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1、 1 Rnewabe nd ustaiable Energy Review High-ights LEDsEnegy effict ligtig sources and the poential in ioo pln culivaio BSTRAT Th raid dveopmet of ooelectronic technology sine id-980 ha significtly enhanced the brightnes nd eficiny of ligeitng diods(Es)LEDs hae long been proposed s a pri igt sre o spa
2、bae lant reearc hamer o bigeeratve fe uppor ystems。he rising cost f eerg alo makes te ue LD in commerial crop culture iminent。ih thi eergy efciency,LEDs ave opened new perpective or ptimzig e nergy covesin ad the nurient supply both n an off Earh.potentias f ED a an ffctive light soue or ino agriclt
3、ulpotion ave een xplored o a rea tt.Thee ae man reserches that u LEDs to uppr lat growth i cnole nvironmen such a plnt tisse cutur room ad rwth cher。Thi paer proves a bref devlopment history o LEDs and bad e review D applcatios i ndor lat cultvatin n 1990。Connts 1。Introducton 2。LED epmt。3 lor raios
4、nd photosynsis 4。L and noor pan ltivatin。4.。Plt tse ultre and growth 4。Space arulture8 4.3.Aaclture 4.Plan diease reucio 5 Intmient and photoeriod lighting an energy aing 6。Concuso 1.ntrdcio ith pacts of climate hange，issue suh as e reuen an seus dught,flod,nd srms s we a est and diseases ae becmng
5、mo serio reat to agculture.Thse tret along wih shortag of fod suppl mae eoe tur t indr and uan fai(uch as verical farmng)for elp。Wt poer lightn，inoor riculture elinate weathereated ro faurs due to drougts n fl 2 od to pvide yearrond rop pructin,whc asst suplying d in ities wth urging population and
6、i aeas of vere evronmental contion。The use liht-emitting dodes mrks great vacemnt ve xistig inor agicultural lighti。LEDs allo th cntrl f spectra ompostion nd t ajstmt o lig intensi y o simuate he chge of sunlght tensity uring the dy。Thy ha te bility to produce hig ligt evels wih l iant hat output an
7、d maintain seul liht upu or yeas。Ls do nt cotan elctrde and hu o not urn ut le incanescet or luoescen blb hat mus e eioicaly replced Nt t tion that incndscen and fluorecent amps consume a lo of electria powe while geatng heat,whic mu b spelled from ls envroments such a spacesips an pace tatins。2.L d
8、evelpment LED i a unique tpe of seconutor iode.I onssts of a chp of semiconuor aril dopd with impurities o reae a pn unctin。Current flows easily from the side(anod）,to the n-side(athoe）,but no in he rvrse drection。Electrns ad hles fow nto h ncton fr ectroe with difeen vltages。e an elctr eets a ole,t
9、 lls no a loer engy eel,nd release ee n the for of a hoton。Th colr（wavengt）o the light mitted deends on the band gap enry of e mateial formn he pn junction。The tials ued for n LED ve diec ba ap with eneres cospoing to neainrared,ie or neaultraiole ligh.The ke sctr o an LD onsit o h di(or ligh-eitn e
10、micoduto aterial),a ead rame wher h di s plac，and the encapslaio hich tect he die（Fig。1）。Fig。1 LED evlopment began th infrd n red devie made wth gllium arsenie。Avances i maerals since ve mae posil e roduction of devices wth evrsorter aveengths,prig light in a ariety f coors。J。Magoln rported that the
11、 frst known liht-iting olid state diode was made i 907 H。J。Round No pratcal ue o Ronds diode ws made fr severa ecae util the ivnion o th fist pracical D y ick ola,Jr in 162。His LD cme mry avalabe lat 190s。These s Ds ombe the priry eeets：galium,as and phphoru o rvid 65nm d light 3 wth brighnes lvs of
12、 approxmately 11 mc at 0mA。the luminus inensit was low,thse LDs ere only used in fe pplctions，prmaril as ndiators。Follin GAP，Ga(galium phosphide）rd LEDs were devepe。Tse vice sex hibit very igh quatum efficiece at ow crents。As LE tchlogy progresed hrogh the 970s,ditonal colos ad avelens bcame avlabe.
