Sea buckthorn

Sea-buckthorn is a hardy, deciduous suckering shrub that can grow between high, rarely , forming extensive clonal colonies by root sprouts. It has rough, brown or black bark and a thick crown of greyish-green foliage. It is dioecious, with male and female flowers growing on different shrubs. The male inflorescence is built up of four to six apetalous flowers, while the female inflorescence normally consists of only one apetalous flower and contains one ovary and one ovule. The globose to oval fruit are 6–8 mm diameter, grow in compact dense clusters, and are typically bright orange, but vary from pale yellow to dark orange. Vegetative reproduction of the plants occurs rapidly via root suckers. Species belonging to genus Hippophae accumulate oil both in the pulp and in seed of the fruit. Major sugars in sea-buckthorn fruit are fructose and glucose, with total sugar content of 2.7–5.3 g/100 ml of juice. The typical sourness of the fruit is due to high content of malic acid (0.8–3.2 g/100 ml of juice) while astringency is related to quinic acid (1.2–2.1 g/100 ml of juice). Flavonols were found to be the predominating class of phenolic compounds, while phenolic acids and flavan-3-ols (catechins) represent minor components. == Taxonomy ==

Hippophae rhamnoides is in the family Elaeagnaceae in the order Rosales. The subspecies vary in size, shape, number of main lateral veins in the leaves and quantity and colour of stellate hairs. ==Etymology==

The genus name Hippophae comes from Ancient Greek ἵππος (híppos), meaning 'horse', and φάος (pháos), meaning 'light', and is due to the ancient Greeks use of sea-buckthorn leaves as horse fodder to make their coats shine more. The specific epithet rhamnoides derives from Rhamnus plus -oides, resembling, referring to the superficial similarity to the buckthorn genus Rhamnus. == Distribution ==

Hippophae rhamnoides is native to cold-temperate regions of Europe and Asia, the Gulf of Bothnia in Sweden, as well as coastal areas of the United Kingdom, Norway and the Netherlands. In Asia, H. rhamnoides can be found in the northern regions of China, throughout most of the Himalayan region, including India, Nepal and Bhutan, Pakistan and Afghanistan. H. rhamnoides has also recently been planted in countries such as Canada, the United States, Bolivia, Chile, Japan and South Korea. Of these, approximately 2.5 million ha are situated in China (1.0 million ha of wild plants and 1.5 million ha in plantations), 20 000 ha in Mongolia, 12 000 ha in India and 3 000 ha in Pakistan. and over 250 000 mature fruit-producing plants were grown on the Canadian prairies with an estimated annual fruit supply of 750 000 kg. Other countries that grow H. rhamnoides as an agricultural plant include for example Germany and France. == Ecology ==

It is particularly drought- and salt-tolerant and can thus be successfully used for land reclamation, against further soil erosion, as shelterbelt or in agroforestry. providing a habitat to different birds and small mammals. In regions like Ladakh, these shrubs support a range of native wildlife, providing both cover and food for birds and small mammals. In the Canadian prairies, species such as sharp-tailed grouse, grey partridge, and common pheasants rely on sea-buckthorn for food and shelter. Its importance as a wildlife habitat has been documented across multiple regions, highlighting its role in promoting biodiversity. This process supports soil fertility by increasing nitrogen content, along with added phosphorus and organic matter. This progressive soil enhancement makes sea-buckthorn valuable for land restoration, particularly in degraded temperate regions. Land reclamation Sea-buckthorn can be used for land reclamation, alongside trees like pine, larch, black locust, alder, sycamore maple, manna ash, silverberry, and wild privet. Its strong root system effectively stabilises slopes, reduces surface runoff, and controls sediment transport, particularly in areas prone to erosion from rainstorms. ==Uses==

Nutrition The fruit has a high vitamin C content, approximately 400 mg per 100 grams. Additionally, the fruit has high concentrations of vitamin E and vitamin K. The berries also contain vitamin B12. The main carotenoid is the provitamin A, beta-carotene, while other carotenoids include zeaxanthin, and lycopene. The most prevalent dietary minerals in sea-buckthorn fruit are potassium (300–380 mg/100 g), manganese (0.28–0.32 mg/100 g), and copper (0.1 mg/100 g). Culinary The berries are usually washed and then pressed, resulting in pomace and juice. The leaves of the shrub can be air dried, eventually ground, and used for tea. The weight of livestock and poultry has been shown to increase considerably after being fed sea buckthorn. Parts of the sea buckthorn plant are applied in traditional medicine, particularly in Russia and Northeast Asia. H. rhamnoides oil may be used to produce cosmetics, such as hand cream, shampoo or massage oils. ==Cultivation==

