Plant Type
Normal Conditions (21oC)
With Heater
With Fan (21oC)
With Lamp (21oC)

(27oC)

Arrowhead 3.6mL 6.6mL 7.5mL 4.0mL
Coleus
0.9mL 3.9mL 6.0mL 3.0mL
Devil’s Ivy 2.9mL 4.1mL 4.6mL 3.0mL
Dieffenbachia
4.1mL 6.0mL 7.7mL 3.9mL
English Ivy 1.8mL 3.2mL 5.1mL 2.1mL
Geranium
1.2mL 5.8mL 4.7mL 2.4mL
Rubber Plant 4.9mL 6.8mL 8.4mL 4.3mL
Weeping Plant 3.3mL 4.9mL 6.1mL 2.5mL
Zebra Plant 4.2mL 6.1mL 7.6mL 3.2mL
2. Transpiration is the process of moisture carried through plants from roots to small pores on the bottom side of leaves, where it changes to vapor and is released to the atmosphere. In our experiment, transpiration is the passage of watery vapor from a living plant through a membrane or pores.
3. If the air flow is directed onto the upper surface, then the transpiration rate would be smaller compared to the original result.
4. Light and fan variables would lose the most mass through transpiration and the fan and mist variables would lose the least amount, with room condition in the middle. Light and fan variables lost the most amount of mass because sunlight promote photosynthesis to occur and wind causes the emission of water to occur due to a lower water potential outside the flower. The dark and mist variables lost the least amount of mass because transpiration was kept to a minimum due to lower water potential in the plant and no need to follow through with photosynthesis. The room condition remained in the middle of the mass loss because it was the constant variable and there were no influences for or against transpiration, allowing the natural rate of transpiration to take place. The room condition remained in the middle of the mass loss because it was the constant variable and there were no influences for or against transpiration, allowing the natural rate of transpiration to take place.
5. The rubber plant that I tested had the highest transpiration rate. Each species of plant has a transpiration rate ideal for its domestic environment. Higher transpiration rates may be indicative of a wetter climate, while lower transpiration rates may be used to conserve water in places like a desert where rainfall is minimal.
6. Water moves from the xylem into the mesophyll cells, evaporates from their surfaces and leaves the plant by diffusion through the stomata.
7. The roots have two main functions, to anchor the plant in the soil and to meet the water requirements of the leaves. Almost all the water that a plant takes from the soil enters through the younger parts of the root. Absorption takes place directly through the epidermis of the root, largely in the region of root hairs.
8. Closing the stomata prevents water from evaporating. This means the plant can get by on less water because it isn't wasted. The disadvantage of closing the stomata cuts off the supply of CO2 from the air and traps oxygen inside the leaf. This prevents the plant from doing photosynthesis. A typical solution to this problem is for the plant to separate photosynthesis into two processes that can be carried out at different times. During the day the plant stores energy from light in a temporary form. At night it opens the stomata and uses that energy to fix CO2.
9. a. The cuticle is a waterproof epidermal layer that blocks water loss. The plant will have a cuticle thickness proportionate to their habitat's aridity.
b. Guard cells open and close the stomatal pore with the aid of the surrounding cells, which movements are driven by the changing turgidity of the cells. When opening, the potassium- and sugar-content of the guard cells increase, what results osmotic water uptake and so the swelling of the cells. They also regulates the size of stomata. This in turn regulates the amount of water loss, oxygen and carbon dioxide exchange in plant leaf.
c. Trichomes may serve a variety of functions; they may form a pubescence on the surface or serve the function of secretion (glandular hairs). They also discourage predation. To sum up, their functions are expansion of the boundary layer, retardation of water loss, control of heat exchange, light piping, storage of secondary compounds, secretion and protection.

10. found in stems - collenchyma thin-walled, many-sided cells - parenchyma dead at maturity - sclerenchyma contain lignin - sclerenchyma thick-walled, irregularly shaped - sclerenchyma photosynthetic cells - parenchyma
11. There is usually many more under the leaf than that on top. Many plant species have none on the top surface. In majority of grasses the number is equal on both the surfaces. There is hardly any plant with greater number of stomata on the upper surface of its leaf .
12. Transpiration remains in effect after the flower has been cut from the parent plant. Thus, water in the xylem is pulled up the remaining stem, and it is not replaced. By cutting off a portion of the remaining stem, a transpirational stream re-established , and thus the flower wilts at a reduced rate, in effect “apparently” living longer. Therefore, one needs to make the cuts under water to re-establish the stream.
13. vessel elements are the conducting cells of the xylem, they have elaborate secondary-wall thickenings and lose their cytoplasm at maturity; that is, they are dead when functional. Tracheids overlap each other, whereas vessel elements have open end walls and are arranged end to end to form a larger unit called a vessel.
14. A negative water potential gradient causes water and minerals to move in xylem.
15. The mechanism of sugar from sources to sinks, is called pressure flow. At the sources, sugar molecules are moved into the phloem cells through active transport. First step is sugars are loaded into sieve tube elements, creating a high concentration of solutes. Second step, water enters the sieve tube elements by osmosis. Third step is the movement of water and carbohydrates through the sieve tube elements toward a sugar sink. Last step is sugars are removed from cells at sugar sink, keeping the concentrations of sugars low.
16. The cohesion-tension theory, first described by Dixon and Joly in 1894, describes the manner in which water moves upward through a plant against gravity. Water exists in a continuous "column" from the trees down to the roots and can be put under tension just like a rope that is holding a weight.
Water has strong coheisive and adhesive properties. Cohesion is one water molecule clinging to another through hydrogen bonding, adhesion is one water molecule clinging to something else like the cell wall. These two forces are responsible for capillary action and can actually cause water to move up a tube with-out any other force exerted, however xylem cells are too big and too numerous to transport water this way.
As water evaporates from small pores in the leaves, the cohesion of that molecule to the one behind it pulls that next molecule to where it was, this action is translated down through the water column of the entire plant. In effect water is pulled up the plant by the suction caused by water evaporating. This movement can be defined as bulk flow.
Root pressure and osmosis have little to do with the cohesion-tension theory of water movement. Root pressure is hypothesized to refill xylem cells in spring and to reestablish the water column. Root pressure is created by root cells creating an osmotic gradient that forces water up the tree instead of it being pulled up the tree. Root pressure exerts a positive pressure while the cohesion-tension theory of water movement is accomplished under negative pressure.