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Ukufunxwa kwezinto ezininzi zezakhamzimba yinkqubo enxulumene kakhulu nemisebenzi ye-metabolic yeengcambu zezityalo. Ezi nkqubo zifuna amandla aveliswa kukuphefumla kweeseli zeengcambu, kwaye ukufunxwa kwamanzi kulawulwa bubushushu nokuphefumla, kwaye ukuphefumla kufuna inxaxheba yeoksijini, ngoko ke ioksijini kwindawo yeengcambu inempembelelo ebalulekileyo ekukhuleni okuqhelekileyo kwezityalo. Umxholo weoksijini enyibilikisiweyo emanzini uchatshazelwa bubushushu kunye netyuwa, kwaye ulwakhiwo lwe-substrate lumisela umxholo womoya kwindawo yeengcambu. Ukunkcenkceshela kunomahluko omkhulu ekuvuseleleni nasekuncediseni umxholo weoksijini kwiindawo zeengcambu ezineemeko ezahlukeneyo zomxholo wamanzi. Kukho izinto ezininzi zokuphucula umxholo weoksijini kwindawo yeengcambu, kodwa inqanaba lempembelelo yento nganye lahlukile kakhulu. Ukugcina amandla okubamba amanzi kwindawo yeengcambu afanelekileyo (umxholo womoya) sisizathu sokugcina umxholo ophezulu weoksijini kwindawo yeengcambu.

Imiphumo yobushushu kunye netyuwa kumxholo weoksijini ogcweleyo kwisisombululo

Umxholo weoksijini onyibilikisiweyo emanzini

Ioksijini enyibilikisiweyo inyibilika kwioksijini engabotshelelwanga okanye ekhululekileyo emanzini, kwaye umxholo weoksijini enyibilikisiweyo emanzini uya kufikelela kwinqanaba eliphezulu kubushushu obuthile, obungumxholo weoksijini ehluthisiweyo. Umxholo weoksijini ehluthisiweyo emanzini uyatshintsha ngobushushu, kwaye xa ubushushu busanda, umxholo weoksijini uyancipha. Umxholo weoksijini ehluthisiweyo wamanzi acacileyo uphezulu kunowolwandle olunetyuwa (Umfanekiso 1), ngoko ke umxholo weoksijini ehluthisiweyo wezisombululo zezondlo ezinezinga ezahlukeneyo uya kwahluka.

Ukuthuthwa kweoksijini kwi-matrix

Ioksijini efunyanwa ziingcambu zezityalo eziluhlaza kwisisombululo sezondlo kufuneka ibe kwimeko ekhululekileyo, kwaye ioksijini ithuthwa kwi-substrate ngomoya namanzi kunye namanzi ajikeleze iingcambu. Xa ilingana nomxholo weoksijini emoyeni kubushushu obuthile, ioksijini enyibilikisiweyo emanzini ifikelela kwinqanaba eliphezulu, kwaye utshintsho lomxholo weoksijini emoyeni luya kukhokelela kutshintsho olulinganayo lomxholo weoksijini emanzini.

Iziphumo zoxinzelelo lwe-hypoxia kwindawo yeengcambu kwizityalo

Izizathu ze-hypoxia yengcambu

Kukho izizathu ezininzi zokuba kutheni umngcipheko we-hypoxia kwi-hydroponics nakwiinkqubo zokulima i-substrate uphezulu ehlotyeni. Okokuqala, umxholo we-oksijini egcwalisiweyo emanzini uya kuncipha njengoko ubushushu bunyuka. Okwesibini, i-oksijini efunekayo ukugcina ukukhula kweengcambu iyanda ngokunyuka kobushushu. Ngaphezu koko, ubungakanani bokufunxwa kwezondlo buphezulu ehlotyeni, ngoko ke imfuno ye-oksijini yokufunxwa kwezondlo iphezulu. Oku kukhokelela ekunciphiseni umxholo we-oksijini kwindawo yeengcambu kunye nokungabikho kwesongezelelo esisebenzayo, okukhokelela kwi-hypoxia kwindawo yeengcambu.

