Persian Walnut
Encyclopedia
Juglans regia, the Persian walnut, English walnut, or especially in Great Britain, Common walnut, is an Old World
walnut tree species native to the region stretching from the Balkans
eastward to the Himalayas and southwest China
. The largest forests are in Kyrgyzstan
, where trees occur in extensive, nearly pure walnut forests at 1,000–2,000 m altitude (Hemery
1998)—notably at Arslanbob
in Jalal-Abad Province
.
tree
attaining heights of 25–35 m, and a trunk up to 2 m diameter, commonly with a short trunk and broad crown, though taller and narrower in dense forest competition. It is a light-demanding species, requiring full sun to grow well.
The bark is smooth, olive-brown when young and silvery-grey on older branches, and features scattered broad fissures with a rougher texture. Like all walnuts, the pith
of the twigs contains air spaces; This chambered pith is brownish in color. The leaves
are alternately arranged, 25–40 cm long, odd-pinnate
with 5–9 leaflets, paired alternately with one terminal leaflet. The largest leaflets the three at the apex, 10–18 cm long and 6–8 cm broad; the basal pair of leaflets much smaller, 5–8 cm long, the margins of the leaflets entire. The male flowers are in drooping catkin
s 5–10 cm long, and the female flowers terminal, in clusters of two to five, ripening in the autumn into a fruit
with a green, semi-fleshy husk and a brown corrugated nut
. The whole fruit, including the husk, falls in autumn; the seed
is large, with a relatively thin shell, and edible, with a rich flavor.
wal- and Old English
wealhhnutu, literally "foreign nut", wealh meaning "foreign" (wealh is akin to the terms Welsh and Vlach; see Walha
and History of the term Vlach
). For the walnut to be identified as a "foreign" nut by Anglo-Saxons arriving in the fifth century, native Britons must have passed to them the tradition that it had been introduced to England from Gaul
and Italy
. The Latin
name for the walnut was nux Gallica, "Gallic
nut"; the Gaulish region of Galatia in Anatolia
lies in highlands at the western end of the tree's presumed natural distribution.
Walnut does not distinguish the tree from other species of Juglans. Other names include Common Walnut in Britain
; Persian Walnut in South Africa
and Australia
; and English Walnut in North America, Great Britain, New Zealand
, and Australia, the latter name possibly because English sailors were prominent in Juglans regia nut distribution at one time. Alternatively, Walter Fox Allen stated in his 1912 treatise What You Need to Know About Planting, Cultivating and Harvesting this Most Delicious of Nuts: "In America it has commonly been known as English Walnut to distinguish it from our native species."
In the Chinese language
, the edible, cultivated walnut is called 胡桃 (hú táo in Mandarin), which means literally "Hu peach", suggesting that the ancient Chinese associated the introduction of the tree into East Asia with the Hu
barbarians of the regions north and northwest of China. In Mexico, it is called nogal de Castilla, suggesting that the Mexicans associate the introduction of the tree into Mexico with Spaniards from Castile
.
The Old English term "wealhhnutu" is a late book-name (Old English Vocabularies, Wright & Wulker) therefore the remark that the Anglo-Saxons inherited the Walnut tree from the Romans
does not follow from this name.
province of western China, parts of Kazakhstan
, Uzbekistan
and southern Kirghizia and from lower ranges of mountains in Nepal
, Bhutan
, Tibet
, northern India and Pakistan
, through Afghanistan
, Turkmenistan
and Iran
to portions of Azerbaijan, Armenia, Georgia and eastern Turkey
. In these countries, there is a great genetic variability, in particular ancestral forms with lateral fruiting. During its migration to western Europe, the common walnut lost this character by natural selection on account of competition with other vigorous forest species such as oaks. They became big trees with terminal fruiting. A small remnant population of these J. regia trees have survived the last glacial period in Southern Europe, but the bulk of the wild germplasm found in the Balkan peninsula and much of Turkey was most likely introduced from eastern Turkey by commerce and settlement several thousand years ago.