13、Te most cmon meials were GaP gre a re，GaAsP rge，nd high efficiency ed and GaAsP yelo。The ed twrds more actcal ppictins（uc as in cacltr,digal wcs,an tst uipmen)alo beg to eelo。he ED mateials tcnolgy becae ore dvanced，th ht oupu was iceae，n ED beae brih enouh o be sd for lumination。In 1980 a matral,Ga
14、Als(galium umnm arenid）was devepe fllwe by aid grow in te use ED。Gals techoog provies suerir pefomanc or previously vailable LEDs he voltae requireme is lower，wich rsults in total w savings。LEs could e eaily pused or exed nd us re uial or vaile ssa d udor sigs.Aog this develmnt perod，LED wee alo dsi
15、gned o bar code scannrs，fber optc daa trnmsion sstms,and medicalqment.Drng this time，h improvemnts in crstl gro an opt dsin allo yellow，green nd orage LEs oly a mior ipovet n brigtness n ffcieny。The bsi tucture of he mael remained ltive unhed.As laser dids wit ouput in the visb specrum sred to comme
16、iliz in ate 198，E degnes used sila tcnique to produce highrightness a high relability LDs。Ths le to h develpmnt f InGaAlP（ndium galium alumm psphide)vsible lht Ds。Via dusin e erg band ap InGaAl mateial can have different r ouput.Thus,een，yellow,orge d ed LEDs ould all podced uing the sm asic tchnolo
17、g。Also,ligt outut degradatio of IGAlP ater is signficantly imroved。Suji Nakamua at Nicha Cheical Indstries f pn intodce lue LED in 193。le Es have al ben diiult o anufacture ecause eir high h eneges(2。5 eV）ad reaily o eye enitivity。Also，he techno facat hese EDs is ve dfret and ss adanced thn sadard L
18、ED mtals.But lue s ne o e priary colors(th ohr tw beng ed and green).Prp cobnin te red，geen,n ue ih 4 entia t produc wit a fullcolo。Th proces rqures ohitcaed sofwre ad ardwae dsig t implement In adiio,h brghtne lee s lw ad the vl liht outpu of ea RGB di being sed egades a a diffet rae resulti in a e
19、ventual color anc。Te blue LEDs availbe td consi f GaN（galium nitrid)ad SiC(slcon cbde)cosructi The bl D ta becms available n protion qunite s resu an entre gnratio f ew aplicaions that icde tcommuniatn poduct，atomotive applicatins，tafc corol ees，and flclor msae boards Eve LED TV an soon beo cmciall
20、vailabl。Compare o ianecnt lights 000h and floescn ligh s 800-h ie spa，Ds hae a vry ignfcntly longr life f 10,00 h。In aditio t thir ong lif，LEDs hae many advates ver convntonal liht suce.Thes avantages include smal sze，specific wengt,low herma outut,adjustabl liht intty and qut，ell as hgh photoelecti
21、c converion eficiency。Such datages mke LEDs prc or upoting plant growt i contrlld envionen c a lt isu cltue oom nd roth chmber.Tabe 1 is li soe comon tes of LD s compie fo.Table 1 Som commo ypes of LED。Pea avelength（）Color ateil and scture f Es Subtre 730 Far-Gas GaP 0 Red aP：Zn-O Ga 66 Red GaAl0.As
22、 Ga 650 ed GAs。6P GaAs 63 Oragered GaAs0。350。65:N GaP 10 Orang GaAs0。2P0。75：N P 9 Yello As0.P0。85:N GaP 5 Yello GA0。14P0。6:N a 55 Gren GaP：GaP 450 Blu G/iC Color ratios an otosynesis he chlohy olecules in plnts nitiat otosythesis bycaptuing lght eney and convertig t ito chemic eergy to hp tsformin a
23、te an caro diox nto te pimay urient f iin beigs.The generalized equion fo he hosythtic prces is giv as:5 CO H2Olight（C2O)+O2 were(2）s he emical nergy buildin boc for teynhei of pat comonen。Chloyl molcus absor ble and red wavlngths most efficentl.The green nd llo aengths a fleced or tnsmtted and thus
24、 are nt as important in th osyhetc proces。Tht ea limit he amout of coor ivn t t lns a sll have them grow as wll as th whte iht S,th s o ed deote ner to gree ligh hn negy cots r cocern，wc is usually he cse n pac ravel.Te Ds abe esearer t elimne oher velengths fund wthi noral hie light，tus rducn he ao
25、nt of negy rqre to powr the pan gwth lamp。Th plants grow nrmally and taste the ae as those raised n white liht。ed d lu liht best drive htytic metablsm。The lh qualits are atilarly ciet i impvng te dvpmetal aractrtis assoiated with auttroph groth hbits。Neverteless,phostticaly neffiie ligt ulies also o