Ukufunxwa kunye nokukhula

Ukufunxwa kwezona zondlo zibalulekileyo kuxhomekeke kwiinkqubo ezinxulumene kakhulu nemetabolism yeengcambu, ezifuna amandla aveliswa kukuphefumla kweeseli zeengcambu, oko kukuthi, ukubola kweemveliso ze-photosynthetic xa kukho ioksijini. Izifundo zibonise ukuba i-10% ~ 20% ye-assimilates iyonke yezityalo zetamatato isetyenziswa kwiingcambu, i-50% yazo isetyenziselwa ukufunxwa kwee-ion zezondlo, i-40% yokukhula kwaye i-10% kuphela yokugcina. Iingcambu kufuneka zifumane ioksijini kwindawo ethe ngqo apho zikhupha khona i-CO2.₂. Phantsi kweemeko ze-anaerobic ezibangelwa kukungangeni kakuhle komoya kwiindawo eziphantsi komhlaba kunye ne-hydroponics, i-hypoxia iya kuchaphazela ukufunxwa kwamanzi kunye nezondlo. I-Hypoxia isabela ngokukhawuleza ekufunxweni okusebenzayo kwezondlo, oko kukuthi i-nitrate (NO)₃^-), i-potassium (K) kunye ne-phosphate (PO2₄^3-), nto leyo eya kuphazamisa ukufunxwa kwe-calcium (Ca) kunye ne-magnesium (Mg) ngaphandle kokwenza njalo.

Ukukhula kweengcambu zezityalo kufuna amandla, umsebenzi oqhelekileyo weengcambu udinga uxinzelelo lweoksijini oluphantsi, kwaye uxinzelelo lweoksijini olungaphantsi kwexabiso le-COP luba yinto ethintela imetabolism yeeseli zeengcambu (i-hypoxia). Xa inqanaba lomxholo weoksijini liphantsi, ukukhula kuyehla okanye kuyeke. Ukuba i-hypoxia yeengcambu engaphelelanga ichaphazela amasebe namagqabi kuphela, inkqubo yeengcambu inokubuyisela inxalenye yenkqubo yeengcambu engasasebenziyo ngesizathu esithile ngokwandisa ukufunxwa kwendawo.

Indlela yokusebenza kwe-metabolism yezityalo ixhomekeke kwi-oksijini njenge-electron acceptor. Ngaphandle kwe-oksijini, ukuveliswa kwe-ATP kuya kuma. Ngaphandle kwe-ATP, ukuphuma kweeprotoni ezivela kwiingcambu kuya kuma, incindi yeseli yeeseli zengcambu iya kuba yi-asidi, kwaye ezi seli ziya kufa kwiiyure ezimbalwa. I-hypoxia yexeshana neyexeshana ayizukubangela uxinzelelo lwesondlo olungenakuguqulwa kwizityalo. Ngenxa yendlela "yokuphefumla nge-nitrate", isenokuba yindlela yokutshintsha ixesha elifutshane ukuze kujongwane ne-hypoxia njengendlela eyahlukileyo ngexesha le-hypoxia yeengcambu. Nangona kunjalo, i-hypoxia yexesha elide iya kukhokelela ekukhuleni okucothayo, ukuncipha kwendawo yamagqabi kunye nokuncipha kobunzima obutsha nobomileyo, okuya kukhokelela ekwehleni okukhulu kwesivuno sesivuno.

I-ethylene

Izityalo ziya kwenza i-ethylene xa zihleli phantsi koxinzelelo olukhulu. Ngokwesiqhelo, i-ethylene isuswa kwiingcambu ngokusasazeka emoyeni womhlaba. Xa amanzi ehlala emanzini, ukwakheka kwe-ethylene akuyi kwanda nje kuphela, kodwa nokusasazwa kwayo kuya kuncipha kakhulu kuba iingcambu zijikelezwe ngamanzi. Ukwanda koxinzelelo lwe-ethylene kuya kukhokelela ekwakhiweni kwezicubu zomoya kwiingcambu (Umfanekiso 2). I-ethylene inokubangela ukukhula kwamagqabi, kwaye ukusebenzisana phakathi kwe-ethylene kunye ne-auxin kuya kwandisa ukwakheka kweengcambu ezizikhulelayo.

