食虫植物——捕蝇草

食虫植物——捕蝇草

奇妙的大自然充满了许多奇妙有趣的现象，公认“吃斋念佛”的植物竟然也有“大开杀戒”者，是谁呢？一起来看看吧！

From ucalgary.ca

译/赵娜

The Venus Flytrap is the best- known of the carnivorous1) plants. It grows in a circular2) cluster3) which is about 15cm across when fully developed. Each leaf in the cluster can grow up to 7 or 8cm in length. At the end of each leaf is a deadly trap for insects!

The trap is green on the outside and a bright red color inside with a sweet-tasting liquid which attracts insects. Two wing-like lobes4) create the shape of the trap. The lobes are joined together at one end and open at the other with stiff, long bristles5) along the outer edge. Inside each lobe there are 3 or 4 short trigger6) hairs. These hairs activate7) the trap to snap shut. The trap does not close every time a trigger hair is touched, because a lot of energy would be used up this way. A trigger hair must be touched more than once or two trigger hairs must be touched at the same time. This is how the trap knows to snap8) on a moving insect and not on a raindrop which only touches a trigger hair once.

When the insect touches these hairs it sends an electric impulse9) throughout the leaf. This electric impulse causes the leafs cells to expand like balloons and this sudden expansion forces the trap to close. If the trap closes on a piece of grass, it later opens in one day because the trap can not digest10) the grass.

When the trap closes on an insect it releases digestive juices. The digestive juices flow out of the leaf and dissolve11) the insects body into smaller pieces. The lobes of the leaf stay closed from 8 to 10 days. The digested insect pieces are dissolved into a liquid soup and absorbed by the leaf as nutrients12). After that, the trap opens with only an insect skeleton remaining and the wind will blow it away. The Venus Flytrap is again ready for another insect meal.

Almost any insect can be a meal for the Venus Flytrap, such as ants, butterflies, bees and moths. Large insects like grasshoppers13) may be strong enough to force their way out of the trap. But if not, the trap may have trouble closing because the insect is too big.

The Venus Flytrap grows taller in the spring, than after any meal. A 30cm-long stem14) bearing white flowers grows straight up towards the sky during the spring time. The white flowers have seeds which the wind scatters15) in different areas and then new Venus Flytrap plants grow.

捕蝇草是最有名的一种食肉类植物。它外形呈圆形簇状，成熟植株直径可达15厘米长。簇上的每片叶子都能长到7～8厘米。每片叶子末端是捕获昆虫的致命陷阱！

陷阱外部呈绿色，里面却是鲜红色，还分泌一种甜丝丝的液体吸引昆虫。两个翼状的圆裂片构成陷阱。裂片的一端连在一起，另一端张开，其外沿长有硬硬的长毛。每个圆裂片内都有3到4根触发陷阱的短毛。这些短毛会触发陷阱猛然关闭。并非短毛每次被触动时，陷阱都关闭，因为这样会消耗很多能量。短毛必须受到一次以上的碰触，或者有两根短毛同时受到碰触时，陷阱才会关闭。这就是陷阱如何知道困住的是一只移动的昆虫而非雨滴的原因，因为雨滴只会碰触一次短毛。

当昆虫接触到这些短毛时，它们就向整个叶子发出一种电脉冲。这种电脉冲会使叶子的细胞像气球一样膨胀，而这种突然的膨胀会迫使陷阱关闭。如果陷阱关进的是一片草叶，那么一天后，它就会打开，因为陷阱无法消化草叶。

如果陷阱里掉进一只昆虫，它就会分泌出一种消化液。这种消化液从叶片中流出来，将昆虫的躯体分解成小块。叶子的裂片会持续关闭8～10天。被分解的昆虫躯体碎片在被溶解成一种汤状物后，会被叶子作为营养物质吸收。之后陷阱打开，只留下一副昆虫的骨架在里边，而风会将骨架吹走。捕蝇草又做好了吃下一顿昆虫大餐的准备。

几乎任何昆虫都可以是捕蝇草的食物，比如蚂蚁、蝴蝶、蜜蜂和蛾子。像蚱蜢之类的大型昆虫或许有力气挣扎着逃出陷阱，但假使没逃脱，陷阱也可能很难关上，因为它们的个头实在是太大了。

捕蝇草在春季长得较高，比它任何一次进餐后都要高。春天的时候，捕蝇草长约30厘米的茎上会长出直面天空的白花。白花里藏有种子，它们会随风传播到不同地方，并在那里长出新的捕蝇草。

Vocabulary

1.carnivorous [kB:5nIvErEs] adj. 食肉类的

2.circular [5sE:kjulE] adj. 圆形的

3.cluster [5klQstE] n. 一束；一簇

4.lobe [lEub] n. [植]圆裂片

5.bristle [5brIsl] n. 短而硬的毛

6.trigger [5trI^E] n. 触发器

7.activate [5AktIveIt] vt. 刺激，使活动

8.snap [snAp] v. 猛地咬住

9.electric impulse：电脉冲

10.digest [daI5dVest] vi. 消化

11.dissolve [dI5zClv] v. 溶解，解散

12.nutrient [5nju:trIEnt] n. 营养物

[5^rB:7shRpE(r)] n. 蚱蜢

14.stem [stem] n. 茎，干

15.scatter [5skAtE] v. 分散，撒开

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