Correct Option
The correct option isSmaller roots branching out from the main primary root.
Explanation
In the majority of dicotyledonous plants, the direct elongation of the radicle leads to the formation of the primary root, which grows vertically downward into the soil. The taproot system consists of this main primary root and its branches.
Option Analysis
- Adventitious roots arising from the stem. is Incorrect: Roots that arise from parts of the plant other than the radicle (such as the stem or leaves) are termed adventitious roots (e.g., Grass, Monstera, Banyan tree).
- Smaller roots branching out from the main primary root. is Correct: The primary root bears roots of several orders, referred to as secondary, tertiary, etc. These smaller roots branching out from the main primary root are collectively known as lateral roots.
- Roots specifically found in plants with parallel venation. is Incorrect: The taproot system is characteristic of dicotyledonous plants, which typically exhibit reticulate venation. Plants with parallel venation (monocots) usually possess a fibrous root system.
- Modified roots intended for food storage. is Incorrect: While roots can be modified for food storage (e.g., carrot, turnip), the term "lateral roots" refers to the structural branching pattern, not specifically to modified storage organs.
Key Takeaway: In a taproot system, the main axis is the primary root, and the branches arising from it (secondary and tertiary roots) are termed lateral roots.