View source for Biology:Astrobotany

{{short description|Study of plants grown in spacecraft}}
[[File:Space zucchini.jpg|thumb|A zucchini being grown on the International Space Station]]'''Astrobotany''' is an applied sub-discipline of botany that is the study of plants in space environments. It is a branch of astrobiology and botany.

Astrobotany concerns both the study of extraterrestrial vegetation discovery, as well as research into the growth of terrestrial vegetation in [[Astronomy:Outer space|outer space]] by humans.<ref name=":3">{{Citation |last=Briot |first=Danielle |title=The Creator of Astrobotany, Gavriil Adrianovich Tikhov |date=2013 |url=https://doi.org/10.1007/978-3-642-35983-5_8 |work=Astrobiology, History, and Society: Life Beyond Earth and the Impact of Discovery |series=Advances in Astrobiology and Biogeophysics |pages=175–185 |editor-last=Vakoch |editor-first=Douglas A. |access-date=2023-03-15 |place=Berlin, Heidelberg |publisher=Springer |language=en |doi=10.1007/978-3-642-35983-5_8 |bibcode=2013ahs..book..175B |isbn=978-3-642-35983-5}}</ref>

It has been a subject of study that plants may be grown in [[Astronomy:Outer space|outer space]] typically in a weightless but pressurized controlled environment in specific space gardens.<ref name="Mizuna">{{cite web|url = https://www.nasa.gov/missions/station/ways-the-international-space-station-helps-us-study-plant-growth-in-space/|date = 7 April 2021|title = Ways the International Space Station Helps Us Study Plant Growth in Space |work = NASA|first = Ana|last = Guzman}}</ref> In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere.<ref>{{cite web|url = http://www.nasa.gov/audience/foreducators/spacelife/topics/plants/index.html|website = NASA |title = Plants in Space|archive-url =https://web.archive.org/web/20230719095347/https://www.nasa.gov/audience/foreducators/spacelife/topics/plants/index.html |archive-date = 19 July 2023|date = 27 July 2016}}</ref> Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity.<ref name="zvet" /> Growing plants in space may provide a psychological benefit to human spaceflight crews.<ref name="zvet" />

The first challenge in growing plants in space is how to get plants to grow without gravity.<ref name="root">[http://www.nasa.gov/mission_pages/station/research/news/tages.html NASA – Getting to The Root of Plant Growth Aboard The Space Station]</ref> This runs into difficulties regarding the effects of gravity on root development, providing appropriate types of lighting, and other challenges. In particular, the nutrient supply to root as well as the nutrient biogeochemical cycles, and the microbiological interactions in soil-based substrates are particularly complex, but have been shown to make possible space farming in hypo- and micro-gravity.<ref>{{Cite Q|Q55950873|author1=Maggi, Federico|author2=Pallud, Céline}}</ref><ref>{{Cite journal | doi=10.1016/j.pss.2010.09.025| title=Space agriculture in micro- and hypo-gravity: A comparative study of soil hydraulics and biogeochemistry in a cropping unit on Earth, Mars, the Moon and the space station| journal=Planetary and Space Science| volume=58| issue=14–15| pages=1996–2007| year=2010| last1=Maggi| first1=Federico| last2=Pallud| first2=Céline| bibcode=2010P&SS...58.1996M}}</ref>

NASA plans to grow plants in space to help feed astronauts, and to provide psychological benefits for long-term space flight.<ref>{{Cite web |title=Crew Members Sample Leafy Greens Grown on Space Station |url=http://www.nasa.gov/mission_pages/station/research/news/meals_ready_to_eat |website=NASA |access-date=23 January 2016 |first=Kristine |last=Rainey|date=7 August 2015 }}</ref>

== Extraterrestrial vegetation ==
[[File:Exoplanet Surface Water Life Exomoon.png|thumb|Astrobotany has been the investigation of the idea that alien plant life may exist on other planets. Here an artist has envisioned alien plants on shores of an exomoon exosea.<ref>{{cite journal|author=F. J. Ballesteros|author2=A. Fernandez-Soto|author3=V. J. Martinez|title=Title: Diving into Exoplanets: Are Water Seas the Most Common?|date=2019|doi=10.1089/ast.2017.1720|journal=Astrobiology|pmid=30789285|volume=19|issue=5|pages=642–654|hdl=10261/213115|s2cid=73498809 |hdl-access=free}}</ref>]]

=== Vegetation red edge ===
The vegetation red edge (VRE) is a [[Astronomy:Biosignature|biosignature]] of near-infrared wavelengths that is observable through telescopic observation of Earth, and has increased in strength as evolution has made vegetative life more complex.<ref name=":4">{{Cite journal |last1=O'Malley-James |first1=Jack T. |last2=Kaltenegger |first2=Lisa |date=2018-09-01 |title=The Vegetation Red Edge Biosignature Through Time on Earth and Exoplanets |url=https://www.liebertpub.com/doi/10.1089/ast.2017.1798 |journal=Astrobiology |volume=18 |issue=9 |pages=1123–1136 |doi=10.1089/ast.2017.1798 |pmid=30204495 |arxiv=1809.08832 |bibcode=2018AsBio..18.1123O |s2cid=52189956 |issn=1531-1074}}</ref> On Earth, this phenomenon has been detected through analysis of [[Astronomy:Planetshine|planetshine]] on the Moon, which can show a reflection spectrum that spikes at 700&nbsp;nm.<ref name=":4" /> In an article published in ''Nature'' in 1990, [[Biography:Carl Sagan|Sagan]] et al. described [[Astronomy:Galileo project|''Galileo's'']] detection of infrared light radiating from Earth as evidence of "widespread biological activity" <ref>{{Cite journal |last1=Sagan |first1=Carl |last2=Thompson |first2=W. Reid |last3=Carlson |first3=Robert |last4=Gurnett |first4=Donald |last5=Hord |first5=Charles |date=October 1993 |title=A search for life on Earth from the Galileo spacecraft |url=https://www.nature.com/articles/365715a0 |journal=Nature |language=en |volume=365 |issue=6448 |pages=715–721 |doi=10.1038/365715a0 |pmid=11536539 |bibcode=1993Natur.365..715S |s2cid=4269717 |issn=1476-4687}}</ref> on earth, with evidence of photosynthesis a particularly strong factor.

