听力文摘：如何挑选美味番茄

Most of us have had the same experience.

大多数人都有过这样的经历，

We see a big, red tomato in the grocery store, take it home for our salad, and find out that it tastes like cardboard.

从商店里挑选出又大又红的番茄回去做沙拉，然后一尝，味同嚼蜡。

You might think that the tomato is sub-par because it's been picked before it ripened², or shipped across the country.

你可能认为买回的番茄味道不好是因为它没有成熟就被摘下，或者是运输过久的原因。

Those things can be true, but scientists have found another reason why modern tomatoes have little or no taste.

这的确是一部分原因，然而科学家们发现现今的番茄不好吃还有其它原因，

It's in their genes³.

那就是它们的基因问题。

The problem began with old fashioned or heirloom tomatoes.

这个问题要追溯到从前的天然番茄，

They didn't ripen¹ consistently.

它们并不总能完全长熟，

Someareas would be red, while other areas, usually near the stem, would be white or green.

番茄的有些部分是红的，而其它地方，尤其是靠近茎蒂的地方，往往是白色或绿色的。

About seventy years ago, tomato breeders accidentally discovered a variety that turned red uniformly.

大约70年以前，番茄种植者们偶然间发现一种全红的番茄品种，

Consumers liked the way the tomatoes looked, and companies that made ketchup⁴ and tomato sauce could make better looking products.

不仅消费者们喜欢这种模样的番茄，番茄酱制造公司也能生产出卖相更好的产品，

The trouble was, red did not equal tasty.

然而问题也出现了，看起来好看并不代表它的口感好。

While experimenting with weed genes that turned tomatoes dark green, geneticists accidentally discovered one of the reasons why today's tomatoes lack taste.

基因学家在对使番茄呈墨绿色的基因进行实验的过程中，意外发现了现今西红柿乏味的另外一大原因。

Modern tomatoes are light green before they turn uniformly red.

现在的西红柿在全部变红之前是呈浅绿色的，

Surprisingly, the mutation⁵ that gives tomatoes uniform red color actually disables some of the ripening⁶ genes.

令人惊奇的是，让番茄变红的变异却恰恰抑制了成熟基因的作用。

Those genes allow the fruit to make its own sugar which makes the tomato sweeter.

而成熟基因可以使水果产生糖分，从而使番茄变甜，

The genes also increase the amount of carotenoid pigments,which give tomatoes the red color.

同时产生更多的类胡萝卜素，使番茄变红。

When researchers turned the ripening genes back on, their experimental tomatoes had twenty percent more sugar and up to thirty percent more carotenoids.

当研究者们尝试着将成熟基因恢复到原有数量后，他们的实验番茄中所含的糖分增加了20%，类胡萝卜素提高了30%。

Unfortunately, regulations prohibited researchers from tasting their experimental fruits, but youcan try eating heirloom tomatoes.

遗憾的是，由于法规的原因，研究者们无法品尝自己的实验番茄，不过你们可以试着尝尝那些纯天然的番茄。

They aren't as pretty looking, but are tastier.

它们不中看，但是很好吃。

1 ripen   

vt.使成熟；vi.成熟

参考例句：

• I'm waiting for the apples to ripen.我正在等待苹果成熟。
• You can ripen the tomatoes on a sunny windowsill.把西红柿放在有阳光的窗台上可以让它们成熟。

2 ripened   

v.成熟，使熟( ripen的过去式和过去分词 )

参考例句：

• They're collecting the ripened reddish berries. 他们正采集熟了的淡红草莓。 来自《简明英汉词典》
• The branches bent low with ripened fruits. 成熟的果实压弯了树枝。 来自《现代汉英综合大词典》

3 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

4 ketchup   

n.蕃茄酱，蕃茄沙司

参考例句：

• There's a spot of ketchup on the tablecloth.桌布上有一点番茄酱的渍斑。
• Could I have some ketchup and napkins,please?请给我一些番茄酱和纸手巾？

5 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

6 ripening   

v.成熟，使熟( ripen的现在分词 )；熟化；熟成

参考例句：

• The corn is blossoming [ripening]. 玉米正在开花[成熟]。 来自《现代汉英综合大词典》
• When the summer crop is ripening, the autumn crop has to be sowed. 夏季作物成熟时，就得播种秋季作物。 来自《简明英汉词典》