Commonly used laboratory dye, once triggered a hundred-year battle between Britain and the West
When it comes to Tsai wood, people may feel unfamiliar, and its other name, ink tree, cannot be considered a familiar name. Only when hematoxylin is mentioned will those familiar with medicine or biology smile: this is a famous biological tissue stain – and this stain, which comes from our chai wood.
Still not impressed? Take a look at this hematoxylin-eosin stained section, and I wonder if it will jog your memory a little.
A familiar and unfamiliar tree
Cai Mu (Haematoxylum campechianum), also known as Yang Su Mu and Ink Tree, is a plant of the genus Cai Mu in the legume family. As we all know, the legume family is a large family with 751 genera and more than 19,000 known species, and is the third largest family in the embryonic plants, after the Asteraceae and Orchidaceae.
Unlike peas and broad beans they are small deciduous trees that usually grow to 5 to 10 meters tall, with the tallest said to be 15 meters. Their trunks have short main trunks from which multiple branches extend, which elongate and drop down to form a broad, circular canopy, so they sometimes grow in the form of shrubs. A pickerel tree growing in a wetland in Belize. Photo: Cephas / wiki commons
Cephas has light gray bark and a trunk with some sunken grooves. As the tree grows older, the bark cracks and flakes, becoming rougher.
The trunk of the tree.
Similar to most leguminous plants, the leaves of Caiwu have a pinnately compound leaf structure, with compound leaves 5 to 10 cm long and 2 to 4 pairs of leaflets. Each leaflet is obcordate or ovate in shape. As a deciduous plant native to the tropics, the deciduous habits of Caiwu differ from those of most temperate plants: their leaves are shed in the dry season rather than in winter, naturally to conserve water, and new leaves grow back only when the rainy season arrives.
The pale yellow flowers of Zea mays are small and clustered together in racemes. Unlike the familiar butterfly-shaped flowers of the legume family, the five petals are not equal, but still look very much like a radially symmetrical structure.
Don’t be alarmed, though, because the flowers of the entire subfamily of the Leguminosae look like this – the flowers of the Mimosa subfamily of the Leguminosae are all really radially symmetrical!
Also interesting are the pods of Caiwu. Normally, the pods of legumes split along the dorsal and ventral sutures, like peas, but the pods of Caiwu split lengthwise down the middle of the pod wall to expose the seeds.
Although it sounds increasingly unfamiliar, it is often grown as a garden plant because of its slender branches and fragrant flowers (look it up!). . In addition, the nectar of the wood has a light amber color and is almost transparent, making it an important nectar plant in its native range.
The wood is the focus
More than the less important garden and nectar uses, the essence of the wood is in the wood.
The wood is hard and naturally resistant to decay, making it a good raw material for wood, but the size of the tree’s diameter prevents it from being used for larger implements, only for small items such as flooring, bows, coffins or combs. Freshly cut wood wood density of about 0.96 to 1.04 tons per cubic meter, it is easy to sink into the water, held in the hand is also heavy, very weighty. Just look at the trunk, you can see that it is difficult to grow thick. Photo: iplantz.com
The most special part of the wood is its purplish-red heartwood – the origin of the genus name Haematoxylum, which is composed of two Greek roots, haima meaning blood and xylon meaning wood, which together means bloodwood.
A cross-section of a huge log: the dark part is the heartwood, and the thin, light-colored ring around it is the sapwood
The sapwood is stripped from the wood, the heartwood is cut into small pieces and soaked in boiling water for at least 12 hours to allow the wood to ferment and be fully extracted. Then water is added and boiled for 20 minutes to obtain a bright purple-red dye. In industrial production, the dye solution is also vacuum dehydrated to make dye crystals for sale.
Dye dissolved from the ink tree.
This dye can dye fabrics purple. Also, depending on the pH of the water, the color varies between grayish purple to purple. And if an acid is added, the dye turns yellow – in other words, the extract of the chai wood also acts as an acid-base indicator. In addition to this, different colors can be obtained by adding different mordants: adding aluminum is purple, but additional copper or iron is needed to make it less likely to fade in the light. Adding copper makes the color bluish, while adding additional iron produces an elegant and attractive black color. In 18th century Europe, most high-class black clothes were dyed with it. In addition to being used to dye clothes, it can also be used to dye or dye hair back to black.
