Science and technology
科学技术
Robot plants Putting down roots
植物机器人 落地生根
A robotic model of what plants get up to under the surface
模仿植物根部工作的机器人模型
PEOPLE often forget, when looking at a garden, meadow or forest, that half of almost every plant in it is underground.
在人们望着花园，草原或者森林时，常常会忽略一点几乎所有生长于斯的植物的身体中有一半都长于地下。
Stems, leaves and flowers are pretty.
茎干，叶片和花朵都很美丽，

But plants' roots, though ugly and invisible, are probably their smartest parts.
但是既不露面又不好看的根部却很可能是植物身上最有智慧的部分。
They collect information on the physical properties and chemical composition of the soil they are growing through
它们在土壤中成长，并搜集土壤的物理性质及化学组分的信息，
and use that to decide in which direction to continue growing.
然后决定新的生长方向。
They can pierce the ground employing only a fraction of the energy that worms, moles or man-made drills consume.
它们只耗用一点能量便能在土地中钻行，仅相当于蠕虫，鼹鼠或人造钻机所耗能量的一小部分。
Plant roots are thus the most efficient systems known for underground exploration.
因此植物的根可说是地下勘探中最有效率的系统。
But not, perhaps, for much longer.
但或许这个名头保持不了多久了。
Researchers working on the Plantoid project, led by Barbara Mazzolai of the Italian Institute of Technology, in Pontedera,
参与植物机器人计划的研究人员想要开发出至少与真正的根不相上下的机器根，
hope to develop robot plant roots that will be as good as the real things, if not better.
该计划的负责人是意大利理工学院的芭芭拉·玛佐莱。
In doing so, they seek to understand how real roots work and also to devise machines that might monitor soil pollution, prospect for minerals and look for water.
在开发过程中，研究人员不仅要设法了解真正的根是如何工作的，还力图设计处可以监测土壤污染，勘探矿物及寻找水源的设备。
The plantoid, of which Dr Mazzolai plans to demonstrate a partial prototype on July 29th at a conference at the Natural History Museum in London, will have a central stem containing a reservoir of liquid plastic of a sort that can be frozen by ultraviolet light.
玛佐莱博士计划在7月29日于伦敦自然历史博物馆召开的会议上演示植物机器人非完全体原型，该机器人有一条主干，里面有一个装有液态塑料的储液囊，这种液态塑料受到紫外线照射时将会凝固。
Half a dozen cylindrical roots will branch off this stem, and the plastic will flow through these from the reservoir to the tip.
主干上分出六条柱状根，液态塑料从储液囊中流过这些柱状根，直至其顶端。
As in a real root, the tip will be a specialised structure.
和真的根一样，柱状根的顶端是一种特别的结构。
Instead of being a cone containing a meristem it will be a cone containing a motor, a light-emitting diode and a battery.
两者都是圆锥结构，不过前者里面有一个分生组织，而后者里面是电机，发光二极管和电池各一个。
The motor will suck liquid plastic through the root and push it to the periphery of the cone.
电机将液态塑料吸入根部再将之推至圆锥体表层。
Once there, the liquid will be solidified by ultraviolet rays from the diode, extending the cylinder and forcing the cone farther into the soil.
液态塑料到达该位置后马上会因二极管发出的紫外线照射凝固，使圆柱体增长，促使锥体在土壤中更进一步。
As in real life, the gentle but relentless pressure of the root's growth should be enough to make it advance through the soil, fractions of a millimetre at a time.
对真正的根来说，由根部生长带来的和缓但从不间断的压力足以使之在土壤中前进，一次能前进几丝米。
The researchers expect their prototypical robotic roots to be able to penetrate up to a metre of real soil.
研究人员希望自己的机器根原型最多可穿透1米深的真正土壤。
The direction of growth is controlled by a material known as an electro-rheological fluid, which is also stored in the cone.
生长方向是由一种叫做电力流变液的物质控制的，该物质也储存在圆锥中。
Such fluids become more viscous when an electric current is applied to them, and changing the viscosity on one side of a root but not the other,
当有电流通过时，该液体会变得更加粘稠，通过电池提供的电流改变根部一侧的粘稠度，而另一侧不变，
using current from the battery, causes the direction of growth to vary.
从而改变生长的方向。
One thing missing from the prototypes is a control system that responds to the root's environment.
该原型中缺少一套可以对根的外部环境产生响应的控制系统。
The plan is to fit the next generation of cones with sensors that look for whatever the root is designed to find, and control its growth accordingly.
计划是在下一代的圆锥体中装上传感器，用以根据机器根的设计目的进行勘探，并相应地控制其生长方向。
Writing the software for these sensors may illuminate how real roots work.
要为这些传感器编写软件，先得弄明白真正的根的工作原理。
According to Dr Mazzolai, the first person to ask about that was Charles Darwin.
据玛佐莱博士称，第一个论及此事的人是查尔斯·达尔文。
He could not come up with an answer, and 130 years later no one else has either.
达尔文没有找到答案，130年以后也还没人能找到这个答案。