Uxinzelelo lweoksijini lukhokelela ekukhuleni okunciphileyo kwamagqabi

I-ABA iveliswa kwiingcambu namagqabi ukuze ikwazi ukumelana noxinzelelo oluhlukeneyo lokusingqongileyo. Kwindawo engqonge iingcambu, impendulo eqhelekileyo kuxinzelelo kukuvalwa kwe-stomatal, okubandakanya ukwakheka kwe-ABA. Ngaphambi kokuba i-stomata ivalwe, umphezulu wesityalo ulahlekelwa luxinzelelo lokudumba, amagqabi aphezulu ayabuna, kwaye ukusebenza kakuhle kwe-photosynthesis nako kunokuncipha. Izifundo ezininzi zibonise ukuba i-stomata isabela ekwandeni koxinzelelo lwe-ABA kwi-apoplast ngokuvala, oko kukuthi, umxholo opheleleyo we-ABA kwizityalo ezingengawo amagqabi ngokukhupha i-ABA yangaphakathi kwiseli, izityalo zinokunyusa uxinzelelo lwe-apoplast ABA ngokukhawuleza kakhulu. Xa izityalo ziphantsi koxinzelelo lokusingqongileyo, ziqala ukukhupha i-ABA kwiiseli, kwaye isignali yokukhululwa kweengcambu ingadluliselwa ngemizuzu endaweni yeeyure. Ukwanda kwe-ABA kwizicubu zamagqabi kunokunciphisa ukwandiswa kodonga lweseli kwaye kukhokelele ekwehleni kokwandiswa kwamagqabi. Esinye isiphumo se-hypoxia kukuba ixesha lobomi bamagqabi lifutshane, eliya kuchaphazela onke amagqabi. I-Hypoxia idla ngokukhokelela ekwehleni kokuhanjiswa kwe-cytokinin kunye ne-nitrate. Ukunqongophala kwe-nitrogen okanye i-cytokinin kuya kunciphisa ixesha lokugcinwa kwendawo yamagqabi kwaye kumise ukukhula kwamasebe namagqabi kwiintsuku ezimbalwa.

Ukuphucula imeko-bume ye-oksijini yenkqubo yengcambu yesityalo

Iimpawu ze-substrate zibaluleke kakhulu ekusasazweni kwamanzi kunye ne-oksijini. Uxinzelelo lwe-oksijini kwindawo yeengcambu zemifuno eluhlaza lunxulumene kakhulu namandla okugcina amanzi e-substrate, ukunkcenkceshela (ubukhulu kunye nokuphindaphinda), ulwakhiwo lwe-substrate kunye nobushushu bomcu we-substrate. Kuphela xa umxholo we-oksijini kwindawo yeengcambu ubuncinci ungaphezulu kwe-10% (4~5mg/L) apho umsebenzi weengcambu ungagcinwa ukwimeko efanelekileyo.

Inkqubo yengcambu yezityalo ibaluleke kakhulu ekukhuleni kwezityalo nasekumelaneni nezifo zezityalo. Amanzi kunye nezondlo ziya kufunxwa ngokweemfuno zezityalo. Nangona kunjalo, inqanaba leoksijini kwindawo yengcambu limisela kakhulu ukusebenza kakuhle kokufunxwa kwezondlo namanzi kunye nomgangatho wenkqubo yengcambu. Inqanaba leoksijini elaneleyo kwindawo yengcambu linokuqinisekisa impilo yenkqubo yengcambu, ukuze izityalo zibe nokumelana ngcono neentsholongwane ezibangela izifo (Umfanekiso 3). Inqanaba leoksijini elaneleyo kwindawo engaphantsi komhlaba likwanciphisa umngcipheko weemeko ze-anaerobic, ngaloo ndlela kunciphisa umngcipheko weentsholongwane ezibangela izifo.

Ukusetyenziswa kweoksijini kwindawo engcambu

Ubuninzi bokusetyenziswa kweoksijini kwizityalo bunokuba phezulu ukuya kwi-40mg/m2/h (ukusetyenziswa kuxhomekeke kwizityalo). Ngokuxhomekeke kubushushu, amanzi okunkcenkceshela anokuba neoksijini ukuya kuthi ga kwi-7~8mg/L (Umfanekiso 4). Ukuze kufikelelwe kwi-40 mg, kufuneka kunikwe i-5L yamanzi rhoqo ngeyure ukuze kuhlangatyezwane nesidingo seoksijini, kodwa eneneni, ubungakanani bokunkcenkceshela ngosuku olunye busenokungafikelelwa. Oku kuthetha ukuba ioksijini ebonelelwa kukunkcenkceshela idlala indima encinci. Uninzi lobonelelo lweoksijini lufikelela kwindawo yeengcambu ngeembobo kwi-matrix, kwaye igalelo lobonelelo lweoksijini ngeembobo lifikelela kwi-90%, kuxhomekeke kwixesha losuku. Xa ukufuma kwezityalo kufikelela kwinqanaba eliphezulu, ubungakanani bokunkcenkceshela bufikelela kwinqanaba eliphezulu, elilingana ne-1~1.5L/m2/h. Ukuba amanzi okunkcenkceshela aqulethe ioksijini eyi-7mg/L, aya kubonelela ngeoksijini eyi-7~11mg/m2/h kwindawo yeengcambu. Oku kufana ne-17%~25% yesidingo. Kakade ke, oku kusebenza kuphela kwimeko yokuba amanzi okunkcenkceshela angenawo umoya-mpilo kwi-substrate athatyathelwa indawo ngamanzi okunkcenkceshela amatsha.

