The root is usually the first organ which emerges from the seed . However, because roots spend most of their time below ground, they are understudied and underappreciated. Root systems can be as extensive or more extensive than shoot systems.
Roots are generally nonphotosynthetic.
However, a few, like a small orchid I spotted in Puerto Rico, are capable of photosynthesis and in this particular case, the root is the major source of photosynthate. The roots are decidedly green and they have velamen . The velamen may serve a protective and regulatory function with regards to water loss and photosynthesis. It may act like the large scales of Tillandsia , which are opaque when dry and translucent when wet. Fibrous root systems do not have a dominant Primary root.