In the fourth century BC, Alexander the Great introduced this "Persian nut" (Theophrastus
' καρυα ή Περσική) in Macedonia and Greece ancestral forms with lateral fruiting from Iran and Central Asia. They hybridized with terminal-bearing forms to give lateral bearing trees. These lateral bearers were spread in southern Europe and northern Africa by Romans. Recent prospections in walnut populations of the Mediterrean Basin allowed to select interesting trees of this type. In the Middle Ages, the lateral bearing character was introduced again in southern Turkey by merchants traveling along the Silk Road. J. regia germplasm in China is thought to have been introduced from Central Asia about 2 000 years ago, and in some areas has become naturalized. Cultivated distribution now includes North and South America (Chile, Argentine), Australia, New Zealand, South Africa and Japan. So, the Persian walnut is grown from 30 to 50 degrees of latitude in the Northern hemisphere and from 30 to 40 degrees in the Southern hemisphere.
The walnut was introduced into western and northern Europe
very early, by Roman
times or earlier, and to the Americas by the 17th century, by English colonists. Important nut-growing regions include France
, Serbia
, Greece
, Bulgaria
, and Romania
in Europe, China
in Asia, California
in North America, and Chile
in South America. Lately the crop has spread to other regions: New Zealand
and the southeast of Australia
. It is cultivated extensively for its high-quality nuts, eaten both fresh and pressed for their richly flavored oil; numerous cultivar
s have been selected for larger nuts with thinner shells.
s of J. regia in Turkey
showed significant variations in fatty acid content:
-mediated systemic reactions in some individuals.
The extracts of walnuts have antioxidant and antiproliferative activity due to a high phenolic
content.
In vitro
tests of walnut extract has shown a high anti-atherogenic potential and osteoblastic activity suggesting a potential beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.
The extract from walnut leaves is an antioxidant, decreases the blood sugar level and has a positive impact on lipid metabolism. The extract suppresses functional insufficiency of liver links synthethising enzymes, increases the antitoxic action of hepatocytes and improves the functional insufficiency of kidneys. The ethanolic extract from leaves of J. regia has an antidiabetic effect on diabetes-induced rats.
Bark and leaf crude extracts of Juglans regia ,and Juglans mollis , showed in vitro anti-Mycobacterium tuberculosis
activity.
, a Greek island in the Aegean Sea, local legend suggests that whoever plants a walnut tree will die as soon as the tree can "see" the sea. This has not been proven as fact; however, it might take some time to find a local arborist
willing to take on the job of planting a walnut tree. Most planting is done by field rats (subfamily Murinae
). In Flanders
, a folk saying
states: "By the time the tree is big, the planter sure will be dead" (Dutch
: Boompje groot, plantertje dood). This saying refers to the relatively slow growth rate of the tree.
to provide disease resistance. Other plants often will not grow under walnut trees because the fallen leaves and husks contain Juglone
, a dark brown chemical which acts as a natural herbicide. Horses should not eat walnut leaves or they may develop laminitis
, a hoof ailment. Mature trees may reach 50 feet in height and width, and live more than 200 years, developing massive trunks more than eight feet thick.
American pioneers used juglone from ground walnut husks and leaves to make a deep brown ink, paints and wood stains.
Green husk extracts of walnut have insecticidal properties. It killed 98% of Tetranychus cinnabarinus
(Spider mite)
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
walnut tree species native to the region stretching from the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...
eastward to the Himalayas and southwest China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. The largest forests are in Kyrgyzstan
Kyrgyzstan
Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...
, where trees occur in extensive, nearly pure walnut forests at 1,000–2,000 m altitude (Hemery
Gabriel Hemery
Dr Gabriel Hemery is an English forest scientist and silvologist. He co-founded the Sylva Foundation with Sir Martin Wood, a tree and forestry charity established in 2009.- Career:...