Ukongeza ekusetyenzisweni kweengcambu, iintsholongwane ezikwindawo engcambu zikwasebenzisa ioksijini. Kunzima ukuqikelela oku kuba akukho kulinganiswa kwenziweyo ngale ndlela. Ekubeni ii-substrates ezintsha zitshintshwa minyaka le, kunokucingelwa ukuba iintsholongwane zidlala indima encinci ekusetyenzisweni kweoksijini.

Lungiselela ubushushu obungqongileyo beengcambu

Ubushushu obungqongileyo benkqubo yengcambu bubaluleke kakhulu ekukhuleni nasekusebenzeni okuqhelekileyo kwenkqubo yengcambu, kwaye ikwayinto ebalulekileyo echaphazela ukufunxwa kwamanzi kunye nezondlo yinkqubo yengcambu.

Ubushushu obuphantsi kakhulu be-substrate (ubushushu beengcambu) bunokubangela ubunzima ekufunxeni amanzi. Kwi-5℃, ukufunxwa kuphantsi ngama-70% ~ 80% kunakwi-20℃. Ukuba ubushushu obuphantsi be-substrate buhamba nobushushu obuphezulu, kuya kukhokelela ekubuneni kwezityalo. Ukufunxwa kwee-ion ngokucacileyo kuxhomekeke kubushushu, nto leyo ethintela ukufunxwa kwee-ion kubushushu obuphantsi, kwaye uvakalelo lwezinto ezahlukeneyo zezakhamzimba kubushushu lwahlukile.

Ubushushu obuphezulu kakhulu be-substrate abunamsebenzi, kwaye bunokukhokelela kwinkqubo yeengcambu enkulu kakhulu. Ngamanye amazwi, kukho ukusasazwa okungalinganiyo kwezinto ezomileyo kwizityalo. Ngenxa yokuba inkqubo yeengcambu inkulu kakhulu, ilahleko ezingafunekiyo ziya kwenzeka ngokuphefumla, kwaye le nxalenye yamandla alahlekileyo ibinokusetyenziselwa inxalenye yokuvuna yesityalo. Kubushushu obuphezulu be-substrate, umxholo we-oksijini enyibilikisiweyo uphantsi, nto leyo enefuthe elikhulu kumxholo we-oksijini kwindawo yeengcambu kune-oksijini etyiwa ziintsholongwane. Inkqubo yeengcambu itya i-oksijini eninzi, kwaye ide ikhokelele kwi-hypoxia kwimeko ye-substrate embi okanye isakhiwo somhlaba, ngaloo ndlela kunciphisa ukufunxwa kwamanzi kunye nee-ion.

Gcina umthamo ofanelekileyo wokugcina amanzi kwi-matrix.

Kukho unxibelelwano olubi phakathi komxholo wamanzi kunye nomxholo wepesenti weoksijini kwi-matrix. Xa umxholo wamanzi usanda, umxholo weoksijini uyancipha, kwaye ngokuchaseneyo. Kukho uluhlu olubalulekileyo phakathi komxholo wamanzi kunye neoksijini kwi-matrix, oko kukuthi, umxholo wamanzi we-80% ~ 85% (Umfanekiso 5). Ukugcinwa kwexesha elide komxholo wamanzi ongaphezulu kwe-85% kwi-substrate kuya kuchaphazela ukunikezelwa kweoksijini. Uninzi lonikezelo lweoksijini (75% ~ 90%) ludlula kwiimbobo kwi-matrix.

Ukongezwa kokunkcenkceshela kumxholo weoksijini kwi-substrate

Ukukhanya kwelanga okungakumbi kuya kukhokelela ekusetyenzisweni okuphezulu kweoksijini kunye noxinzelelo lweoksijini oluphantsi kwiingcambu (Umfanekiso 6), kwaye iswekile engaphezulu iya kwenza ukusetyenziswa kweoksijini kube phezulu ebusuku. Ukuphefumla kunamandla, ukufunxwa kwamanzi kukhulu, kwaye kukho umoya omninzi kunye neoksijini engaphezulu kwisiseko. Kungabonakala ngasekhohlo kuMfanekiso 7 ukuba umxholo weoksijini kwisiseko uya kwanda kancinci emva kokunkcenkceshela phantsi kwemeko yokuba amandla okugcina amanzi kwisiseko aphakamileyo kwaye umxholo womoya uphantsi kakhulu. Njengoko kubonisiwe ngasekunene kuMfanekiso 7, phantsi kwemeko yokukhanya okungcono, umxholo womoya kwisiseko uyanda ngenxa yokufunxwa kwamanzi amaninzi (ngamaxesha afanayo okunkcenkceshela). Impembelelo yokunkcenkceshela kumxholo weoksijini kwisiseko incinci kakhulu kunamandla okugcina amanzi (umxholo womoya) kwisiseko.

