RESPIRATION

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MATERIALS AND METHODS

One-fourth kilogram of viable mongo seeds were soaked in water for twenty-four hours to start seed germination and then drained. One-half of the soaked seeds were put in a beaker (500-mL) and treated with 10% formalin for five minutes to poison them. The other half was left untouched. One Erlenmeyer flasks (250-mL) was filled to about three-fourth full of soaked and partly sprouted mongo seeds. A clean thermometer was inserted into the flask with soaked seeds with the thermometer tip reaching the midst. The flask with seeds and thermometer was plugged with absorbent cotton, keeping the thermometer in upright position. The same procedure was done with another flask using soaked mongo seeds which were previously poisoned with formalin.

Both setups were put in a dim cupboard for twenty-four hours and temperature was recorded every two hours.

WATER TRANSPORT IN THE STEM AND LATERAL WATER MOVEMENT

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Figure 1. Erlenmeyer flask with soaked and partially sprouted mongo seeds (Left) and flask with soaked mongo seeds poisoned with formalin (Right).

MATERIALS AND METHODS

Two leafy shoots of Kamantigue plant ( Impatiens balsamina) were prepared by cutting its base in observing the path of water transport. A concentration of 0.01% Eosin dye and 0.01% Fuchsin dye were used as an indicator for the path which the researchers signed out from the stockroom. One shoot was immersed in an Erlenmeyer flask containing the 0.01% Eosin dye solution while the other shoot was immersed in the flask with 0.01% Fuchsin dye solution. It was then set aside for 15 minutes. After the given time, the branches were removed from the flask. Each of it was cut longitudinally and then measured the length of the stem covered by the dye. A cross- section from each stem covered by the dye was mounted and was observed under the microscope and the tissues stained were identified and labeled.

Another three Kamantigue (Impatiens

balsamina) shoots about 15-20 cm were prepared to observe the lateral water movement in the stem. The ends of the shoots were cut and split 5cm longitudinally. The first shoot was dipped with one-half of the cut part in a test tube containing water. The next shoot was dipped with both halves in another test tube with water. The last shoot was dipped with both halves in a test tube with the presence of water. The set-up was left undisturbed and then observed after twenty-four hours.

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Figure2. Erlenmeyer flask with immersed Kamantigue (Impatiens balsamina) in Fuchsin dye (Left) and Kamantigue in flask with Eosin dye (Right).

Figure 3.1 Test tube A with half of the Figure3.2 Test tube B with both halves Figure 3.3 Test tube C with the stemstem immersed in water of the stem immersed in water immersed in tube without water

The study was conducted at Room 213 of the College of Science and Mathematics, MSU- Iligan Institute of Technology on May 5, 2013.

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TRANSPIRATION IN PLANTS

MATERIALS AND METHODS

Two small flower pots with Soil were brought, one with growing plant and the other one is without growing plant, also four pieces of transparent plastic bags and rubber bands were used to cover the two small flower pots with soil. The two small flower pots were watered and each of it was covered tightly with the plastic bag and rubber band. The potted plant is the set-up A which was covered twice. First was the pot until to the base of the stem and then it was covered as a whole, including the plant for the second time. The flower pot with soil only is the set-up B which was covered also twice with plastic and rubber band.

After twenty-four hours, the droplets of water along the inner wall of the plastic bag was observed. Then the two set-ups were compared.

The study was conducted at Room 213 of the College of Science and Mathematics, MSU- Iligan Institute of Technology on May 5, 2013.

HEAT PRODUCED DURING RESPIRATION

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RESULTS AND DISCUSSION

Table 1. The heat released during respiration of mongo seeds.

Temperature reading after time (hours)

Average temperature readings when thermometer bulb is with

Seeds soaked overnight Seeds soaked overnight but are treated with formalin

0 (Initial) 31BC 29.5BC

2 33BC 29BC

1. Which setup shows rise in temperature? Answer with a check (√)

√

2. Which setup shows fall of temperature? Answer with a check (√)

√

The temperature of the soaked and untouched seedlings was higher compared to the seedlings treated with formalin on the first two hours primarily it is due to the heat energy released during respiration of the germinating mongo seeds without formalin. The purpose of adding formalin to the soaked mongo seeds is to kill or poison the germinating seeds and therefore stopping its process of respiration. The reason for the rise in temperature in the setup with soaked seeds and fall of temperature in the setup with soaked seeds added with formalin is the continued respiration of the germinating seeds. Since seed germination is a period of rapid cell division and high respiration rates, and the products of respiration are carbon dioxide, water, and heat energy, it follows that more heat is released in the first setup compared to the other which has seeds no longer germinating.

WATER TRANSPORT IN THE STEM AND LATERAL WATER MOVEMENT

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RESULTS AND DISCUSSION

Table 2. Transport of water in the stem of plants

Fuchsin Dye Eosin Dye

Height (mm)

Time (min)

Rate of Ascent (mm/min)

Height (mm)Time (min)

Rate of Ascent (mm/min)

55 mm 15min 3.7 mm/min 60 mm 15min 4.0 mm/min

After fifteen minutes, both dyes were able to ascend to the plant’s stem. However, the Eosin dye has a higher transport rate at 4.0 mm/min than that of the Fuchsin dye at the rate of only 3.7 mm/min. The tissue that moves water in plants is Xylem. Water molecules have several characteristics that make it easy for transpiration to occur. They have a cohesive and adhesive quality that enables them to move upward gravity under. The oxygen ends are negatively charged and the hydrogen end is positively charged. So, one water molecule will be attracted to other water molecules. As the water travel up the xylem, each water molecule pulls each other in a tight chain. This is cohesion, when two alike substances attract each other. Adhesion is the attraction of two different materials. Because of the height of trees, it would be hard for water to travel up that distance. What makes it easier is that water can stick to the surface of the xylem walls.

