Why does stem of cactus plant perform photosynthesis and not leaves??
Answers
Cacti perform photosynthesis in the same place as all other plants, inside cellular organelles called chloroplasts. What you are really asking is where are chloroplasts located in "leafless" plants like cacti? The most familiar cacti are stem succulents, one of many adaptations plants have to very dry environments. Stem succulents have thick water storing stems. Not all cacti are succulents, and not all succulents are cacti, but this is an answer to another common question. To limit water loss many desert adapted plants have very small or vestigial leaves. This presents a trade- off problem because reducing water loss with smaller leaves also reduces the number of chloroplast containing cells in the leaves. To compensate, the photosynthesis function is transferred to cortical cells in the fleshy stem, and so their green color. This is not so unusual because many plants have green stems when they are young. Photosynthetic stems must also have stomate, pores, through which gas exchange takes place. Again there is a functional trade-off problem because while gas exchange is necessary for photosynthesis, water is lost through the pores. Cacti are among a group of plants that solve this problem by capturing solar energy by day, and finishing the photosynthesis by night when the stomata can be open with minimal water loss.
No, the cactus performs this through stems as the leaves are modified into spines. Photosynthesis is a physiochemical or photo-biochemical process(anabolic and endergonic ) in which organic compounds are synthesized into inorganic raw materials in the presence of light and pigment. Oxygen is evolved in the process.