Abalawuli bokukhula kwezitshalo (ama-PGR)kuyindlela engabizi kakhulu yokuthuthukisa ukuzivikela kwezitshalo ngaphansi kwezimo zokucindezeleka. Lolu cwaningo luhlole ikhono lamabiliAma-PGR, i-thiourea (TU) kanye ne-arginine (Arg), ukuze kuncishiswe ukucindezeleka kukasawoti kukolweni. Imiphumela ibonise ukuthi i-TU ne-Arg, ikakhulukazi uma zisetshenziswa ndawonye, zingalawula ukukhula kwezitshalo ngaphansi kokucindezeleka kukasawoti. Ukwelashwa kwazo kwandise kakhulu imisebenzi yama-enzyme e-antioxidant ngenkathi kunciphisa amazinga ezinhlobo ze-oxygen ezisabelayo (ROS), i-malondialdehyde (MDA), kanye nokuvuza kwe-electrolyte okuhlobene (REL) ezitshalweni zikakolweni. Ngaphezu kwalokho, lokhu kwelashwa kunciphisa kakhulu ukugxila kwe-Na+ kanye ne-Ca2+ kanye nesilinganiso se-Na+/K+, ngenkathi kukhulisa kakhulu ukugxila kwe-K+, ngaleyo ndlela kugcina ibhalansi ye-ion-osmotic. Okubaluleke kakhulu, i-TU ne-Arg zandise kakhulu okuqukethwe kwe-chlorophyll, izinga le-photosynthetic eliphelele, kanye nesilinganiso sokushintshana kwegesi kwezithombo zikakolweni ngaphansi kokucindezeleka kukasawoti. I-TU ne-Arg ezisetshenziswa zodwa noma zihlangene zingandisa ukuqongelela kwezinto ezomile ngo-9.03–47.45%, futhi ukwanda kwaba kukhulu kakhulu lapho zisetshenziswa ndawonye. Ekuphetheni, lolu cwaningo luqokomisa ukuthi ukugcina i-homeostasis ye-redox kanye nebhalansi ye-ion kubalulekile ekuthuthukiseni ukubekezelelana kwezitshalo ekucindezelweni kukasawoti. Ngaphezu kwalokho, i-TU ne-Arg zanconywa njengezingaba khonaabalawuli bokukhula kwezitshalo,ikakhulukazi uma kusetshenziswa ndawonye, ukuthuthukisa isivuno sikakolweni.
Izinguquko ezisheshayo kwesimo sezulu kanye nemikhuba yezolimo zandisa ukuwohloka kwezindawo zemvelo zezolimo1. Omunye wemiphumela emibi kakhulu ukuswakama komhlaba, okusongela ukuphepha kokudla emhlabeni jikelele2. Ukuswakama komhlaba njengamanje kuthinta cishe ama-20% omhlaba olimekayo emhlabeni jikelele, futhi lesi sibalo singakhuphuka sifinyelele kuma-50% ngo-20503. Ukucindezeleka kukasawoti-alkali kungabangela ukucindezeleka kwe-osmotic ezimpandeni zezitshalo, okuphazamisa ibhalansi ye-ionic esitshalweni4. Izimo ezinjalo ezimbi zingaholela nasekuqhekekeni kwe-chlorophyll okusheshayo, ukwehla kwamazinga e-photosynthesis, kanye nokuphazamiseka kwe-metabolic, ekugcineni okuholela ekunciphiseni kwesivuno sezitshalo5,6. Ngaphezu kwalokho, umphumela ovamile ongathi sína ukwanda kokukhiqizwa kwezinhlobo ze-oxygen ezisebenzayo (ROS), okungabangela umonakalo we-oxidative kuma-biomolecule ahlukahlukene, kufaka phakathi i-DNA, amaprotheni, kanye nama-lipid7.
