Green House in the Sky

Outer space offers plant breeders some curious advantages.

外太空给植物育种家带来神奇好处。

Plants grown in orbit,and thereby deprived of the comforting directional pull of Earth’s gravity,typically struggle to distinguish up from down.This makes it harder for them to carry water and nutrients around themselves.It also fouls up their ability to draw carbon dioxide needed for photosynthesis from the air.The stress caused by all this seems to increase the level of genetic mutation induced by a given amount of radiation—of which there is much in space,in the form of cosmic rays and effluvia from the sun.And mutations are the lifeblood of plant breeders.

种在太空轨道上的植物失去了舒适且定向的地球引力牵引，通常很难区分上下。这使得它们难以将水和养分输送到身体各处。它们从空气中汲取二氧化碳以供光合作用的能力也遭到破坏。这些困难引发的应激反应似乎提升了由一定量辐射诱发的基因突变水平，而太空中最不缺的就是以宇宙射线和太阳流出物形式存在的辐射。而基因突变则是植物育种家的命脉。

2 On Earth,breeders induce them by exposing plants and seeds to radioactive isotopes,x-rays and so on.Most are harmful.But some hit the jackpot,conferring properties like drought resistance,blight resistance or shorter stems,favoured by farmers,and sweeter flavours,brighter colours or thinner peel,favoured by consumers.Plucked from their progenitors by selective breeding and added to cultivars,such mutations are worth millions.Mutagenesis,then,is an important business.

2 在地球上，育种家通过把植物和种子暴露在放射性同位素、X 射线等环境下诱导它们变异，但这类突变大多有害。不过，也有一些中了头彩，变得耐干旱、抗枯萎病、茎短，深受农民喜爱；变得味道更甜、颜色更亮丽、果皮更薄，广受消费者欢迎。通过选育从植物祖先中摘出突变，并将其作为栽培品种，这种突变利润丰厚。因此，诱导基因突变是一门重要的生意。

3 And StarLab Oasis,a firm in Abu Dhabi that was spun out of a Texan enterprise called Nanoracks in 2021,reckons it may be able to perform better.As the firm’s name hints,the plan is to do the job using the natural radiation of space.Its researchers intend to start sending payloadsof seeds to the International Space Station (ISS)later this year.Once there,those seeds will be cultivated by astronauts on board the station and allowed to grow and breed.

3 位于阿布扎比的星际绿洲实验室公司，2021年从一家名为Nanoracks 的得州企业中分离出来，他们认为这项业务前景会更好。正如公司名字所示，他们计划用宇宙中的自然辐射完成这项工作。按照该公司研究人员的打算，今年晚些时候，种子将搭载航天器进入国际空间站。到达之后，这些种子将由站内宇航员培育，进而生长繁殖。

4 Subsequent generations of seeds resulting from this breeding will be returned to Earth and germinated in StarLab Oasis’s greenhouses.They will then be subjected to ills including drought,pathogens,poor soil,excessive heat and voracious insects.Those which best endure these assaults will be bred from in their turn,in the hope that something valuable emerges.

4 通过这种培育产生的后代种子会返回地球，在星际绿洲实验室公司的温室里发芽成长，然后经受干旱、病原体、贫瘠土壤、高温和虫害等考验。研究人员将挑选最能经受每种考验的品种依次培育，希望能有所收获。

5 A cut-down version of this approach,launching packets of seeds on satellites and returning them to Earth after a period of exposure to cosmic radiation,has had some success.China says it has conducted more than 30 such missions,and that these have yielded at least 200 improved crop varieties.StarLab Oasis’s boss,Allen Herbert,believes,however,that his firm is the first private organisation set up to take this route and,in particular,actually to raise plants in space for the purpose.

