Q.37 A cavity, lysigenous in origin and possessing volatile oil is found in the pericarp of one of the following
plants. Identify the CORRECT answer.
(A) Litchi
(B) Citrus
(C) Mango
(D) Coconut
The correct answer is (B) Citrus. Lysigenous cavities, formed by the dissolution of cells and containing volatile oils, occur in the pericarp of Citrus fruits like oranges and lemons.
Option Analysis
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(A) Litchi: The pericarp consists of epicarp, mesocarp, and endocarp without lysigenous cavities; volatiles are present but not stored in such structures.
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(B) Citrus: Mesocarp features oval lysigenous oil glands holding essential oils like limonene, a classic example in plant anatomy.
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(C) Mango: Contains schizogenous resin ducts in the pericarp, not lysigenous cavities with volatile oils.
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(D) Coconut: Pericarp has fibrous sclereids in mesocarp and hard endocarp; no lysigenous cavities or volatile oils noted.
Lysigenous cavity volatile oil pericarp structures define Citrus anatomy, forming through cell breakdown to store essential oils in fruits like lemon. These cavities aid defense and aroma, vital for competitive exams like CSIR NET Life Sciences.
What is Lysigenous Cavity?
Lysigenous cavities arise from programmed cell death dissolving internal cells, creating spaces lined by secretory epithelium. Unlike schizogenous types (cell separation), they store volatiles in pericarp mesocarp.
Role in Citrus Pericarp
In Citrus, oval glands in mesocarp hold terpenes like limonene, released via rupture for pest repulsion. Development involves schizolysigeny, but classically termed lysigenous.
Comparisons Across Options
| Plant | Pericarp Structure | Cavity Type | Volatile Oil Presence |
|---|---|---|---|
| Litchi | Thin epicarp, fleshy mesocarp | None | Volatiles in tissues |
| Citrus | Spongy mesocarp with glands | Lysigenous | Yes, in cavities |
| Mango | Fleshy with resin ducts | Schizogenous | Resins, not oil cavities |
| Coconut | Fibrous mesocarp, stony endocarp | None | Fixed oils in endosperm |
