Which of the following tissue is not present in angiosperms?

Question

Accepted Answer

The correct option is 2: Plectenchyma

The tissue that is definitively not present in Angiosperms (flowering plants) is **Plectenchyma**. This term describes a pseudo-tissue structure that is characteristic of the Kingdom Fungi, not Plantae. Plectenchyma is formed by the tight interweaving, entanglement, and eventual fusion of individual fungal filaments, known as hyphae, to create a complex, macroscopic structure. This type of organization is responsible for forming the familiar parts of fungi, such as the fruiting bodies (mushrooms) and the hard, resting masses called sclerotia. Since Angiosperms are complex, multi-cellular, vascular plants built from highly differentiated cells that form true tissues and organs, a structure derived from fungal hyphae is entirely absent from their anatomical composition, making it the incorrect botanical term in this context.

The incorrect option is 1: Parenchyma

Parenchyma is fundamentally the most common and metabolically active simple permanent tissue present in all Angiosperms. It is the 'filler' tissue, composed of living, relatively undifferentiated, thin-walled cells that are essential for nearly all basic cellular processes. Parenchyma cells are responsible for critical functions such as food storage in the roots and stems (e.g., potato), lateral transport of water and nutrients, and wound healing or regeneration throughout the plant. Furthermore, when parenchyma cells contain chloroplasts and perform photosynthesis, they are specifically termed **chlorenchyma**, forming the vital mesophyll layer of leaves in flowering plants.

The incorrect option is 3: Sclerenchyma

Sclerenchyma is a key simple permanent tissue widely present in Angiosperms, primarily functioning to provide mechanical support, rigidity, and protection. Unlike parenchyma, mature sclerenchyma cells are typically dead and possess extremely thick, hard secondary cell walls heavily impregnated with lignin, which gives them immense strength. This tissue exists in two main forms: long, narrow **fibres** (found in vascular bundles and wood for support, such as in flax and cotton) and irregular, shorter **sclereids** (responsible for the gritty texture in fruits like pears and the hardness of seed coats and nut shells). Its presence is vital for the structural integrity of the plant body.

The incorrect option is 4: Aerenchyma

Aerenchyma is a highly specialized form of Parenchyma tissue that is specifically present in many Angiosperms, particularly those adapted to aquatic or marsh environments (hydrophytes and helophytes). This tissue is uniquely characterized by the presence of exceptionally large, interconnected air cavities or spaces within its structure, which are formed either by cell separation (schizogenous) or cell breakdown (lysigenous). Its dual purpose is critical for the survival of water-logged plants: it provides essential buoyancy for floating leaves and stems, and, crucially, it acts as a pathway for the diffusion of oxygen from the aerial parts down to the submerged roots.