The bark on the outermost layer of the tree is the protective layer of the tree and an important organ for tree growth. It consists of the epidermis, timber layer, cortex and phloem .
epidermis is the outermost layer of the tree trunk and has a protective effect. The wood plug layer is in the epidermis. After the wood plug layer is formed, the skin gradually dies and falls off. The wood plug layer replaces the epidermis and plays a protective role. The texture of the timber timber layer is soft and elastic. There is a plant called cork . It has a thick layer of wood trunk. Cut it off and it is the industrially widely used " cork ".
cortex is inside the timber layer. Its cells contain chloroplast , which makes the stem appear green, so young stems can produce photosynthesis .
phloem, which contains sieve phloem fibers. The sieve tube is an adjacent cell with an upper and lower surface, and there are sieve holes on the wall to make cytoplasmic connect. The screen tube is a pipeline that transports organic nutrients, allowing nutrients produced by photosynthesis of leaves and stems to be supplied to the growth of trees through the screen tube. Another layer inside
is phloem fibers, and its cells are dead cells, which are often combined into bundles to play a supporting role. Therefore, if the bark is stripped naked, the trees will not be alive.
In addition to this, the bark has great value. The bark has been used as medicine for 2,000 years. " Shennong Bencao Jing " records the medicinal use of various tree barks. The well-known Eucommia ulmoides, Magnolia officinalis, and the bark of cinnamon can all be used as medicine. The common willow bark can treat rheumatism. It is reported that recently, my country has also extracted cancer-treating substances from the bark of Sanjian shank .
bark can be made into daily necessities. Birch bark has good elasticity and can be made into boxes, cradles, and raincoats. Palm bark can be used as straw raincoats, spinning brown ropes to make brown boxes, etc.
extracted from the bark of various trees such as bayberry, casuarina , maple poplar , etc. It is an important raw material for the industry of roasted glue, tanning leather and artificial boards. It can also extract activated carboligin, plant wax plastic filler, and can also be made into dyes, etc.
bark is edible. The bark of wood salt trees can secrete salt as seasoning. Elm bark powder is used as dry food. After hydrolysis, glucose can be isolated, and then fermented and processed to make feed.
bark can be made of paper. The rice paper that won the gold medal at the Panama International Expo was made of sandalwood bark. Snowflake bark can be made of paper; pentagonal maple bark is also an industrial raw material for artificial cotton.
bark can also be made into various artificial boards such as light texture, uniform structure, sound insulation, insulation, and thermal insulation. For example: particle board , bark fragments and bark insulation board, etc.
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