Making paper also requires transgenic technology? Yes, you read that right.
When it comes to myrtle, many people think of the ghost of the young female student who floats around the bathroom in the Harry Potter series. Strictly speaking, this unfortunate student Myrtle's name comes from the Mediterranean plant Myrtus communis, rather than the native tree species of southern China, Rhodomyrtus tomentosa. But clearly, compared with the dry-sounding "Myrtus communis," "Myrtle" really does have more of a fantasy-novel heroine's name flavor.
Today we introduceEucalyptus grandis(Eucalyptus grandis), which is a plant in the Myrtaceae family.
Eucalyptus grandis, as its name suggests, is very tall. Image: Poyt448 Peter Woodard / wikimedia
A large family mostly in the Southern Hemisphere
Eucalyptus grandis, Myrtus communis and Rhodomyrtus tomentosa are all plants of the Myrtaceae family. In terms of species count, Myrtaceae ranks as the world'seighth largest family of angiosperms, with more than 6000 species currently known. However, for the Northern Hemisphere, it is a small family, for a simple reason: Myrtaceae is mainly distributed inthe tropical and temperate regions of the Southern Hemisphere. As the northern edge of the distribution of Myrtaceae, China has only a mere 100-plus species. As for Europe, the only native Myrtaceae plant is Myrtus communis; all others are introduced.
Only when you come toAustraliathelargest distribution centerof Myrtaceae, can you most fully appreciate the diversity of the world's eighth largest family - here there is Callistemon with flower spikes like brushes, Leptospermum scoparium with flowers like plum blossoms, and naturally also various kinds of eucalyptus.
Myrtus communis (left) and Rhodomyrtus tomentosa (right). Image: Forest & Kim Starr & Fakhruddin Hamzah / wikimedia
Callistemon (left) and Leptospermum scoparium (right). Image: Wula Kuake & Krzysztof Ziarnek, Kenraiz / wikimedia
Eucalyptus grandis belongs to the genus Eucalyptus, of which more than 1000 species are now known, accounting for one sixth of Myrtaceae. Apart from a few species also found from Papua New Guinea north of Australia to Indonesia, all are endemic to Australia.
The geographical distribution of Eucalyptus grandis in Australia. Image: HelloMojo / wikimedia
Eucalyptus is not only trees
In fact, eucalyptus has rich internal diversity; for example, some eucalyptus distributed in arid regions are low shrubs, making it hard to think of them as eucalyptus too. Indeed, the eucalyptus in most people's minds is always a tall tree, with perhaps a few koalas chewing leaves on it. This counts as a hard-to-reversestereotype.
However, even among these tall tree eucalyptus that are too high to reach the branches, there is still great variety. Some eucalyptus prefer cool conditions, some prefer warmth, some prefer moisture, and some require a bit more dryness. These ecological differences determine that when other parts of the world introduce tree eucalyptus,they need to choose species suited to the local climate. For example, Eucalyptus grandis is a tropical eucalyptus, so naturally it is mainly introduced only to tropical regions, such as Brazil, which is at roughly the same latitude as Australia.
The brown bark of Eucalyptus grandis near the ground is rougher, creating a skirt-like effect. Image: Casliber / wikimedia
Why do other countries introduce tree eucalyptus? Because they are both goodtimber treesand goodpulpwood trees. As for pulp, this year's Species Calendar, when discussing reeds, said that wood pulp made from tree wood is superior to grass pulp made from the stems of herbaceous plants, becausewood pulp has a low impurity content(especially lacking the silica common in grass pulp), and the fiber quality is good. And among pulp trees, eucalyptus fiber quality is even better.
Not only that, many tree eucalyptus are also fast-growing species, growing quickly and reaching usable timber in just a few years. Compared with some other fast-growing species,when growing the same volume of wood, eucalyptus requires less water. These advantages all make eucalyptus an important crop.
Eucalyptus grandis being harvested. Image: T. Grove, CSIRO
Paper making also needs transgenics
Yes, eucalyptus used for paper making is essentially acrop, even if it cannot be eaten, even if it is a tall woody plant.
For more than ten years, environmental organizations have been denouncing eucalyptus forests in southern China, accusing them of having no grass growing beneath and no birds flying among them, accusing them of lowering water levels, and accusing eucalyptus plantations of destroying native vegetation. However, as long as one understands the crop nature of eucalyptus, one can know that most of these accusations make little sense.
In Nanping Yao Ethnic Township, Shangsi County, Guangxi, beneath fast-growing eucalyptus forest grows a kind of small grass with many hairs and very fine branches and leaves; in misty and rainy weather, dense dewdrops cling to the grass, forming a "sea of dewdrops." Image: Liang Fuying / Oriental IC
For example, we would not accuse a wheat field or a sunflower field of "having no grass growing beneath it"; on the contrary, large fields of neatly growing wheat or sunflowers have always been a scenery people love. But why is it that when it comes to eucalyptus "fields," rich biodiversity beneath the forest is required?
In the end, we stillexpect too much from planted forests, hoping they can both provide high-quality forest products and play the ecological role of natural forests, and also require no human management like natural forests. However, there is no such perfect thing in the world.
Eucalyptus grandis forest. Image: Tatiana Gerus / wikimedia
As a crop, eucalyptus now also encounters the same problem as some other crops - genetic modification. Brazil is a major cultivating country for pulp eucalyptus, mainly cultivating hybrids of Eucalyptus grandis and E. urophylla. Brazil's Fibria company and Suzano company are respectively the world's first and second largest eucalyptus pulp producers (currently, these two have agreed to merge, becoming an even larger pulp production "giant"), among which a biotechnology company under Suzano developed the world's only transgenic eucalyptus line currently permitted for commercial planting. In fact, it is alsothe world's first transgenic line of a woody plant permitted for commercial planting。
This line was transformed witha gene from Arabidopsis, named CEL1. The enzyme expressed by this gene can participate in breaking down existing cellulose molecules in the cell, allowing old cellulose to be quickly used to synthesize new cellulose when the cell elongates, therebyaccelerating the growth rate of eucalyptus. Such a transgenic variety has naturally also met opposition from anti-GMO people across society, and although it obtained a permit in Brazil in 2015 (but has not yet obtained any permit from the People's Republic of China), it seems it will not be easy to promote.
"Giant" paper rolls produced by the pulp production "giant." Image: latinlawyer.com
At present, China's demand for eucalyptus pulp is still growing. Whether high-quality publication paper or high-quality tissue paper, eucalyptus pulp is needed to make it. At the same time, eucalyptus forests in southern China will continue to develop amid controversy. The only question is whether the current public opinion environment in China will allow our scientists to also introduce transgenic eucalyptus lines with independent intellectual property rights?
This article is the 258th article of the fourth year of Species Calendar, from Species Calendar author @Liu Su.
Yesterday, Calendar Mom gave the second clue and the second question, and everyone's answers were all excellent. Today we continue, catchthe third clue to the"Species Calendar 2019" theme!
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Ancient tower 1406
The layered terraces and pavilions built by ancient craftsmen unexpectedly became the home of swifts - the bracket sets and flying eaves let these birds, accustomed to nesting in rock crevices, find their own place in the city. Yet times have changed, classical architecture is no longer popular, and old city redevelopment and ancient building protection have step by step pushed the swifts in big cities toward dire straits. Can the swift tower built in the Olympic Forest Park keep Beijing's swifts? We still do not know.
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Myrtaceae Psidium guajava