negatively geotropic and positively phototropic

positively geotropic and negatively phototropic

positively geotropic and positively phototropic

negatively phototropic and negatively geotropic

Match the items in column A with those of column B (a) Auxin (i) apical dominance (b) Gibberellin (ii) cell-division (c) Cytokinin (iii) fruit ripening (d) Ethylene (iv) internodal elongation

(a)-(i) Auxin also plays a role in maintaining apical dominance. Most plants have lateral (sometimes called axillary) buds located at nodes (where leaves attach to the stem). Auxin maintains this dormancy. As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant. If the apex of the shoot is removed, the auxin is no longer produced. This will cause the lateral buds to break their dormancy and begin to grow. In effect, the plant becomes bushier. When a gardener trims a hedge, they are applying apical dominance. (b)-(iv) Gibberellin is a plant hormone which helps in the growth of internodes. It is of different types like GA 1 , GA 2 , GA 3 , GA 4 and so on. GA 3 is the most studied one. It is called Gibberellic acid. It also delays senescence (ageing). (c)-(ii) Cytokinin is the hormone which promotes the division of the cell by dividing the cytoplasm. There occurs a constriction in the mid of the cytoplasm. Division of cytoplasm is followed by the division of the nucleus. (d)-(iii) Ethylene is known to be a key player of plant ageing, including fruit ripening, and flower and leaf senescence. (a) Auxin (i) apical dominance (b) Gibberellin (iv) internodal elongation (c) Cytokinin (ii) cell-division (d) Ethylene (iii) fruit ripening