Anatomy of Flowering Plants

Large central vacuole

Meristematic cells lack a large central vacuole. A large vacuole would push the nucleus to the periphery, making cell division inefficient. They have dense cytoplasm, large prominent nuclei, and thin cellulosic walls.

Apical meristem

Apical meristem is located at the tips of roots and shoots and is responsible for increase in length (primary growth). Lateral meristem (vascular cambium + cork cambium) is responsible for increase in girth (secondary growth).

Cellulose and pectin at corners

Collenchyma walls are unevenly thickened with cellulose, hemicellulose, and pectin at the corners. Lignin is ABSENT from collenchyma — this keeps the cells living and flexible. Lignin is the hallmark of sclerenchyma.

Pear

Sclereids (stone cells) are present in the pulp of pear fruit, giving it its characteristic gritty texture. They are isodiametric sclerenchymatous cells with thick, highly lignified walls.