Although it is already winter，Under the large trees in the Temple of Heaven Park，Ophiopogon japonicus is still growing vigorously in the cold wind，The leaves are neither yellow nor withered，It’s like laying an evergreen carpet on the earth。
In the eyes of ordinary people，Yishan Ophiopogon japonicus、Carex、Native land cover plants such as Potentilla and others are often regarded as "weeds"，They are all “old neighborhoods” of Beijing citizens，Born and raised in Beijing。As Beijing promotes "ground cover change" in the field of landscaping，They are gradually replacing the cool-season lawns that once were used，Let the garden be green all year round，Less dust，More living creatures，The landscape effect and ecological effect are both improved。
However，We know very little about the secrets of these "old neighbors"。Why are they cold-resistant、Jiulv？How to better cultivate and plant？To answer these questions，Duan Liusheng, Dean of Beijing Agricultural College, established the country’s first ground cover plant research team，March into blank areas of scientific research。Just 4 years，This young scientific research team has achieved fruitful results: cold tolerance of Ophiopogon japonicus、Important progress has been made in shade tolerance gene mining；Analysis of the molecular mechanism of drought resistance and water conservation in Carex；The biological regulator developed is sprayed on the leaves like a "skin care product"，can enhance the plant’s ability to withstand low temperatures、Extend the green period...in the future，In the streets of Beijing、In the park，Better quality、Better-looking native land cover plants will appear more，Achieve “increasing color and extending greenness”。
Duan Liusheng (right) and team members check the growth of Ophiopogon japonicus plants. Photo by our reporter Wang Haixin
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Winter of 2019，Just completed the job transfer，Duan Liusheng, who came to Beijing Agricultural College from China Agricultural University, often lingers at the door of the school cafeteria，He noticed an inconspicuous green plant in the flower bed in front of the cafeteria--Ophiopogon japonicus。
The cold wind howls in Beijing in winter，The temperature can reach as low as minus ten degrees Celsius，Workers on campus after clearing snow and ice，I often pile snow and ice into flower beds and wait for it to melt，Ophiopogon japonicus often has thick snow on its head in this mountain area。In the severe cold and desolation，There is always a patch of green in the flower bed，This is exactly the characteristic of Ophiopogon japonicus - staying green through the winter。
In the mountains、Ophiopogon japonicus can be seen everywhere on the street，People rarely pay attention，There is very little research on it in academia。Duan Liusheng discovered this vacuum zone of scientific research。
“Urban greening is largely a human choice，Not only natural factors must be considered，Also depends on socioeconomic factors。”more than 20 years ago，Domestic urban ground greening mainly relies on the introduction of cool-season lawns，From grass seeds to maintenance machinery，Almost all depends on imports。At that time，Duan Liusheng is still working as a postdoctoral fellow at Beijing Forestry University，Although the main research is corn、Cotton and other field crops，But living in Beijing，Hot issues in the field of landscaping，Inevitably become his co-mentor、Topics often discussed by Yin Weilun, an academician of the Chinese Academy of Engineering。
Research on food crops，Need to pursue high yield、High quality、Efficient。In Duan Liusheng’s view，Production value is only one dimension of agriculture，Especially in the field of urban agriculture，Ecological value、The value of life and cultural tourism value are equally important。He gave an example，Under construction of agricultural product picking garden，Fruit trees are particular about their plant type and height，We must try our best to ensure that citizens who come to pick are within easy reach，“As for how many fruits an acre of land can produce，It’s not the most important thing。”
Landscaping is even more special，In the city，A large amount of green bet365 online sports bettingland is the corner land left in the reinforced concrete jungle，Lack of soil is a big challenge for plant growth。Let the places in the city where plants cannot grow before be greened，Make already green places more pleasant，Also reduce maintenance costs。Duan Liusheng thinks，This should be the goal of landscaping scientific research。
The optimum growing temperature for cool-season lawns is 15 to 20 degrees Celsius，If planted in Beijing，About one-third will die every winter。At the same time，This kind of lawn needs to be watered every two days in summer，One acre of land requires about 60 to 100 tons of water，And it needs to be pruned every one or two weeks，The resource cost and labor cost consumption are extremely high。While studying abroad，Duan Liusheng discovered，The climate of central European countries is suitable for the growth of cool-season lawns，But to the northern United States，The lawn in winter is also not green。
