juuriston

Juuriston, or the root system, refers to the network of roots that anchors a plant and enables water and nutrient uptake. While most of the root system resides underground, some roots can be aerial. The system typically includes a primary root and its branching roots, forming a three‑dimensional structure that supports the shoot system and interacts with the soil environment.

The root system is organized into functional zones. The root tip contains a root cap and an apical meristem that drive growth. Behind the tip are the division, elongation, and maturation zones; the latter houses root hairs that greatly increase surface area for absorption. The endodermis with the Casparian strip regulates selective uptake into the stele, where xylem and phloem transport water and sugars to the rest of the plant. Root architecture varies by species and conditions, with taproot systems featuring a dominant central root and fibrous systems consisting of many thinner roots. Depth, lateral spread, and hair density adapt to soil type, moisture, nutrients, and competition.

Beyond uptake, roots perform storage, especially in storage roots such as carrots and beets, and engage in crucial ecological interactions. They exude compounds that influence the rhizosphere and form symbioses with soil microbes, including mycorrhizal fungi that extend nutrient access and nitrogen-fixing bacteria in legume root nodules. Root systems also affect soil structure and carbon dynamics, contributing to erosion control and carbon sequestration. Understanding juuriston is essential for agriculture, ecology, and sustainable land management.