AmaCytokinins

Ama-hormone ezitshalo afaka amanye abizwa ngama-cytokinins. Kuya ngokujwayeleka ukubathola kumikhiqizo yezentengiso yezolimo, njengoba zingasiza ukukhuphula ikhwalithi nobungako bezithelo zezitshalo ezithile. Lokhu kungenxa yokuthi umsebenzi wawo omkhulu ukuhlukanisa amaseli.

Noma kunjalo ama-phytohormones afundwe kahle kakhulu namuhla futhi zisetshenziswa njalo ezitshalweni, bambalwa kakhulu abantu abazi ukuthi izitshalo zinamahomoni azo. Ukuze kucaciswe ukungabaza ngama-cytokinins, sizophawula kule ndatshana ukuthi ziyini, zenzani, yiziphi izicelo zazo ezingeni lezolimo nokuthi zitholwe ngubani.

Yini ama-cytokinins?

Eyaziwa nangokuthi ama-cytokinins, ama-cytokinins angama-phytohormones, okungukuthi, ama-hormone ezitshalo, inhloso yawo ukukhuthaza ukuhlukaniswa kwamaseli nokwehlukaniswa kwawo. Igama lalaba linemvelaphi yalo egameni elithi "cytokinesis", elihlobene nenqubo yokuhlukaniswa kwamaseli. Lawa mahormone ezitshalo abalulekile ekwakhekeni kwezitho ezitshalweni nasekulawuleni izinqubo ezahlukahlukene zomzimba, njengokulandelayo:

• Ukubusa kwe-apical (umthethonqubo wokukhula)
• I-Photosynthesis
• Ubungqingili
• Isitshalo sokuzivikela (ukumelana namagciwane)
• I-apoptosis (ukufa okuhleliwe)
• Ukubekezelelana nokuvikela izilwane ezidla imifino

Enzani ama-cytokinins?

Isikhathi eside, abalimi basebenzisa ama-phytohormones ahlukahlukene ukuphatha izilimo zabo. Ezinsizeni, zisebenzisa i-IBA ukuthola ukhula lwenkohlakalo, i-2,4-D njenge-herbicide ne-ANA yokwehlisa izithelo. Uma befuna ukukhuthaza ukukhula kwesitshalo nezithelo zaso, imvamisa basebenzisa ama-gibberellins afana ne-gibberellic acid, kuyilapho i-ethephon ijwayele ukusetshenziselwa ukuvuthwa kwezithelo nokuwa kwezitho.

Ngokuqondene nama-cytokinins, ukusetshenziswa kwawo ezingeni lezolimo kukhula kancane kancane. Namuhla kunemikhiqizo eminingana yezentengiselwano amafomula ayo asebenza kakhulu. Ukusetshenziswa kwayo kungenzeka kuzo zonke izinhlobo zemifino, amagilebhisi etafuleni, izitshalo zokuhlobisa, izihlahla zezithelo nezilimo eziningi. Mayelana nezinga lokuphendula kwesitshalo ngasinye, lokhu kucacisiwe futhi kuya ngezici ezahlukahlukene, njengesikhathi sokufaka isicelo noma ubudala besitshalo. Isici esiphawulekayo salezi phytohormones ukuthi umsebenzi wayo uphakeme kakhulu, ngakho-ke amanani adingekayo aphansi impela.

I-athikili ehlobene:

I-Auxin

Inhloso enkulu lapho usebenzisa ama-cytokinins kwezolimo ukwandisa usayizi, ubuningi kanye nekhwalithi yezithelo. Ngokulandelayo sizoxoxa ngezicelo zayo ezivame kakhulu.

Izithelo zokubamba nokukhula

Kunezinhlobo eziningana zemifino lapho ama-cytokinins abonakala ekhuthaza ukubopha izithelo noma ukubamba, ikakhulukazi kwezinenyama. Lo mphumela uyathuthukiswa uma kusetshenziswa ama-gibberellins nama-auxins ezindaweni ezinomqondo ophansi ngasikhathi sinye.

Njengengxenye ebalulekile yokukhula kwezithelo ezinezinyama nezingezona ezomzimba kwenzeka ngokuhlukaniswa kweseli kwezicubu zabo, ama-cytokinins nawo adlala indima ebalulekile kule ndawo. Lapho la ma-phytohormones enziwa ngesikhathi lapho ukuhlukaniswa kwamaseli kukhulu kakhulu, izithelo zigcina ngokuba zinkulu, okugcina kuba nomthelela omuhle esivunweni naseqophelweni lesitshalo.