1998)—notably at Arslanbob
Arslanbob
Arslanbob is small town, sub district, valley, mountain range, and a large wild walnut forest in the Jalal-Abad Province of Kyrgyzstan. Kyrgyzstan's first known export to Europe was the Arslanbob walnut...
in Jalal-Abad Province
Jalal-Abad Province
Jalal-Abad Province, also known as Jalalabat , is a province of Kyrgyzstan. Its capital is the city of the same name, Jalal-Abad. It is surrounded by Talas Province, Chui Province, Naryn Province, Osh Province and Uzbekistan. The Jalal-Abad Province was established on November 21, 1939...
.
Description
Juglans regia is a large deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
attaining heights of 25–35 m, and a trunk up to 2 m diameter, commonly with a short trunk and broad crown, though taller and narrower in dense forest competition. It is a light-demanding species, requiring full sun to grow well.
The bark is smooth, olive-brown when young and silvery-grey on older branches, and features scattered broad fissures with a rougher texture. Like all walnuts, the pith
Pith
Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots...
of the twigs contains air spaces; This chambered pith is brownish in color. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are alternately arranged, 25–40 cm long, odd-pinnate
Pinnate
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...
with 5–9 leaflets, paired alternately with one terminal leaflet. The largest leaflets the three at the apex, 10–18 cm long and 6–8 cm broad; the basal pair of leaflets much smaller, 5–8 cm long, the margins of the leaflets entire. The male flowers are in drooping catkin
Catkin
A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect pollinated . They contain many, usually unisexual flowers, arranged closely along a central stem which is often drooping...
s 5–10 cm long, and the female flowers terminal, in clusters of two to five, ripening in the autumn into a fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
with a green, semi-fleshy husk and a brown corrugated nut
Nut (fruit)
A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...
. The whole fruit, including the husk, falls in autumn; the seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
is large, with a relatively thin shell, and edible, with a rich flavor.
Taxonomy
The word 'walnut' derives from the GermanicGermanic languages
The Germanic languages constitute a sub-branch of the Indo-European language family. The common ancestor of all of the languages in this branch is called Proto-Germanic , which was spoken in approximately the mid-1st millennium BC in Iron Age northern Europe...
wal- and Old English
Old English language
Old English or Anglo-Saxon is an early form of the English language that was spoken and written by the Anglo-Saxons and their descendants in parts of what are now England and southeastern Scotland between at least the mid-5th century and the mid-12th century...
wealhhnutu, literally "foreign nut", wealh meaning "foreign" (wealh is akin to the terms Welsh and Vlach; see Walha
Walha
Walhaz is a reconstructed Proto-Germanic word, meaning "foreigner", "stranger", "Roman", "Romance-speaker", or "Celtic-speaker". The adjective derived from this word can be found in , Old High German walhisk, meaning "Romance", in Old English welisċ, wælisċ, wilisċ, meaning "Romano-British" and in...
and History of the term Vlach
History of the term Vlach
Vlach is a Slavic-derived term , which is used to designate the Romance speaking peoples of South-Eastern Europe: Romanians, Aromanians, Megleno-Romanians and Istro-Romanians....
). For the walnut to be identified as a "foreign" nut by Anglo-Saxons arriving in the fifth century, native Britons must have passed to them the tradition that it had been introduced to England from Gaul
Gaul
Gaul was a region of Western Europe during the Iron Age and Roman era, encompassing present day France, Luxembourg and Belgium, most of Switzerland, the western part of Northern Italy, as well as the parts of the Netherlands and Germany on the left bank of the Rhine. The Gauls were the speakers of...
and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. The Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
name for the walnut was nux Gallica, "Gallic
Gaul
Gaul was a region of Western Europe during the Iron Age and Roman era, encompassing present day France, Luxembourg and Belgium, most of Switzerland, the western part of Northern Italy, as well as the parts of the Netherlands and Germany on the left bank of the Rhine. The Gauls were the speakers of...
nut"; the Gaulish region of Galatia in Anatolia
Galatia
Ancient Galatia was an area in the highlands of central Anatolia in modern Turkey. Galatia was named for the immigrant Gauls from Thrace , who settled here and became its ruling caste in the 3rd century BC, following the Gallic invasion of the Balkans in 279 BC. It has been called the "Gallia" of...
lies in highlands at the western end of the tree's presumed natural distribution.
