Ukukhanya kunikeza izitshalo amandla adingekayo kwi-photosynthesis, okuzivumela ukuthi zikhiqize izinto eziphilayo kanyeguqula amandla ngesikhathi sokukhula nentuthuko. Ukukhanya kunikeza izitshalo amandla adingekayo futhi kuyisisekelo sokuhlukaniswa kwamaseli nokwehlukaniswa kwawo, ukwakheka kwe-chlorophyll, ukukhula kwezicubu kanye nokunyakaza kwesisu. Ukuqina kokukhanya, isikhathi sokukhanya kanye nekhwalithi yokukhanya kudlala indima ebalulekile kulezi zinqubo. Ukuguqulwa koshukela ezitshalweni kuhilela izindlela eziningi zokulawula. Ukukhanya, njengenye yezici zokulawula, kuthinta ukwakheka kodonga lweseli, ama-granule esitashi, ukwakheka kwe-sucrose kanye nokwakheka kwama-bundle emithambo yegazi. Ngokufanayo, kumongo wokuguqulwa koshukela okulawulwa ukukhanya, izinhlobo zikashukela kanye nezakhi zofuzo nazo ziyathinteka. Sihlole izizindalwazi ezikhona futhi sathola ukubuyekezwa okumbalwa okufanele. Ngakho-ke, lesi sihloko sifingqa imiphumela yokukhanya ekukhuleni nasekuthuthukisweni kwezitshalo kanye nokuguqulwa koshukela futhi sixoxa ngezindlela zemiphumela yokukhanya ezitshalweni ngokuningiliziwe, sinikeza ukuqonda okusha ngezindlela zokulawula zokukhula kwezitshalo ngaphansi kwezimo zokukhanya ezahlukene.
Ukukhanya kunikeza amandla e-photosynthesis yezitshalo futhi kusebenza njengesignali yemvelo elawula izici eziningi ze-physiology yezitshalo. Izitshalo zingazwa izinguquko ezimweni zokukhanya kwangaphandle ngama-photoreceptor ahlukahlukene njenge-phytochromes nama-phototropins futhi zimise izindlela ezifanele zokubonisa izimpawu ukulawula ukukhula nokuthuthukiswa kwazo. Ngaphansi kwezimo zokukhanya okuphansi, okuqukethwe okuphelele kwezitshalo ezomile kuyehla, njengoba kwenza izinga le-photosynthesis, izinga lokuphefumulela, ukuhamba kwesisu, kanye nobubanzi besiqu. Ngaphezu kwalokho, ukuqina kokukhanya kuyinqubo ebalulekile yokulawula okuguquguqukayo njengokuhluma kwezitshalo, ukwanda kwamaqabunga nokukhula, ukuthuthukiswa kwesisu, i-photosynthesis, kanye nokuhlukaniswa kwamaseli. Ikhwalithi yokukhanya edluliselwa ngama-photoreceptors ilawula umjikelezo wokuphila wezitshalo wonke, kanye nekhwalithi yokukhanya ehlukile enemiphumela ehlukile ekubunjweni kwezitshalo, i-photosynthesis, ukukhula kanye nokuthuthukiswa kwezitho. Izitshalo zingalawula ukukhula kwazo kanye nokuthuthukiswa kwazo ngokuphendula isikhathi se-photo, okukhuthaza izinqubo ezifana nokuhluma kwembewu, ukuqhakaza kwezimbali kanye nokuvuthwa kwezithelo. Iphinde ihileleke ezimpendulweni zezitshalo ezicini ezimbi, zivumelane nezinguquko ezahlukahlukene zesizini (Bao et al., 2024; Chen et al., 2024; Shibaeva et al., 2024).