The average annual precipitation in Beijing is only about 600 mm，And the seasonal distribution is uneven，80% of the annual precipitation is concentrated from June to August，Such climate conditions also determine，To save water、Drought Resistance、Research on easy-to-maintain ground cover plants is urgent。In the long-term evolution process of native land cover plants，Has adapted to local climate conditions，And a wide variety of species have been produced、Rich variations、A branch with strong resistance to stress。
Many local “specialties” are grown on the campus of Beijing Agricultural University。Under the tree、The shade behind the house，Most ornamental plants are difficult to survive，Ophiopogon japonicus can thrive，Even in the cold winter bet365 online casinoof minus 10 degrees Celsius，Still green and bright。Carex is slightly less cold-resistant than Ophiopogon japonicus，The leaf tips may turn yellow in winter，But its annual maintenance cost is only 2 to 3 yuan per square meter，Save 68% to 91% more water than cool-season lawns。
“Then why not use our native green plants to decorate Beijing’s winter？”Duan Liusheng’s decision，Concentrate efforts on studying native ground cover plants in Beijing。Previously，Across the country，There is no scientific research team focusing on research in this field。
Start from scratch，The difficulty is obvious。When the team was formed in 2019，Many members have never even heard of Ophiopogon japonicus，At that time，They are in corn、Potato、Respective achievements have been made in the scientific research fields of roses and other crops。When Duan Liusheng proposed the idea of conducting research on native land cover plants，They all decided to “transform”，Get to know Ophiopogon japonicus from the beginning、Carex、Potentilla, these "weeds" that have multiplied on the land of Beijing for generations。
“Tell the truth，When I first started working on the project，I still can’t tell the difference between Ophiopogon japonicus and Carex，They really look alike。”Talk about this experience，Team member、Gao Yuerong, a lecturer in the Horticulture Department of Beijing Agricultural College, couldn’t help laughing。Although these "weeds" are growing around us，But they "cannot be burned out by wildfire"，The secret behind the tenacious vitality of "spring breeze blows and rebirths"，Never revealed。The scientific research team sorted out the common native ground cover plants in North China，Looking forward to using biological research methods，A molecular analysis of their drought tolerance、The mechanism of cold resistance，And select better quality germplasm resources，Solution to Beijing’s Greening and Winter Cold、Contradiction between water shortage。
Ophiopogon japonicus in full bloom
Find the secret to anti-freeze
Cold resistant、Heat resistance、Drought tolerance、Shade tolerance、Saline and alkali resistant、Poor resistance...among many "weeds"，The evergreen Ophiopogon japonicus has many stress-resistance properties，You can grow in Beijing relying only on natural precipitation，Good ground coverage in just one growing season，No need to fertilize、Spraying medicine、Trim，It can also grow normally in the understory space with 80% shading degree，It is an excellent ground cover plant。Therefore，It has become a key research object of the team。
Team member、Peng Zhen, a lecturer in the Horticulture Department of Beijing Agricultural College, is responsible for Ophiopogon japonicus breeding research and genome analysis，But it’s hard for a clever woman to make a meal without rice，The first difficulty before him，It is the lack of research materials。
bet365 online casinoAll teachers and students in the research team were mobilized，Whenever you have free time，They went into the mountains and forests on the outskirts of Beijing，Finding and collecting wild Ophiopogon japonicus plants。Go to your hometown to look for wild mountain Ophiopogon japonicus，It has also become a holiday homework for students。“Ophiopogon japonicus is very conspicuous in the wild，Especially in winter，Look for the green in the mountains，Correct！”Soon，Peng Zhen became old friends with this kind of "little grass"，And with other teachers，Guide students to collect large-scale germplasm resources of wild Ophiopogon japonicus。
However，The first batch of wild Ophiopogon japonicus brought back to the laboratory，Failed to thrive as everyone expected。What kind of lighting conditions does it need、Temperature and humidity environment，How often should you water，What nutrients should be provided to it...when raising them，These problems have repeatedly frustrated Peng Zhen。“Ophiopogon japonicus is planted downstairs in our experiment，It grows very well on campus，But it’s not good in the laboratory，This hit us hard。”
Turn off the lights in the nursery halfway，Reduce light，The temperature has also dropped to about 18 degrees Celsius - with the accumulation of experience，The answer slowly emerges。But the challenges go beyond that，In the wild，Ophiopogon japonicus rarely encounters insect pests；However，In the closed environment of the laboratory，One bug can reproduce a population。When there is insufficient experience in the early stage，The team did not isolate wild material from other experimental plants，Pest thrips eat leaves and cause pests and diseases。“It always starts with trial and error。" Peng Zhen sighed。