Walnut does not distinguish the tree from other species of Juglans. Other names include Common Walnut in Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
; Persian Walnut in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
; and English Walnut in North America, Great Britain, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and Australia, the latter name possibly because English sailors were prominent in Juglans regia nut distribution at one time. Alternatively, Walter Fox Allen stated in his 1912 treatise What You Need to Know About Planting, Cultivating and Harvesting this Most Delicious of Nuts: "In America it has commonly been known as English Walnut to distinguish it from our native species."
In the Chinese language
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, the edible, cultivated walnut is called 胡桃 (hú táo in Mandarin), which means literally "Hu peach", suggesting that the ancient Chinese associated the introduction of the tree into East Asia with the Hu
Wu Hu
Wu Hu was a Chinese term for the northern non-Chinese nomadic tribes which caused the Wu Hu uprising, and established the Sixteen Kingdoms from 304 to 439 AD.-Definition:...
barbarians of the regions north and northwest of China. In Mexico, it is called nogal de Castilla, suggesting that the Mexicans associate the introduction of the tree into Mexico with Spaniards from Castile
Castile (historical region)
A former kingdom, Castile gradually merged with its neighbours to become the Crown of Castile and later the Kingdom of Spain when united with the Crown of Aragon and the Kingdom of Navarre...
.
Cultivars
J. regia 'Buccaneer' Produces an abundant crop of seeds. A self-fertile cultivar, it produces pollen over a long period and is thus a valuable pollinator for other cultivars. The tree is about the same size as a seedling walnut, it comes into leaf very late and so usually avoids damage by late frosts.The Old English term "wealhhnutu" is a late book-name (Old English Vocabularies, Wright & Wulker) therefore the remark that the Anglo-Saxons inherited the Walnut tree from the Romans
does not follow from this name.
Distribution and habitat
J. regia is native to the mountain ranges of Central Asia, extending from XinjiangXinjiang
Xinjiang is an autonomous region of the People's Republic of China. It is the largest Chinese administrative division and spans over 1.6 million km2...
province of western China, parts of Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
, Uzbekistan
Uzbekistan
Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
and southern Kirghizia and from lower ranges of mountains in Nepal
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
, Bhutan
Bhutan
Bhutan , officially the Kingdom of Bhutan, is a landlocked state in South Asia, located at the eastern end of the Himalayas and bordered to the south, east and west by the Republic of India and to the north by the People's Republic of China...
, Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...
, northern India and Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
, through Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...
, Turkmenistan
Turkmenistan
Turkmenistan , formerly also known as Turkmenia is one of the Turkic states in Central Asia. Until 1991, it was a constituent republic of the Soviet Union, the Turkmen Soviet Socialist Republic . Turkmenistan is one of the six independent Turkic states...
and Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
to portions of Azerbaijan, Armenia, Georgia and eastern Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
. In these countries, there is a great genetic variability, in particular ancestral forms with lateral fruiting. During its migration to western Europe, the common walnut lost this character by natural selection on account of competition with other vigorous forest species such as oaks. They became big trees with terminal fruiting. A small remnant population of these J. regia trees have survived the last glacial period in Southern Europe, but the bulk of the wild germplasm found in the Balkan peninsula and much of Turkey was most likely introduced from eastern Turkey by commerce and settlement several thousand years ago.
In the fourth century BC, Alexander the Great introduced this "Persian nut" (Theophrastus
Theophrastus
Theophrastus , a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age, and initially studied in Plato's school. After Plato's death he attached himself to Aristotle. Aristotle bequeathed to Theophrastus his writings, and...
