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AS IT IS
The Right Way to Move Plants Outdoors
May 05, 2019
This undated photo shows seedlings in New Paltz, N.Y. Gradual exposure of seedlings to outdoor conditions readies them for eventual planting out in the garden.
Gardening can be both personally satisfying and a good activity for the mind and body. Flowers beautify your surroundings, while fresh vegetables provide some of the tastiest foods on your table.
Plant scientist and gardening expert Lee Reich knows all about these things. He has written a number of books and “how to” guides. The Associated Press news agency publishes his stories on gardening and caring for plants of all sizes.
A seedling is a young plant grown from a seed. It can be easy to grow seedlings inside the home. But what happens when they get bigger?
Reich says seedlings that start indoors or in a greenhouse need to go through a period of transition before they can safely remain outdoors. This period is called “hardening off.” It will prepare the seedlings for wind, stronger sunlight and up-and-down temperatures.
Here is what Reich suggests for hardening off your seedlings:
First, make the transition from indoors to outdoors slowly, over a week or two. A good place to harden off seedlings is in a partly protected area outside the home, such as a coldframe. A coldframe is usually an open-bottomed box with a clear, removable cover.
You can also harden off seedlings near a wall in an area where there is a mix of sun and shade. Or keep the seedlings fully exposed to outdoor weather conditions – for short, but increasing periods.
Temperature transitions
The lower temperatures of the hardening-off period will lead to changes in the seedlings.
Seedlings of vegetables like cabbage and lettuce can develop the ability to survive freezing temperatures. Plants like snapdragons and pansies can also develop this ability. They gain strength against cold weather by building up sugars in their cells.
But seedlings of tomatoes, marigolds and other plants have trouble in temperatures below freezing. They can even suffer damage when temperatures fall below 10 degrees Celsius. Damage from cold prevents sunlight from producing photosynthesis – the process by which a green plant turns water and carbon dioxide into food.
As tomatoes and other sun-loving plants harden off through slow exposure to cooler air, they are better able to repair and prevent cold damage.
Avoid sunburn
Next, there is sunlight. Sunlight can damage the leaves of seedlings that have grown indoors. Even without cold, outdoor sunlight can be as much as 10 times more intense than light from the inside of a sunny window.
Slow exposure to more intense light thickens cell walls as well as existing and new leaves. This exposure can begin in areas of partial shade, or with just a few hours each day of full sun. With increasing light exposure, leaves also turn darker green.
And stomata become more quickly able to open and close in changing conditions. Stomata are the very small openings in leaves through which water is lost, oxygen released, and carbon dioxide taken in.
Shelter from wind
Reich notes that stomata also play a role in a plant’s slow adaptation to wind.
During the hardening-off period, plants become able to react more quickly to drying winds by closing their stomata. Even movement of the plant, whether from wind or something else, affects how reactive stomata are.
Movement of plants has yet another effect: It slows growth of their stems. This adds to the short, pretty green look that shows a plant has been well hardened off.
So, you can blow on, shake or softly touch your seedlings often to help them become strong, but short plants that are better able to survive in a garden. Spending a week or so outdoors in a sheltered area or for only part of the day will ease your seedlings’ move to the garden. So they will almost not realize they have been moved – and that, Reich says, is how it should be.
I’m Alice Bryant.
Lee Reich wrote this article for the Associated Press. Alice Bryant adapted it for Learning English.
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Words in This Story
gardening – n. the activity of tending and cultivating an area of ground where plants, such as flowers or vegetables, are grown
greenhouse – n. a building or part of a building that has glass walls and a glass roof and that is used for growing plants
transition – n. a change from one state or condition to another
shade – n. an area of slight darkness that is produced when something blocks the light of the sun
adaptation – n. a change in a plant or animal that makes it better able to live in a particular place or situation
stem – n. the main long and thin part of a plant that rises above the soil and supports the leaves and flowers
AS IT IS
Southeast Asia: Stop Sending Us Mountains of Plastic Waste
May 05, 2019
Wealthy countries are exporting millions of tons of plastic waste to Southeast Asia, where local recycling systems cannot process all of it.
Greenpeace and the Global Alliance for Incinerator Alternatives, or GAIA, studied the issue. Their joint investigation found that the exports of plastic waste are causing widespread pollution problems.
In early 2018, China banned the import of plastic waste for recycling. The ban sent the international trade in recycled materials into disorder.
Greenpeace and GAIA workers gathered information from the top 21 importers and exporters of plastic waste. They looked at the recycling trade before and after the Chinese ban.
Over half of the plastic --more than 3 million tons a year -- used to go to China. It is now being sent to Southeast Asia. Huge mountains of plastic are growing in Thailand, Malaysia and Vietnam, among other countries.