5 通过卫星搭载几包种子升空，在其暴露于宇宙辐射一段时间后返回地球，这种简化版育种方法已经取得了一定的成功。中国称已经进行了30 余次这种任务，至少培育出了200 种改良作物品种。而星际绿洲实验室的老板艾伦·赫伯特认为，他的公司是第一家用这种方法进行太空育种并以在太空种植植物为实际宗旨的私人机构。

6 Mutagenesis is not,moreover,the only facility offered by space which may be of interest to botanists.The stress responses themselves also yield useful information.

6 此外，在太空提供的众多便利条件中，植物学家感兴趣的不仅仅是诱导基因突变，应激反应本身也能产生有用信息。

7 Robert Ferl and Anna-Lisa Paul are joint heads of the Space Plants Lab at the University of Florida,Gainesville,which already has experiments on board the ISS.These are studying how,a species of cress that is botany’s equivalent of animal scientists’ mice and fruit flies,responds to the rigours of orbital free fall.The answer is that the plants switch on some genes which would normally remain dormant,while switching off others that would normally be active.

7 罗伯特·费尔和安娜-丽莎·保罗是位于盖恩斯维尔的佛罗里达大学空间植物实验室的联合负责人，该实验室已经在国际空间站上做了实验，研究拟南芥（一种十字花科植物，相当于动物研究中的小白鼠和果蝇）在太空轨道上是如何应对自由落体运动状态下的艰苦条件的。研究结果表明，植物会开启一些通常处于休眠状态的基因，同时关闭其他通常处于活跃状态的基因。

8 In particular,as Dr Ferl,Dr Paul and their colleagues have found,spacefaring specimens frequently divert resources away from tasks,such as strengthening the rigidity of cell walls,which are less pertinent when the directional pull of gravity is missing.Conversely,in a bid better to determine which way is “up”,they become more sensitive to light.As Dr Paul puts it,plants “reach into their metabolic toolbox” to cope with the unusual stress.In doing so they pull out tools that may be used rarely on Earth,but which plant breeders might be able to deploy in advantageous ways by improving gas exchange,inducing better root growth or reducing stem size.

8 尤其如费尔博士、保罗博士和他们的同事发现的那样，太空中的标本经常把资源从诸如加强细胞壁硬度等活动中转移出来，因为没有了定向的引力牵引，这些就不那么重要了。相反，为了更好地确定哪边是“上”，它们变得对光更加敏感。就像保罗博士说的，植物为了应对异常的压力，会“在自己的新陈代谢工具箱里找办法”，找到它们在地球上不常用的“工具”。而植物育种家通过改善气体交换、诱导根系更好地生长或缩小茎的尺寸等方式，或许能够有效利用这些“工具”。

9 The ISS will not,though,last for ever.And Nanoracks is involved in a proposal to replace it.As the name of its progeny in Abu Dhabi also suggests,this is Starlab,a putativecrewed space station planned by a group led by Lockheed Martin.

9 然而，国际空间站不会永远存在。Nanoracks 参与了一项旨在取代国际空间站的计划。正如它在阿布扎比的子公司的名字所示，这是一个“星际实验室”——预想的载人空间站，由洛克希德·马丁公司所率团队设计。

10 Starlab is intended to be a commercial enterprise,with plant breeding as one of its sources of revenue.It is not planned to go into orbit until 2027,and the schedule for such projects is in any case almost always optimistic.But if it does get off the ground,the idea that one of its modules might,in effect,be a plant-growing annexto the main living space,akin to a conservatory on Earth,has a pleasing domesticity to it.Perhaps the crew will relax there after a hard day’s work.■

10 星际实验室计划成为一家商业性企业，以植物育种作为其收入来源之一。按计划，它要2027年才进入太空轨道，而这类项目在时间安排上怎么看几乎总是过于乐观。但如果真的如期开始建设，那么在主生活空间隔壁可能真的安排一个种植舱的想法会给实验室增添家的舒适，这个种植舱就类似地球上的温室。工作人员辛苦一天后，也许能去那里放松放松。 □