Carrot
The carrot is a root vegetable, typically orange in colour, though heirloom variants including purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, Daucus carota, native to Europe and Southwestern Asia. The plant probably originated in Iran and was originally cultivated for its leaves and seeds.
The carrot is a biennial plant in the umbellifer family, Apiaceae. World production of carrots for 2022 was 42 million tonnes, led by China producing 44% of the total.
The characteristic orange colour is from beta-carotene, making carrots a rich source of vitamin A. A myth that carrots help people to see in the dark was spread as propaganda in the Second World War, to account for the reason of British pilots' ability to fight in the dark; the real explanation was the introduction of radar.
Etymology
The word is first recorded in English around 1530 and was borrowed from the Middle French carotte, itself from the Late Latin carōta, from the ancient Greek καρωτόν, originally from the Proto-Indo-European root ker-, due to its horn-like shape. In Old English, carrots were not clearly distinguished from parsnips. The word's use as a colour name in English was first recorded around 1670, originally referring to yellowish-red hair.Description
Daucus carota is a biennial plant. In the first year, energy is stored in the taproot to enable the plant to flower in its second year.Soon after germination, carrot seedlings show a distinct demarcation between taproot and stem: the stem is thicker and lacks lateral roots. At the upper end of the stem is the seed leaf. The first true leaf appears about 10–15 days after germination. Subsequent leaves are alternate, spirally arranged, and pinnately compound, with leaf bases sheathing the stem. As the plant grows, the bases of the seed leaves, near the taproot, are pushed apart. The stem, located just above the ground, is compressed and the internodes are not distinct. When the seed stalk elongates for flowering, the tip of the stem narrows and becomes pointed, and the stem extends upward to become a highly branched inflorescence up to tall.
Most of the taproot consists of a pulpy outer cortex and an inner core. High-quality carrots have a large proportion of cortex compared to core. Although a carrot completely lacking xylem is not possible, some cultivars have small and deeply pigmented cores; the taproot can appear to lack a core when the colour of the cortex and core are similar in intensity. Taproots are typically long and conical, although cylindrical and nearly spherical cultivars are available. The root diameter can range from to as much as at the widest part. The root length ranges from, although most are between.
Flower development begins when the flat meristem changes from producing leaves to an uplifted, conical meristem capable of producing stem elongation and a cluster of flowers. The cluster is a compound umbel, and each umbel contains several smaller umbels. The first umbel occurs at the end of the main floral stem; smaller secondary umbels grow from the main branch, and these further branch into third, fourth, and even later-flowering umbels.
A large, primary umbel can contain up to 50 umbellets, each of which may have as many as 50 flowers; subsequent umbels have fewer flowers. Individual flowers are small and white, sometimes with a light green or yellow tint. They consist of five petals, five stamens, and an entire calyx. The stamens usually split and fall off before the stigma becomes receptive to receive pollen. The stamens of the brown, male, sterile flowers degenerate and shrivel before the flower fully opens. In the other type of male sterile flower, the stamens are replaced by petals, and these petals do not fall off. A nectar-containing disc is present on the upper surface of the carpels.
Flowers change sex in their development, so the stamens release their pollen before the stigma of the same flower is receptive. The arrangement is centripetal, meaning the oldest flowers are near the edge and the youngest flowers are in the center. Flowers usually first open at the outer edge of the primary umbel, followed about a week later on the secondary umbels, and then in subsequent weeks in higher-order umbels.
The usual flowering period of individual umbels is 7 to 10 days, so a plant can be in the process of flowering for 30–50 days. The distinctive umbels and floral nectaries attract pollinating insects. After fertilization and as seeds develop, the outer umbellets of an umbel bend inward causing the umbel shape to change from slightly convex or fairly flat to concave, and when cupped it resembles a bird's nest.
The fruit that develops is a schizocarp consisting of two mericarps; each mericarp is a true seed. The paired mericarps are easily separated when they are dry. Premature separation before harvest is undesirable because it can result in seed loss. Mature seeds are flattened on the commissural side that faced the septum of the ovary. The flattened side has five longitudinal ribs. The bristly hairs that protrude from some ribs are usually removed by abrasion during milling and cleaning. Seeds also contain oil ducts and canals. Seeds vary somewhat in size, ranging from less than 500 to more than 1000 seeds per gram.