Ushukela, into eyisisekelo yokukhula nokuthuthukiswa kwezitshalo, udlula enkambisweni eyinkimbinkimbi yokuthutha nokuqoqana ethonywa futhi ilawulwa yizici eziningi. Ukuguqulwa koshukela ezitshalweni kuhlanganisa ukwakheka, ukuguquguquka, ukusetshenziswa, kanye nokuguqulwa koshukela ezitshalweni, okuhlanganisa ukuthuthwa kwe-sucrose, ukudluliselwa kwesignali, kanye nokwakheka kwesitashi kanye ne-cellulose (Kudo et al., 2023; Li et al., 2023b; Lo Piccolo et al., 2024). Ukuguqulwa koshukela kusebenzisa futhi kulawula ushukela ngempumelelo, kuhlanganyela ekuzivumelaniseni nezitshalo nezinguquko zemvelo, futhi kunikeza amandla okukhula nokuthuthukiswa kwezitshalo. Ukukhanya kuthonya ukuguqulwa koshukela ezitshalweni nge-photosynthesis, ukusabalalisa ushukela, kanye nokulawulwa kwesikhathi se-photoperiod, kanye nezinguquko ezimweni zokukhanya ezibangela izinguquko kuma-metabolites ezitshalo (Lopes et al., 2024; Zhang et al., 2024). Lokhu kubuyekezwa kugxile emiphumeleni yokukhanya ekusebenzeni kwe-photosynthesis yezitshalo, ukukhula nokuthuthukiswa, kanye nokuguqulwa koshukela. Lesi sihloko sixoxa nangenqubekela phambili ocwaningweni ngemiphumela yokukhanya ezicini zomzimba wezitshalo, ngenhloso yokuhlinzeka ngesisekelo semfundiso yokusebenzisa ukukhanya ukulawula ukukhula kwezitshalo nokuthuthukisa isivuno kanye nekhwalithi. Ubudlelwano phakathi kokukhanya nokukhula kwezitshalo abukacaci futhi buphakamisa iziqondiso zocwaningo ezingaba khona.
Ukukhanya kunezakhiwo eziningi, kodwa amandla akho kanye nekhwalithi kunomthelela omkhulu ezitshalweni. Amandla okukhanya avame ukusetshenziswa ukukala ukukhanya komthombo wokukhanya noma amandla okukhanya. Ngokusekelwe kubude besikhathi, ukukhanya kungahlukaniswa kube yi-ultraviolet, ebonakalayo, kanye ne-infrared. Ukukhanya okubonakalayo kuhlukaniswa kabanzi kube obomvu, o-orenji, ophuzi, oluhlaza okotshani, oluhlaza okwesibhakabhaka, i-indigo, kanye ne-violet. Izitshalo ngokuyinhloko zimunca ukukhanya okubomvu nokuluhlaza okwesibhakabhaka njengamandla ayinhloko e-photosynthesis (Liang et al., 2021).
Kodwa-ke, ukusetshenziswa kwekhwalithi yokukhanya ehlukile ensimini, ukulawulwa kwe-photoperiod, kanye nemiphumela yokushintsha kokukhanya ezitshalweni kuyizinkinga eziyinkimbinkimbi ezidinga ukuxazululwa. Ngakho-ke, sikholelwa ukuthi ukusetshenziswa okunengqondo kwezimo zokukhanya kungakhuthaza ngempumelelo ukuthuthukiswa kwe-ecology yokumodela izitshalo kanye nokusetshenziswa kwezinto kanye namandla okuhamba kancane, ngaleyo ndlela kuthuthukiswe ukusebenza kahle kokukhula kwezitshalo kanye nezinzuzo zemvelo. Sisebenzisa inkolelo-mbono yokwenza ngcono imvelo, ukuzivumelanisa kwe-photosynthesis yezitshalo nokukhanya kwesikhathi esiphakathi nesikhathi eside kufakwa kumodeli yesistimu yoMhlaba ukuze kuncishiswe ukungaqiniseki kokumodela kwe-photosynthesis futhi kuthuthukiswe ukunemba kwemodeli (uLuo noKeenan, 2020). Izitshalo zivame ukuzivumelanisa nokukhanya kwesikhathi esiphakathi nesikhathi eside, futhi amandla azo e-photosynthesis kanye nokusebenza kahle kokusetshenziswa kwamandla okukhanya esikhathini esiphakathi nesikhathi eside kungathuthukiswa, ngaleyo ndlela kufezwe ngempumelelo ukumodela kwe-ecology kokulinywa kwensimu. Ngaphezu kwalokho, lapho kusetshenziswa ukutshala ensimini, amandla okukhanya alungiswa ngokuya ngezinhlobo zezitshalo kanye nezici zokukhula ukuze kukhuthazwe ukukhula kwezitshalo okunempilo. Ngesikhathi esifanayo, ngokulungisa isilinganiso sekhwalithi yokukhanya nokulingisa umjikelezo wokukhanya wemvelo, kungenzeka ukusheshisa noma ukunciphisa ijubane lokuqhakaza nokuthela kwezitshalo, ngaleyo ndlela kufezwe ukulawulwa okunembile kwezemvelo kokumodela kwensimu.