Kate Lin is a project leader at Greenpeace. She told VOA that these Southeast Asian countries do not have the ability to make all that plastic useful again.
"They do not have enough capacities for handling such a large amount of imported foreign waste, so there is some pollution to the local environment."
The Malaysian village of Jenjarom is about 50 kilometers outside Kuala Lumpur. Nearby, one finds huge piles of plastic waste on the ground in the middle of a palm oil farm. Nobody is working to reduce the size of the piles. The writing on the bottles, boxes and plastic bags shows where they came from. Much of the waste has traveled thousands of kilometers from Europe and North America.
People are suffering because of this waste, said local environmentalist Pua Lay Peng.
"They just dump the non-recyclable plastic or the rejected product, and then they burn [it] in the backyard of these factory. So, those toxic steam (fumes) actually already caused a lot of health problems to our residents."
Kate Lin said wealthy countries are simply exporting their waste problems. They do not follow up on what happens after it crosses the border.
"They have good collection facilities, but actually they are sending half of their collected waste to other countries. Before the China ban, they just sent it to China for recycling, but they do not take the further step to ensure those recyclables are properly recycled. And now after the China waste ban, they just try other new places to send their recyclables to."
Many Southeast Asian countries are beginning to restrict plastic waste imports. That forces the trash into markets with fewer controls, such as Indonesia and India.
At a United Nations conference in Geneva this week, 180 countries have been discussing a new rule that may help. The rule would force plastic waste exporters to get permission from officials of the countries before they accept the waste. The system, known as "prior informed consent," is already used for more hazardouswaste.
For those dealing with the effects of the waste, the changes can't come soon enough, said Pua.
"We are killing ourselves by using too many plastic(s). We [are] too dependent on plastic. Please manage and handle your own trash. Don't dump to our country."
Greenpeace said improving recycling is not the final solution. Instead, the world must severely reduce plastic production and consumption worldwide.
I’m Jill Robbins.
Henry Ridgwell reported on this story for VOA News. Jill Robbins adapted it for Learning English. George Grow was the editor.
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Words in This Story
recycle - v. to send (used newspapers, bottles, or cans) to a place where they are made into something new
capacity– n. the ability to hold or contain people or things — usually singular
toxic – adj. containing poisonous material
fume – n. a smoke or gas
consent - n. permission for something to happen or be done
hazardous - n. involving risk or danger
consumption - n. the use of something (such as fuel)
What happens to the plastic waste where you live? Write to us in the Comments Section.
AS IT IS
German Scientists Create See-Through Human Organs
May 05, 2019
Dr. Ali Ertuerk, Group Leader at the Institute for Stroke and Dementia Research (ISD) at the Ludwig Maximillian's University, looks at a transparent human brain at his laboratory in Munich, Germany April 23, 2019. (REUTERS/Michael Dalder)
Scientists in Germany say they have used new technology to create see-through human organs. They say the technology could lead to production of three-dimensional (3D) body parts for use in transplant operations.
The scientists are with Ludwig Maximilians University in Munich. They said they developed a process that uses a solvent to make transparent organs, such as the brain and kidneys.
The German researchers use lasers in a microscope to scan the organ to be replaced. The laser light helps them see the blood vessels and every single cell inside.
The researchers use this information to print out the structure of the whole organ. For this, they need special equipment. They use a 3D printer to manufacture the structure – one that has height, width and length.
The researchers then load the printer with stem cells, which can become any kind of cell in the body. The stem cells act as “ink” in the printer. They are injected into the correct position, making the organ fully operational.
The leader of the study, Ali Erturk, described the new technology as a major development for 3D printing in the medical field.
Until now 3D-printed organs lacked detailed cellular structures because they were based on two kinds of medical scanning technology, he explained. The two are computed tomography (CT) scans and magnetic resonance imaging.
“We can see where every single cell is… we can actually replicate it exactly the same,” Erturk said. “I believe we are much closer to a real human organ for the first time now,” he added.
Erturk and his team plan to start by creating a transparent, bioprinted pancreas over the next two to three years. They hope to develop a human kidney within 5-6 years.
The researchers will first test to see if animals can live with bioprinted organs and could start tests within five to 10 years, he predicted.
I’m Susan Shand.
The Reuters News Agency reported this story. Susan Shand adapted it for Learning English. The editor was George Grow.
Write to us in the Comments Section or on our Facebook page.
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Words in This Story
three-dimensional – adj. having length, height and depth
transplant - v. to perform a medical operation in which an organ or other part that has been removed from the body of one person is put into the body of another person
transparent – adj. something one can see through completely
solvent – n. a liquid used for breaking down other substances
scan – v. to look at the inside of (something) by using a special machine
ink – n. a colored liquid used for writing
replicate – v. to recreate something exactly