Ukukhula kwezitshalo

Yize ukusetshenziswa kwe-gibberellic acid kunikeza ukukhula kwezitshalo ngokushesha, ama-cytokinins asetshenziswa kabanzi. Lokhu kunempendulo ehamba kancane kepha enamandla. Balungisa isitshalo ukukhiqiza izithelo nezimbali. Futhi ukusetshenziswa kwama-cytokinins kusebenza kakhulu lapho izitshalo bezingaphansi kwezimo zokucindezeleka. Ngaphezu kwalokho, ukusebenzisa la ma-phytohormones emifinweni esiteji sabantu abadala kungavuselela isivuno, ngaleyo ndlela kwandise futhi kugcine ukukhula kwaso.

Ukuthuthukiswa kwamahlumela e-lateral

Phakathi kwezicelo eziningi zama-cytokinins futhi ukwenziwa kokuvulwa kwe-lateral bud ezinhlotsheni ezahlukahlukene zezitshalo. Kwezinye izimo lapho ukubusa kwehlumela lokugcina kukhulu ngokweqile, ukusetshenziswa kwama-cytokinins kunganciphisa kancane lokhu kubusa futhi ngaleyo ndlela kukhuthaze ukuhluma kwamahlumela asemuva.

I-athikili ehlobene:

I-Microbiology

Ukwakheka nokusatshalaliswa kwe-photosynthates

Njengoba ama-cytokinins adlala indima ebalulekile ekwakheni ama-chloroplast, ziyindlela enhle yokuthuthukisa i-photosynthesis. Ngabo, isibonelo, kukhuthazwa ukuhlanganiswa kwe-chlorophyll nokusebenza kwama-enzyme.

I-senescence ebambezelekile

Ungasho ukuthi ubuningi bulingana nokuguga. AmaCytokinins ngokuvamile ahlobene nokukhiqizwa kwe-chlorophyll. Ngakho-ke, izicubu ezincane zivame ukuba nomsebenzi ophakeme nezinga lale phytohormone. Kokubili ngenxa yengcindezi nobudala, izitho zingalahlekelwa yikhono lazo lokugcina umsebenzi we-metabolic. Ngenxa yalokho, izitshalo zihlanganisa ama-cytokinins amancane.

Ukuhluma kwembewu

Amazinga we-cytokinins angapheli akhulisa okuqukethwe kwawo lapho inqubo yokuhluma iphela, ikukhuthaza kakhulu. Ngokuvamile, lawa ma-phytohormones unethonya elithile enqubeni lapho kusetshenziswa amanye ama-hormone njenge-gibberellic acid ndawonye noma ngaphambilini.

Ubani owathola ama-hormone esitshalo ama-cytokinins?

Ukutholakala kwama-cytokinins kusanda kwenzeka futhi uphenyo lwayo olukhulu lwenziwa kusukela ngonyaka we-1950 nguMiller noSkoog. Labososayensi ababili bathola ukuthi ezinye izicucu zezitshalo ezithile nazo zazinamandla amakhulu okuvula amaseli.

Ngakho-ke, la ma-phytohormones akhuthaza ukwanda kwamaseli futhi agcina ukukhula kwezicubu zezitshalo ezikhuliswe ku-vitro. Ngokushesha ngemuva kwalokhu kutholakala, uMiller noSkoog baphakamisa umbono wokuthi kungenxa yokulinganisela phakathi kwama-auxins nama-cytokinins okungakhiwa izitho zezitshalo. Bobabili ososayensi bazame izitshalo zikagwayi futhi bakhombisa ukuthi ibhalansi ephezulu ye-cytokinin ikhetha ukwakheka kwesiqu, ngenkathi ibhalansi ephezulu ivumela ukwakheka kwezimpande.

AmaCytokinin nawo adlala ezinye izindima ngaphandle kokuba ngabalawuli bokwakhiwa kwezitho ezintsha. Ngaphezu kwalokho, bayangenelela ekucindezelweni kokubusa kwe-apical, ekuvulekeni kwe-stomata nasekuvinjelweni kwe-senescence yamaqabunga.

Njengoba sibona, i-botany yizwe lonke ngaphandle kwalo nsuku zonke lapho singafunda khona izinto eziningi. Uma unemibuzo noma isipiliyoni ngemikhiqizo equkethe ama-cytokinins, ungashiya amazwana.