（双语文稿）开花植物知多少？

Flowering plants are very important to Earth's ecosystems. They are necessary for life on Earth.
开花植物对地球的生态系统非常重要，它们是地球上生命所必需的。
Flowering plants are also called angiosperms. They are the largest and most diverse plant group. Flowering plants include corn, wheat, rice and potatoes to maple, oak, apple and cherry trees.
开花植物也叫被子植物。它们是最大和最多样化的植物群。开花植物包括玉米、小麦、水稻、土豆，也包括枫树、橡树、苹果树和樱桃树。

New research based on genome data for 9,506 species of flowering plants provides the deepest understanding yet of their evolutionary history. The research explains how angiosperms appeared and became widespread during the age of dinosaurs. It also offers explanations for how such plants have changed over time.
基于9506种开花植物基因组数据的最新研究提供了迄今为止对其进化史的最深入理解。这项研究解释了被子植物是如何在恐龙时代出现并广泛传播的，它还解释了这些植物是如何随着时间而变化的。
The team of scientists created a new tree of life for angiosperms. A tree of life is a tool that biologists use to see the evolutionary relationships among plants, animals and other life forms. Their new tree of life covers 15 times more kinds of flowering plants than the closest comparable study.
这组科学家为被子植物创造了一个新的生命树。生命树是生物学家用来观察植物、动物和其它生命形式之间进化关系的工具。他们的新生命树涵盖的开花植物种类比最接近的同类研究多15倍。
"It is a massive leap forward in our understanding of plant evolution," said William Baker. He is a plant expert with the Royal Botanic Gardens, Kew, in London. He is senior writer of the research study, which appeared last week in the publication Nature.
“这是我们对植物进化理解的巨大飞跃，”威廉•贝克说。他是伦敦邱园皇家植物园的植物专家，也是上周发表在《自然》杂志上的这项研究的资深作者。
Angiosperms are plants that produce flowers and produce their seeds in fruits. They are made up of about 330,000 species. About 80 percent of the world's plants are angiosperms. They include, among others, all the major food crops, grasses, most large-leaved trees and most aquatic plants.
被子植物是一种开花并在果实中产生种子的植物。它们由大约33万个物种组成。世界上大约80%的植物是被子植物。它们包括所有主要的粮食作物、草、大多数大叶树和大多数水生植物等。
Their closest relatives are the gymnosperms, a group that came before them on Earth.
它们最近的亲戚是裸子植物，在它们之前就出现在地球上。
The study identified two periods of diversification among angiosperms. The first one occurred around 150 million to 140 million years ago during the Mesozoic era. At that time, 80 percent of major angiosperm species arose. The next one happened about 100 million years later during the Cenozoic era, after the extinction of the dinosaurs and the rise of mammals. That period saw decreasing world temperatures.
该研究确定了被子植物的两个多样化时期。第一次发生在1.5亿到1.4亿年前的中生代。那时，80%的主要被子植物物种出现了。第二次发生在大约1亿年后的新生代，在恐龙灭绝和哺乳动物兴起之后。那一时期全球气温下降。
Baker said angiosperms are more successful at reproducing than gymnosperms.
贝克说被子植物在繁殖方面比裸子植物更成功。
Gymnosperms and angiosperms both have seeds. But the flowering plants have enclosed seeds that protect them from dehydration. This permits them to survive in a wider range of environments, from deserts to Antarctica.
裸子植物和被子植物都有种子，但开花植物有封闭的种子，保护它们免于脱水。这使它们能够在从沙漠到南极洲的更广泛环境中生存。
They also evolved the flower, a structure that permitted them to form relationships with animal pollinators, especially insects. Gymnosperms usually depend upon the wind for pollination. Angiosperms evolved a high diversity of fruit types, permitting effective seed spread.
他们还进化出了花，这种结构使他们能够与动物传粉者，尤其是昆虫建立关系。裸子植物通常依靠风来授粉。被子植物进化出了高度多样化的果实类型，使种子能够有效地传播。
Flowering plants provide most of the calories that humans eat, from grains to fruits to vegetables.
从谷物到水果再到蔬菜，开花植物提供了人类摄入的大部分卡路里。
"They are sources of many of our medicines and hold potential solutions to global challenges, such as climate change, biodiversity loss, human health, food security and renewable energy," Baker said.
贝克说:“它们是我们许多药物的来源，并拥有应对气候变化、生物多样性丧失、人类健康、粮食安全和可再生能源等全球挑战的潜在解决方案。”
The study could help scientists better understand disease and pest resistance in angiosperms. And the research could help find new medicines.
这项研究可以帮助科学家更好地了解被子植物的疾病和害虫抗性，也有助于发现新药。
Alexandre Zuntini is Royal Botanical Gardens botanist and a lead writer of the study. He said that some plant "lineages may hold chemical compounds or even genes that can be useful for survival of our species."
亚历山大•祖蒂尼是皇家植物园的植物学家，也是该研究的主要作者。他说，一些植物的“谱系可能含有对我们物种的生存有用的化合物甚至基因。
I'm Dan Novak.