Ukuguqulwa kukashukela okulawulwa ukukhanya ezitshalweni kunegalelo ekuthuthukiseni ukukhula nokuthuthukiswa kwezitshalo, ukuzivumelanisa nezimo kanye nokumelana nezinto ezibangela ukucindezeleka kwemvelo. Ushukela, njengama-molecule okubonisa izimpawu, ulawula ukukhula nokuthuthukiswa kwezitshalo ngokusebenzisana namanye ama-molecule okubonisa izimpawu (isib. ama-phytohormone), ngaleyo ndlela kuthonye izinqubo zomzimba zezitshalo (Mukarram et al., 2023). Sikholelwa ukuthi ukufunda izindlela zokulawula ezixhumanisa indawo yokukhanya nokukhula kwezitshalo kanye nokuguqulwa kukashukela kuzoba isu eliphumelelayo lezomnotho lokuqondisa imikhuba yokuzalanisa nokukhiqiza. Ngokuthuthuka kobuchwepheshe, ucwaningo lwesikhathi esizayo ekukhethweni kwemithombo yokukhanya, njengobuchwepheshe bokukhanyisa okwenziwe kanye nokusetshenziswa kwama-LED, lungenziwa ukuze kuthuthukiswe ukusebenza kahle kokukhanya kanye nokukhiqizwa kwezitshalo, kuhlinzekwe ngamathuluzi okulawula amaningi ocwaningo lokukhula nokuthuthukiswa kwezitshalo (Ngcobo noBertling, 2024). Kodwa-ke, ubude bokukhanya okubomvu nokuluhlaza okwesibhakabhaka yiwona asetshenziswa kakhulu ocwaningweni lwamanje ngemiphumela yekhwalithi yokukhanya ezitshalweni. Ngakho-ke, ngokuphenya imiphumela yezimfanelo zokukhanya ezahlukahlukene njenge-orange, ophuzi nohlaza ekukhuleni nasekuthuthukisweni kwezitshalo, singathuthukisa izindlela zokusebenza kwemithombo yokukhanya eminingi ezitshalweni, ngaleyo ndlela sisebenzisa ngempumelelo izimfanelo ezahlukene zokukhanya ezisetshenzisweni ezisebenzayo. Lokhu kudinga ucwaningo olwengeziwe kanye nokuthuthukiswa. Izinqubo eziningi zokukhula kwezitshalo zilawulwa yi-phytochromes kanye ne-phytohormones. Ngakho-ke, ithonya lokusebenzisana kwamandla e-spectral kanye nezinto ezingokwemvelo ekukhuleni kwezitshalo kuzoba yisiqondiso esibalulekile socwaningo lwesikhathi esizayo. Ngaphezu kwalokho, ucwaningo olujulile lwezindlela zama-molecule lapho izimo zokukhanya ezahlukene zithinta khona ukukhula kwezitshalo, i-metabolism kashukela, kanye nemiphumela yokusebenzisana kwezinto eziningi zemvelo ezitshalweni, kuzofaka isandla ekuthuthukisweni okuqhubekayo nasekusetshenzisweni kwamandla ezitshalo ezahlukahlukene, okuzovumela ukusetshenziswa kwazo ezindaweni ezifana nezolimo kanye ne-biomedicine.
Isikhathi sokuthunyelwe: Septhemba 11-2025