Question 1: Xylem and Phloem are specialised tissues in plants responsible for transport. Describe the primary functions of each tissue.

Answer: Xylem transports water and mineral salts from roots to leaves; Phloem transports sugars and organic nutrients from leaves to other parts of the plant.

Question 2: Explain how the structure of Xylem vessels supports their function in water transport.

Answer: Xylem vessels are long, hollow tubes with thick walls reinforced by lignin, which provides strength and prevents collapse under the tension of water transport.

Question 1: In a study measuring water flow in plant stems, the flow rate through Xylem was recorded as 50 ml per hour, while the flow rate through Phloem was 10 ml per hour. What can you infer about the relative transport capacities of these tissues?

Answer: Xylem has a higher transport capacity for water than Phloem has for sugars, indicating water moves more quickly through the plant's vascular system.

Question 2: A plant's stem analysis shows that Xylem tissue constitutes approximately 40% of the vascular tissue, while Phloem makes up about 15%. What does this suggest about the relative importance of these tissues?

Answer: It suggests that water transport via Xylem is a more dominant function in the stem, while Phloem, though important, occupies a smaller proportion of the vascular tissue.

Question 1: Describe a simple experiment to demonstrate the movement of water through Xylem in a plant. Include the variables involved and safety precautions.

Answer: A common experiment involves placing a cut flower in coloured water to observe the dye moving up the Xylem vessels. Variables include the type of dye, water temperature, and stem length. Safety precautions include handling scissors carefully, avoiding spillage, and ensuring the plant is secure to prevent injury.

Question 2: Identify two variables that could affect the rate of transport in Phloem during an experiment and suggest how to control them.

Answer: Variables include temperature and sugar concentration. To control them, keep temperature constant using a water bath, and standardise sugar concentration used for all samples.

Question 1: Explain how understanding Xylem and Phloem transport is important in developing drought-resistant crops.

Answer: Knowledge of Xylem and Phloem helps scientists develop crops that can maintain water and nutrient transport during drought conditions, for example by breeding plants with more efficient Xylem vessels or modifying Phloem flow to optimise sugar distribution.

Question 2: Identify one technological advancement that utilises knowledge of plant vascular tissues and describe its purpose.

Answer: Hydroponic systems use knowledge of plant vascular tissues to optimise nutrient delivery directly to roots, improving growth efficiency in controlled environments.