Transpiration

Question 1

What is the main organ responsible for transportation?

Answer 1

The vacular bundle
it consist of the
-xylem
-pholem
- and cambium

Question 2

What are the characteristics of the xylem vessel

Answer 2

• It is non-living , consist of walls ened to end which are hallowed out
• it has no nucleus or cytoplasm.
• Their walls are stengthened with a woody substance called lingin.
• They can only carry water and minerals throughout the plant.

Question 3

What is the role of the xylem vessel

Answer 3

It is responsible for carrying water from the root to the leaves

Question 4

What is the cambium and what is it responsible for ?

Answer 4

• The cambium is the area found between the xylem and pholem.
• It is responsible for making new cells (growth).
• As a tree grows the distance in between the xylem and pholem increases as the cambium grows (ring around the tree)

Question 5

What are the characteristics of the pholem

Answer 5

• The pholem sieve tubes are made up of cells whose walls are perforated with small holes called sieve plate.
• These cells are living are stil living
• they contain some cytoplasm and a nucleus to control the activities of the cell.

Question 6

What is the leaf responsible for

Answer 6

1. Increases the surface area for photosynthesis
2. To allow gas exchange - (plants take in carbon dioxide and release oxygen)
3. The site for transpiration- the evaporation of water vapor from the leaf of plants

Question 7

What is the pholem responsible for?

Answer 7

The pholem carries substances in all directions; but mostly fom the leaves to the roots. (carries food)

Question 8

What does the pholem transport?

Answer 8

It carries three main substances:
1. sucrose: made from glucose manufactured in photosynthesis. It is transported to the non-photosynthetic parts of the plants (eg. roots) to be used as food.

2. Amino acids: manufactured using glucose and mineral salts ( especially nitrates) needed for growth and repair , therefore they carry it whereever growth and repair takes place
3. Hormones (auxins): these are chemical messengers which contro such processes are growth, response to light, time to flower, time to disperse seeds.

Question 9

What is Water ?

Answer 9

Water is a universal solvent and essential resource for plants.

It assist in keeping the plant upright
( via turgid pressure)

Its used in the process of photosynthesis, as a solvent

It is lost in the form of water vapor evaporating out of the stomata of the leaves

Question 10

What is transportation?

Answer 10

Transpiration is the evaporation of water fr the leaves of the plant

Question 11

Why is transpiration important?

Answer 11

It keeps water moving through the xylem vessel.

The evaporation from the lead has a cooling effect, which helps prevent direct sunlight from damaging the leaf.

Retain moisture and maintain turgidity cell - the cells of the spongy mesophyll are kept moist which enables carbon dioxide entering the leaf ( for photosynthesis) to dissolve

Question 12

How does plants absorb water ?

Answer 12

Plants absorb water from soil through root hairs.

Root hairs are adapted to absorbs water because of their large surface area.

Water enters the root hair cells by osmosis and travels up the root cortex cells by osmosis. Water reaches the xylem vessel and begin to flow up the leaves.

Question 13

How does water travel against gravity, up the xylem

Answer 13

• Root pressure- when water enters the root hair cell displacement occurs and water is pushed along the root cortex and upwards in the xylem
• Transpiration - the evaporation of the water from the leaves. When the water water reaches the air spaces inside the spongy mesophyll, it evaporates because of the heat that the leaves are exposed to
• As water molecules leave they creat a space ( pressure is reduced ) which creates a vacuum and water is pulled through the xylem vessel to fill the space
• ( by capillary action - the attraction between liquid molecules and the sides of very fine tubes which helps water to rise.)
• Transpiration steam- ( the flow of water through the xylem vessels )

Question 14

Factors that affect the rate of transpiration

Answer 14

light intensity, temperature, wind speed, humidity ( amount of moisture in the air)

Question 15

how does temperature affect transpiration rate?

Answer 15

• Heat causes water to evaporate faster
• The high the temperature, the more water the air can hold
• Transpiration increases with temperature

Question 16

how does humidity affect transpiration rate?

Answer 16

• the amount of moisture in the air
• It is easier for water to evaporate into dryer air than into more saturated air as no more water can evaporate in it
• the more humid it is the less evaporation will occur

Question 17

how does light intensity
affect transpiration rate?

Answer 17

Light will trigger the stomata to open, more water is lost during daylight, when the stomata are open, then at night they are closed

Question 18

how does wind movement affect transpiration rate?

Answer 18

Movement of air over the surface of the leaf removes the molecules of water vapor allowing a space to be created for more water molecules to move in.

Question 19

How is transpiration measured

Answer 19

• A parometer - is used to measure water intake.
• Its not an accurate measure because the amount of water lost in transpiration is less than the amount of water taken in by the roots because some of tbe water is used in photosynthesis

Question 20

if transpiraton occurs to rapidly..

Answer 20

too much water is lost causing the plant to wilt and die
The packing cells lose water becomes flaccid and the stem becomes floopy and droops .

Question 21

What happen if there is sufficient water

Answer 21

the packing cells are full of fluid ( turgid ) and the stem stands upright.

Question 22

what are adaptations to help plants conserve water

( epidermis , succlent tissue , hairy leaves

Answer 22

• Thick epidermis , waxy leaves - acts as a barrier to prevent diffusion ( mangrove , cactus)
• Succulent tissue - store water to provide small surface area for evaporation ( mangrove)
• Hairy leaves and suken stomata - traps moist air around the stomata ( pusley )

Question 23

what are adaptations to help plants conserve water

(needle leaves , deep roots )

Answer 23

needle leaves - reduce surface area for transpiration
( pine , cactus)

Deep roots - Inreased root area (easy access to underground water
( mango , oak )

Question 24

What is layer 1 of the internal leaf and its function

Answer 24

The waxy cuticle, itprevents water loss and infection by bacteria or fungi