' καρυα ή Περσική) in Macedonia and Greece ancestral forms with lateral fruiting from Iran and Central Asia. They hybridized with terminal-bearing forms to give lateral bearing trees. These lateral bearers were spread in southern Europe and northern Africa by Romans. Recent prospections in walnut populations of the Mediterrean Basin allowed to select interesting trees of this type. In the Middle Ages, the lateral bearing character was introduced again in southern Turkey by merchants traveling along the Silk Road. J. regia germplasm in China is thought to have been introduced from Central Asia about 2 000 years ago, and in some areas has become naturalized. Cultivated distribution now includes North and South America (Chile, Argentine), Australia, New Zealand, South Africa and Japan. So, the Persian walnut is grown from 30 to 50 degrees of latitude in the Northern hemisphere and from 30 to 40 degrees in the Southern hemisphere.
The walnut was introduced into western and northern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
very early, by Roman
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....
times or earlier, and to the Americas by the 17th century, by English colonists. Important nut-growing regions include France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, Serbia
Serbia
Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...
, Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...
, and Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
in Europe, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
in Asia, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in North America, and Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
in South America. Lately the crop has spread to other regions: New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and the southeast of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is cultivated extensively for its high-quality nuts, eaten both fresh and pressed for their richly flavored oil; numerous cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected for larger nuts with thinner shells.
Nutritional value
A study of ten cultivarCultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s of J. regia in Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
showed significant variations in fatty acid content:
- 62% - 71% fatFatFats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
- saturated fatSaturated fatSaturated fat is fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain. That is, the chain of carbon atoms is fully "saturated" with hydrogen atoms...
(as a percentage of total fatty acid):- 5.2% - 7.3% palmitatePalmitic acidPalmitic acid, or hexadecanoic acid in IUPAC nomenclature, is one of the most common saturated fatty acids found in animals and plants. Its molecular formula is CH314CO2H. As its name indicates, it is a major component of the oil from palm trees . Palmitate is a term for the salts and esters of...
- 2.6% - 3.7% stearateStearic acidStearic acid is the saturated fatty acid with an 18 carbon chain and has the IUPAC name octadecanoic acid. It is a waxy solid, and its chemical formula is CH316CO2H. Its name comes from the Greek word στέαρ "stéatos", which means tallow. The salts and esters of stearic acid are called stearates...
- 5.2% - 7.3% palmitate
- unsaturated fatUnsaturated fatAn unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fat molecule is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond. Where double bonds are formed, hydrogen atoms are...
(as a percentage of total fatty acid):- 21.2% - 40.2% oleateOleic acidOleic acid is a monounsaturated omega-9 fatty acid found in various animal and vegetable fats. It has the formula CH37CH=CH7COOH. It is an odorless, colourless oil, although commercial samples may be yellowish. The trans isomer of oleic acid is called elaidic acid...
(monounsaturated) - 43.9% - 60.1% linoleateLinoleic acidLinoleic acid is an unsaturated n-6 fatty acid. It is a colorless liquid at room temperature. In physiological literature, it has a lipid number of 18:2...
(diunsaturated) - 6.9% - 11.5% linolenateAlpha-linolenic acidα-Linolenic acid is an organic compound found in many common vegetable oils. In terms of its structure, it is named all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is given the name 18:3 ....
(triunsaturated)
- 21.2% - 40.2% oleate
- saturated fat
Potential biological effects
Walnuts and other tree nuts are important food-allergen sources that have the potential to be associated with life-threatening, IgEIGE
IGE was one of the largest services company buying and selling virtual currencies and accounts for MMORPG. During its peak time, it had offices in Los Angeles, China , and headquarters & customer service centre in Hong Kong. IGE was one of the main monopoly in virtual economy services, also known...
-mediated systemic reactions in some individuals.
The extracts of walnuts have antioxidant and antiproliferative activity due to a high phenolic
Natural phenol
Natural phenols, bioavailable phenols, plant phenolics, low molecular weight phenols or phenoloids are a class of natural products. They are small molecules containing one or more phenolic group. These molecules are smaller in size than polyphenols, containing less than 12 phenolic groups...
content.
In vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
tests of walnut extract has shown a high anti-atherogenic potential and osteoblastic activity suggesting a potential beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.