Soil and climate requirements In nature H. rhamnoides is found growing profusely on a wide range of soil types, but does better in soils with a light physical structure, rich in nutrient compounds and with a pH near neutral (pH 6.5–7.5). H. rhamnoides is considered drought resistant, but it is a moisture-sensitive plant especially in the spring when plants are flowering and young fruit are beginning to develop. Planting in arid or semiarid areas is possible, if water is supplied for establishment. It can bear fruit at altitudes up to 2000 m above sea level. Planting Hippophae rhamnoides needs a period of 4 to 5 years from the appearance of the first shoots from the seeds to the beginning of fruit and peaks at the 7–8th year of plant life, remaining productive for 30 years with intermittent pruning. Spring is the best time for planting H. rhamnoides. An orchard planting can yield 10 tonnes of berries per hectare. A number of seeds per planting site is recommended at spacing of 1 m within the row and 4 m between the rows, south-east sloping terrain is recommended to facilitate the maximum sunlight exposure and rows should be oriented in a north– south direction to provide maximum light. Mass selection is still practiced in many areas, although it is gradually replaced by hybridisation and polyploidy breeding. The most important characteristics that need improvement are: yield, fruit size, winter hardness, thornlessness, fruit and pollen quality and early maturity, long pedicel (to facilitate mechanical harvest) and nitrogen fixing ability. Harvesting and challenges in mechanisation The fruit ripens in the autumn, and frequently clings on the shrub until the following spring. An orchard planting of about 2,500 trees per hectare, having a 1:7 male-to-female ratio and between rows with between plants, should yield approximately 10 tonnes. Fruit harvest is the most time-consuming operation in growing H. rhamnoides. The relatively small fruit size, short pedicel, force required to pull off each fruit, the density of fruit on the branch, and the thorniness of the plant, are main disadvantages during harvesting. Except when frozen on the shrub, fresh fruit mechanical harvesting is still in the development stage during the early 21st century. This is mainly due to the difficulty in separating the stem (pedicel) from the berry (pericarp). Mechanical harvesting – with the sequence of cutting a branch from the tree, freezing it, then shaking the branch to release the berries – eliminates the necessity for maintenance pruning, leaving a hedge that has been uniformly cut back, with high-quality berries. A trunk clamp-on vibrator harvester may be used when the fruit is frozen on the shrub, but with this method leaf and wood contamination is high, and an additional step of berry cleaning is necessary. 'Leikora' is a dense-fruit cultivar, while 'Pollmix' is used as a pollinator for female clones. Cultivar Sprite has dense, compact vines growing to tall and wide, characteristics possibly making it useful as a low hedge near the sea. == Interactions ==

Symbionts Hippophae rhamnoides plants that are 1–2 years old develop root nodules containing actinobacteria of the genus Frankia, which are capable of fixing nitrogen. As a result of this relationship, the soils in stands of H. rhamnoides are enriched in nitrogen. The nitrogen-fixing activity of the symbiotic bacteria is not constant, but depends on external factors such as the climate or whether additional nitrogen fertilisation occurred. Diseases and insect pests Both in Asia and in Europe, sea buckthorn losses occur notably due to environmental stress, wilt disease and insect pests. It is estimated that more than 60,000 ha of natural and planted sea buckthorn stands have died in China since the year 2000 due to these three factors, and approximately 5,000 ha perish each year. "shrivelled disease", "dry rot" or "dry atrophy". In China, it causes fruit yield losses of 30–40% and annual losses of mature plantations of 4 000 ha. as well as F. rhizoctonia and F. solani and F. sporotrichioides • the genus Stigmina • the genus Verticillium (Verticillium wilt): V. albo-atrum and V. dahliae • the species Plowrightia hippophaes • the species Phellinus hippophaeicola • the species Phomopsis spp. Cultivars of H. rhamnoides that were relatively resistant to wilt disease have also been identified. They are usually found in the new growth on shoot tips where they stunt growth and cause yellowing of the leaves. This is then followed by shrinking of the leaves along their central vein, after which they drop prematurely. Another serious pest is the seabuckthorn fruit fly (Rhagoletis batava), whose larvae feed on the fruit flesh, rendering the fruit unsuitable for use. and insecticide soap can be employed against green aphid infestations Hippophae rhamnoides is also involved in interactions with various animals (birds, rodents, deer, livestock) that can lead to damage in plantations. Weed control Weed control is important, especially during the early growth stages of H. rhamnoides, since it grows slower than weeds due to its less vigorous root system. Weeds should be removed before planting by preparing the land adequately, and they should subsequently be controlled during the first four to five years, until the shrubs are high enough to shade out the weeds. Weed control is done both mechanically and manually. Weeding should however not be too deep so as not to damage the root system of H. rhamnoides. As of 2003, no herbicides were registered for use in orchards of H. rhamnoides. == See also ==