1 . The world loves a cup of tea. It only takes a few grams to make a cup of tea and millions of tons of tea are consumed every year. Tea can be good for you because it contains some things that help lower cholesterol and reduce the risk of cardiovascular disease. Tea also contains caffeine(咖啡因), which improves not only mental alertness but can also increase anxiety and cause other problems.

What would be agreeable is a tea plant that provides all the taste and goodness but with little or none of caffeine. Chen Liang and Jin Jiqiang in the Tea Research Institute, Chinese Academy of Agricultural Sciences think they have found just such a plant, growing wild in a remote area in southern China’s Fujian Province. Known locally as hongyacha, the discovered plant grows only between 700 meters and 1,000 meters above sea level around a handful of Chinese villages. As they report in the Journal of Agricultural and Food Chemistry, not only is the tea plant naturally caffeine-free but it also contains a number of unique medicinal compounds that, the locals believe, offer considerable health benefits.

The researchers are now exploring methods to protect hongyacha in its natural habitat while further studies are carried out. It can take time—and sometimes it does not work—for new plant varieties to be bred for commercial use. A pair of naturally caffeine-free coffee plants were discovered in 2003, but little progress has been reported. Tea lovers will be watching hongyacha with interest. And others will wonder what else is out there.

2 . With spring around the corner, stores are offering gardeners many choices for seeds. Starting a garden from seeds, rather than buying young plants, is a low-cost way to enjoy many kinds of flowers and food crops.

    1     Everything the plant needs to start growing is in the seed. All you have to do is put it into soil that is a little wet and not let the soil dry out while the seed does its own job. If there are any special requirements, they are usually printed in the simple directions on the back of every seed container.

Planting big seeds is simple.     2     Put the tip of a pencil in water and then use it to pick up each seed. It will hold one seed as you put it into its starting container.

When choosing containers to start plants, you can use any old plastic containers, newspapers or cardboards.     3     But remember to put drainage (排水) holes in each one. If you do not add holes, water can build up in the bottom and cause the seeds to rot.

Gardeners are reminded to be aware that it would be a shame to grow something in a container and then forget what it is called.     4    

And it is never too early to think about the next growing season. Once you have established plants in your garden, consider letting some “go to seed.”     5     That way you will have your own seeds for next year’s garden, and you will not have to buy them at all.

3 . High-resolution (高分辨率) satellite imagery has been used to map every single tree in Africa, showing a technique that could help improve the monitoring of deforestation (森林砍伐) across the world. Florian Reiner at the University of Copenhagen, Denmark, and his colleagues used images from sate lies to map canopy (树冠) across the entire African continent.

Modern sate lies usually catch tree canopies at a resolution of 30 meters — fine for measuring the size of forests, but less good at mapping individual trees. The satellite data Reiner and his colleagues used had a resolution of 3 meters, enabling the study to map all trees, including those not part of a forest.

The results suggest that 30 percent of all trees in Africa aren’t in a forest and instead are across farmland, savannah and urban areas. “Many countries in Africa lack thick forests, but have a lot of trees.” says Reiner. “These trees are extremely important to the local ecosystems, the people and the economy. By tracking every single tree, researchers can start to monitor how these trees are coping with climate change or whether they are sensitive to deforestation.” It could also improve the monitoring of reforestation efforts, which are growing in popularity as a way of removing carbon dioxide from the atmosphere.

“At a local level, being able to consistently monitor when and where trees are disappearing or reappearing can lead to more actionable insights,” says John Francis at the Alan Turing Institute in London.

“The study is a proof of concept rather than a map ready for immediate commercial use,” says Reiner. “It’s research work. It’s showing what could be done,” he says. But he is already working with colleagues to scale up the tracking approach to cover the entire global canopy: “We’re hoping that this will be seen as a way forward in monitoring tree resources.”

4 . Yellow flower carpeted fields are a sure sign of summer. In Denmark alone, more than 200,000 hectares of rapeseed (油菜籽) are planted every year. But until now, the plant has only been used for oil and animal food, as it is both bitter and unsafe for human consumption.

To protect themselves, the rapeseed plants produce a group of substances (物质) called glucosinolates (硫苷), which give the plants a strong and bitter taste that scares off insects and disease. As a result rapeseed is unhealthy to eat and the rapeseed cake, which is the remains of the seeds after the oil has been squeezed out, has only been used as feed for pigs and chickens, despite its 30 — 40 percent protein content.

Now, researchers from the University of Copenhagen have discovered the three proteins that help to store the bitter substances in seeds of thale cress (阿拉伯芥), a plant closely related to the rapeseed. The new knowledge makes it possible to prevent the accumulation (积聚) of these substances in the seed by removing the proteins through “transport engineering” technology. In doing so, the defensive substances remain in all other parts of the plant, allowing it to continue to defend itself.

So far, the researchers have shown that their method works in thale cress. “The next task is to apply our method to the closely related rapeseed plant, which we are now working on,” says Professor Halkier, leader of the research.

“Half of plant proteins in the EU come from rapeseed. The climate crisis demands that we reduce meat consumption and eat more plants, which is where rapeseed has great potential as a new source of plant protein. Our latest research results bring us a step closer to making full use of rapeseed,” says Professor Halkier.

