Question

in cactus both leaves and stems are modified to perform different functions .name the modification and identify their functions​

Answer 1

Explanation:(i) Entire Leaf is Modified into Tendril, e.g., Lathyrus aphaca (wild pea) (Fig. 4.19).

(ii) Upper Leaflets Modified into Tendrils, e.g, Pisum sativum (pea) (Fig. 4.20), Lathyrus odoratus (sweet pea).

(iii) Terminal leaflets Modified into Tendrils, e.g., Naravelia (Fig. 4.21).

Leaf Tendrils

(iv) Leaf Tip Modified into Tendril, e.g., Gloriosa (Glory lily) (Fig. 4.22).

(v) Petiole Modified into Tendril, e.g., Clematis (Fig. 4.23).

(vi) Stipule Modified into Tendril, e.g., Smilax (Fig. 4.24).

Leaf Tendrils

3. Leaf-spines:

Leaves of certain plants become wholly or partially modified for defensive purpose into sharp, pointed structures known as spines. Thus, in prickly pear (Opuntia; fig. 4.25) the minute leaves of the axillary bud are modified into spines. The leaf-apex in date-palm, dagger plant (Yucca) etc., is so modified, while in plants like prickly or Mexican poppy (Argemone), Amercian aloe (Agave), Indian aloe (Aloe), etc., spines develop on the margin as well as at the apex. In barberry the leaf itself becomes modified into a spine; while the leaves of the axillary bud are normal.

4. Scale-leaves:

Typically these are thin, dry, stalkless, membranous structures, usually brownish in colour or sometimes colourless. Their function is to protect the axillary bud that they bear in their axil. Sometimes scale-leaves are thick and fleshy, as in/onion; then their function is to store up water and food. Scale-leaves are common in parasites, saprophytes, underground stems, etc. They are also found in Casuarina, Asparagus etc.

Leaf Tendrils

5. Leaflet Hooks:

In Bignonia unguiscati the three terminal leaflets of leaf get modified into claw like hooks which help in climbing (Fig. 4.29).

6. Leaf Roots:

In case of Salvinia three leaves are present at one node. Out of these two leaves are normal and third gets modified into adventitious roots which help in floating over the surface of water (Fig. 4.30).

Answer 2

Functions of cactus Plant

Explanation:

• Practically all cacti flora are succulents, which means they have thickened, meaty parts adjusted to store water
• In contrast to numerous different succulents, the stem is the main part of most prickly plants where this indispensable procedure happens
• Most types of desert plants have lost genuine leaves, retaining just spines, which are modified leaves
• The stems are photosynthetic, green, and fleshy
• Inside the stem is either light or empty (contingent upon the desert flora).
• A thick, waxy coating shields the water inside the desert flora from evaporating
• Numerous cacti plants have extremely long, stringy roots, which retain dampness from the soil