Plants and Water - Introduction

Introduction

Plants are a diverse group of organisms that include over 250,000 species. They live in a range of environmental conditions, from mountaintops to the ocean floor. They can claim the world's largest organism, a redwood tree that can stretch to a height of 364 feet (110 meters), and the world's oldest organism, the 4,700-year-old bristle-cone pine tree.

Without plants, life on Earth as it is now could not exist. Plants make their own food by photosynthesisChemical process by which plants containing chlorophyll use sunlight to manufacture their own food by converting carbon dioxide and water into carbohydrates, releasing oxygen as a by-product., a process that uses the energy of the Sun to make sugar and oxygen. Humans and other organisms use the oxygen released by photosynthesis to survive. Plants are also used for food, shelter, and protection by organisms in every known environment.

Plants depend on water for several essential functions. Water is needed for photosynthesis and to help transport nutrients through a plant's system. Most growing plants contain about 90 percent water. This water maintains the plant's internal temperature and provides it structure. Without water or with too much water, a plant dies. How plants take in water and what they do with it is essential for their survival.