光合作用與限制因素：练习题

The rate of transpiration can be calculated by measuring the volume of water lost over time. If a plant loses \( 0.45\text{ cm}^3 \) of water in \( 15\text{ minutes} \), what is the rate of transpiration in \( \text{cm}^3\text{ per hour} \)?

Translocation is the movement of sucrose through the phloem. Which of the following features is essential for this process to occur according to the pressure-flow hypothesis?

The xylem and phloem are specialised transport tissues in plants. Which of the following is a structural feature of xylem that is essential for its function in transporting water and mineral ions?

In phototropism, a plant shoot bends towards a light source. Which of the following describes the role of auxins in this response?

How does the root hair cell adaptation of an elongated projection assist in the uptake of mineral ions against a concentration gradient?

A student uses a potometer to compare water loss in two different conditions. In Condition A, the air bubble moves \( 30\text{ mm} \) in \( 10\text{ minutes} \). In Condition B, the bubble moves \( 12\text{ mm} \) in the same time. If the internal diameter of the capillary tube is \( 0.8\text{ mm} \), calculate the difference in the rate of water uptake between the two conditions in \( \text{mm}^3\text{ per hour} \).
(Use \( \pi = 3.14 \); \( \text{Volume of a cylinder} = \pi r^2 h \))

The structure of a leaf is highly adapted to maximise the rate of photosynthesis and regulate gas exchange.
a) Explain how stomata and guard cells work together to control the loss of water vapour during the day.
b) Describe the adaptation of the palisade mesophyll layer that allows it to absorb the maximum amount of light energy.
c) Predict and explain the effect on the rate of transpiration if the surrounding air becomes very humid.