Biology 9700 · AS & A Level · Control and coordination in plants

Control and coordination in plants — practice question

Rice, Oryza sativa, is a crop species that has become adapted to living in flooded fields. Fig. 1.1 shows the effects of flooded-field growth on rice plants.
(a)[3]

Using Fig. 1.1, state the names of: substance A; substance B; tissue C.

(b)[1]

Describe the response of root cells to a high concentration of substance B.

(c(i))[2]

Fig. 1.2 shows how gibberellin concentration affects stem length in rice plants. Describe the relationship shown in Fig. 1.2.

(c(ii))[3]

ABA in rice plant cells inhibits the action of gibberellin. With reference to Fig. 1.1 and Fig. 1.2, explain the importance of ethylene production for the growth of rice plants in flooded fields.

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