Now，In the laboratory of Duan Liusheng’s team，Pats of different varieties of Ophiopogon japonicus are filled to the brim。Establishment of germplasm resource bank，It is the study of the origin of crops、Evolution，The basis for cultivating new crop varieties and other work，After repeated comparison、Filter，More than 120 Ophiopogon japonicus germplasm resources have been “incorporated”。Although they belong to the genus Ophiopogon japonicus，But different varieties of Ophiopogon japonicus plants，Tall or short、Blade width、There are obvious differences in flower color etc.，The leaves of some varieties are even trimmed with "gold edges"，Stress resistance is also different。
To find the anti-freeze secret of Ophiopogon japonicus，Need to use some "extraordinary means" first。Peng Zhen once introduced a mountain Ophiopogon japonicus variety with excellent cold resistance，Place it in an environment of minus 25 degrees Celsius for 24 hours。“Almost all its leaves were frostbitten，Harsh conditions where the temperature drops rapidly，In fact, it is rare in the natural environment。" Peng Zhen said，Usually the ambient temperature gradually decreases，The plant will have a domestication、The process of adaptation。At that time，Team members all believe that it is difficult for this Ophiopogon japonicus to survive again，Unexpectedly, it was left in the culture room for a period of time，The sprouts are sprouting out of the ground again - it's still alive！
“This is a very high-quality germplasm resource，around it，We can carry out research on the cold resistance mechanism and variety optimization of Ophiopogon japonicus。”Use this batch of samples，Duan Liusheng’s team conducted in-depth exploration of the cold resistance of Ophiopogon japonicus。However，During plant growth，There are many metabolites in the body，After metabolomics analysis and screening，The number of metabolites that may be related to cold resistance is as high as 400。The next step is hard work，They first cultivate healthy and consistent Ophiopogon japonicus plants，Use a certain metabolite for external processing，Try one by one。The trial and error process lasted for nearly two years，Repeated experiments have become the norm，“The probability of less than one in a hundred，It’s normal to find the wrong one。”
Hard work pays off，Several main metabolic pathways are gradually becoming clear: metabolism of flavonoids and trehalose and abscisic acid、Signal transduction of nitric oxide，Plays an important role in the cold tolerance of plants。Experimental display，When the trehalose content in the plant increases，Cold resistance will be enhanced accordingly；Treat with appropriate concentration of trehalose，In the laboratory's quenching environment bet365 online casinoof minus 10 degrees Celsius，The damage rate of plant leaves is less than 50%。
External characteristics of living things，In the final analysis, it is the role of genes。Utilize collected germplasm resources，Duan Liusheng’s team completed the sequencing of the Ophiopogon japonicus genome、Assembly and parsing，Based on sequencing results，The difficulty of mining various functional genes is greatly reduced。“For example, a certain variety is particularly cold-resistant，Let’s compare it with the reference genome，Finding which gene has mutated。"Duan Liusheng said，Many mountain Ophiopogon japonicus varieties are very ornamental，But slightly less resistant to stress，Influenced subsequent application promotion。
Currently，The team has achieved important results in the discovery of stress resistance genes from Ophiopogon japonicus，Selected for cold resistance、Candidate functional genes for shade tolerance，The analysis of its mechanism of action is in progress。This discovery can not only improve Ophiopogon japonicus varieties，Also helps to improve the stress resistance of other ground cover plants，Beijing’s winter is expected to be more green。
Now，Peng Zhen has completely fallen in love with this inconspicuous "weed"，He changed his WeChat avatar to a field of Ophiopogon japonicus in full bloom，Proudly introduce it to everyone: Ophiopogon japonicus can decorate the cold winter with green，It can also bloom purple flowers in summer，“There are sceneries in all seasons，Every season is different"。
Develop plant “skin care products”
Although Ophiopogon japonicus is grown more and more widely in Beijing，But the variety is relatively single，Available colors、There are not many plant types，Color-leaf varieties are generally less cold-resistant。Using gene editing technology and breeding methods，Duan Liusheng’s team is continuing to develop new Ophiopogon japonicus varieties with more advantageous traits。Ophiopogon japonicus germplasm "1032" that can withstand low temperatures of minus 15 to 20 degrees Celsius、New broad-leaved mountain Ophiopogon japonicus germplasm "1072" with excellent shade tolerance and flowering performance, etc.，Already coming out。
