Which of the following is not a stem modification?

Explanation

(c) : Pitcher of Nepenthes is a modification of leaf. The correct answer is Pitcher of Nepenthes.Tendrils of cucumber, flattened structures of Opuntia, and thorns of citrus are all stem modifications. Stem modifications are structures that have evolved from stems to perform specific functions. Tendrils of cucumber: Tendrils are thin, thread-like structures that help plants climb. They are modified from axillary buds, which are small buds that are located in the axils of leaves. Tendrils wrap around objects, such as branches or fences, to support the plant as it grows. Flattened structures of Opuntia: Opuntia is a genus of cacti that includes the prickly pear. The flattened structures of Opuntia are called phylloclades. Phylloclades are modified stems that have become flattened and fleshy. They perform photosynthesis, which is the process by which plants produce food from sunlight, water, and carbon dioxide. Phylloclades also store water, which helps the plants survive in desert environments. Thorns of citrus: Thorns are sharp, pointed structures that protect plants from herbivores. They are modified from axillary buds. Thorns deter animals from eating the plants, which can damage the plants and reduce their ability to reproduce. Pitcher of Nepenthes: Nepenthes is a genus of carnivorous plants. The pitchers of Nepenthes are modified leaves that trap and digest insects. The pitchers have a slippery surface and a pool of digestive fluid at the bottom. Insects are attracted to the pitchers by the sweet nectar that is produced by the plant. Once an insect falls into the pitcher, it cannot escape and is eventually digested by the plant.