The increase-in-strength of Earth's VRE biosignature has been assessed through modelling of early Earth radiation.<ref name=":4" /> [[Biology:Moss|Moss]]es and [[Biology:Fern|fern]]s, which were dominant on Earth in the [[Earth:Ordovician|Ordovician]] and [[Earth:Carboniferous|Carboniferous]] periods, produce weaker detectable infrared radiation spikes at 700&nbsp;nm than modern Earth vegetation.<ref name=":4" /> Astrobotanists focused on extraterrestrial vegetation have thus theorized that by using these same models, it could be possible to measure whether exoplanets in their respective [[Astronomy:Circumstellar habitable zone|Goldilocks zones]] currently hold vegetation, and by comparing VRE biosignatures to modelled historic Earth radiation, estimate the complexity of this vegetation.<ref name=":5">{{Cite web |last=@NatGeoUK |date=2018-09-27 |title=How Earth's Vegetation Holds Clues to Alien Life on Other Planets |url=https://www.nationalgeographic.co.uk/space/2018/09/how-earths-vegetation-holds-clues-to-alien-life-on-other-planets |access-date=2023-03-15 |website=National Geographic |language=en-gb}}</ref>

There are a number of obstacles to the detection of exoplanetary VREs:

* Galileo's detection of Earth's VRE was facilitated by the satellite's physical proximity to Earth; up until the launch of the [[Astronomy:James Webb Space Telescope|James Webb Space Telescope]] in December 2021, telescopic technology was not yet advanced enough to detect the telltale infrared radiation spikes of VRE in distant exoplanet systems.
* Heavy cloud cover has been observed to be detrimental to the detection of VRE, as more cloud cover increases overall [[Earth:Albedo|albedo]], which makes it more difficult to detect radiation wavelength variety.<ref name=":6">{{Cite journal |last1=Seager |first1=S. |last2=Turner |first2=E.l. |last3=Schafer |first3=J. |last4=Ford |first4=E.b. |date=1 June 2005 |title=Vegetation's Red Edge: A Possible Spectroscopic Biosignature of Extraterrestrial Plants |journal=Astrobiology |volume=5 |issue=3 |pages=372–390 |arxiv=astro-ph/0503302 |bibcode=2005AsBio...5..372S |doi=10.1089/ast.2005.5.372 |issn=1531-1074 |pmid=15941381 |s2cid=11589855}}</ref> In addition, clouds are detrimental to surface observation, leading to an estimation of ≥20% vegetation cover AND cloud-free surface present as the minimum for detectable exoplanetary VRE visible from telescopes on Earth.<ref name=":7">{{Cite journal |last=Kiang |first=Nancy Y. |date=April 2008 |title=The Color of Plants on Other Worlds |url=https://www.scientificamerican.com/article/the-color-of-plants-on-other-worlds |journal=Scientific American |volume=298 |issue=4 |pages=48–55 |doi=10.1038/scientificamerican0408-48 |pmid=18380141 |bibcode=2008SciAm.298d..48K |issn=0036-8733}}</ref>
* Certain minerals have been shown to demonstrate similar sharp edge reflective spectra as light-harvesting photosynthetic pigments. This means that mineral origins for VRE-like effects must first be ruled-out before a biological explanation can be confirmed.<ref name=":6" /> This may be difficult to achieve from Earth as minerals in finer regolith particle form demonstrate different reflective characteristics than large crystal forms found on Earth. One suggestion made by [[Biography:Sara Seager|Sara Seager]] et al. is to use atmospheric measurements to determine the level of atmospheric oxygen, which if high would rule out surface abundance of non-oxidised minerals.<ref name=":6" />

=== Vegetation searches ===
Dubbed ‘the creator of astrobotany’,<ref name=":3" /> Gavriil Adrianovich Tikhov coined the term in 1945 to describe the emerging field surrounding the search for extraterrestrial vegetation. Owing to [[Astronomy:Climate of Mars|storms on Mars]] that cause surface darkening visible from Earth, Tikhov's contemporaries often believed in the existence of Martian vegetation comparable to Earth's seasonal vegetation color changes.<ref name=":7" /><ref name=":3" /> Building off of conclusions reached through examining [[Astronomy:Earthlight|earthshine]] on the Moon in 1914, in 1918 and 1921 Tikhov discovered through using telescopic color filters that [[Biology:Chlorophyll|chlorophyll]]s were undetectable on the Martian surface, leading him to hypothesize that the character of Martian vegetation was likely to be blue hued, composed mostly of mosses and lichens.<ref name=":3" /> Tikhov's research into astrobotany would later develop into research into growing plants in space, or demonstrating the possibility of plants to grow in extraterrestrial conditions (especially comparing the climate of Mars and Siberia), but he was the first known astronomer to use color to attempt to measure the level of vegetation on an extraterrestrial satellite.<ref name=":3" />

After Galileo's 1990 fly-by demonstrating the VRE effect on Earth, astrobotanical interest in extraterrestrial vegetation has mainly focused on examining the feasibility of VRE detection,<ref name=":4" /><ref name=":6" /><ref>{{Cite journal |last1=Takizawa |first1=Kenji |last2=Minagawa |first2=Jun |last3=Tamura |first3=Motohide |last4=Kusakabe |first4=Nobuhiko |last5=Narita |first5=Norio |date=2017-08-08 |title=Red-edge position of habitable exoplanets around M-dwarfs |journal=Scientific Reports |language=en |volume=7 |issue=1 |pages=7561 |doi=10.1038/s41598-017-07948-5 |issn=2045-2322 |pmc=5548919 |pmid=28790357|arxiv=1708.03773 |bibcode=2017NatSR...7.7561T }}</ref><ref name=":8">{{Cite web |last=Holt |first=Chris |date=April 22, 2022 |title=How the James Webb Space Telescope will search for extraterrestrial l |url=https://astronomy.com/news/2022/04/how-the-james-webb-space-telescope-will-search-for-extraterrestrial-life |access-date=2023-03-15 |website=Astronomy.com |language=en}}</ref> and a number of projects have been proposed:

* Both the [[Organization:European Space Agency|European Space Agency]] [[Engineering:Darwin (spacecraft)|Darwin]] project and [[Organization:NASA|NASA]] [[Astronomy:Terrestrial Planet Finder|Terrestrial Planet Finder]] were cited<ref name=":9">{{Cite news |last1=Randerson |first1=James |last2=correspondent |first2=Science |date=2007-04-11 |title=Alien 'plants' could be purple or yellow, say Nasa scientists |language=en-GB |work=The Guardian |url=https://www.theguardian.com/science/2007/apr/11/spaceexploration.plants |access-date=2023-03-15 |issn=0261-3077}}</ref> as projects that could have analyzed exoplanetary VRE biosignatures before being cancelled in 2007 and 2011, respectively.
* The [[Organization:European Southern Observatory|ESO]] [[Astronomy:Extremely Large Telescope|Extremely Large Telescope]], set to launch in 2028,<ref>{{Cite web |last= |title=Timeline {{!}} ELT {{!}} ESO |url=https://elt.eso.org/about/timeline/ |access-date=2023-03-15 |website=elt.eso.org |language=en}}</ref> has also been cited<ref name=":5" /><ref>{{Cite web |date=2017-10-23 |title=How Extremely Large Telescopes will reveal exoplanets |url=https://cosmosmagazine.com/space/how-extremely-large-telescopes-will-reveal-exoplanets/ |access-date=2023-03-15 |website=cosmosmagazine.com |language=en-AU}}</ref> as another telescope that will be able to detect exoplanetary VRE biosignatures.
* Future NASA space telescopes, such as the [[Astronomy:Habitable Exoplanet Imaging Mission|Habitable Exoplanet Imaging Mission]], have been planned with the capacity to examine for VRE biosignatures.<ref>{{Cite journal |last1=Mennesson |first1=Bertrand |last2=Gaudi |first2=Scott |last3=Seager |first3=Sara |last4=Cahoy |first4=Kerri |last5=Domagal-Goldman |first5=Shawn |last6=Feinberg |first6=Lee |last7=Guyon |first7=Olivier |last8=Kasdin |first8=Jeremy |last9=Marois |first9=Christian |last10=Mawet |first10=Dimitri |last11=Tamura |first11=Motohide |last12=Mouillet |first12=David |last13=Prusti |first13=Timo |last14=Quirrenbach |first14=Andreas |last15=Robinson |first15=Tyler |date=2016-08-24 |editor-last=MacEwen |editor-first=Howard A. |editor2-last=Fazio |editor2-first=Giovanni G. |editor3-last=Lystrup |editor3-first=Makenzie |editor4-last=Batalha |editor4-first=Natalie |editor5-last=Siegler |editor5-first=Nicholas |editor6-last=Tong |editor6-first=Edward C. |title=The Habitable Exoplanet (HabEx) Imaging Mission: preliminary science drivers and technical requirements |url=http://proceedings.spiedigitallibrary.org/proceeding.aspx?doi=10.1117/12.2240457|journal=Proceedings, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave |series=Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave |volume=9904|location=Edinburgh, United Kingdom |pages=99040L |doi=10.1117/12.2240457|bibcode=2016SPIE.9904E..0LM |hdl=1721.1/116467 |s2cid=1289944 |hdl-access=free }}</ref>

The James Webb Space Telescope has been searching the [[Astronomy:TRAPPIST-1|TRAPPIST-1 exoplanet system]] since 2021 for signs of extraterrestrial vegetation through capturing atmospheric data, including a VRE biosignature, that is made visible when TRAPPIST-1's exoplanets pass across the face of the star. NASA have judged three of TRAPPIST-1's rocky exoplanets ([[Astronomy:TRAPPIST-1e|1e]], [[Astronomy:TRAPPIST-1f|1f]], and [[Astronomy:TRAPPIST-1g|1g]]) as within the habitable zone for liquid water (and other biological matter, such as vegetation).<ref name=":8" /><ref>{{Cite web |title=The TRAPPIST-1 Habitable Zone |url=https://hubblesite.org/contents/media/images/2017/07/3986-Image |access-date=2023-03-15 |website=HubbleSite.org |language=en}}</ref>

=== Character of extraterrestrial vegetation ===
Accurate description of extraterrestrial vegetation character is highly speculative, but follows "solid physics and atmospheric chemistry" principles, according to Professor John Albert Raven from the [[Organization:University of Dundee|University of Dundee]].<ref name=":9" />

One factor determining the character of extraterrestrial vegetation is the star at the centre of the system. The [[Astronomy:Sun|Sun]] is a [[Astronomy:G-type main-sequence star|G-type main-sequence star]], which provides the conditions for chlorophyll [[Earth:Photosynthesis|photosynthesis]], and radiation levels that govern atmospheric conditions such as wind, affecting evolutionary development. TRAPPIST-1 is an ultra-cool [[Astronomy:Red dwarf|red dwarf]] star, providing almost half the energy as the Sun, leading to astrobotanical speculation that vegetation in the TRAPPIST-1 exoplanet system could be much darker, even black to human eyes.<ref name=":7" />

[[Astronomy:F-type main-sequence star|F-type main-sequence star]]s, on the other hand, such as [[Astronomy:Sigma Boötis|sigma Boötis]], have been speculated to encourage the growth of either yellow-tinted,<ref name=":9" /> or blue-tinted <ref name=":7" /><ref>{{Cite web |date=2012-04-01 |title=Life under alien skies |url=https://physicsworld.com/a/life-under-alien-skies/ |access-date=2023-03-15 |website=Physics World |language=en-GB}}</ref> extraterrestrial vegetation within its exoplanet system, in order to reflect back the high levels of blue [[Physics:Photon|photon]]s emitted by stars of its type.