Figure3. Label of the cross section of the stained portion of the stemCross section of Impatiens balsamina

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Cross-sections of the two stems with different dyes were observed under the microscope. A clear indication of its Xylem was seen as it was stained with much darker shade in the two dyes. Also, the Eosin dye gives more stain to the nucleus and cytoplasm while the Fuchsin is obvious in the fibers. The lateral movement of water includes the Apoplastic and the Symplastic movement.

The apoplast and symplast pathways are two different pathways by which water can move through the root of a plant.

Water in the apoplast pathway moves from cell to cell via spaces in the cellulose cell walls until it reaches the endodermis. At the endodermis, there is the 'apoplast block' - the cellulose cell walls of the cells of the endodermis have a substance called suberin which is impermeable and prevents the movement of water. The suberin makes up what is called the Casparian strip. At this point, all the water has to move into the vacuolar and symplast pathways. The function of the apoplast block is to prevent harmful substances from entering the xylem.

The symplast pathway is where water moves from cell to cell in the cytoplasm via the plasma membranes and plasmodesmata. Water moves along the root by osmosis down a water potential gradient (as water moves into one cell, this cell then has a higher water potential than the adjacent cell, so water moves from cell to cell by osmosis). Water moves in this way along in the cytoplasm from the root hair cell to the endodermis.

TRANSPIRATION IN PLANTS

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Figure4. Impatiens balsamina stems soaked in test tubes, 2 with water and 1 containing no water.

RESULTS AND DISCUSSION

Water is lost from the stomata of the plant. Stomata are pores found in the epidermis of the

underside of leaves. They are located on the lower surface of leaves to reduce water loss due to

minimized solar radiation. The moist air in these spaces has a higher water potential than the

outside air, and water tends to evaporate from the leaf surface. The stomata act as pumps which

pull water and nutrients from the roots through the rest of the plant to the leaves.

The moisture came through the plant by transpiration in the form of vapor. Transpiration

occurs during photosynthesis when the stomata open for the passage of carbon dioxide gas.

Carbon dioxide is a necessary component of photosynthesis that the plant must get from their

environment. Water transported to the leaves is converted to a gas. As carbon dioxide is allowed

into the leaf, water vapors escape through evaporation to the atmosphere. Plants lack membranes

that are permeable to carbon dioxide and impermeable to water making transpiration an

inevitable consequence of photosynthesis.

On the set-up B, there were no droplets of water formed since no transpiration happened to

give off moisture and transpiration needs a plant to complete the process.

CONCLUSION

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Figure 5.1. Set-up A (Potted Plant)

Figure 5.2. Set-up B (Soil only)

HEAT PRODUCED DURING RESPIRATION

The researchers therefore conclude that the seedlings respire aerobically because of the presence of oxygen that is trapped inside the flasks. Furthermore, it can also be concluded that germinating seedlings release heat, while non-germinating seedlings do not. Lastly, it was observed that respiration could not take place in seeds treated with formalin and therefore there is no heat produced.

WATER TRANSPORT IN THE STEM AND LATERAL WATER MOVEMENT

The researchers therefore conclude that plants transport water from the roots to the other parts with the aid of the Xylem. The xylem serves as the water conductor capable of bringing and holding water molecules inside the plant. Also the lateral movement of water in plants name the apoplastic and the symplastic movement enables water molecules to penetrate in and out of the cells. The researches then concluded that these can help in the longevity of the plants life water can penetrate to all cells and by the aid of the xylem, it can move up.

TRANSPIRATION IN PLANTS

There are environmental factors that could affect the transpiration. First is the light. Plants transpire more rapidly in the light than in the dark. This is largely because light stimulates the opening of the stomata. Light also speeds up transpiration by warming the leaf. Second is temperature, plants transpire more rapidly at higher temperatures because water evaporates more rapidly as the temperature rises. At 30°C, a leaf may transpire three times as fast as it does at 20°C. Third is the humidity, the rate of diffusion of any substance increases as the difference in concentration of the substances in the two regions increases. Diffusion of water out of the leaf goes on more rapidly when the surrounding is dry. Fourth is the wind. The air surrounding a leaf becomes increasingly humid when there is no breeze thus reducing the rate of transpiration. The humid air is carried away and replaced by drier air when a breeze is present. Lastly is the soil water. A plant cannot continue to transpire rapidly if its water loss is not made up by replacement from the soil.

REFERENCES

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

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

http://sahiljhamb.wordpress.com/2012/11/13/water-uptake-and-movement-up-the-stem/

http://toxics.usgs.gov/definitions/transpiration.html

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Transpiration.html

http://water.me.vccs.edu/courses/SCT112/lecture3b.htm

http://wizznotes.com/biology/transport-in-plants/factors-affecting-transpiration

http://www.ask.com/question/what-is-the-function-of-the-cortex-in-plants

http://www.merriam-webster.com/dictionary/xyem

http://www.nature.com/scitable/knowledge/library/water-uptake-and-transport-in-vascular-plants-103016037

http://www.ucar.edu/learn/1_4_2_18t.htm

https://ph.answers.yahoo.com/question/index?qid=20081211123429AAKTFNp

https://ph.answers.yahoo.com/question/index?qid=20120315093054AAvONVx

Merriam-Webster Dictionary

Orbita, M.L.S et. al. 2013. Biology 103.2. Fundamentals of Plant Biology Laboratory Manual.

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