Transport in the Xylem of Plants (DP IB Biology: HL)

Identify the set of conditions under which transpiration would occur at the slowest rate.

When a very narrow glass tube known as a capillary tube is dipped into water, water can flow up the tube despite the opposing force of gravity.

What is this model demonstrating?

The following steps describe the process of transpiration.

1. Water is drawn from xylem vessels to replace the water lost
2. A pulling force is transmitted throughout the xylem vessels all the way down the stem of the plant and to the ends of the xylem in the roots
3. Water evaporates from the surfaces of cells inside a leaf
4. A low pressure is generated within the xylem

What is the correct order of the steps?

Which of the following relates to xylem vessels?

1. Transport organic compounds from source to sink
2. Transport mineral ions from roots to leaves
3. Provides mechanical support to the plant
4. Closely associated with companion cells to assist with loading of sucrose

A student drew a diagrammatic representation of a transverse section of a plant stem based on what they saw using a light microscope.

Identify the correct labels required for the drawing above.

Identify which of the adaptations below is not found amongst the group of plants known as xerophytes.

When water is taken up by roots, what process is responsible for this and what is the cause behind this process?

What does a potometer measure?

Certain environmental factors can affect the rate of transpiration in plants. The effect of one environmental factor on transpiration rate is shown in the graph below.

Identify the environmental factor that is having this effect on transpiration rate.

Identify the process by which mineral ions in soil move towards the root cell membrane.

Which of these is not a function of plasmodesmata in plant cells?

Certain plants have developed a mutualistic relationship with soil fungi, in which the plant provides sugars to the fungus for respiration.

In what way does the plant receive a benefit in return?

Which table gives the most accurate summary of the movement of water via the apoplast and symplast pathways?

The following data were gathered from an experiment into the rate of transpiration in samples of plants in the genus Coelus, commonly grown by gardeners for herbaceous borders. Coelus grows easily in UK gardens and thrives in the relatively high rainfall that the UK experiences.

Marram grass is a xerophyte that is found on sand dunes and other fast-draining soils in coastal areas. The same experimental set-up was repeated with marram grass. 

Which graph of A - D would be the most likely graph for a comparable experiment carried out on marram grass?

The diagram shows a potometer set up to measure the rate of transpiration in a piece of cut plant. 

For a potometer with a cylindrical capillary of the internal diameter of d mm, the bubble was measured to travel h mm in an experimental time of s seconds. 

Which is the correct formula to calculate the rate of transpiration (as a volume of water uptake per unit time) in this experiment?