Plant Ecology

Orchid Care Tips

Orchid Growing Training Course

Get Instant Access

The study of the interactions between plants and the environment is called plant ecology. The most important interaction involves the ability of plants to capture solar energy through photosynthesis. In photosynthesis, plants absorb carbon dioxide from the air, produce sugar and starch, and break apart water, releasing oxygen into the air. Consumers, like the one shown in Figure 27-8, use sugar and oxygen in cellular respiration and produce carbon dioxide and water. Organic compounds from plants provide consumers with energy, cellular "building blocks," and essential compounds such as vitamins and fiber.

Plants also provide organisms with inorganic nutrients. Plant roots are very efficient at mining the soil for inorganic nutrients, such as nitrogen, phosphorus, potassium, iron, and magnesium. Plants use these inorganic nutrients for metabolism and to make organic compounds. Consumers ingest these organic compounds and incorporate the inorganic nutrients into their own bodies.

figure 27-8

About half of the world's species of plants and animals live in tropical rain forests. One of the reasons scientists are very concerned about the destruction of rain forests is because many plant species have yet to be researched.

About half of the world's species of plants and animals live in tropical rain forests. One of the reasons scientists are very concerned about the destruction of rain forests is because many plant species have yet to be researched.

Eventually, these same inorganic nutrients are returned to the soil when the consumer's waste material or dead body is decomposed by bacteria and fungi. Plants thus play a major role in the continuous cycling of the Earth's water, oxygen, carbon dioxide, and inorganic nutrients.

Plants are also responsible for the formation and maintenance of soil. Roots bind soil particles together, leaves reduce the soil-eroding impact of wind and rain, and dead plant parts add organic matter to the soil.

Plant-Animal Interactions

Plants interact with animals in many fascinating ways. Many flowering plants attract pollinators, animals that carry pollen from one plant to another. Usually the pollinator gets a reward for its efforts in the form of food from nectar. The size, shape, color, and odor of many flowers make them attractive to their pollinators. For example, Figure 27-9 shows that in some orchid species, the flowers have evolved to look and smell like the female of their wasp or bee pollinators. A male wasp or bee lands on a flower believing he has located a mate. The pollen he touches sticks to his body and is transferred to the next orchid he visits. In this case, the flower lures the pollinator with the promise of a mate, but fools the insect into picking up pollen without receiving a reward.

Plant-Microbe Interactions

Two important aspects of plant ecology are plant interactions with fungi and with bacteria. Plant-microbe interactions may be harmful to plants, as in the case of fungal and bacterial diseases. Diseases often cause major crop losses. However, bacteria and fungi also form important beneficial relationships with plants.

The majority of plant species form mycorrhizae, which are symbiotic relationships between fungi and the roots of a plant. A mycorrhizal fungus penetrates a root, often changing the root structure. However, the fungus does not harm the root. Instead, it greatly increases the root's ability to absorb water and other inorganic nutrients, such as phosphorus and potassium. In return, the root supplies the fungus with energy.

The roots of many plant species also form beneficial associations with bacteria. Some bacteria can take nitrogen gas from the air and "fix" it, or convert it to a form that plants can use. Plants of the legume family, such as peas, beans, and peanuts, commonly host bacteria that fix nitrogen.

Plant-Human Interactions

We protect and care for many plants that provide us with food, clothing, shelter, medicine, and many other products. However, humans have drastically changed natural plant populations by introducing foreign plant species, diseases, and animals. Introduced plants, such as the water hyacinth shown in Figure 27-10, kudzu, crabgrass, and dandelion have become widespread weeds.

figure 27-9

Some orchid species have evolved to resemble their wasp or bee pollinators.

figure 27-9

Some orchid species have evolved to resemble their wasp or bee pollinators.

figure 27-10

The water hyacinth has become a weed that clogs waterways in the southeastern United States.

figure 27-10

The water hyacinth has become a weed that clogs waterways in the southeastern United States.

Weeds are undesirable plants that often crowd out crop plants or native plant species. For example, water hyacinths float on lakes and rivers, growing so fast and dense that they impede boats and shade underwater plants. The introduction of a fungal disease, chestnut blight, in 1904 virtually wiped out the American chestnut as a dominant forest tree in the eastern United States. Government inspectors now carefully screen plant materials entering the country to prevent the introduction of plant pests and diseases that native plants have no resistance against.

Was this article helpful?

0 0
Sirens Sleep Solution

Sirens Sleep Solution

Discover How To Sleep In Peace And Harmony In A World Full Of Uncertainty And Dramatically Improve Your Quality Of Life Today! Finally You Can Fully Equip Yourself With These “Must Have” Tools For Achieving Peace And Calmness And Live A Life Of Comfort That You Deserve!

Get My Free Ebook


Post a comment