==Growing plants in space==
The study of plant response in space environments is another subject of astrobotany research. In space, plants encounter unique environmental stressors not found on Earth including microgravity, ionizing radiation, and oxidative stress.<ref>http://astrobotany.com/plants-and-spaceflight/ | Challenges of Growing Plants in Space</ref> Experiments have shown that these stressors cause genetic alterations in plant metabolism pathways. Changes in genetic expression have shown that plants respond on a molecular level to a space environment.<ref>{{Cite journal | doi=10.1007/s11431-016-0232-7|title = The impact of space environment on gene expression in Arabidopsis thaliana seedlings| journal=Science China Technological Sciences| volume=60| issue=6| pages=902–910|year = 2017|last1 = Li|first1 = Huasheng| last2=Lu| first2=Jinying| last3=Zhao| first3=Hui| last4=Sun| first4=Qiao| last5=Yu| first5=Futong| last6=Pan| first6=Yi| last7=Chen| first7=Yu| last8=Su| first8=Liang| last9=Liu| first9=Min|bibcode = 2017ScChE..60..902L|s2cid = 125206061}}</ref> Astrobotanical research has been applied to the challenges of creating life support systems both in space and on other planets, primarily Mars.

==History==
Russian scientist [[Biography:Konstantin Tsiolkovsky|Konstantin Tsiolkovsky]] was one of the first people to discuss using photosynthetic life as a resource in space agricultural systems. Speculation about plant cultivation in space has been around since the early 20th century.<ref>https://www.degruyter.com/downloadpdf/j/opag.2017.2.issue-1/opag-2017-0002/opag-2017-0002.pdf  | Agriculture for Space: People and Places Paving the Way</ref> The term ''astrobotany'' was first used in 1945 by Soviet astronomer and astrobiology pioneer Gavriil Adrianovich Tikhov.<ref name=":3" /> Tikhov is considered to be the father of astrobotany. Research in the field has been conducted both with growing Earth plants in space environments and searching for botanical life on other planets.

=== Seeds ===
The first organisms in space were "specially developed strains of seeds" launched to {{convert|134|km|mi|abbr=on}} on 9 July 1946 on a U.S. launched [[Engineering:V-2 rocket|V-2 rocket]]. These samples were not recovered. The first seeds launched into space and successfully recovered were [[Biology:Maize|maize]] seeds launched on 30 July 1946, which were soon followed  by [[Biology:Rye|rye]] and [[Biology:Cotton|cotton]]. These early [[Engineering:Suborbital|suborbital]] biological experiments were handled by [[Organization:Harvard University|Harvard University]] and the Naval Research Laboratory and were concerned with [[Physics:Ionizing radiation|radiation exposure]] on living tissue.<ref name=Beischer1962>{{cite report |author=Beischer, DE |author2=Fregly, AR |title=Animals and man in space. A chronology and annotated bibliography through the year 1960 |publisher=US Naval School of Aviation Medicine |volume=ONR TR ACR-64 |issue=AD0272581 |date=January 1, 1962|url=https://apps.dtic.mil/sti/citations/AD0272581 |access-date=November 5, 2022}}</ref> In 1971, 500 tree seeds (Loblolly pine, [[Biology:Sycamore|Sycamore]], [[Biology:Liquidambar|Sweetgum]], Redwood, and [[Biology:Douglas fir|Douglas fir]]) were flown around the Moon on [[Engineering:Apollo 14|Apollo 14]]. These Moon trees were planted and grown with controls back on Earth where no changes were detected.

=== Plants ===
[[File:ISS-53 Mizuna being cultivated inside the Veggie facility.jpg|thumb|The arugula-like lettuce Mizuna growing for Veg-03]]
In 1982, the crew of the [[Place:Soviet Union|Soviet]] [[Engineering:Salyut 7|Salyut 7]] space station conducted an experiment, prepared by Lithuanian scientists (Alfonsas Merkys and others), and grew some [[Biology:Arabidopsis|Arabidopsis]] using Fiton-3 experimental micro-greenhouse apparatus, thus becoming the first plants to flower and produce seeds in space.<ref>{{cite web |url=http://www.guinnessworldrecords.com/world-records/first-species-of-plant-to-flower-in-space |title=First species of plant to flower in space |access-date=20 January 2016}}</ref><ref>{{cite web |url=http://nasawatch.com/archives/2016/01/no-nasa-these-a.html |title=No NASA, These Are Not The First Plants To Flower in Space |date=16 January 2016 |access-date=20 January 2016}}</ref> A [[Engineering:Skylab|Skylab]] experiment studied the effects of gravity and light on [[Biology:Rice|rice]] plants.<ref name=ed/><ref>[https://history.nasa.gov/SP-401/ch5.htm NASA SP-401 – Chapter 5]</ref> The SVET-2 Space Greenhouse successfully achieved seed to seed plant growth in 1997 aboard space station ''[[Astronomy:Mir|Mir]]''.<ref name=zvet>[http://www.space.bas.bg/astro/Aerosp16/tania1.pdf T.Ivanova, et al. – First Successful Space Seed-to-Seed Plant Growth Experiment in the SVET-2 Space Greenhouse in 1997]</ref> Bion 5 carried ''[[Biology:Daucus carota|Daucus carota]]'' and Bion 7 carried [[Biology:Maize|maize]] (aka corn).

