Why do cactuses have green stems?

Answer 1

Chlorophyll gives cactus stems their green color. A cactus has chlorophyll because of the stem's photosynthetic interaction with sunlight to make cactus foods. In many other plants, photosynthesis takes place in the leaves. But cactus needles don't offer a large enough surface for photosynthesis to take place or for photosynthetic byproducts to be stored. Instead, needles have reduced surface areas to stop surface evaporation of moisture. So photosynthesis instead must take place within the larger surface area of the stem.

Answer 2

cactus stems carry out photosynthesis and store water. Unlike many other succulents, the stem is the only part of a true cactus where this takes place. Much like many other plants that have waxy coatings on their leaves, Cacti often have a waxy coating on their stems to prevent water loss. This works by preventing water from spreading on the surface and allowing water to trickle down the stem to be absorbed by the roots and used for photosynthesis. Cacti have a thick, hard-walled, succulent stem - when it rains, water is stored in the stem. The stems are photosynthetic, green, and fleshy. The inside of the stem is either spongy or hollow (depending on the cactus). A thick, waxy coating keeps the water inside the cactus from evaporating.

Answer 3

They contain chlorophyll, like any plant.