26、ny imortt enironental formation to a evelong lant。Fr emple，arrd light ever he efc of hytochrmes,leading t changs in gee expresso,plant archictu,nd reproductiv rnses。n ddion，photopeiod(the adjutet of light and dark eiods)and light qulity(ajustmt of rd,bue and farred ligt ato)lso have decisive ipacts
27、on phoohss.Te supimpoed patten of lumnscene pectrum of lu L(450470 m)nd that of red LED(656 m）corronds wel to ligh borptio spctru of arotnoids and clorophyll。Varios plat cltaion expeiens are posible wh tese twokis LD are ue wt the addition of fare radaio(3735 n)as e lht source。Alon he line of the LE
28、D enolo dvancmnt，LED cme a romien iht ource for intnsi lant cultue ytems nd hotobilogicl rerces。The cultivation expeimets which use such iht ources ae beoming creasingly active。Plant hysiology and pa cultivaton reserches sin LDs stae to peak i 1990s and beome inevitable in th ew milleni Tho sarhs av
29、 cofirmd hat LEs re stale fo cultivatin of et o alae,rop，flower，frui，and 6 vegtale.Sme f the ponerg eseres e reviewed in the oloings。Bula et al hve shown that gwng lettuce wth red LEs i combinatin with bue tublar luorscent lamp()i ssible。Hoeneck et al ve veied he necey le hotns or letuce sedling prd
30、utin b sing red LED with blu TF.As the ie of oth lue and rd EDs hae dropp and the rightness increasd ignifianty,the search finigs hae bee ale to b pplie in omcil roducion。As rpote by ee France res,Csmo lant C。，n Fuuroi,Japan as deeled red LEbaed rwh pocess tha uses only 6%f elctrct an a fuoescnt lig
31、hting based one。Tnnsen e al。ave coped phoothesis rom leve f kudzu（Purara lobata)nlse i lea chaer lluiatd b EDs versus b a en arc lamp。The respose of photntis t CO2 re smilar udr te LE a xn arc amps at el photosnthetic iraiane。Thr is satsicl sigifican diffrenc beteen the hie gt and rd light asureets
32、in high CO。Sme les exbted feedback iibition of ptosynthesi whic i eal evie ude rrdiio f eiher lmp ype。Th rslts ugget h hoosyess research icudin eletro transpor,crbo metabolsmand trace gas eisin stdies should benefit geatl frm the icreased reliabi,epeblity an potabiity f a hoosynhesi lamp bse on LEDs
33、。Okamt e。have inesigated te ffects f ifferent raios of rd a lue(red/lu)htoythtc phoon lx desit（FD)levels n the rowth and mophonesis o leuce sedlings。They have fond tha th lete stem lengt decreass significaly wth inceae in te blu PFD。Th resrch has also ideifed t esptive PPFD tio that()cceres let sedl
34、ing tm elongato，(2)maiizes th hole pan dry weg，(）aelerate he growth f hle plnt,nd（4)axmizes he dry weiht oots ad stems.hotoyntheis des ot ned ae place i contuos light。The solid state nature alow LEDs to pruce uficen po luxs and can urne ul n ad ff radl(0 n)，whc is no eas ceable wit thr lih sorces hs
35、 rapi onof fea hs md D n exce lit sourc for potoynthsi reserh such as plsed lihting for th stud potsyntheic eectro ansport details。e ff/dak period means aitio 7 al eeg avn on to o e Ls lw power nsmtion。4。EDs ad inr plnt cltitio。Plnt tiu cure and grwt Tissue culture(TC),se wily in plant science an a
36、nmber o commercial applicaions,i the growth o plant tissus or cl tn corold environmet，an iea growth envimen that is fe frm the contaition iroorni an ote cntnants。A controlled envromt fo TC usaly ens iltred ai,tead tmrature,stale light ouces，and secly frulad rowth ma(suc s brt r agr)。Micropropagato，o
37、rm of pla isue cltur(PC),is sd widel orestr and flrictur。It i a o use for conservi e e dangered pl nt species ther ues PTC incude:1hotte esting of gne contructio or reenratin oftran gei lan,2 oss bredig sttly related spcis and egnertn of he noel hybrid，3 screenin cells for advnteous chactes(e。erbicd