Plant research continued on the [[Astronomy:International Space Station|International Space Station]]. Biomass Production System was used on the ISS [[Astronomy:Expedition 4|Expedition 4]]. The [[Biology:Vegetable Production System|Vegetable Production System]] (Veggie) system was later used aboard ISS.<ref>{{Cite web |url=http://www.nasa.gov/mission_pages/station/research/experiments/Veggie.html |title=NASA – VEGGIE |access-date=9 May 2018 |archive-url=https://web.archive.org/web/20181222054716/https://www.nasa.gov/mission_pages/station/research/experiments/Veggie.html |archive-date=22 December 2018 |url-status=dead }}</ref> Plants tested in Veggie before going into space included lettuce, Swiss chard, radishes, Chinese cabbage and peas.<ref name="nasa.gov">{{Cite web |url=http://www.nasa.gov/mission_pages/station/research/news/veggie.html |title=NASA – Station Investigation to Test Fresh Food Experience}}</ref> Red Romaine lettuce was grown in space on [[Astronomy:Expedition 40|Expedition 40]] which were harvested when mature, frozen and tested back on Earth. [[Astronomy:Expedition 44|Expedition 44]] members became the first American astronauts to eat plants grown in space on 10 August 2015, when their crop of Red Romaine was harvested.<ref>{{Cite magazine |url=http://time.com/3991352/lettuce-space-station/ |title=Why Salad in Space Matters |first=Jeffrey |last=Kluger |magazine={{wipe|Time (magazine)}} |date=10 August 2015}}</ref> Since 2003 Russian cosmonauts have been eating half of their crop while the other half goes towards further research.<ref>{{cite web |last1=Bauman |first1=Joe |title=USU EXPERIMENT FEEDS ASTRONAUTS' MINDS, TASTE BUDS |url=http://www.sdl.usu.edu/media-events/news/press/2003/jun16-dnlada |publisher=Deseret News, Space Dynamics Laboratory |date=16 June 2003 |access-date=9 May 2018 |archive-date=14 February 2019 |archive-url=https://web.archive.org/web/20190214003503/http://www.sdl.usu.edu/media-events/news/press/2003/jun16-dnlada |url-status=dead }}</ref> In 2012, a sunflower bloomed aboard the ISS under the care of NASA astronaut Donald Pettit.<ref>{{cite web |url=https://blogs.nasa.gov/letters/2012/06/29/post_1340814534271/ |title=June 17–26 – Diary of a Space Zucchini |date=29 June 2012 |access-date=20 January 2016}}</ref> In January 2016, US astronauts announced that a [[Biology:Zinnia|zinnia]] had blossomed aboard the ISS.<ref>{{Cite news |url=http://www.cnet.com/news/behold-the-first-flower-to-bloom-in-space-a-cheerful-zinnia/ |title=Behold the first flower to bloom in space, a cheerful zinnia |work=CNET |date=18 January 2016 |first=Amanda |last=Kooser}}</ref>

in 2018 the Veggie-3 experiment was tested with plant pillows and root mats.<ref>{{Cite web|url=http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|title=NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef|website=spaceref.com|language=en|access-date=8 February 2018|archive-date=1 October 2021|archive-url=https://web.archive.org/web/20211001060242/http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|url-status=dead}}</ref> One of the goals is to grow food for crew consumption.<ref>{{Cite web|url=http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|title=NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef|website=spaceref.com|language=en|access-date=8 February 2018|archive-date=1 October 2021|archive-url=https://web.archive.org/web/20211001060242/http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|url-status=dead}}</ref> Crops tested at this time include [[Biology:Cabbage|cabbage]], [[Biology:Lettuce|lettuce]], and [[Biology:Mizuna|mizuna]].<ref>{{Cite web|url=http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|title=NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef|website=spaceref.com|language=en|access-date=8 February 2018|archive-date=1 October 2021|archive-url=https://web.archive.org/web/20211001060242/http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|url-status=dead}}</ref>

=== Known terrestrial plants grown in space ===
[[File:ISS-39 Steve Swanson with Veggie in the Columbus module.jpg|thumb|'Outredgeous' red lettuce cultivar grown aboard the International Space Station.]]
Plants that have been grown in space include:

* ''[[Biology:Arabidopsis thaliana|Arabidopsis]]'' (Thale cress)<ref>{{Cite news|url=https://www.nasa.gov/mission_pages/station/research/news/tages.html|title=Getting to The Root of Plant Growth Aboard The Space Station|last=Administrator|first=NASA|date=7 June 2013|work=NASA|access-date=8 April 2018|language=en}}</ref><ref name=":2">{{Cite news|url=https://www.airspacemag.com/space/growing-pains-4148507/|title=Growing Pains|work=Air & Space Magazine|access-date=8 April 2018|language=en}}</ref>
* [[Biology:Bok choy|Bok choy (Tokyo Bekana)]] ([[Biology:Chinese cabbage|Chinese cabbage]])<ref>{{Cite news|url=https://www.nasa.gov/feature/cabbage-patch-fifth-crop-harvested-aboard-space-station|title=Cabbage Patch: Fifth Crop Harvested Aboard Space Station|last=Heiney|first=Anna|date=17 February 2017|work=NASA|access-date=8 April 2018|language=en}}</ref>
* Tulips<ref name=":2" />
* ''[[Biology:Kalanchoe|Kalanchoe]]''<ref name=":2" />
* [[Biology:Flax|Flax]]<ref name=":2" />
* Onions, peas, radishes, [[Biology:Lettuce|lettuce]], [[Biology:Wheat|wheat]], [[Biology:Garlic|garlic]], cucumbers, [[Biology:Parsley|parsley]], [[Biology:Potato|potato]], and [[Biology:Dill|dill]]<ref name=":2" />
* [[Biology:Cinnamon basil|Cinnamon basil]]<ref>{{Cite web|url=https://www.nasa.gov/audience/foreducators/pgig003.html|title=NASA – A Plant Growth Chamber|website=www.nasa.gov|language=en|access-date=8 April 2018}}</ref>
* [[Biology:Cabbage|Cabbage]]<ref>{{Cite web|url=http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|title=NASA Space Station On-Orbit Status 6 February 2018 – Celebrating 10 Years of ESA's Columbus Module – SpaceRef|website=spaceref.com|language=en|access-date=8 April 2018|archive-date=1 October 2021|archive-url=https://web.archive.org/web/20211001060242/http://spaceref.com/international-space-station/nasa-space-station-on-orbit-status-6-february-2018---celebrating-10-years-of-esas-columbus-module.html|url-status=dead}}</ref>
* ''Zinnia hybrida'' ('Profusion' var.)<ref>{{Cite news|url=https://www.floridatoday.com/story/tech/science/space/2015/12/29/flowers-could-soon-bloom-aboard-international-space-station-kennedy-space-center-experiment-nasa/77986792/|title=ISS space flowers may need some help from 'Martian'|work=Florida Today|access-date=8 April 2018|language=en}}</ref>
* Red romaine lettuce ('Outredgeous' var.)<ref>{{Cite news|url=https://www.medicaldaily.com/pulse/outredgeous-red-romaine-lettuce-grown-aboard-international-space-station-be-taste-346980|title='Outredgeous' Red Romaine Lettuce, Grown Aboard The International Space Station, To Be Taste-Tested By Astronauts|date=10 August 2015|work=Medical Daily|access-date=8 April 2018|language=en}}</ref>
* [[Biology:Helianthus|Sunflower]]<ref>{{Cite web|url=https://spaceflight.nasa.gov/gallery/images/station/crew-38/html/iss038e000734.html|archive-url=https://web.archive.org/web/20140421082645/http://spaceflight.nasa.gov/gallery/images/station/crew-38/html/iss038e000734.html|url-status=dead|archive-date=21 April 2014|title=Photo-iss038e000734|website=spaceflight.nasa.gov|access-date=8 April 2018}}</ref>
* ''[[Biology:Ceratopteris richardii|Ceratopteris richardii]]''<ref>{{Cite journal|last1=Salmi|first1=Mari L.|last2=Roux|first2=Stanley J.|date=December 2008|title=Gene expression changes induced by space flight in single-cells of the fern Ceratopteris richardii|journal=Planta|volume=229|issue=1|pages=151–159|doi=10.1007/s00425-008-0817-y|issn=0032-0935|pmid=18807069|s2cid=30624362}}</ref>
* ''[[Biology:Brachypodium distachyon|Brachypodium distachyon]]''<ref>{{Cite news|url=https://www.nasa.gov/feature/nasa-science-to-return-to-earth-aboard-spacex-dragon-spacecraft-1|title='NASA Science to Return to Earth aboard SpaceX Dragon Spacecraft|date=1 May 2018|work=NASA|access-date=8 May 2018|language=en}}</ref>

