Basil (, ;
There are many varieties of basil including sweet basil, Thai basil ( O. basilicum var. thyrsiflora), and Mrs. Burns' Lemon ( O. basilicum var. citriodora). O. basilicum can cross-pollinate with other species of the Ocimum genus, producing hybrids such as lemon basil ( O. × citriodorum) and African blue basil ( O. × kilimandscharicum).
Description
Basil is an
Annual plant, or sometimes
perennial, herb. Depending on the variety, plants can reach heights of between .
Basil
leaves are glossy and ovulate, with smooth or slightly toothed edges that typically cup slightly; the leaves are arranged oppositely along the square stems.
Leaves may be green or purple. Its flowers are small and white, and grow from a central
inflorescence, or spike, that emerges from the central stem atop the plant. Unusual among
Lamiaceae, the four
and the
pistil are not pushed under the upper lip of the corolla, but lie over the inferior lip. After
entomophily pollination, the corolla falls off and four round
develop inside the bilabiate calyx.
Phytochemistry
The various basils have such distinct scents because the volatile aromatic compounds vary with cultivars.
The essential oil from European basil contains high concentrations of
linalool and
methyl chavicol (estragole), in a ratio of about 3:1.
Other constituents include: 1,8-cineole,
eugenol, and
myrcene, among others.
The
clove scent of sweet basil is derived from eugenol.
The aroma profile of basil includes 1,8-cineole
and
methyl eugenol.
In this species eugenol is synthesised from coniferyl acetate and NADPH.
Similar species
Some similar species in the same genus may be commonly called "basil", although they are not varieties of
Ocimum basilicum.
-
Camphor basil, African basil ( O. kilimandscharicum)
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Clove basil, also African basil ( Ocimum gratissimum)
-
Holy basil ( Ocimum tenuiflorum, formerly known as O. sanctum)
Taxonomy
The exact taxonomy of basil is uncertain due to the immense number of cultivars, its ready polymorphy, and frequent cross-pollination (resulting in new hybrids) with other members of the genus
Ocimum and within the species.
Ocimum basilicum has at least 60 varieties, which further complicates taxonomy.
Cultivars
Most basils are cultivars of sweet basil. Most basil varieties have green leaves, but a few are purple, such as, 'Purple Delight'.
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Anise basil, Licorice basil, or Persian basil ( O. basilicum 'Liquorice')
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Cinnamon basil ( Ocimum basilicum 'Cinnamon')
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Dark opal basil ( Ocimum basilicum 'Dark Opal')
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Genovese basil or Sweet Basil ( Ocimum basilicum)
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Greek basil ( Ocimum basilicum var. minimum)
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Globe basil, dwarf basil, French basil ( Ocimum basilicum 'Minimum')
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Lettuce leaf basil ( Ocimum basilicum 'Crispum')
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Naples basil, also known as Napoletano basil, Neapolitan basil, Mammoth basil, Bolloso Napoletano basil, Napolitano Mammoth-Leafed basil, or Italian Large-Leaf basil ( Ocimum basilicum)
-
Purple basil ( Ocimum basilicum 'Purpurescens')
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Rubin basil ( Ocimum basilicum 'Rubin')
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Thai basil ( Ocimum basilicum thyrsifolium)
Hybrids
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African blue basil ( Ocimum basilicum × O. kilimandscharicum)
-
Lemon basil ( Ocimum basilicum × O. americanum)
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Spice basil ( Ocimum basilicum × O. americanum), which is sometimes sold as holy basil
Etymology
The name "basil" comes from the
Latin basilius, and the
Greek language βασιλικόν φυτόν (), meaning "royal/kingly plant", possibly because the plant was believed to have been used in production of royal perfumes.
Basil is likewise sometimes referred to in
French language as "l'herbe royale" ('the royal herb').
The Latin name has been confused with
basilisk, as it was supposed to be an
antidote to the basilisk's venom.
Distribution and habitat
Basil is native to
India and other tropical regions stretching from Africa to South East Asia, but has now become globalized due to human cultivation.
Cultivation
Growing conditions
Basil is sensitive to cold, with best growth in hot, dry conditions. Basil prefers high light conditions and grows best under full sun conditions. Increasing light intensity, particularly the photosynthetic photon flux density, can significantly enhance the plant'.s fresh weight, dry matter content, and height
However, due to its common use, basil is cultivated in many countries around the world. Production areas include countries in the Mediterranean area, those in the temperate zone, and others in subtropical climates.
In Northern Europe, Canada, the northern states of the U.S., and the South Island of New Zealand, basil grows best if sown under glass in a peat pot, then planted out in late spring/early summer
Although basil grows best outdoors, it can be grown indoors in a pot and, like most herbs, will do best on a sun-facing windowsill, kept away from cold drafts. A greenhouse or row cover is ideal if available. It can, however, even be grown in a basement under fluorescent lights. Supplemental lighting produces greater biomass and phenol production, with red + blue specifically increasing growth and flower bud production. increases the volatiles in O. basilicum essential oil, which has not been reproducible in other plants, and so may be unique to the genus or even to this species.
Basil prefers well-drained organic soils, as adequate oxygen availability in the root zone is essential for optimal plant growth. Poor soil drainage can lead to root hypoxia, which negatively affects overall plant development and essential oil yield.
Pruning, flowering, and seeding
Once a stem produces flowers, foliage production stops on that stem, the stem becomes woody, and essential oil production declines. To prevent this, a basil-grower may pinch off any flower stems before they are fully mature. Because only the blooming stem is so affected, some stems can be pinched for leaf production, while others are left to bloom for decoration or seeds. Picking the leaves off the plant helps promote growth, largely because the plant responds by converting pairs of leaflets next to the topmost leaves into new stems.