Yarns of various colors dyed with extracts of harvested wood.
Natural dyes are certainly an important resource in an era when dyes are scarce. As with other cash crops native to South America, the economic value of cedarwood gave it a place in the history of the great seafaring era. Especially in contrast to other expensive natural red and purple dyes, cedarwood was quite cost-effective as a dye. Between 1581 and 1662, the English Parliament even banned the use of wood-picking for dyeing due to protests from a large number of dyestuff dealers, but even this did not prevent people from continuing to use it under a different name.
The war caused by wood harvesting
In the 16th century, after the Spaniards discovered the dyeing properties of the wood near the state of Campeche in southeastern Mexico (where the species campechianum comes from), they made it their money tree and forbade others from harvesting it. Of course, where there is money and law, there are lawbreakers. Hobos from other countries smelled the money and ran over to steal the logging, while Spain sent privateers to attack the logging camps and logging boats. The attacked loggers turned into pirates, who in turn attacked the Spanish army, and eventually the pirates also set their sights on the logging ships. Several forces in the Caribbean Sea for more than two hundred years, you and me, not too happy.
The infamous Caribbean pirate “Blackbeard” Edward Titch also did not do less wood harvesting business. Although the scale of logging is far less than the legal trade, such as tobacco, it has also led to war.
The small Central American nation of Belize (formerly British Honduras) was a Spanish colony that started out as a logging operation. Originally belonging to the Maya, the Spanish found the land in the early 16th century and claimed it as a Spanish colony. However, due to the harsh environment and tribal hostility, the Spaniards did not settle here.
In the 17th to 18th centuries, British pirates found a large amount of extracted wood here. In order to benefit, they endured mosquito infestation and established logging camps and ports in the swamps. The group of loggers who settled in the area were called “baymen”, and by squeezing slaves trafficked from Africa and the West Indies, they were able to produce as much as 13,000 tons of wood per year, when the price of harvested heartwood could be sold in England for 100 pounds per ton.
The ancient Mayan site of Altonha is located in Belize.
Naturally, the Spaniards did not sit idly by, and they used military and diplomatic means to evict the camps established by the British loggers on several occasions. The British, in turn, fought back against the Spanish for this huge profit, and the two countries fought over the land until the British completely drove the Spanish out in 1796 – but by then, as other dyes began to enter the market, the logging market was becoming saturated and prices had dropped dramatically, and large-leaf mahogany had replaced wood-picking as the main export of the area.
The area has undergone several changes from a Spanish colony to what became British Honduras and now an independent country, Belize, but what remains the same is that its flag still depicts two lumberjacks, one black and one white, recording the story of those days.
The flag of Belize.
The rebirth of wood harvesting
Time has come to modern times, as a clothing dye, pick wood has long been replaced by synthetic dyes, and easy decolorization is its fatal wound. Today, they can only be seen occasionally in vintage wood dyeing workshops. But the wood still has its irreplaceable uses.
A substance called Haematoxylin, which is not a dye per se, can be extracted from harvested wood, but is used extensively in scientific research for cell staining.
Molecular structure of hematoxylin.
In order to observe the internal structure of a cell, something is needed to selectively stain a portion of the cell with the color of the substance. Hematoxylin can be oxidized to form hematoxylin (Haematein), which can combine with certain specific metal ions (mainly trivalent iron and aluminum ions) to form colored complexes. The aluminum-hematoxylin complex is alkaline and can stain nucleic acids purple-blue, while another pigment, eosin, is acidic and can stain cell The other pigment, eosin, is acidic and can stain the cell pulp pink. When used together, this is the legendary hematoxylin-eosin stain (often abbreviated as H&E stain), which has contributed much to the development of biology and medicine by clearly distinguishing the various components of the cell.
Section of Brenner’s tumor stained by H&E.
Zea mays has also been used historically for medicine, but there is no scientific basis for its effectiveness.