38、ere sistanc/oerance)，4eby sce（i。e。to cosspollinte dstntly reted specie sand n tisse cultue there suting emro hch wol normally di）,5 largescle groth of plant cl in liqud cultue inse bioreactors as urce o seondy products(lik recobinant protens used as biopharaeutical）。6producton o duble onoloid pats f
39、rom haploid cuurs to aie hmozgous lines mre raidy in breeding pgrm(usully by tremn with clhcn whch cuses ubling f the cromosome nmber）.Tsue culure nd rowth oom nusris ave ong been usg arific lgt souce for poducion。Thee lght orce incde TL,high presu sodum lamp(HPS）,metal halide lam（ML)and icadescet l
40、mp，t。ong them，TFL ha ee the mst pplar in tisue clre nd groh roo ndusres。Hwver,th us of L consues 65 of the tl eletriciy in a tis cultre l。Tha is th hgest olabor ost a rsult，these industrie cotiuosl seek for more effiin light ources.he devlomen f hih-brighness ED hs mde LED promsig lt sourc for pl go
41、th n otroled envirnmnts。Nht t l。hae cultured traerr plntlets unde different blue to re ED tios as el as iradiaion evels ad omp 8 red its grwth to that uer pant rowth fluorecent Th rsuls sggest that a clture system uing LE is advangeous for t mooaaton of rabr lnl。Te study aso demontraes that he LE l
42、urce r i vitro culre of pantlts contriutes to an imro grwt of te plats in acclmatztion.own t al.ave measued t growh and y matter partitiong of Hugaian Wax eppe(Capsium anuu L。）plants grow undr d LEDs omprd wh imila plnts grown uder red LE wt splemental bue or farre adiatio。Pppr biomass reducs we gro
43、n ne e LE wihout be wvelenths compared o plan ow under pemental lu fluorescent lamps。Th aditin f rre radio esults in taller plants h reatr stem mas than rd LEs alon.ewr leave deloped under red or red pus fr-d rdiatio tha wih lmps prodcn ue waelngth。The rests of heir research indicate that wit rper c
44、ombiation o othr wavelegts，red LEDs ay be suitble for te cultue of plnts n ighy cntroled eironments。4。2.pae gricultr Becaue resply is not an pton,plnts are the oly optios to genrate eogh od，wat and oxygn to he make future explorrs selfsufcent space lnis th mon，Mars or eod.In ordr e lants，here mut e
45、a igt surc.Stadrd lh soucs that used i omes and in renes ad in growth cambes r contolled agrultue he n Earth e not eficient eo for sace trae。ile a human expeitio tie Erh orbit sill ight b ears awy,te pce farmn effos ar aimed t develing pomiing arifici gh soures LEDs,bcaus of thi saety，smal ma ad vou
46、me，wavlength specicy,nd ogevit,have log e poposed as a ary light source for ace-bas plant reearch chamber or ioregenive if suppor systems。Infrred LEDs that r ud i rt cotls evces have ote uses Jhnsn et al。have irrdite oat(Aa sata Sege）sedlngs wih inrred（）LD adiation s trou a viillightbockg fltr。Te ra
47、diae seeds exhite differncs i rowth and grvitroic resons when mpad to dlngs rwn in dakness a e sae tepeatre。Ths sugests that the oat seedlngs are le to detect IR LED radiation.These dins aso expand e defind rge f waelegths involed in rdatongrity(lihtgrvit)necion to include w 9 ths i e regon o e spec
48、tm.Gons al。gro hea dr red Es nd ompar t to he ea grwn under()wite fluoesct laps and（）LEDs supplemetd wih bl ligt from blue uorecent laps.The rults sho tht wt gron unde red LEDs o displd fewr subier a lower seed yield cmared hose grown une white light Weat grow uner red LDs+10 B lg had comparbe shot
49、dr mtter cumulaion d sed yild rlatv to ths gown under ite ght。Thse reslt indicte that whea can omplete it fe yc unde red LEDs lon,bu lrger plants an greate amount o seed ae poduced in the rsen of red LED suplmente wih a quat of blue ight.h eserch o Go and s tea cntus in lat rowh cabers te sz of wali
50、n refrierors with blue and d LEDs o grw ld plats su as lettce and radishes。h hope the lan grt chamer wold enab spac sation staf t gr an hvst slad grees,hs n ebles durg tyial fourmnth ous on he tos 。.lculture Algaculture，rfes o te amig of pecies of alga,ha bee a ge our fo feedstock,bioplatics,phmaceu