Jojoba (; botanical name: Simmondsia chinensis)also commonly called goat nut, deer nut, pignut, wild hazel, quinine nut, coffeeberry, and gray box bushis an evergreen, dioecious shrub native to the Southwestern United States and northern Mexico. Simmondsia chinensis is the sole species of the family Simmondsiaceae, placed in the order Caryophyllales.
Jojoba is grown commercially in its area of origin and in other (semi-)arid regions to produce jojoba oil, a liquid wax ester extracted from its seed. Jojoba oil is highly valued in the cosmetics industry.
Distribution
The plant is a native shrub of the Sonoran Desert, Colorado Desert, Baja California desert, and California chaparral and woodlands habitats in the Peninsular Ranges and San Jacinto Mountains. It is found in southern California, Arizona, and Utah (U.S.), and Baja California state (Mexico).
Jojoba is endemic to North America, and occupies an area of approximately between latitudes 25° and 31° North and between longitudes 109° and 117° West. Jojoba is an evergreen, but it sometimes shed its leaves as a response to severe droughts. The fruit is an acorn-shaped ovoid, three-angled capsule long, partly enclosed at the base by the sepals. The mature seed is a hard oval that is dark brown and contains an oil (liquid wax) content of approximately 54%. An average-sized bush produces of pollen, to which few humans are allergic. In the Northern Hemisphere, pollination occurs during February and March. In the Southern Hemisphere, pollination occurs during August and September.<sup>[?]</sup>
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File:Jojoba-weibliche-blüte.JPG|Female flower
Image:Simmondsia chinensis male flower.jpg|Close-up of male Simmondsia chinensis flowers
File:Jojoba.jpg|Jojoba fruits
Image:Jojoba.seed.jpg|Jojoba seed
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Genetics
The jojoba genome was sequenced in 2020 and reported to be 887 Mb, consisting of 26 chromosomes and is predicted to have 23,490 protein-coding genes. Somatic cells of jojoba are tetraploid; the number of chromosomes is 2n = 4x = 52.
Taxonomy
Despite its scientific name Simmondsia chinensis, the plant is not native to China. The botanist Johann Link originally named the species Buxus chinensis, after misreading a collection label "Calif", referring to California, as "China". Jojoba was collected again in 1836 by Thomas Nuttall who described it as a new genus and species in 1844, naming it Simmondsia californica, but priority rules require that the original specific epithet be used.
The common name "jojoba" originated from the Oʼodham name Hohowi.
Uses
thumb|upright=0.6|[[Jojoba oil in a clear glass vial]]
Jojoba foliage provides year-round food for many animals, including deer, javelina, bighorn sheep, and livestock. Its seeds are eaten by squirrels, rabbits, other rodents, and larger birds.
Only Bailey's pocket mouse, however, is known to be able to digest the wax found inside the jojoba seed. In large quantities, jojoba seed meal is toxic to many mammals. Later this effect was found to be due to simmondsin, which inhibits hunger. The indigestible wax acts as a laxative in humans.
Consistent use of jojoba oil is thought to help regulate the skin's oil production. Additionally, it has a longer shelf life than other natural oils, making it a durable ingredient in skincare products. Medically, jojoba oil can relieve headaches, throat inflammation, and treat wounds. It has anti-inflammatory, antimicrobial, antifungal, and insecticidal properties. After oil extraction, the leftover jojoba meal can be used as a low-cost livestock feed. Jojoba leaves also contain antioxidant flavonoids, which have been studied for their potential in treating asthma, inflammation, and cancer.
Contemporary uses
thumb|right|Wild jojoba seed market on the [[San Carlos Apache Indian Reservation in Arizona]]
Jojoba is grown for the liquid wax, commonly called jojoba oil, in its seeds. The oil is rare in that it is an extremely long (C36–C46) straight-chain wax ester and not a triglyceride, making jojoba and its derivative jojoba esters more similar to whale oil than to traditional vegetable oils. Jojoba oil has also been discussed as a possible biodiesel fuel, but it cannot be cultivated on a scale to compete with traditional fossil fuels, so its use is restricted to personal care products.
Cultivation
Plantations of jojoba have been established in a number of desert and semi-desert areas, predominantly in Argentina, Australia, Israel, Mexico, Peru and the United States. It is currently the Sonoran Desert's second most economically valuable native plant (overshadowed only by Washingtonia filifera—California fan palms, used as ornamental trees).
Jojoba prefers light, coarsely textured soils. Good drainage and water penetration is necessary. It tolerates salinity and nutrient-poor soils. Soil pH should be between 5 and 8. Jojoba grows best in young, coarse soils with minimal profile development. These soils, primarily derived from acid igneous materials, are typically found on slopes exceeding 3 up to over 30 percent. On north-facing slopes, the moisture retention is often better and thus can better support jojoba, especially young plants.
High temperatures are tolerated by jojoba, but frost can damage or kill plants. Jojoba can endure extreme temperature, with summer temperatures up to . However, they can on the other hand experience leaf damage in cold conditions. The seedlings are more vulnerable, suffering damage or death at temperatures between three and nine degrees below freezing. Factors such as drought, freezing conditions, and biotic pressures can significantly impact seedling survival.
Jojoba thrives at various elevations, ranging from sea level to lower mountain slopes. In Arizona's Sonoran Desert, it is commonly found between . This elevation range provides an ideal environment for jojoba, characterized by well-drained, dry slopes or along wadis, where water runoff can support plant growth. Supplemental irrigation could maximize production where rainfall is less than . Jojoba is normally harvested by hand because seeds do not all mature in the same time. Yield is around depending on the age of the plantation. Its ability to withstand high salinity up to 12 ds ⋅ m<sup>−1</sup> at pH 9 (deciSiemens per meter or ECe Salt tolerance of crops) and the high value of jojoba products make jojoba an interesting plant for the use of desertification control. It has been used to combat and prevent desertification in the Thar Desert in India.
Research continues on options to further increase yields. There are already findings on the types of pruning techniques for the bushes, which are expected to make a difference in yields.
Processing technology
Jojoba oil is traditionally extracted by mechanically pressing the seeds, often with the use of hexane to maximize yield, resulting in a typical oil extraction of 35–43%. Other methods using organic solvents like chloroform or isopropanol can increase the yield to up to 55%.
A more environmentally friendly, but more expensive, method is supercritical CO<sub>2</sub> extraction. This method can be enhanced by adding co-solvents such as ethanol.
Transesterification is used to convert jojoba oil into biodiesel, where the oil reacts with alcohol (e.g., methanol) in the presence of a catalyst (e.g., sodium hydroxide). Both homogeneous and heterogeneous catalysts can be used, as well as enzymatic catalysts, which are more environmentally friendly but costlier.
Molecular breeding
Jojoba is a dioecious plant, which brings one of its main challenges. Only the female bushes bear seeds that can be used for jojoba oil production. The sex of the plant is only visible to the eye after flowering (3-4 years after planting).
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External links
- USDA Plants Profile for Simmondsia chinensis (jojoba)
- Calflora Database: Simmondsia chinensis (jojoba)
- Jepson Manual (TJM93) treatment of Simmondsia chinensis
- Selected Families of Angiosperms: Rosidae—an explanation of the scientific name
- Newscientist.com: Jojoba oil as biodiesel
- Hort.purdue.edu: Alternative Field Crops Manual
- Uses and Benefits of Jojoba Oils