This method is known as explant culture. Even with all the advantages to explant culture, there still are several caveats. Those phenolics originate both from explant tissues and from explant secretions. The ZLI was first discovered in the chick using explant and lineage-labeling experiments. Many neurobiological processes have been studied with retinal explant cultures. Organogenesis and morphogenesis in fetus have been studied with explant cultures. The term "explant" can be applied to samples obtained from any part of the organism. The tissue obtained from a plant to be cultured is called an explant. Historically, explant culture has been used in several areas of biological research. In explant cultures (which allow direct cell-cell interactions) the same cells differentiate into epidermis.