Xoxa

Kwimveliso yokwenyani, umxholo weoksijini (umoya) kwindawo yengcambu yesityalo kulula ukuwujonga, kodwa yinto ebalulekileyo ukuqinisekisa ukukhula okuqhelekileyo kwezityalo kunye nophuhliso olusempilweni lweengcambu.

Ukuze ufumane isivuno esiphezulu ngexesha lemveliso yezityalo, kubaluleke kakhulu ukukhusela imeko-bume yenkqubo yeengcambu kwimeko engcono kangangoko kunokwenzeka. Izifundo zibonise ukuba i-O₂umxholo kwindawo yeengcambu ezingaphantsi kwe-4mg/L uya kuba nefuthe elibi ekukhuleni kwesityalo.₂Umxholo okwindawo engqonge iingcambu uphenjelelwa kakhulu kukunkcenkceshela (ubungakanani bokunkcenkceshela kunye nokuphindaphinda), ulwakhiwo lwendawo engqonge iingcambu, umxholo wamanzi kwi-substrate, ubushushu begreenhouse kunye nobushushu be-substrate, kwaye iipatheni ezahlukeneyo zokutyala ziya kwahluka. I-algae kunye neentsholongwane zinobudlelwane obuthile nomxholo we-oksijini kwindawo engqonge iingcambu zezityalo ze-hydroponic. I-Hypoxia ayibangeli nje kuphela uphuhliso olucothayo lwezityalo, kodwa ikwanyusa uxinzelelo lwezifo ezibangelwa ziingcambu (pythium, phytophthora, fusarium) ekukhuleni kweengcambu.

Icebo lokunkcenkceshela linempembelelo enkulu kwi-O₂umxholo kwi-substrate, kwaye ikwayindlela elawulekayo ngakumbi kwinkqubo yokutyala. Ezinye izifundo zokutyala iirozi zifumanise ukuba ukwandisa kancinci umxholo wamanzi kwi-substrate (kusasa) kunokufumana imeko engcono ye-oksijini. Kwi-substrate enomthamo omncinci wokubamba amanzi, i-substrate inokugcina umxholo ophezulu we-oksijini, kwaye kwangaxeshanye, kuyimfuneko ukuphepha umahluko womxholo wamanzi phakathi kwe-substrate ngokusebenzisa ubuninzi bokunkcenkceshela kunye nexesha elifutshane. Okukhona umthamo wokugcina amanzi we-substrate uphantsi, kokukhona umahluko omkhulu phakathi kwe-substrate. I-substrate emanzi, ubuninzi bokunkcenkceshela kunye nexesha elide kuqinisekisa ukutshintshwa komoya okuninzi kunye neemeko ezilungileyo ze-oksijini.

Ukutsalwa kwamanzi kwi-substrate yenye into enefuthe elikhulu kwisantya sokuhlaziya kunye ne-gradient yoxinzelelo lwe-oksijini kwi-substrate, kuxhomekeke kuhlobo kunye nomthamo wamanzi we-substrate. Ulwelo lokunkcenkceshela akufuneki luhlale ezantsi kwe-substrate ixesha elide, kodwa kufuneka lukhutshwe ngokukhawuleza ukuze amanzi okunkcenkceshela amatsha atyebileyo kwi-oksijini akwazi ukufikelela ezantsi kwe-substrate kwakhona. Isantya sokutsalwa kwamanzi sinokuchaphazeleka zizinto ezilula, ezifana ne-gradient ye-substrate kwicala elide nelobubanzi. Okukhona i-gradient inkulu, kokukhona isantya sokutsalwa kwamanzi sikhawuleza. Ii-substrate ezahlukeneyo zinemingxuma eyahlukeneyo kwaye inani leendawo zokuphuma nalo lahlukile.

ISIPHELO

[ulwazi lwesicatshulwa]

Xie Yuanpei. Imiphumo yomxholo weoksijini kwindalo esingqongileyo kwiingcambu zezityalo eziluhlaza okwesibhakabhaka ekukhuleni kwesityalo [J]. Agricultural Engineering Technology, 2022,42(31):21-24.