Some plants, like tobacco and morning glory, have not been directly grown in space but have been subjected to space environments and then germinated and grown on Earth.<ref>{{Cite journal|last1=Tepfer|first1=David|last2=Leach|first2=Sydney|title=Survival and DNA Damage in Plant Seeds Exposed for 558 and 682 Days outside the International Space Station|journal=Astrobiology|volume=17|issue=3|pages=205–215|doi=10.1089/ast.2015.1457|pmid=28263676|pmc=5369387|bibcode=2017AsBio..17..205T|year=2017}}</ref>

=== Plants for life support in space ===
[[File:Growing Plants and Vegetables in a Space Garden.jpg|thumb|Lettuce being grown and harvested in the International Space Station before being frozen and returned to Earth.]]
Algae was the first candidate for human-plant life support systems. Initial research in the 1950s and 1960s used ''Chlorella, Anacystis, Synechocystis, Scenedesmus, Synechococcus,'' and ''Spirulina'' species to study how photosynthetic organisms could be used for {{O2}} and {{CO2}} cycling in closed systems.<ref name=":0">{{Cite journal|last=Wheeler|first=Ray|date=1 January 2011|title=Plants for human life support in space: From Myers to Mars|url=https://www.researchgate.net/publication/228484167|journal=Gravitational and Space Biology|volume=23}}</ref> Later research through Russia's BIOS program and the US's CELSS program investigated the use of higher plants to fulfill the roles of atmospheric regulators, waste recyclers, and food for sustained missions. The crops most commonly studied include starch crops such as [[Biology:Wheat|wheat]], [[Biology:Potato|potato]], and [[Biology:Rice|rice]]; protein-rich crops such as soy, peanut, and common bean; and a host of other nutrition-enhancing crops like lettuce, [[Biology:Strawberry|strawberry]], and kale.<ref>{{Cite journal|last1=Wheeler|first1=Ray|last2=Sager|first2=John|date=1 February 2003 |title=Crop Production for Advanced Life Support Systems - Observations From the Kennedy Space Center Breadboard Project |url=https://ntrs.nasa.gov/citations/20030032422|journal=NASA Technical Reports}}</ref> Tests for optimal growth conditions in closed systems have required research both into environmental parameters necessary for particular crops (such as differing light periods for short-day versus long-day crops) and cultivars that are a best-fit for life support system growth.

Tests of human-plant life support systems in space are relatively few compared to similar testing performed on Earth and micro-gravity testing on plant growth in space. The first life support systems testing performed in space included gas exchange experiments with wheat, potato, and giant duckweed (''Spyrodela polyrhiza''). Smaller scale projects, sometimes referred to as "salad machines", have been used to provide fresh produce to astronauts as a dietary supplement.<ref name=":0" /> Future studies have been planned to investigate the effects of keeping plants on the mental well-being of humans in confined environments.<ref>{{Cite web|url=http://elib.dlr.de/94135/|title=Demonstration test of electrical lighting systems for plant growth in HI-SEAS analog mars habitat|last1=Lucie|first1=Poulet|last2=D.|first2=Massa, G.|date=2014|website=elib.dlr.de|language=en|access-date=8 April 2018|last3=R.|first3=Wheeler|last4=T.|first4=Gill|last5=R.|first5=Morrow|last6=C.|first6=Steele|last7=T.|first7=Swarmer|last8=K.|first8=Binsted|last9=J.|first9=Hunter}}</ref>

