Plant adaptation and modification - class-VII

Some plants are characterized by well-developed pulvini, small swelling at the base of the leaves, on the shoots. These leaves are individually attached, flattened and helically arranged. Pulvinus facilitates growth independent movement and is common in members of Fabaceae family.

A) Tridex is the flowering plant that belongs to family Asteraceae.

The onion is an underground stem. It is a stem modification thta gets modified to store food. There is a disc-like a stem which makes up e edible part of the onion. It is called a bulb.

The tendril of sweet pea is a modification of the terminal leaflet of the leaf into a slender wiry and coiled structure that helps in support of the plant.

• Trichomes are the epidermal outgrowths on the vegetative and reproductive parts of the plant. 
• These are hair-like structures which may be unicellular or multicellular.
• Some trichomes are secretory in nature and are known as glandular trichomes. For example, tannins, resins, gum etc., are some products secreted by trichomes.
• Trichomes help in the absorption of water and minerals.

The venus fly trap which looks and smells like a flower to insects. When they land on it, they touch a trigger hair which slams the trap shut and they are then digested by the plant.

The insectivorous plants are the carnivorous plants which feed on the insects. These plants have adapted to grow in the extreme conditions of the soil such as acidic pH. Generally, these plants are known to grow in the soil which is deficient in the mineral nutrients due to the presence of acid. The plant can grow in the soil which have low levels of nitrogen. 

• Cuscuta is a large and widely distributed genus of twining leafless parasitic herbs.
• Viscum is a common example of partial stem parasites, which grow as parasitic epiphytes on host plants. But it can carry out photosynthesis and manufacture their own food.
• Rafflesia is a parasitic plant that lacks chlorophyll and contains a single very large flower.
• Orobanche is the genus of more than 200 species of the parasitic nature plants.

So, option B is correct.

Aldrovanda vesiculosa, also famous as the waterwheel plant. This plant captures small aquatic invertebrates using water flea traps. The traps are arranged in spirals around a central, free-floating stem. This is one of the rare plant species capable of rapid movement.

So option B is correct.

A) Tendrils are the modification of leaves that help climbers to climb the support.

Leaf pitcher is found in Nepenthes is a modified leaf which is converted into a lid to capture small insects and digest it to overcome nitrogen deficiency.

Leaves of some plant get modify to form tendrils. These are thin, wiry, and spirally coiled. It holds the support by coiling around it and help the weak stem to climb the support.

1. Onion leaves are modified to store food and water called scale leaves.
2. Opuntia or prickly pear leaves modified into spines for defensive purpose.
3. Nepenthes leaves are modified into leaf-pitcher to trap insects so that they fulfill their nitrogen deficiency.
4. Utricularia is an insectivorous plant that grows in water and their leaves get modified to leaf-bladder for digesting insects.

Areoles are the evolutionary modification in the cacti. These modifications give rise to spines and glochids which are the means of self-defense. These spines effectively cover the cacti. These evolved as abortive branch buds while their spines evolved as vestigial leaves.

'Fleshy scale leaves' in garlic and onion are edible plant parts.

The leaves close under various other stimuli, such as touching, warming, blowing, or shaking. ... The stimulus can also be transmitted to neighboring leaves. It is not known exactly why Mimosa pudica evolved this trait, but many scientists think that the plant uses its ability to shrink as a defense from herbivores.
So, the correct option is "C" (Leaf movement).

In Duranta, axillary buds and in Carrisa the apical bud is modified into stem thorns, for ulex both stem thorns as well as leaf spines are modified.
Hence, option D is correct.