Epiphytes, Parasites, and Carnivores

Unlike most animals, plants cannot move from one place to another in search of food.

To survive, plants gather light and nutrients by growing and adjusting their position. Plants get food through two different means: autotrophy and heterotrophy.

Autotrophic plants make their own food through photosynthesis. Chloroplasts capture light energy, which drives the production of sugars that nourish the plant.

Heterotrophic plants, however, rely on another organism for nourishment. Heterotrophs, such as the dodder vine, often lack chloroplasts and cannot make their own food.

The dodder vine is a leafless, climbing plant parasite. It absorbs nutrients from its host plant, which can harm or sometimes kill the host.

Modified root projections, called haustoria, invade the host plant’s vascular tissues and divert water and nutrients to support the parasite’s growth. Dodder can also spread to nearby plants, forming a network that supplies it with nutrients.

The staghorn fern has chloroplasts, so it is an autotroph. The staghorn fern shows a different kind of nutritional adaptation—it is an epiphyte, or “air plant,” that grows on other plants, such as trees, for physical support.

Epiphytes benefit from this relationship because the host plant often places them in a higher position in the forest canopy, where more light is available for photosynthesis. The host plant is not harmed.

Epiphytes have specialized roots that may anchor them to the host. They also take in water and nutrients from the air or from organic debris that collects near their anchoring point. The leaves of epiphytes also absorb moisture and nutrients from the air and rain.

Pitcher plants are mixotrophic, meaning they are both autotrophic and heterotrophic carnivorous plants that live in sunny, acidic, nutrient-poor bogs. Since bog soil lacks nitrogen, pitcher plants rely on carnivory to supplement their nutrition. The pitcher plant’s specialized leaves form funnel-shaped structures that trap and drown prey, such as insects and small animals, in digestive fluid. The digested prey provides nutrients, including nitrogen, that help support the plant’s growth.

Even though plants are stationary, they have evolved remarkable adaptations to reduce the effects of environmental stressors, such as low light or poor nutrient availability. Plants like the staghorn fern, pitcher plant, and dodder vine access valuable resources by using other organisms in their environment.