Ziziphus spina-christi

Description

Forming dense, sometimes impenetrable thickets, Christ’s thorn (Ziziphus spina-christi) grows as a shrub or small tree, armed with short spines that are positioned in pairs along the branches, one of which is straight and the other curved or hooked. Christ’s thorn is covered in whitish-brown or pale grey bark which is deeply fissured and cracked, with a twisted trunk which branches widely, drooping at the ends to form a rounded, usually umbrella-shaped crown. The simple, alternate leaves are oval, becoming more pointed at the tips, with three conspicuous veins running along the length. The leaves are hairless on the upper surface, with a fine, downy covering of small hairs on the underside. Christ’s thorn produces small, greenish-yellow flowers, which cluster tightly in the axils of the leaves, and red-brown coloured, small, fleshy fruits that enclose a hard stone in the centre.
Referred to throughout history by many cultures and religions as a sacred or holy tree, Christ’s thorn has also traditionally been used in medicine, carpentry and as a source of food
Also known as
Christ’s thorn jujube , siddir, sidr.
Synonyms
Zizyphus spina-christi.

Biology

Christ’s thorn is extremely drought tolerant, due in part to the presence of long, deep taproots which facilitate the plants ability to reach underground water sources. Christ’s thorn usually flowers between August and December, with fruits produced between October and January. The seeds of this desert plant (the hard stone in the centre of the fruit) have tough, woody coats and it is thought that in order to germinate, they must first pass through the digestive tracts of an animal to break down the outer layers

Range

Christ’s thorn is found in West and North Africa, the Middle East, northwest India and the eastern Mediterranean

A simple and efficient protocol for the clonal micropropagation of Ziziphus spina-christi (L.) Desf., a multipurpose native tree species highly adapted to the harsh environmental conditions of Kuwait, has been established using shoot tips and stem nodal segments as explants. The explants were cultured on Murashige and Skoog (MS) basal medium with and without growth regulators. The nodal segments and shoot tips isolated from the primary cultures were cultured on hormone-free MS media containing 100 mg/l myo-Inositol, 150 mg/l glutamine and 2.5% sucrose for plant growth and elongation. Shoots for multiplication were maintained on MS media with low concentrations of 6-benzylaminopurine (BA) and subcultured every 20 days. However, explants cultured in higher concentrations of cytokinin and auxin induced callus. Shoots transferred to the MS media containing 10 mg/l Indole-3-butric acid (IBA) were rooted. Rooted plantlets were transferred to sterile soil media for acclimatisation and field evaluation.


Brief Summary

Christ's Thorn Jujube (Ziziphus spina-christi) derives both its common and scientific names from the belief by many that this tree provided the crown of thorns said to have been placed on Jesus' head before he was crucified. Throughout history, but especially in the Middle Ages, the tree was seen as sacred and was used for food. Today, in parts of its range it is still heavily used for a range of purposes, including its reputed medicinal properties.
Christ's Thorn Jujube is found over the whole Sahelian region from Senegal to Sudan and across a large portion of North Africa, the Middle East, eastern Afghanistan, and northwestern India. It can generally be found up to around 600 m, but has been reported from elevations as high as 1,500 m. It can tolerate high temperatures and grows in desert areas with annual rainfall of 50 to 300 mm, but is also often found in wadis where underground water is available. In some areas, such as the Nile Valley in Egypt, the tree is cultivated in villages and parks. The fruits of Christ's Thorn Jujube are used as food especially by people in western and central Sudan and other Saharan regions, as well as in Oman. Fruits are collected by women and children and sold in local markets.
Christ's Thorn Jujube was once the dominant tree in Mediterranean savannoid vegetation in Israel, but in recent years there has been concern over the large-scale mortality in remaining stands of this species, particularly in northern Israel. A proposed explanation for the high mortality of these trees is the increased infestation by the hemiparasitic mistletoe Plicosepalus (formerly Loranthus) acaciae (Loranthaceae). In some areas, up to 80% of Christ's Thorn Jujube trees are infested by P. acaciae. The invasion of new habitats by P. acaciae throughout its distribution in Israel is believed to be the result of the increase in the population of its main seed disperser, the Yellow-vented Bulbul (Pycnonotus xanthopygos) (this species is closely associated with human settlements, which have increased in both number and size since the 1960s). The increase in bulbul populations and increased abundance and dispersion of P. acaciae is correlated with the large-scale mortality that has also been recorded in the three Acacia tree species that are the common desert hosts of P. acaciae and it is possible that these acacias and Christ's Thorn Jujube are suffering from increased mistletoe infestation facilitated by Yellow-vented Bulbul populations that are thriving as a result of their association with expanding human settlements. Christ's Thorn Jujube is very patchily distributed in Israel and often occurs in isolated clumps of just a few individuals, making its persistence sensitive to a range of negative impacts on its population.
A simple and efficient protocol for the clonal micropropagation of Ziziphus spina-christi (L.) Desf., a multipurpose native tree species highly adapted to the harsh environmental conditions of Kuwait, has been established using shoot tips and stem nodal segments as explants. The explants were cultured on Murashige and Skoog (MS) basal medium with and without growth regulators. The nodal segments and shoot tips isolated from the primary cultures were cultured on hormone-free MS media containing 100 mg/l myo-Inositol, 150 mg/l glutamine and 2.5% sucrose for plant growth and elongation. Shoots for multiplication were maintained on MS media with low concentrations of 6-benzylaminopurine (BA) and subcultured every 20 days. However, explants cultured in higher concentrations of cytokinin and auxin induced callus. Shoots transferred to the MS media containing 10 mg/l Indole-3-butric acid (IBA) were rooted. Rooted plantlets were transferred to sterile soil media for acclimatisation and field evaluation.

Status

Christ’s thorn has yet to be classified by the IUCN.

Threats

Christ’s thorn is not currently listed on any specific conservation legislation and is still considered to be widespread and fairly common throughout much of its range. However, it is thought that in parts of Sudan, stands of this hardy plant are quickly coming under threat as a result of intensive livestock browsing and over-collection . In addition, reports from some locations suggest that Christ’s thorn is susceptible to invasion and parasitism by the mistletoe Plicosepalus acaciae, which is causing premature senescence (aging) and increased mortality of this species

Order Now