Crude extracts from oat and squash seedlings can mimic the behavior of a light-sensitive plant protein called phytochrome. When these extracts are exposed to red light, they show similar properties to phytochrome found in living plants. Extracts from tissue that has been treated with red and far-red light also exhibit these characteristics. The researchers suggest that the far-red form of phytochrome in the extracts may still be active and connected to its natural function in plants.