Lysigenous cavity is present in
A. Stem of helianthus
B. Root of zea mays
C. Leaves of helianthus
D. Stem of zea mays

Hint: Lysigenous is derived from a greek word meaning loosening. When the cells undergo dissolution, there is formation of a space in between the cells. This is known as the lysigenous cavity. These spaces are used by the plant as reservoirs. They store gases, water and all the required essential oils.

Complete answer:
Lysigenous is derived from a greek word meaning loosening. When the cells undergo dissolution, there is formation of a space in between the cells. This is known as the lysigenous cavity. These spaces are used by the plant as reservoirs. They store gases, water and all the required essential oils. This is seen in plants under the water and monocotyledons stems e.g. citrus, eucalyptus, gossypium. These plants have both xylem and phloem as a part of their vascular supply. Phloem is on the outer surface and on the inner lies the xylem. These spaces are absent in monocot leaves and roots. These are absent in helianthus. These are present in monocot stems.
Option A. These spaces are absent in helianthus.
Option B. Intercellular spaces are absent in root.
Option C. Intercellular spaces are absent in leaves.
Option D. Intercellular spaces are present in monocot stems. This is the correct answer.

Note:
They store gases, water and all the required essential oils. This is seen in plants under the water and monocotyledons stems e.g. citrus, eucalyptus, gossypium. These spaces are absent in monocot leaves and roots. These are absent in helianthus. These are present in monocot stems.