The extract from walnut leaves is an antioxidant, decreases the blood sugar level and has a positive impact on lipid metabolism. The extract suppresses functional insufficiency of liver links synthethising enzymes, increases the antitoxic action of hepatocytes and improves the functional insufficiency of kidneys. The ethanolic extract from leaves of J. regia has an antidiabetic effect on diabetes-induced rats.
Bark and leaf crude extracts of Juglans regia ,and Juglans mollis , showed in vitro anti-Mycobacterium tuberculosis
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a pathogenic bacterial species in the genus Mycobacterium and the causative agent of most cases of tuberculosis . First discovered in 1882 by Robert Koch, M...
activity.
Culture
In SkopelosSkopelos
Skopelos , ancient Peparethos or Peparethus , is a Greek island in the western Aegean Sea. Skopelos is one of several islands which comprise the Northern Sporades island group. The island is located east of mainland Greece, northeast of the island of Euboea and is part of the Thessaly Periphery....
, a Greek island in the Aegean Sea, local legend suggests that whoever plants a walnut tree will die as soon as the tree can "see" the sea. This has not been proven as fact; however, it might take some time to find a local arborist
Arborist
An arborist, or arboriculturist, is a professional in the practice of arboriculture, which is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants...
willing to take on the job of planting a walnut tree. Most planting is done by field rats (subfamily Murinae
Murinae
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. This subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the...
). In Flanders
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...
, a folk saying
Saying
A saying is something that is said, notable in one respect or another, to be "a pithy expression of wisdom or truth."There are a number of specific types of saying:...
states: "By the time the tree is big, the planter sure will be dead" (Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...
: Boompje groot, plantertje dood). This saying refers to the relatively slow growth rate of the tree.
Cultivation
Walnut trees grow best in rich, deep soil with full sun and long summers, such as the California central valley. In the U.S., Juglans regia is often grafted onto a rootstock of native Black Walnut, Juglans hindsiiJuglans hindsii
Juglans hindsii, the Hinds' black walnut, also called the Northern California walnut, is a large tree endemic to roughly circular area in California centered near Fresno and reaching the San Francisco Bay area. Some authorities Juglans hindsii, the Hinds' black walnut, also called the Northern...
to provide disease resistance. Other plants often will not grow under walnut trees because the fallen leaves and husks contain Juglone
Juglone
Juglone, also called 5-hydroxy-1,4-naphthalenedione or 5-hydroxynaphthoquinone, is an organic compound with the molecular formula C10H6O3. In the food industry, juglone is also known as C.I. Natural Brown 7 and C.I. 75500...
, a dark brown chemical which acts as a natural herbicide. Horses should not eat walnut leaves or they may develop laminitis
Laminitis
Laminitis is a disease that affects the feet of ungulates. It is best known in horses and cattle. Symptoms include lameness, and increased temperature in the hooves...
, a hoof ailment. Mature trees may reach 50 feet in height and width, and live more than 200 years, developing massive trunks more than eight feet thick.
Other Uses
Walnut heartwood is a heavy, hard, open-grained hardwood. Freshly cut live wood may be Dijon-mustard color, darkening to brown over 1-3 days. The dried lumber is a rich chocolate-brown to black, with cream to tan sapwood and may feature unusual figure such as "curly," "bee's wing," "bird's eye" and "rat tail," among others. It is prized by fine woodworkers for its durability, luster and chatoyance and is used for high-end flooring, guitars, furniture, veneers, knobs and handles.American pioneers used juglone from ground walnut husks and leaves to make a deep brown ink, paints and wood stains.
Green husk extracts of walnut have insecticidal properties. It killed 98% of Tetranychus cinnabarinus
Tetranychus
Tetranychus is a genus of spider mite. Tetranychus is one of the most economically important genera of mites, due to its high potential to destroy agriculture. It contains over 140 species, the most significant of which are Tetranychus urticae and Tetranychus cinnabarinus....
(Spider mite)
See also
- Black walnut
- Taxonomy of walnut tree varieties