Study the diagrams given below and answer the following question. Give examples of the plants which show the said phenomenon.

Thigmotropism is the phenomenon shown by the tendrils of the soft plants. Tendrils give support to the plants. Here in the figure, X is the stem tendril and Y is the leaf tendril. An example of stem tendril is Passiflora and an example of leaf tendril is Pea plant. Both types of tendrils have the same function but do not show structural similarities. These are called analogous parts of the plant.

Study the diagrams given below and answer the following question. How do the structures X and Y differ from each other?

X is a stem tendril while Y is leaf tendril. Characteristics Stem tendril Leaf tendril Definition (i) It is a modified stem. (i) It is a modified leaf. Characteristics Stem tendril Leaf tendril Position (ii) It is developed in the position of the stem, bud or flower. (ii) It is developed in the position of the leaf or its parts. Example (iii) Passiflora (iii) Pea

Match the modification of stem given column I, with their respective examples given the column II: Column I (Stem modification) Column II (Plants) (i) Stolon (a) Water hyacinth (ii) Runner (b) Mint (iii) Offset (c) Grape wine (iv) Tendril (d) Opuntia (v) Thorn (e) Doob grass (vi) Phylloclade (f) Rose

(i) - (b) A stolen grows upwards above the ground at some distance and then bends down towards the ground, they form adventitious roots at the nodes. Mint and wild strawberries are examples os stolens. (ii) - (e) Doob grass is an example of a runner. Runners have soft and thin slender branches which creep on the ground. (iii) - (a) Water hyacinth is an example of the offset. It is a sub-aerial modification of stem, which look like runners, but they arise from the axil of the leaf and have thick internodes. (iv) - (c) In grape wine, the stem is modified to form a thin thread-like leafless branch called a tendril. It coils around any object and helps the plant to climb up. (v) - (f) The thorn of a rose is the aerial modification of a stem. It protects the plants from grazing animals. (vi) - (d) Opuntia is an example of a phylloclade. In opuntia, the stem is thick, flat, green and with nodes and internodes. In such types of stems, the food is prepared by the stem and the leaves are modified to spines to prevent the loss of water that usually takes place by transpiration. Column I (Stem modification) Column II (Plants) (i) Stolon (b) Mint (ii) Runner (e) Doob grass (iii) Offset (a) Water hyacinth (iv) Tendril (c) Grape wine (v) Thorn (f) Rose (vi) Phylloclade (d) Opuntia