Sieve tube elements, which are part of the phloem in plants, do not have chloroplasts. The primary function of sieve tube elements is to transport sugars and other organic nutrients throughout the plant. Since they are specialized for transport, they lack many of the organelles found in other plant cells, including chloroplasts.
Chloroplasts are essential for photosynthesis, the process by which plants convert light energy into chemical energy. However, sieve tube elements do not perform photosynthesis. Instead, they rely on the products of photosynthesis (such as sugars) that are produced in the mesophyll cells of leaves and then transported to other parts of the plant.
In summary, sieve tube elements do not have chloroplasts because their role is focused on nutrient transport rather than photosynthesis.