5 . “A beautiful field of flowers can be a rather noisy place. It’s just that we can’t hear the sounds.” Scientists at Tel Aviv University have conducted a six-year experiment, proving that plants make noise in certain stressful situations.

Plants produce a high frequency (频率) clicking sound, and when short of water, or damaged, the clicks become far more regular. They also made different sounds, depending on whether they were thirsty or injured. “Each plant and each type of stress is related to a specific sound,” said Professor Lilach Hadany, who led the research study.

Focusing particularly on tomatoes, wheat and corn, the plants were placed in a soundproof(隔音的)room and recorded by microphones. Some plants were starved of water, others cut, and a control group was left undamaged. The researchers used an algorithm (算法) to separate the noises, suecessfully telling the difference between the sounds depending on whether they were dry or cut. The algorithm did this in a greenhouse setting which included far more surrounding sounds, but it was still able to recognize the particular cries for help of the plants.

On average, the human ear can hear sounds up to around 20kHz, while the sounds produced by plants are in the 40-80kHz region, far beyond our hearing. “The sounds made by plants can’t be heard by humans but can probably be heard by various animals, such as bats, mice and insects,” Hadany tells us. Though this has yet to be proven, it’s possible that these creatures use this information to choose which plants to eat.

A study led by Reda Hassanien of China Agriculural University in Beijing years ago, also proved that plants reacted to sound waves, with some plants greatly increasing their yield. While evidence shows that plants can react to sounds, there’s no evidence today that they can actually hear them.

With high yield and superior quality, Chinese hybrid rice varieties have been introduced around the world,     1     (benefit) more people. The export of China’s hybrid rice technology started many years ago. In 1979, China provided hybrid rice seeds to another country for the first time, and 40 years later, in     2     (real), China’s hybrid rice has been planted in dozens of countries in the world.

In the past 40 years, Chinese scientists     3     (devote) to providing assistance to many other countries. China has trained more than 14,000 hybrid rice professionals for more than 80 developing countries through international training courses. This technology has spread     4     more and more places in the world so far.

Yuan Longping,     5     cultivated the world’s first high-yield hybrid rice strain not only earned respect from Chinese people but also the global community. His hybrid rice research has been     6     (entire) saving millions of people from hunger. Yuan’s dream was     7     (solve) the global food shortage and promote hybrid rice around the world. China has achieved     8     great wonder, feeding nearly one fifth of the world’s population with less than nine percent of the world’s total land. And China is     9     (will) to contribute to global food security and calls for joint efforts to end global hunger and poverty.

It     10     (believe) that Yuan’s dream will come true one day.

9 . During the holidays, many people hang mistletoe (槲寄生) over doorways. People share kisses under this evergreen plant. It is a popular Christmas tradition. But don’t let the image of romantic plant used during the happy times of the holidays fool you. In the forests they’re from, mistletoe plants can do some real damage. Let’s take a look at how and why.

The mistletoe plant is evergreen. This means it has leaves that remain green throughout the year. It is also poisonous and has white berries (浆果) and small, yellow flowers. The mistletoe lives on other plants, taking water and nutrients from them. For this reason, mistletoe plants are considered parasites (寄生植物).

The white berries of mistletoe plants contain seeds. Some birds and mammals like to feed on these berries. When they do, the seeds may stick to the animal eating the berries. The animal may carry the seeds to another part of the tree of bush. They may also carry the seeds to another plant altogether. The seeds start to grow roots that dig through the bark of the tree or bush. The roots grow into the tissues of the plant they’ve taken over. That’s how mistletoe plants take nutrients and water away from the host plants. Mistletoe can be hard to remove once it infects (感染) a plant. The best way to fight off a mistletoe infection is to cut off the infected branch completely. If the mistletoe takes over more parts of the plant, it can start to weaken the plant and make it harder for it to grow.

As mistletoe plants grow in the trees, they become a thick mix of branches and roots. This big mass is sometimes called a “witch’s broom.” Some animals nest in these witches’ brooms.

10 . There are many theories that suggest different ways of improving memory or thinking more clearly. One of those is the idea that adding rosemary (迷迭香) to your food or water, or even breathing in its fragrance, can give your brain a boost.

First, it’s important to understand what rosemary is.     1     It’s a perennial, meaning that once you plant it, it should re-grow every year when the weather is warm enough for it to do so. It’s native to Asia and the Mediterranean.     2    

Rosemary is related to the mint (薄荷) family of plants. When it blooms, its flowers are white, purple, pink or deep blue. It is often used as a flavor in food, including soups, meat, fish and other Mediterranean food. And it has a somewhat bitter flavor. Some people also enjoy tea flavored with rosemary.     3    

One study that involved 28 older adults found that consumption of a small amount of dried rosemary powder was associated with statistically significantly improved memory speed.     4     Researchers found that their memory of images and numbers improved when the essential oil of rosemary was sprayed in the room.

    5     But one theory is that rosemary appears to have some antioxidant (抗氧剂) properties that may offer some healing for the damage in our bodies. Another idea is that rosemary appears to lower anxiety, which in turn, may increase the ability to concentrate.

While rosemary shows some promise for boosting our brain power, it’s important to check with your doctor before you begin having it.