The flesh of pear, guava and sapota fruit is gritty because of the presence of:

Question

Accepted Answer

The correct option is 1: Sclereids

Sclereids are a specialized type of dead, supportive tissue known as sclerenchyma, which is responsible for providing rigidity and hardness to plant parts. The characteristic gritty or sandy texture that you experience when eating the flesh of fruits like pear, guava, and sapota is a direct result of the abundant presence of these sclereids. These cells are also commonly referred to as "stone cells" or "grit cells" because of their distinct morphology. They are typically short, irregular, or roughly spherical (isodiametric) in shape, and their most distinguishing feature is the extremely thick, secondary cell wall that has been heavily impregnated with lignin. This dense lignification makes the cell walls very hard and non-flexible, and because these cells are scattered throughout the soft, fleshy parenchymatous tissue of the fruit pulp, they create the tough, granular sensation upon mastication. This anatomical feature is a clear evolutionary trait for mechanical protection or seed dispersal in these specific fruit types.

The incorrect option is 2: Amyloplast

Amyloplasts are non-pigmented plastids, a type of organelle found in certain plant cells, and their principal biological role is the synthesis and long-term storage of starch. They are highly concentrated in storage organs such as potato tubers, seeds, and the storage parenchyma of fruits. Although they are found in the cells of pear and guava, they are soft, microscopic, intracellular components and do not possess the structural integrity or rigid, lignified cell walls that are necessary to impart a coarse or gritty texture to the entire tissue. The presence of amyloplasts is significant for the fruit's carbohydrate content and energy reserve, but they do not influence the hard, mechanical texture perceived during eating.

The incorrect option is 3: Sclerenchymatous fibres

Sclerenchymatous fibres, while related to sclereids as they are both forms of sclerenchyma, are incorrect because they have a distinct morphology and location. Fibres are typically very long, narrow, and tapering cells, whereas the gritty texture is caused by the shorter, isodiametric sclereids. Plant fibres primarily function to provide maximum tensile strength and mechanical support to plant organs that require structural reinforcement, such as the stems and the vascular bundles within leaves, exemplified by the strong fibres of materials like linen and hemp. They generally occur in bundles and contribute to the toughness of the plant, but they are not the specific cells scattered within the fruit pulp that cause the characteristic granular mouthfeel.

The incorrect option is 4: Collenchyma

Collenchyma is a simple plant tissue composed of living cells that primarily provides flexible, non-rigid support to the growing parts of the plant, such as young stems, petioles, and the margins of leaves. These cells are characterized by their unevenly thickened primary cell walls, usually concentrated at the corners of the cells, which allows for strength and elasticity without restricting growth. Since the primary function of collenchyma is flexible support, this tissue entirely lacks the heavy lignification and extreme hardness required to produce the characteristic gritty or stony texture of pear, guava, and sapota flesh.