Plants generally rely on their root systems for several crucial functions, including anchoring them in the soil, absorbing water and nutrients, and sometimes even storing energy. However, there are some exceptions and alternative growth strategies:

1. Hydroponic Systems: In hydroponics, plants are grown in a nutrient-rich solution instead of soil. The roots are suspended in the solution or a growth medium that supports their development, so while they’re not in traditional soil, they still have a root system functioning for nutrient uptake.

2. Aeroponics: In aeroponic systems, plants are grown with their roots suspended in air and misted with a nutrient solution. This allows for efficient nutrient and oxygen delivery directly to the roots.

3. Epiphytes: Some plants, like orchids and certain types of ferns, are epiphytes. They grow on other plants or surfaces but don’t extract nutrients from them. Instead, they absorb moisture and nutrients from the air and rain. While they still have roots, these roots are not used for anchoring in the soil but rather for nutrient uptake and anchorage on their host plants.

4. Rootless Plants: Some very specialized plants, such as certain types of algae or aquatic plants like duckweed, can survive and thrive without a traditional root system. These plants have adapted to absorb nutrients and water through other parts of their structure.

In summary, while most plants need a root system to grow properly, some have evolved to thrive without traditional roots or in unconventional growing conditions.