More recent research has been focused on extrapolating these life support systems to other planets, primarily Martian bases. Interlocking closed systems called "modular biospheres" have been prototyped to support four- to five-person crews on the Martian surface.<ref>{{Cite journal|date=1 January 2003|title=Development and research program for a soil-based bioregenerative agriculture system to feed a four person crew at a Mars base|journal=Advances in Space Research|language=en|volume=31|issue=1|pages=69–75|doi=10.1016/S0273-1177(02)00661-0|pmid=12577934|issn=0273-1177|bibcode=2003AdSpR..31...69S|last1=Silverstone|first1=S|last2=Nelson|first2=M|last3=Alling|first3=A|last4=Allen|first4=J}}</ref> These encampments are designed as inflatable greenhouses and bases.<ref name=":1">{{Cite book|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050182966.pdf#page=130|title=Mars Greenhouses: Concepts and Challenges|last=Wheeler|first=R.M.|publisher=NASA|year=2000}}</ref> They are anticipated to use Martian soils for growth substrate and wastewater treatment, and crop cultivars developed specifically for extraplanetary life.<ref>{{Cite journal|date=1 January 2003|title=Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype|journal=Advances in Space Research|language=en|volume=31|issue=7|pages=1799–1804|doi=10.1016/S0273-1177(03)00013-9|pmid=14503520|issn=0273-1177|bibcode=2003AdSpR..31.1799N|last1=Nelson|first1=M|last2=Alling|first2=A|last3=Dempster|first3=W. F|last4=Van Thillo|first4=M|last5=Allen|first5=John}}</ref> There has also been discussion of using the Martian moon Phobos as a resources base, potentially mining frozen water and carbon dioxide from the surface and eventually using hollowed craters for autonomous growth chambers that can be harvested during mining missions.<ref name=":1" />

== Plant research ==
The study of plant research has yielded information useful to other areas of botany and horticulture. Extensive research into hydroponics systems was fielded successfully by NASA in both the CELSS and ALS programs, as well as the effects of increased photoperiod and light intensity for various crop species.<ref name=":0" /> Research also led to optimization of yields beyond what had been previously achieved by indoor cropping systems. Intensive studying of gas exchange and plant volatile concentrations in closed systems led to increased understanding of plant response to extreme levels of gases such as carbon dioxide and ethylene. Usage of LEDs in closed life support systems research also prompted the increased use of LEDs in indoor growing operations.<ref>{{Cite journal|last=Morrow|first=Robert C.|date=1 December 2008|title=LED Lighting in Horticulture|journal=HortScience|language=en|volume=43|issue=7|pages=1947–1950|issn=0018-5345|doi=10.21273/HORTSCI.43.7.1947|doi-access=free}}</ref>

== Experiments ==
[[File:Mars Food Production - Bisected.jpg|thumb|400px|Illustration of plants growing in a hypothetical Mars base.]]
Some experiments to do with plants include:
*[[Engineering:Bion (satellite)|Bion]] satellites
*Biomass Production System, aboard ISS
*[[Biology:Vegetable Production System|Vegetable Production System]] (Veggie), aboard [[Astronomy:International Space Station|ISS]].<ref>{{Cite web |title=NASA – Station Investigation to Test Fresh Food Experience |url=http://www.nasa.gov/mission_pages/station/research/news/veggie.html |website=www.nasa.gov |access-date=23 January 2016 |language=en}}</ref>
*[[Astronomy:SVET plant growth system|SVET]]<ref name="zvet" />
*SVET-2, aboard [[Astronomy:Mir|Mir]].<ref name="zvet" />
*ADVASC
*TAGES, aboard ISS.<ref>[https://science.nasa.gov/science-news/science-at-nasa/2013/06may_arabidopsis/ Glow-in-the-Dark Plants on the ISS]</ref>
*Plant Growth/Plant Phototropism, aboard [[Engineering:Skylab|Skylab]]<ref name="ed">{{Cite web |url=http://mix.msfc.nasa.gov/abstracts.php?p=1419 |title=Plant Growth/Plant Phototropism – Skylab Student Experiment ED-61/62 |access-date=9 May 2018 |archive-url=https://web.archive.org/web/20140804163056/http://mix.msfc.nasa.gov/abstracts.php?p=1419 |archive-date=4 August 2014 |url-status=dead }}</ref>
*Oasis plant growth unit<ref>[https://web.archive.org/web/20020823063607/http://www.astronautix.com/craft/salyut7.htm Encyclopedia Astronautica Salyut 7]</ref>
*Plant Signaling ([[Engineering:STS-135|STS-135]])<ref>[http://spacebiosciences.arc.nasa.gov/mission/plant-signaling-sts-135 Plant Signaling (STS-135)] {{webarchive|url=https://web.archive.org/web/20130216200154/http://spacebiosciences.arc.nasa.gov/mission/plant-signaling-sts-135 |date=16 February 2013 }}</ref>
*Plant growth experiment ([[Engineering:STS-95|STS-95]])<ref>{{cite journal |pmid=11542477 |volume=13 |issue=1 |title=STS-95 Space Experiments (plants and cell biology) |journal=Biol Sci Space |pages=25–32 |author=Shimazu T, Aizawa S |doi=10.2187/bss.13.25 |year=1999|doi-access=free }}</ref>
*[[Astronomy:NASA Clean Air Study|NASA Clean Air Study]]
*ECOSTRESS, 2018<ref>[https://www.jpl.nasa.gov/news/news.php?feature=7098 NASA's New Space 'Botanist' Arrives at Launch Site]. NASA. 17 April 2018.</ref><ref>[https://ecostress.jpl.nasa.gov/ ECOSTRESS] – Home web site at NASA.</ref>

== Results of experiments ==
[[File:ISS-38 Young sunflower plant.jpg|thumb|A young sunflower plant aboard the ISS<ref>[https://web.archive.org/web/20140421082645/http://spaceflight.nasa.gov/gallery/images/station/crew-38/html/iss038e000734.html SS038-E-000734 (13 November 2013)]</ref>]]

Several experiments have been focused on how plant growth and distribution compares in micro-gravity, space conditions versus Earth conditions. This enables scientists to explore whether certain plant growth patterns are innate or environmentally driven. For instance, Allan H. Brown tested seedling movements aboard the [[Engineering:Space Shuttle Columbia|Space Shuttle ''Columbia'']] in 1983. Sunflower seedling movements were recorded while in orbit. They observed that the seedlings still experienced rotational growth and circumnation despite lack of gravity, showing these behaviors are built-in.<ref>{{cite book|last1=Chamovitz|first1=Daniel|title=What a plant knows : a field guide to the senses|date=2012|publisher=Scientific American/Farrar, Straus and Giroux|location=New York|isbn=978-0-374-28873-0|edition=1st}}</ref>

