The Carrot Root Explained

World Carrot Museum - carrots  logo

History Wild Carrot Today Nutrition Cultivation Recipes Trivia Links Home Contact

 The Main Parts and Functions of the Carrot Root

The roots of certain vegetable crops are important as food. Roots typically originate from the lower portion of a plant or cutting. They possess a root cap, have no nodes and never bear leaves or flowers directly. The principal functions of roots are to absorb nutrients and moisture, to anchor the plant in the soil, to furnish physical support for the stem, and to serve as food storage organs. The purpose of a root is to anchor the plant to the ground and to absorb water and nutrients diagrams below.

The tcommon root type of  carrotap root system develops from the hypocotyl with secondary lateral roots branching from the xylem. Together, the hypocotyl and the tap root form the ‘Carrot Root'. At the center of the root is the light coloured and more woody xylem surrounded by the deep orange and sugar loaded phloem.

The periderm skin is composed of suberin and other waxy substances. Optimum root growth occurs at 60-70°F. Temperatures into the 50’s will affect the colour development and favour longer, more slender roots.

Temperatures above 70°F will cause shorter, thicker roots with a stronger flavour, but less sugar. During flower initiation, the hypocotyl crown shrinks as carbohydrates and water content is shifted to support flower development and the overall root diameter becomes slender.

Examples of typical carrot root shapes here.   (Biology web - Carrots are dicots)

Why and how do carrots make sugar - Carrots make natural sugar to make energy for the plant to reproduce. A carrot is biennial and therefore when the root is left in the ground for a further year it produces a long stalk and a mass of flower and then seeds. All this needs energy.

Carrots send sugar to their storage organs (the root). This is easy to do as it is sent in a dissolved form and will therefore travel easily along conducting vessels. For storage purposes the sugar is converted into starch; being non-soluble it is convenient to store in this way. When the plant requires the energy in the form of sugar it uses an enzyme to do the conversion. The sweetness of carrots and related plants depends on the proportion of sugar still present.

This photo (below) is a good representative sample of carrots, used in the 2014 research study entitled - New insights into domestication of carrot from root transcriptome analyses (Rong et al.: New insights into domestication of carrot from root transcriptome analyses. BMC Genomics 2014 15:895.)

wild and cultivated carrots

The root normally comprises 6 elements:

The root cap

Conical covering of the tip of the root which covers the apical meristem (undifferentiated cells). It protects against scratches while moving through the soil and excretes a mucus like substance called mucigel that allows the root to move through the soil easily.

Epidermis (skin)

Is the hard outer layer on a root absorbing water from surrounding soil through osmosis
Produces root hairs

Also known as the Peel, or periderm - Roots take water from the capillary spaces between soil particles. This function is carried out by the young portions of the roots at the location of minimal cutinisation of the epidermis and at maximum surface area. This location is found in the root-hair zone just proximal from the growing root tip. Thus roots take in their water through very fine roots located at the drip-line of the plant's canopy.

Root hairs

These are small, microscopic hairs on the outside of the epidermis and serve to increase the surface area of the root. They only survive for only a few days

The Cortex

Is located below the epidermis. Makes up the bulk of the primary root. Main purpose is to store starches. The sugar and carotene are contained in the Cortex.

The Cortex is comprised of the phloem, or nutrient conducting tissue - phloem conducts photosynthate from the leaves to the root tips. The metabolism of roots growing in the dark of the soil is essentially dependent upon respiration. This process requires carbohydrate or other organic molecules as fuel. It also requires a supply of oxygen, which is why soil needs to drain well for good plant growth.)


This is the thin layer of cells in the center of the cortex surrounding the xylem and phloem . It forces minerals into the xylem and phloem

Central Core

The Central Core comprised of xylem (a water conducting tissue, transporting water from root to leaf) All Roots contain xylem to conduct water from the soil up the plant and out through the leaves. These xylem tracheids and/or vessels are connected to others in an end-to-end design allowing soil water and minerals to be lifted up to the leaves. The evaporation of water from the leaves is the major pull of water through the xylem, but roots can also develop "root pressure" osmotically when the soil is well-watered and the plant has sufficient reserves.

In the US Department of Agriculture circular dated March 1950 are listed 389 names that have been applied to orange-fleshed carrot varieties or strains. This gave a thorough classification of all varieties of orange rooted carrots found in the US at the time.

On the basis of their general or outstanding characteristics these varieties or strains were classified in 9 major groups, as follows:

I, French Forcing; II, Scarlet Horn ; III, Oxheart ; IV, Chantenay ; V, Danvers ; VI, Imperator; VII, James' Intermediate; VIII, Long Orange; and IX, Nantes.

Type was determined mainly by root size and shape ; but other root characteristics, such as those of the flesh (phloem) and core (xylem), the shape and colour of the shoulder, the size and degree of indentation of the collar, the nature of the surface, the shape of the base, and the kind of top, were also taken into consideration.

(Source -Synonymy of Orange-Fleshed Varieties of Carrots M F  Babb 1950).

Right shows the longitudinal section of a carrot illustrating the terms used in the 1950 circular for varietal descriptions.

For information here is the full botanical classification of a carrot:

Kingdom Plantae – Plants; Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants; Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons; Subclass Rosidae
Order Apiales; Family Apiaceae – Carrot family
Genus Daucus L. – wild carrot P; Species Daucus carota L. ssp. sativus- domestic carrot

(It is generally accepted that domesticated carrot is drawn from the wild variety)

Note - Some classifications show Umbelliferae rather than Apiaceae

Important Note - The chemical constituents of carrot are not there by chance, but perform a function. Many constituents of the orange carrot we now cultivate are also in the white root of the wild carrot, Queen Anne's lace, from which our carrot was developed. This is true of falcarinol, falcarindiol, and myristicin. Carotene (present in small amounts in Queen Anne's lace) has been increased by centuries of selection. Volatile oils have been decreased in this process. Plant scientists must continue to monitor all known constituents nutritive and non-nutritive - as new cultivars of the carrot are developed to keep our vegetables nutritious and safe. Plant breeding for the sake of high yields, appearance, and keeping quality will not be sufficient.

Carotenoid pigments provide red, yellow and orange colours and antioxidant protection to a wide variety of plants, animals, bacteria, and fungi. In plants, carotenoids play a protective role in photosynthesis by dissipating excess light energy absorbed by the photosynthetic mechanism. 

What it means is that carotenoids are good antioxidant compounds which effectively prevent damage to DNA or other important parts of cells. This damage can be caused by ‘free radicals’ which are very reactive molecules generated through the normal living processes of a cell (the release or generation of energy).

In plants, the carotenoids protect the plant cells from damage caused by energy from the sun in the same way. Carotenoids are also a starting point for the construction of other useful compounds, so their function is not always protective. There are possibly more important  parts of the plant containing carotenoids (eg the leaves) where they are less obvious because they are masked by the green colour of chlorophyll. In the parts of the plant which don’t photosynthesize, we can see their presence more easily.

e mail symbol Next Page - The Carrot from 1800 to date carrot pointer

History Wild Carrot Today Nutrition Cultivation Recipes Trivia Links Home ContactSITE SEARCH