Green House in the Sky

Outer space offers plant breeders some curious advantages.

外太空給植物育種家?guī)砩衿婧锰帯?/p>

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.

種在太空軌道上的植物失去了舒適且定向的地球引力牽引，通常很難區(qū)分上下。這使得它們難以將水和養(yǎng)分輸送到身體各處。它們從空氣中汲取二氧化碳以供光合作用的能力也遭到破壞。這些困難引發(fā)的應(yīng)激反應(yīng)似乎提升了由一定量輻射誘發(fā)的基因突變水平，而太空中最不缺的就是以宇宙射線和太陽流出物形式存在的輻射。而基因突變則是植物育種家的命脈。

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，育種家通過把植物和種子暴露在放射性同位素、X 射線等環(huán)境下誘導(dǎo)它們變異，但這類突變大多有害。不過，也有一些中了頭彩，變得耐干旱、抗枯萎病、莖短，深受農(nóng)民喜愛；變得味道更甜、顏色更亮麗、果皮更薄，廣受消費者歡迎。通過選育從植物祖先中摘出突變，并將其作為栽培品種，這種突變利潤豐厚。因此，誘導(dǎo)基因突變是一門重要的生意。

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 位于阿布扎比的星際綠洲實驗室公司，2021年從一家名為Nanoracks 的得州企業(yè)中分離出來，他們認(rèn)為這項業(yè)務(wù)前景會更好。正如公司名字所示，他們計劃用宇宙中的自然輻射完成這項工作。按照該公司研究人員的打算，今年晚些時候，種子將搭載航天器進(jìn)入國際空間站。到達(dá)之后，這些種子將由站內(nèi)宇航員培育，進(jìn)而生長繁殖。

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 通過這種培育產(chǎn)生的后代種子會返回地球，在星際綠洲實驗室公司的溫室里發(fā)芽成長，然后經(jīng)受干旱、病原體、貧瘠土壤、高溫和蟲害等考驗。研究人員將挑選最能經(jīng)受每種考驗的品種依次培育，希望能有所收獲。

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 通過衛(wèi)星搭載幾包種子升空，在其暴露于宇宙輻射一段時間后返回地球，這種簡化版育種方法已經(jīng)取得了一定的成功。中國稱已經(jīng)進(jìn)行了30 余次這種任務(wù)，至少培育出了200 種改良作物品種。而星際綠洲實驗室的老板艾倫·赫伯特認(rèn)為，他的公司是第一家用這種方法進(jìn)行太空育種并以在太空種植植物為實際宗旨的私人機(jī)構(gòu)。

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，在太空提供的眾多便利條件中，植物學(xué)家感興趣的不僅僅是誘導(dǎo)基因突變，應(yīng)激反應(yīng)本身也能產(chǎn)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 羅伯特·費爾和安娜-麗莎·保羅是位于蓋恩斯維爾的佛羅里達(dá)大學(xué)空間植物實驗室的聯(lián)合負(fù)責(zé)人，該實驗室已經(jīng)在國際空間站上做了實驗，研究擬南芥（一種十字花科植物，相當(dāng)于動物研究中的小白鼠和果蠅）在太空軌道上是如何應(yīng)對自由落體運動狀態(tài)下的艱苦條件的。研究結(jié)果表明，植物會開啟一些通常處于休眠狀態(tài)的基因，同時關(guān)閉其他通常處于活躍狀態(tài)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 尤其如費爾博士、保羅博士和他們的同事發(fā)現(xiàn)的那樣，太空中的標(biāo)本經(jīng)常把資源從諸如加強(qiáng)細(xì)胞壁硬度等活動中轉(zhuǎn)移出來，因為沒有了定向的引力牽引，這些就不那么重要了。相反，為了更好地確定哪邊是“上”，它們變得對光更加敏感。就像保羅博士說的，植物為了應(yīng)對異常的壓力，會“在自己的新陳代謝工具箱里找辦法”，找到它們在地球上不常用的“工具”。而植物育種家通過改善氣體交換、誘導(dǎo)根系更好地生長或縮小莖的尺寸等方式，或許能夠有效利用這些“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，國際空間站不會永遠(yuǎn)存在。Nanoracks 參與了一項旨在取代國際空間站的計劃。正如它在阿布扎比的子公司的名字所示，這是一個“星際實驗室”——預(yù)想的載人空間站，由洛克希德·馬丁公司所率團(tuán)隊設(shè)計。

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 星際實驗室計劃成為一家商業(yè)性企業(yè)，以植物育種作為其收入來源之一。按計劃，它要2027年才進(jìn)入太空軌道，而這類項目在時間安排上怎么看幾乎總是過于樂觀。但如果真的如期開始建設(shè)，那么在主生活空間隔壁可能真的安排一個種植艙的想法會給實驗室增添家的舒適，這個種植艙就類似地球上的溫室。工作人員辛苦一天后，也許能去那里放松放松。 □