Ukolweni (i-Triticum aestivum) ungomunye wezitshalo ezibaluleke kakhulu emhlabeni. Akuyona nje kuphela isitshalo se-cereal esikhula kakhulu kodwa futhi sisitshalo esibalulekile sezentengiselwano8. Kodwa-ke, ukolweni uzwela usawoti, okungavimbela ukukhula kwawo, kuphazamise izinqubo zawo zomzimba kanye nezamakhemikhali, futhi kunciphise kakhulu isivuno sawo. Amasu amakhulu okunciphisa imiphumela yokucindezeleka kukasawoti afaka ukuguqulwa kwezakhi zofuzo kanye nokusetshenziswa kwezilawuli zokukhula kwezitshalo. Izinto eziphilayo eziguqulwe izakhi zofuzo (i-GM) ukusetshenziswa kokuhlelwa kwezakhi zofuzo kanye namanye amasu okuthuthukisa izinhlobo zikakolweni ezibekezelela usawoti9,10. Ngakolunye uhlangothi, izilawuli zokukhula kwezitshalo zithuthukisa ukubekezelela usawoti kukolweni ngokulawula imisebenzi yomzimba kanye namazinga ezinto ezihlobene nosawoti, ngaleyo ndlela kuncishiswe umonakalo wokucindezeleka11. Lezi zilawuli ngokuvamile zamukelwa kakhulu futhi zisetshenziswa kabanzi kunezindlela zokuguqula izakhi zofuzo. Zingathuthukisa ukubekezelela kwezitshalo ezingcindezini ezahlukahlukene ze-abiotic ezifana nosawoti, isomiso kanye nezinsimbi ezisindayo, futhi zikhuthaze ukuhluma kwembewu, ukumuncwa kwezakhamzimba kanye nokukhula kokuzala, ngaleyo ndlela zandise isivuno sezitshalo kanye nekhwalithi. 12 Izilawuli zokukhula kwezitshalo zibalulekile ekuqinisekiseni ukukhula kwezitshalo nokugcina isivuno kanye nekhwalithi ngenxa yobungane bazo emvelweni, ukulula kokusetshenziswa, ukusebenza kahle kwezindleko kanye nokusebenza kahle. 13 Kodwa-ke, njengoba lawa ma-modulator enezindlela ezifanayo zokusebenza, ukusebenzisa eyodwa yawo kuphela kungase kungasebenzi. Ukuthola inhlanganisela yabalawuli bokukhula abangathuthukisa ukubekezelela usawoti kukolweni kubalulekile ekuzaleni ukolweni ngaphansi kwezimo ezimbi, kwandise isivuno futhi kuqinisekiswe ukuvikeleka kokudla.
Azikho izifundo ezihlola ukusetshenziswa okuhlangene kwe-TU ne-Arg. Akucaci ukuthi le nhlanganisela entsha ingakhuthaza ukukhula kukakolweni ngokubambisana ngaphansi kokucindezeleka kukasawoti. Ngakho-ke, inhloso yalolu cwaningo kwakuwukuthola ukuthi laba balawuli bokukhula ababili bangayinciphisa yini ngokubambisana imiphumela emibi yokucindezeleka kukasawoti kukolweni. Ngenxa yalokhu, senze ukuhlolwa kwezithombo zikakolweni zesikhashana ukuze sihlole izinzuzo zokusetshenziswa okuhlangene kwe-TU ne-Arg kukolweni ngaphansi kokucindezeleka kukasawoti, sigxile ebhalansi ye-redox kanye ne-ionic yezitshalo. Sacabanga ukuthi inhlanganisela ye-TU ne-Arg ingasebenza ngokubambisana ukunciphisa umonakalo we-oxidative obangelwa ukucindezeleka kukasawoti nokuphatha ukungalingani kwe-ionic, ngaleyo ndlela kuthuthukiswe ukubekezelelana kukasawoti kukolweni.
Okuqukethwe kwe-MDA kwamasampula kunqunywe ngendlela ye-thiobarbituric acid. Kala ngokunembile u-0.1 g wempuphu yesampula entsha, khipha nge-1 ml ye-10% trichloroacetic acid imizuzu eyi-10, faka i-centrifuge ku-10,000 g imizuzu engama-20, bese uqoqa i-supernatant. I-extract ixutshwe nevolumu elinganayo ye-0.75% thiobarbituric acid futhi yafakwa ku-100 °C imizuzu eyi-15. Ngemva kokufushaniswa, i-supernatant yaqoqwa nge-centrifugation, kwathi amanani e-OD ku-450 nm, 532 nm, kanye no-600 nm alinganiswa. Ukuhlushwa kwe-MDA kwabalwa kanje:
Ngokufanayo nokwelashwa kwezinsuku ezi-3, ukusetshenziswa kwe-Arg kanye ne-Tu nakho kwandise kakhulu imisebenzi ye-enzyme ye-antioxidant yezithombo zikakolweni ngaphansi kokwelashwa kwezinsuku ezi-6. Ukuhlanganiswa kwe-TU kanye ne-Arg kwakusasebenza kakhulu. Kodwa-ke, ezinsukwini ezi-6 ngemuva kokwelashwa, imisebenzi yama-enzyme amane e-antioxidant ngaphansi kwezimo ezahlukene zokwelashwa ibonise ukuthambekela kokwehla uma kuqhathaniswa nezinsuku ezi-3 ngemuva kokwelashwa (Isithombe 6).
