Common sea buckthorn

Appearance

"H. rhamnoides" is a deciduous and hardy shrub that can grow between 2 and 4 m high. It has a rough, brown or black bark and a thick, grayish-green crown. The leaves are alternate, narrow and lanceolate, with silvery-green upper faces. It is dioecious, meaning that the male and female flowers grow on different shrubs. The sex of seedlings can only be determined at the first flowering, which mostly occurs after three years. 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. Fertilization occurs solely via wind pollination, which is why male plants need to be planted near the female plants to allow for fertilization and fruit production.

The oval or lightly roundish fruits grow in compact grapes varying from pale yellow to dark orange. Individual fruits weigh between 270 and 480 mg and contain high amounts of vitamin C, vitamin E, carotenoids, flavonoids and health-beneficial fatty acids, as well as higher amounts of vitamin B12 than other fruits.

The plants have a very developed and extensive root system, and the roots live in symbiosis with nitrogen-fixing "Frankia" bacteria. The roots also transform insoluble organic and mineral matters from the soil into more soluble states. Vegetative reproduction of the plants occurs rapidly via root suckers.

Distribution

"H. rhamnoides" is native to the cold-temperate regions of Europe and Asia, between 27 and 69EN latitude and 7EW and 122EE longitude. These regions include the Baltic Coasts of Finland, Poland and Germany, the Gulf of Bothnia in Sweden, as well as coastal areas of the United Kingdom. In Asia, "H. rhamnoides" can be found in the northern regions of China, throughout most of the Himalayan region, including India, Nepal and Bhutan, as well as in the northern regions of Pakistan and Afghanistan. It is found in a variety of locations: on hills and hillsides, valleys, riverbeds, along coastal regions, on islands, in small isolated or continuous pure stands, but also in mixed stands with other shrub and tree species. "H. rhamnoides" has also recently been planted in countries such as Canada, USA, Bolivia, Chile, South-Korea and Japan.

The current total acreage of "H. rhamnoides" is about 3.0 million ha worldwide. This number includes both wild and cultivated plants. Of these, approximately 2.5 million ha are situated in China, 20 000 ha in Mongolia, 12 000 ha in India and 3 000 ha in Pakistan. This makes China the largest agricultural producer of "H. rhamnoides". Approximately 10 000 acres of the plant are planted in China each year for berry production as well as eco-environmental improvement. As of 2003, approximately 100 km of field shelterbelts were planted in Canada each year, and over 250 000 mature fruit-producing plants were grown on the Canadian prariries 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.

Behavior

"H. rhamnoides" is a deciduous and hardy shrub that can grow between 2 and 4 m high. It has a rough, brown or black bark and a thick, grayish-green crown. The leaves are alternate, narrow and lanceolate, with silvery-green upper faces. It is dioecious, meaning that the male and female flowers grow on different shrubs. The sex of seedlings can only be determined at the first flowering, which mostly occurs after three years. 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. Fertilization occurs solely via wind pollination, which is why male plants need to be planted near the female plants to allow for fertilization and fruit production.

The oval or lightly roundish fruits grow in compact grapes varying from pale yellow to dark orange. Individual fruits weigh between 270 and 480 mg and contain high amounts of vitamin C, vitamin E, carotenoids, flavonoids and health-beneficial fatty acids, as well as higher amounts of vitamin B12 than other fruits.

The plants have a very developed and extensive root system, and the roots live in symbiosis with nitrogen-fixing "Frankia" bacteria. The roots also transform insoluble organic and mineral matters from the soil into more soluble states. Vegetative reproduction of the plants occurs rapidly via root suckers.

Habitat

The "H. rhamnoides" plant is particularly drought and salt tolerant and can thus be successfully used for land reclamation, against further soil erosion, as shelterbelt or in agroforestry. These characteristics are mainly due to the deep root system that the plant develops. For example, in eastern China, new agroforestry systems have been developed to reclaim land with high salinity contents and "H. rhamnoides" is included in the system as shelterbelt, providing a habitat to different birds and small mammals.

Reproduction

The large morphological diversity is a good indication for opportunities in selection of desired characteristics for a given region. Mass selection is still practiced in many areas, although it is gradually replaced by hybridization 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 and nitrogen fixing ability.

Food

In general, all parts of the "H. rhamnoides" contain diverse phytochemicals and nutrients. Particularly the fruit contains high vitamin C amounts, exceeding the levels seen in lemons and oranges.

"H. rhamnoides" fruits are processed in the food industry to different products. Usually, the berries are first washed and then pressed, resulting in press-cake and juice. The fruit press cake can be used to gain oil, natural food colour pigments or jam while the juice is further processed and then packaged as final juice product. Even in countries where there is no "H. rhamnoides" production, at least a few products can be found. It is usually possible to buy "H. rhamnoides" jam or fruit concentrate, fruit juices and some cosmetics, such as hand cream, shampoo or massage oils. In southern France for example, "H. rhamnoides" is commonly sold as fruit juice or as an ingredient in non-alcoholic and alcoholic mixed beverages. Typical liquor produced at the same latitudes in Italy, Tuscany, is the officinal Tuscan liquor – Spinello.

The leaves of the shrub can be air dried, eventually ground and used for tea. The drying and milling process do not cause considerable losses of bioactive substances and thus confer a healthy composition to the infusion.

Defense

The fruits ripen in the fall and frequently cling on the shrub until the following March/April. Estimate of orchard planting with 4,000 trees per hectare and a 1:6–8 male and female ratio, should yield approximately 10 tonnes. Good plants will produce up to 7 kg annually. In Asia the fruits are harvested per hand, this process requires about 1500 person-hours/ha. 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 the disadvantages during harvesting.

Difficulties in harvesting are the major barriers of orchard production and development the plants potential as a cash-crop. Harvesting the fruit is problematic because the fruit does not easily release from the stem. Different mechanical harvester have been developed, such as shaking, vacuum and quick freezing, but most have disadvantages of fruit and bark damage and low efficient.
Except when frozen on the shrub, fresh fruit mechanical harvesting is still in the development stage. This is mainly due to the difficulty in separating the stem from the berry. The mechanical harvesting method usually eliminates the necessity for maintenance pruning, leaving a hedge that has been uniformly cut back. A trunk clamp-on vibrator harvester may be used when the fruit is frozen on the shrub, with this method leave and wood contamination is high and an additional step of berry cleaning is necessary.

Uses

"H. rhamnoides" is a very versatile plant and the fruits as well as the leaves can be used. The fruits are processed and then used in the food industry, in traditional medicine, as part of drugs or in the cosmetic industry. The leaves can be used as feed, particularly for ruminants. Because of its tolerance against strongly eroded, nutrient poor and sometime salty soils, the plant is also used for land reclamation or as shelterbelt.