Other experiments have found that plants have the ability to exhibit [[Biology:Gravitropism|gravitropism]], even in low-gravity conditions. For instance, the ESA's European Modular Cultivation System<ref>{{cite journal|last1=Jost|first1=Ann-Iren Kittang|last2=Hoson|first2=Takayuki|last3=Iversen|first3=Tor-Henning|title=The Utilization of Plant Facilities on the International Space Station—The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions|journal=Plants|date=20 January 2015|volume=4|issue=1|pages=44–62|doi=10.3390/plants4010044|issn=2223-7747|pmc=4844336|pmid=27135317|doi-access=free }}</ref> enables experimentation with plant growth; acting as a miniature greenhouse, scientists aboard the [[Astronomy:International Space Station|International Space Station]] can investigate how plants react in variable-gravity conditions. The Gravi-1 experiment (2008) utilized the EMCS to study [[Biology:Lentil|lentil]] seedling growth and amyloplast movement on the calcium-dependent pathways.<ref>{{cite journal|last1=Driss-Ecole|first1=Dominique|last2=Legué|first2=Valérie|last3=Carnero-Diaz|first3=Eugénie|last4=Perbal|first4=Gérald|title=Gravisensitivity and automorphogenesis of lentil seedling roots grown on board the International Space Station|journal=Physiologia Plantarum|date=1 September 2008|volume=134|issue=1|pages=191–201|doi=10.1111/j.1399-3054.2008.01121.x|issn=1399-3054|pmid=18429941}}</ref> The results of this experiment found that the plants were able to sense the direction of gravity even at very low levels.<ref>{{cite web|title=Scientific objectives|url=https://lensesinspace.wordpress.com/objectives-of-the-gravi-experiment-2/|website=Plants in space: GRAVI-2 experiment|date=28 March 2014}}</ref> A later experiment with the EMCS placed 768 lentil seedlings in a centrifuge to stimulate various gravitational changes; this experiment, Gravi-2 (2014), displayed that plants change calcium signalling towards root growth while being grown in several gravity levels.<ref>{{cite web|title=A decade of plant biology in space|url=https://phys.org/news/2016-07-decade-biology-space.html|publisher=European Space Agency}}</ref>

Many experiments have a more generalized approach in observing overall plant growth patterns as opposed to one specific growth behavior. One such experiment from the [[Organization:Canadian Space Agency|Canadian Space Agency]], for example, found that white spruce seedlings grew differently in the anti-gravity space environment compared with Earth-bound seedlings;<ref>{{cite web|title=NASA – Advanced Plant Experiment – Canadian Space Agency 2|url=https://www.nasa.gov/mission_pages/station/research/experiments/70.html|website=www.nasa.gov}}</ref> the space seedlings exhibited enhanced growth from the shoots and needles, and also had randomized [[Biology:Amyloplast|amyloplast]] distribution compared with the Earth-bound control group.<ref>{{cite journal|last1=Rioux|first1=Danny|last2=Lagacé|first2=Marie|last3=Cohen|first3=Luchino Y.|last4=Beaulieu|first4=Jean|title=Variation in stem morphology and movement of amyloplasts in white spruce grown in the weightless environment of the International Space Station|journal=Life Sciences in Space Research|date=1 January 2015|volume=4|pages=67–78|doi=10.1016/j.lssr.2015.01.004|pmid=26177622|bibcode=2015LSSR....4...67R}}</ref>

== In popular culture ==

Astrobotany has had several acknowledgements in science fiction literature and film.

*In the 1972 film ''Silent Running'' it is implied that, in the future, all plant life on Earth has become extinct. As many specimens as possible have been preserved in a series of enormous, greenhouse-like geodesic domes, attached to a large spaceship named ''Valley Forge'', forming part of a fleet of American Airlines space freighters, currently just outside the orbit of Saturn.
*Charles Sheffield's 1989 novel ''Proteus Unbound'' mentions the use of algae suspended in a giant hollow "planet" as a [[Earth:Biofuel|biofuel]], creating a closed energy system.<ref>{{Cite book|title=Proteus Unbound|last=Sheffield|first=Charles|publisher=Random House Publishing Group|year=1989|isbn=9780345344342|location=New York, NY|url-access=registration|url=https://archive.org/details/proteusunbound00shef}}</ref>
*The 2009 film ''Avatar'' features an [[Astronomy:Astrobiology|exobiologist]], Dr. Grace Augustine, who wrote the first astrobotanical text on the flora of Pandora.<ref>Cameron, James, Director. ''Avatar''. Produced by James Cameron and Jon Landau, 20th Century Fox, 2009. Accessed 18 March 2018.</ref>
*The 2011 book and 2015 film ''The Martian'' by Andy Weir highlights the heroic survival of botanist Mark Watney, who uses his horticultural background to grow potatoes for food while trapped on Mars.<ref>{{Cite book|title=The Martian|last=Weir|first=Andy|publisher=CrownPublishing|year=2014|isbn=978-0553418026|location=New York, NY|url-access=registration|url=https://archive.org/details/isbn_9780553418026}}</ref>

== See also ==
[[File:Spacecolony3edit.jpeg|thumb|right|Interior view the hypothetical [[Astronomy:O'Neill cylinder|O'Neill cylinder]] space habitat, showing alternating land and window stripes.]]
* {{annotated link|Astronomy:Bioastronautics}}
* {{annotated link|Biology:Biolab}}
* {{annotated link|Engineering:Bion (satellite)}}
* {{annotated link|Biology:BIOPAN}}
* {{annotated link|Engineering:Biosatellite program}}
* {{annotated link|Biology:Endolith}}
* {{annotated link|Biology:EXPOSE}}
* {{annotated link|Astronomy:List of microorganisms tested in outer space}}
* {{annotated link|Astronomy:Moon tree}}
* Space farming
* {{annotated link|Astronomy:Space food}}
* {{annotated link|Earth:Terraforming}}

==References==
{{Reflist}}

{{Botany}}
{{Astrobiology}}
{{In space}}

[[Category:Branches of botany]]
[[Category:Astrobiology]]

{{Sourceattribution|Astrobotany}}