I-Photosynthesis iyisisekelo sokuqongelela kwezinto ezomile ezitshalweni futhi yenzeka kuma-chloroplast, azwela kakhulu kusawoti. Ukucindezeleka kukasawoti kungaholela ekuqhekekeni kwe-plasma membrane, ukuphazamiseka kwebhalansi ye-osmotic yeselula, ukulimala kwe-chloroplast ultrastructure36, kubangele ukuwohloka kwe-chlorophyll, kunciphise umsebenzi wama-enzyme omjikelezo weCalvin (kufaka phakathi i-Rubisco), futhi kunciphise ukudluliselwa kwama-electron kusuka ku-PS II kuya ku-PS I37. Ngaphezu kwalokho, ukucindezeleka kukasawoti kungabangela ukuvalwa kwesisu, ngaleyo ndlela kunciphise ukugcwala kwe-CO2 yamaqabunga futhi kuvimbele i-photosynthesis38. Imiphumela yethu iqinisekisile okutholakele ngaphambilini ukuthi ukucindezeleka kukasawoti kunciphisa ukuhamba kwesisu kukolweni, okuholela ekunciphiseni izinga lokuphefumula kwamaqabunga kanye nokugcwala kwe-CO2 yangaphakathi kweseli, okuholela ekugcineni ekwehleni kwamandla e-photosynthesis kanye nokwehla kwe-biomass kakolweni (Izithombe 1 no-3). Okuphawulekayo ukuthi ukusetshenziswa kwe-TU kanye ne-Arg kungathuthukisa ukusebenza kahle kwe-photosynthesis kwezitshalo zikakolweni ngaphansi kokucindezeleka kukasawoti. Ukuthuthuka kokusebenza kahle kwe-photosynthesis kwakubaluleke kakhulu lapho i-TU kanye ne-Arg kusetshenziswa ngesikhathi esisodwa (Isithombe 3). Lokhu kungase kube ngenxa yokuthi i-TU ne-Arg zilawula ukuvulwa nokuvalwa kwesisu, ngaleyo ndlela zithuthukise ukusebenza kahle kwe-photosynthesis, okusekelwa yizifundo zangaphambilini. Isibonelo, uBencarti nabanye bathole ukuthi ngaphansi kokucindezeleka kukasawoti, i-TU yandise kakhulu ukuhamba kwesisu, izinga lokumuncwa kwe-CO2, kanye nokusebenza kahle kwe-quantum kwe-PSII photochemistry ku-Atriplex portulacoides L.39. Nakuba kungekho mibiko eqondile efakazela ukuthi i-Arg ingalawula ukuvulwa nokuvalwa kwesisu ezitshalweni ezivezwe ekucindezelweni kukasawoti, uSilveira nabanye babonise ukuthi i-Arg ingakhuthaza ukushintshaniswa kwegesi emaqabunga ngaphansi kwezimo zesomiso22.
Ngamafuphi, lolu cwaningo luqokomisa ukuthi naphezu kwezindlela zazo zokusebenza ezahlukene kanye nezakhiwo ze-physicochemical, i-TU ne-Arg zinganikeza ukumelana okufanayo nokucindezeleka kwe-NaCl ezitshalweni zikakolweni, ikakhulukazi uma zisetshenziswa ndawonye. Ukusetshenziswa kwe-TU ne-Arg kungenza uhlelo lokuvikela ama-enzyme e-antioxidant ezitshalweni zikakolweni lusebenze, kuncishiswe okuqukethwe yi-ROS, futhi kugcinwe ukuzinza kwama-lipid e-membrane, ngaleyo ndlela kugcinwe i-photosynthesis kanye nebhalansi ye-Na+/K+ ezitshalweni. Kodwa-ke, lolu cwaningo lunemikhawulo; yize umphumela wokubambisana we-TU ne-Arg uqinisekisiwe futhi indlela yayo yokusebenza yomzimba ichazwe ngezinga elithile, indlela yokusebenza yama-molecule eyinkimbinkimbi kakhulu ayicaci. Ngakho-ke, kudingeka ucwaningo olwengeziwe ngendlela yokubambisana ye-TU ne-Arg kusetshenziswa izindlela ze-transcriptomic, metabolomic nezinye.
Amasethi edatha asetshenzisiwe kanye/noma ahlaziywe ngesikhathi socwaningo lwamanje ayatholakala kumbhali ohambisanayo uma ecelwa ngokufanele.
Isikhathi sokuthunyelwe: Meyi-19-2025