Botany

Photosynthesis, water transport, and plant hormones

What is botany?

Botany is the study of plants — their structure, how they grow, how they make their own food from sunlight, and how they reproduce. Plants are essential to nearly every ecosystem on Earth, forming the base of most food chains and producing much of the oxygen in the atmosphere.

Photosynthesis: making food from light

Plants are able to produce their own food using photosynthesis, a process that uses energy from sunlight to convert carbon dioxide and water into sugar, releasing oxygen as a byproduct. This process takes place mainly in a plant's leaves, inside structures called chloroplasts, and it's the ultimate energy source that most other life on Earth depends on, directly or indirectly.

Plant structure

A typical plant is organized into roots (which anchor the plant and absorb water and nutrients from soil), stems (which support the plant and transport water and nutrients between roots and leaves), and leaves (where photosynthesis mainly occurs). Many plants also produce flowers, which are specialized structures for reproduction.

How plants reproduce

Many plants reproduce through flowers, which produce pollen and ovules; when pollen from one flower reaches another flower's ovule (a process called pollination, often carried out by insects, birds, or wind), fertilization can occur, eventually producing seeds capable of growing into new plants. Other plants, like ferns and mosses, reproduce through spores instead, a simpler reproductive method that doesn't rely on flowers or seeds at all.

Why botany matters

Botany underlies agriculture and food security, since nearly all human food ultimately traces back to plants (or to animals that themselves eat plants), and it guides forestry, medicine (many drugs originate from plant compounds), and efforts to conserve plant biodiversity and the ecosystems that depend on it.