Biology 0610 · IGCSE · Transpiration

Transpiration — practice question

A student explored how temperature affected the rate of transpiration in a leafy shoot, using the apparatus illustrated in Fig. 3.1. The transpiration rate was estimated by recording how far the air bubble travelled every 3 minutes. The investigation was carried out again at six different temperatures. The findings are given in Table 3.1.
(a)[4]

Complete the sentences about transpiration. Transpiration is the loss of water vapour from leaves. Water evaporates from the surfaces of the [BLANK] cells into the [BLANK] spaces. Water vapour then leaves the leaves through the [BLANK] by the process of [BLANK].

(b(i))[1]

Using the data in Table 3.1, calculate the transpiration rate at 25^{\circ}C.

(b(ii))[3]

Tick (✓) three conclusions from the data in Table 3.1. Statements: As temperature rises, the distance travelled by the air bubble falls. As temperature rises, the transpiration rate falls. As temperature rises, the transpiration rate increases and then stays constant. From 20^{\circ}C to 30^{\circ}C, the transpiration rate triples. From 20^{\circ}C to 45^{\circ}C, the transpiration rate rises by 17 mm per minute. The maximum transpiration rate was 22 mm per minute.

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