Lemon

Citrus limon (L.) Burm. f.

OVERVIEW

Native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. A very popular fruit with a wide range of uses, the plant has been under cultivation for at least 1,000 years, having been first recorded in China around 1,000 AD. It is widely grown for its edible fruit in warm temperate to tropical zones.

VERNACULAR NAMES

Limau nipis (Malay), Limon (Philippines), Krôôch chhmaa vèèng (Cambodia), Naaw th’ééd (Laos), Manao-thet (Thai), Chanh tây (Vietanamese).

AGROECOLOGY

Three main climates are suitable for commercial citrus production – tropical climates, subtropical with winter rain such as in the Mediterranean and semitropical with summer rainfall as found in Florida and southern Brazil. The optimal temperatures for citrus cultivation range between 25 – 30 °C, with the coldest month having an average minimum of at least 15°c. Prefers a moderately heavy loam with a generous amount of compost and sand added and a very sunny position. Prefers a pH between 5 and 6.

MORPHOLOGY

  • Roots – taproot.
  • Stems – long spines but not tight, erect, round, simpodial branching, green twigs.
  • Leaves – Young foliage is initially purple, gradually turning green. Leaves are ovate to lanceolate with toothed leaf margins.
  • Flowers – Purplish white flowers are produced in clusters or solitary, mildly fragrant.
  • Fruits – Yellow, acidic fruits may be round to oval-shaped with an apical mammilla (nipple-shaped structure on the end attached to the branch).
  • Seeds – few in number, ovoid in shape, smooth surface.

CULTIVATION

  • Propagated by seeds – seed is best sown in containers as soon as it is ripe, after thoroughly rinsing it. Sow stored seed in containers as soon as possible]. Germination usually takes place within 2 – 3 weeks at 13 °C. Seedlings are liable to damp off so they must be watered with care and kept well ventilated. When large enough to handle, prick the seedlings out into individual pots and grow them on until they are 10 cm or more tall before planting out into their permanent positions.
  • By cutting of half-ripe wood.

CHEMICAL CONSTITUENTS

  • Essential oils (D-limonene, -pinene, -terpinene), coumarins, phenolic compounds, carboxylic acids, amino acids, flavonoids (diosmin, hesperidin, limocitrin), phenolic acids (ferulic, synapic, p-hydroxybenzoic acids).

TRADITIONAL MEDICINAL USES

  • Lemons are an excellent preventative medicine and have a wide range of uses in the domestic medicine chest. The fruit is rich in vitamin C which helps the body to fight off infections and also to prevent or treat scurvy.
  • Applied locally, the juice is a good astringent and is used as a gargle for sore throats etc. Lemon juice is also a very effective bactericide. It is also a good antiperiodic and has been used as a substitute for quinine in treating malaria and other fevers.
  • Although the fruit is very acid, once eaten it has an alkalizing effect upon the body. This makes it useful in the treatment of rheumatic conditions.
  • The skin of the ripe fruit is carminative and stomachic.
  • The essential oil from the skin of the fruit is strongly rubefacient and when taken internally in small doses has stimulating and carminative properties. An essential oil from the fruit rind is used in aromatherapy.
  • The stem bark is bitter, stomachic and tonic.
  • Some of the plants more recent applications are as sources of anti-oxidants and chemical exfoliants in specialized cosmetics.
  • The bioflavonoids in the fruit help to strengthen the inner lining of blood vessels, especially veins and capillaries, and help counter varicose veins and easy bruising.

Reference Sources

  1. The Plant List . 2010. Citrus limon (L.) Burm. f. http://www.theplantlist.org/tpl/record/tro-28100570. 05-03-22.
  2. Useful Tropical Plants Database. 2021. Citrus limon. https://tropical.theferns.info/viewtropical.php?id=Citrus+limon. 05-03-22.
  3. Flora Fauna Web. 2021. Citrus limon. https://www.nparks.gov.sg
    /florafaunaweb/flora/3/6/3671. 05-03-22.
  4. Szczykutowicz M. K., Szopa A., Ekiert H. 2020. Citrus limon (Lemon) Phenomenon—A Review of the Chemistry, Pharmacological Properties, Applications in the Modern Pharmaceutical, Food, and Cosmetics Industries, and Biotechnological Studies. Plants (Basel), 9(1): 119. dalam https://www.ncbi.nlm.nih.gov/
    pmc/articles/PMC7020168/. 05-03-22.