The carrot is a diploid species, and has nine relatively short, uniform-length chromosomes. The genome size is estimated to be 473 mega base pairs, which is four times larger than Arabidopsis thaliana, one-fifth the size of the maize genome, and about the same size as the rice genome.
Chemistry
can be found in Apiaceae vegetables like carrots where they show cytotoxic activities. Falcarinol and falcarindiol are such compounds. This latter compound shows antifungal activity towards Mycocentrospora acerina and Cladosporium cladosporioides. Falcarindiol is the main compound responsible for bitterness in carrots.Other compounds include pyrrolidine present in the leaves and 6-hydroxymellein.
Cultivation
Taxonomic history
Both written history and molecular genetic studies indicate that the domestic carrot has a single origin in Central Asia. Its wild ancestors probably originated in Greater Persia, which remains the centre of diversity for the wild carrot. Carl Linnaeus described the wild species as Daucus carota in 1753 in his Species Plantarum. Wild carrots were presumably bred selectively in the region of origin over the centuries to reduce bitterness, increase sweetness and minimise the woody core. This process produced the familiar garden vegetable.The domestic carrot is classified as its own subspecies D. carota subsp. sativus, the accepted name published by Gustav Schübler and Georg Matthias von Martens in Flora Würtemberg, 1834. It has 3 synonyms, Carota sativa ; Daucus carota var sativus ; and Daucus sativus.
History
When first cultivated, carrots were grown for their aromatic leaves and seeds rather than their roots. Carrot seeds have been found in Switzerland and Southern Germany dating back to 2000–3000 BC. Some close relatives of the carrot are still grown for their leaves and seeds, such as parsley, coriander, fennel, anise, dill and cumin. The first mention of the root in classical sources is from the 1st century AD; the Romans ate a root vegetable called pastinaca, which may have been the carrot or the closely related parsnip.The plant is depicted and described in the Eastern Roman Juliana Anicia Codex, a 6th-century AD Constantinopolitan copy of the Greek physician Dioscorides' 1st-century pharmacopoeia of herbs and medicines, De Materia Medica. The text states that "the root can be cooked and eaten". Another copy of this work, Codex Neapolitanes from the late 6th or early 7th century, has basically the same illustrations but with roots in purple.
The plant was introduced into Spain by the Moors in the 8th century. In the 10th century, roots from West Asia, India and Europe were purple. The modern carrot originated in Afghanistan at about this time. The 11th-century Jewish scholar Simeon Seth describes both red and yellow carrots, as does the 12th-century Arab-Andalusian agriculturist, Ibn al-'Awwam. Cultivated carrots appeared in China in the 12th century, and in Japan in the 16th or 17th century.
The orange carrot was created by Dutch growers. There is pictorial evidence that the orange carrot existed at least in 512 AD, but it is probable that it was not a stable variety until the Dutch bred the cultivar termed the "Long Orange" at the start of the 18th century. Some claim that the Dutch created the orange carrots to honor the Dutch flag at the time and William of Orange, but other authorities argue these claims lack convincing evidence and it is possible that the orange carrot was favoured by the Europeans because it does not brown the soups and stews as the purple carrot does and, as such, was more visually attractive.
Modern carrots were described at about this time by the English antiquary John Aubrey : "Carrots were first sown at Beckington in Somersetshire. Some very old Man there did remember their first bringing hither." European settlers introduced the carrot to colonial America in the 17th century. Outwardly purple carrots, still orange on the inside, were sold in British stores beginning in 2002.
Propagation
Carrots are grown from seed and can take up to four months to mature, but most cultivars mature within 70 to 80 days under the right conditions. They grow best in full sun but tolerate some shade. The optimum temperature is. The ideal soil is deep, loose and well-drained, sandy or loamy, with a pH of 6.3 to 6.8.Fertilizer should be applied according to soil type because the crop requires low levels of nitrogen, moderate phosphate and high potash. Rich or rocky soils should be avoided, as these will cause the roots to become hairy and/or misshapen. Irrigation is applied when needed to keep the soil moist. After sprouting, the crop is eventually thinned to a spacing of and weeded to prevent competition beneath the soil.