Once the plant is allowed to flower, it may produce seed pods containing small black seeds, which can be saved and planted the following year. If allowed to go to seed, a basil plant will grow back the next year.
Propagation methods
Seeds
The optimal germination temperature for basil seeds ranges between 34.5–39.0°C, while the base germination temperature lies between 9.8–13.2°C. No significant variation in optimal germination temperature has been observed among different basil cultivars.
Prior to sowing, basil (
Ocimum basilicum) seeds can be hydroprimed by soaking in water for 12 hours, which effectively enhances germination rates and seedling vigor.
Cuttings
Basil (
Ocimum basilicum L.) is commonly propagated through cuttings. Compared to seed propagation, basil cuttings tend to result in earlier harvest and higher yield. The typical propagation method involves selecting healthy, non-lignified stem segments approximately 5–10 cm in length, preferably apical shoots that retain 2 to 5 leaves, which are then inserted into moist soil until root development occurs. After rooting, the plantlets are transplanted into the field.
Exposing basil cuttings to blue light significantly accelerates root formation, thereby shortening the growth period.
Diseases
Basil suffers from several plant pathogens that can ruin the crop and reduce
crop yield.
Fusarium wilt is a soil-borne fungal disease that will quickly kill younger basil plants.
may be killed by
Pythium damping off. A common
foliage disease of basil is
gray mold caused by
Botrytis cinerea; it can cause infections post-harvest and is capable of killing the entire plant. Black spot can be seen on basil foliage and is caused by the
fungi genus Colletotrichum.
Downy mildew caused by
Peronospora belbahrii is a significant disease, as first reported in Italy in 2003.
It was reported in the Florida in 2007 and by 2008 had spread along the eastern United States, reaching Canada.
Basil cultivars resistant to
P. belbahrii have been developed.
Non-pathogenic bacteria found on basil include Novosphingobium species.
Uses
Culinary
Basil is most commonly used fresh in recipes. In general, it is added last, as cooking quickly destroys the flavor. The fresh herb can be kept for a short time in plastic bags in the refrigerator, or for a longer period in the freezer, after being blanched quickly in boiling water. It has a flavor resembling that of
liquorice.
Leaves and flowers
The most commonly used Mediterranean basil cultivars are "Genovese", "Purple Ruffles", "Mammoth", "Cinnamon", "Lemon", "Globe", and "African Blue". Basil is one of the main ingredients in
pesto, an
Italian cuisine sauce with
olive oil and basil as its primary ingredients, and is used in other sauces and
.
Many national cuisines use fresh or dried basils in soups and other foods, such as to thicken soups. Basil is commonly steeped in cream or milk to create flavor in ice cream or chocolate truffles. It sometimes used to infuse oils and vinegars.
Lemon basil has a strong smell and flavor due to the presence of citral. It is widely used in Indonesia, where it is called kemangi and served raw as an accompaniment to meat or fish.
Seeds
When soaked in water, the seeds of several basil varieties
hydrophile, and are used in Asian drinks and desserts such as the
Indian cuisine faluda, the
Iranian cuisine , or hột é. In Kashmir, the
Ramadan fast is often broken with
babre beole, a sharbat made with basil seeds.
Folk medicine
Basil is used in folk medicine practices, such as those of
Ayurveda or traditional Chinese medicine.
Insecticide and insect repellent
Studies of the essential oil have shown
Insecticide and
Insect repellent properties,
including potential toxicity to
.
The essential oil is found by Huignard et al. 2008 to inhibit electrical activity by decreasing
action potential amplitude, by shortening the post hyperpolarization phase, and reducing the action frequency of action potentials. In Huignard's opinion this is due to the
linalool and
estragole, the amplitude reduction due to linalool, and the phase shortening due to both.
Callosobruchus maculatus, a pest which affects cowpea, is repelled by the essential oil.
Nematicide
The essential oil is found by Malik et al. 1987 and Sangwan et al. 1990 to be
nematicide against
Tylenchulus semipenetrans,
Meloidogyne javanica,
Anguina tritici, and
Heterodera cajani.
Bacterial and fungal inhibition
The essential oil of the leaf and
terminal shoot is effective against a large number of bacterial species including
Lactiplantibacillus plantarum and
Pseudomonas spp.
The essential oil of the leaf and
terminal shoot is also effective against a large number of fungal species including
Aspergillus spp.,
Candida spp.,
Mucor spp., and
Geotrichum candidum.
In culture
Religion
There are many rituals and beliefs associated with basil. The
and ancient Greeks believed basil would open the gates of heaven for a person passing on.
However,
Herbalist Nicholas Culpeper saw basil as a plant of dread and suspicion.
In Portugal, dwarf bush basil is traditionally presented in a pot, together with a poem and a paper carnation, to a sweetheart, on the religious holidays of John the Baptist (see ) and Saint Anthony of Padua.
Basil has religious significance in the Greek Orthodox Church, where it is used to sprinkle holy water.
Art and literature
In Giovanni Boccaccio's 14th century
The Decameron, the fifth story of the narrative's fourth day involves a pot of basil as a central plot device. This famous story inspired
John Keats to write his 1814 poem "Isabella, or the Pot of Basil", which was in turn the inspiration for two paintings of the Pre-Raphaelite Brotherhood: John Everett Millais's
Isabella in 1849 and in 1868 the
Isabella and the Pot of Basil by William Holman Hunt.
See also
External links