Now，Ophiopogon japonicus "1072" is in the demonstration planting stage。Followup，To achieve rapid reproduction of plants、Expand planting area，Obtain a large number of seedlings through plant tissue culture，Is the fastest way。
In the laboratory of Duan Liusheng’s team，Ophiopogon japonicus varieties with excellent resistance can be rapidly propagated in this way。However，Let the young callus grow healthily，The choice of culture medium is critical。Although the Ophiopogon japonicus planted in the field is particularly thick，Let this perennial herb return to the callus stage where it can differentiate，Tissue culture is very difficult，The conditions are also more stringent。“Different plant media are not universal，Even callus of the same plant at different growth stages，The required culture media also vary。”In order to find the “exclusive nutrition” of Ophiopogon japonicus，Gao Yuerong spent a lot of effort。Refer to the medium formula of similar plants，She tried 13 media，But only 2 effects are acceptable，The experiments of the other groups ended in failure。
Generally speaking，Plant tissue culture will select easily accessible roots、Leaves and other tissues as induction materials，But these are not the best tissue culture materials for Ophiopogon japonicus，Even direct induction using seeds，The effect is not ideal either。“Common options are basically eliminated，I accidentally thought of it，Can you try using tender seed embryos，This idea is rarely used。”This idea brought a turn for the better to Gao Yuerong’s experiment，"Although the seeds are young inside，But the shell is still very hard，It must be cut open carefully and under sterile conditions，Pick out embryos smaller than sesame seeds。Since changing the culture materials，They ‘exploded’ in an instant，Grows up fast。This medium is indeed the most suitable choice，From induction to budding、Rooting，No need to change the formula，It’s all inclusive。”
Now，Gao Yuerong is facing "sweet troubles"。“One bottle can produce hundreds of buds，Cut them out and culture them，The base sprouted again after a few days。To make them grow slower，I have to squeeze them together，To control nutrition，We also need to cool down the culture room。" she said with a smile，"Now，I am very confident in the industrialization of new varieties！”
In the garden，To maintain bet365 best casino gamesthe good growth condition of green plants，It requires a lot of labor costs for pruning、Maintenance，This is the economic cost。But Duan Liusheng pays more attention to the ecological cost，Landscaping requires irrigation water，Plant Pruning、The waste formed by fallen leaves becomes garden waste。Although Beijing has been promoting the replacement of cool-season lawns with native ground covers，But the existing lawn still needs maintenance。If its growth status can be controlled，Make your lawn grow slower、Greener longer，can effectively reduce costs。
Chemical lawn mowing products that can control lawn growth，Compared with similar products, the growth control effect can reach 4 to 5 times，Thus reducing the frequency of manual pruning；Horticultural plant tillering and branching products are beneficial to Ophiopogon japonicus、Poetilla and other ground cover plants work well，can promote its rapid growth into a flat area；Anti-low temperature products can "mask" plants，Reduce water transpiration from leaves，Keep the green color longer..."skin care products" that make plants more colorful and green，Continuously walking out of Duan Liusheng’s laboratory。
Among them，Coronavirus, a biological regulator that makes turfgrass resistant to freezing, has been industrialized for the first time in the world，Its research and development process is also full of ups and downs。“We almost let the active ingredients escape。”Team Member、Yu Chunxin, a lecturer at Beijing Agricultural College said，Due to the first experiment，The concentration interval setting of coronatine is inappropriate，Resulting in unsatisfactory experimental results。“But from a theoretical analysis，It has a high probability of being effective，We have expanded the scope of concentration screening，Multiple attempts，This is the success。”
"Do scientific research，Just to innovate，To do something that no one else has done，Give a new way to solve the problem。”It has been less than 4 years since we opened the door to the field of ground cover plant research，Duan Liusheng has led the team to achieve breakthroughs one after another。Discover the key cold-resistant genes of Ophiopogon japonicus and cultivate excellent new strains、Analysis of the molecular mechanism of drought resistance in Carex、Developing ground cover plant functional substrates and green maintenance products... Duan Liusheng's team continues to bring new understanding of these "old neighborhoods" to Beijing citizens，“We used to grow these native plants，But I don’t know why it can be planted、How to plant better。With the in-depth study of the mechanism，These ‘weeds’ can also be bred through new varieties，Become stronger、More beautiful，Better decorate Beijing。”
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