Yunnan is the hometown of tea. It provides the ideal climate and the ecological environment for large-leaf tea trees, which are located in the
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Yunnan has diverse resources of tea trees. The regulation also advocates proper research and
2 . Animals can adapt quickly to survive unfavorable environmental conditions. Evidence is mounting to show that plants can, too. A paper published in the journal Trends in Plant Science details how plants are rapidly adapting to the effects of climate change, and how they are passing down these adaptations to their offspring(后代).
Plants are facing more environmental stresses than ever. For example, climate change is making winters shorter in many locations, and plants are responding. “Many plants require a minimum period of cold in order to set up their environmental clock to define their flowering time,” says Martinelli, a plant geneticist at the University of Florence. “As cold seasons shorten, plants have adapted to require shorter periods of cold to delay flowering. These mechanisms allow plants to avoid flowering in periods when they have fewer opportunities to reproduce.”
Because plants don’t have neural(神经的) networks, their memory is based entirely on cellular(细胞的),molecular(分子的),and biochemical networks. These networks make up what the researchers call somatic memory(体细胞记忆). “It allows plants to recognize the occurrence of a previous environmental condition and to react accordingly,” says Martinelli.
These somatic memories can then be passed to the plants’ offspring via epigenetics(表现遗传). “Several examples demonstrate the existence of molecular mechanisms modulating plant memory to environmental stresses and affecting the adaptation of offspring to these stresses,” says Martinelli.
Going forward, Martinelli hopes to understand even more about the genes that are being passed down. “We are particularly interested in decoding the epigenetic alphabet without changes in DNA sequence(序列),”he says. “This is especially important when we consider the rapid climate change, we observe today that every living organism, including plants, needs to quickly adapt to survive.”
1. What adaptations have plants made to shortened cold seasons?| A．They have shortened their flowering time. |
| B．They have got more chances to reproduce. |
| C．They have avoided flowering in cold seasons. |
| D．They have adjusted their environmental clock. |
| A．It is entirely based on neural networks. |
| B．It can help the plants’ offspring to survive. |
| C．It can help relieve environmental stresses. |
| D．It disturbs the plants’ biochemical networks. |
| A．Adjusting. | B．Treasuring. |
| C．Recording. | D．Sharing. |
| A．Plants are smart about flowering time |
| B．Plants can also adapt to climate change |
| C．Environmental stresses challenge plants |
| D．Mysteries of plant genes are to be unfolded |
3 . High on the top of California's White Mountains, the hard conditions make it difficult for life to take root. But for a certain type of tree — and for those who have travelled here to study it — this place is a perfect place.
These bristlecone pines are the oldest individual trees in the world. Researchers like Andy Bunn have come to learn from the ancients. "It's remarkable to sit here and have your hand on one of these trees and know that it was growing when the Pyramids were built." Bunn added.
"By studying samples (样本) from the trunks, it's possible to discover their hidden history. Each annual tree ring is like a time capsule of the environment for that year from which it was formed," said Matt Salzer, a scientist at the University of Arizona's Laboratory of Tree Ring Research. "And it contains many different types of information — chemical information, the information on growth, and climate information."
"If you're trying to look at people in the past through time, tree rings give you a way to do it in a way that makes sense in a human life," said University of Arizona Professor Charlotte Pearson. She first became fascinated with the bristlecones after reading about an ancient volcanic eruption on the Greek island of Santorini. "It blew my mind that trees on the other side of the world could possibly be used to date this thing within a single year," she said excitedly.
The oldest known living bristlecone is estimated to be over 4, 800 years old. For Bunn, the climate record written in the rings offers guidance for how we might think about what's happening in the present as we plan for the future. "What we're seeing increasingly is that a lot of the climate events that we are experiencing and living through right now have no example in the paleoclimate (古气候) record," he said. “So, we really are moving into unknown field."
1. Why does Bunn mention the Pyramids in Paragraph 2?| A．To state the trees' age is very old. | B．To prove his discovery is important. |
| C．To attract readers' attention. | D．To stress the hard living condition of the trees. |
| A．The result of the research. | B．The process of the research. |
| C．The method of the research. | D．The significance of the research. |
| A．It confused me. | B．It surprised me. |
| C．It defeated me. | D．It disappointed me. |
| A．Paleoclimate record is hard to find. |
| B．There are lots of unknown things about pines. |
| C．Studying the tree rings is important for climate research. |
| D．There were frequent occurrences of the extreme climate events. |
