Collenchyma
Explanation
Simple permanent tissues in plants are categorized into Parenchyma, Collenchyma, and Sclerenchyma based on their cell wall structure and function. These tissues provide varying degrees of support, storage, and flexibility to the plant body.
Option Analysis
- Collenchyma (Correct): This tissue consists of living cells with unevenly thickened cell walls, primarily at the corners, due to the deposition of cellulose, hemicellulose, and pectin. It provides mechanical support and elasticity (tensile strength) to young dicot stems and petioles. This unique structure allows plant parts, such as tendrils and climbing stems, to bend without breaking.
- Sclerenchyma (Incorrect): This tissue is composed of dead cells with thick, lignified walls. It provides hardness and stiffness to the plant (e.g., the husk of a coconut) rather than flexibility. It makes plant parts rigid.
- Xylem (Incorrect): Xylem is a complex tissue responsible for water and mineral transport. While its lignified elements (tracheids and vessels) provide mechanical strength, they contribute to rigidity rather than flexibility.
- Parenchyma (Incorrect): This tissue consists of living cells with thin cell walls. Its primary functions are photosynthesis, storage, and secretion. It forms the bulk of soft plant parts but does not provide significant mechanical support against bending forces.
Key Takeaway: Collenchyma is the living mechanical tissue responsible for flexibility and bending. Sclerenchyma is the dead mechanical tissue responsible for stiffness and hardness.