sLowlife: Plants in Motion

Roger Hangarter

Tree Curl

Dennis DeHart. In botany, morphology is the study of plants’ form and structure; physiology deals primarily with plants’ functions. The shapes, growth patterns, and environmental influences of plants can often result in a truly arresting form. But a closer look reveals that there is function as well. Here a tree’s unique shape of the branches is a direct result of its mountainside location. The photograph, taken in Guanacaste Province, Costa Rica, documents the tree’s energetic struggle to compete with other plants in an environment limited by such resources as sunlight and water.

Sun Worship

Roger Hangarter. Throughout their lives plants explore and respond to their environment. They orient themselves so that they can better access sunlight, water, and nutrients, and they move to avoid competition or injury. This still image, from a time-lapse movie, illustrates innate plant responses to light and gravity. In response to the light from a small bulb, the surrounding corn seedlings appear to bow, as if in worship of this fleeting source of energy. The bowing behavior of the seedlings shows a conflict between their attraction to light (phototropism) and their tendency to grow upright in response to gravity (gravitropism). These tropistic movements endow plants with the power to explore and adjust to their immediate environment.