IiCytokinins

Iihormone zezityalo zibandakanya ezinye ezibizwa ngokuba zii cytokinins. Kuya kuxhaphaka ukubafumana kwiimveliso zorhwebo kwezolimo, njengoko zinokunceda ukwandisa umgangatho kunye nobungakanani beziqhamo zezityalo ezithile. Kungenxa yokuba owona msebenzi uphambili kukwahlulahlula iiseli.

Nangona kunjalo phytohormones zifundwe kakuhle kakhulu namhlanje kwaye zisetyenziswa rhoqo kwizityalo, bambalwa kakhulu abantu abazi ukuba izityalo zineehomoni zazo. Ukuze ucacise ukungathandabuzeki malunga ne-cytokinins, siza kuphawula kweli nqaku ukuba ziyintoni na, zenzeni, zithini izicelo zazo kwinqanaba lezolimo kwaye ngubani ozifumeneyo.

Yintoni ii-cytokinins?

Eyaziwa ngokuba zii-cytokinins, ii-cytokinins zii-phytohormones, oko kukuthi, ii-hormone zezityalo, Injongo yabo kukukhuthaza ukwahlulwa kweeseli kunye nokwahluka kwazo. Igama lezi linemvelaphi yalo kwigama elithi "cytokinesis", elihambelana nenkqubo yokwahlulwa kweseli. Ezi hormone zezityalo zibalulekile ekwakhiweni kwamalungu kwizityalo nakulawulo lweenkqubo ezahlukeneyo zomzimba, ezinje ngezi zilandelayo:

• Ulawulo lwe-apical (umgaqo wokukhula)
• Iphotosynthesis
• Ubumnandi
• Ukutyala ukhuseleko (ukumelana nezifo)
• I-apoptosis (ukufa okucwangcisiweyo)
• Ukunyamezelana nokuzikhusela kwizilwanyana ezitya uhlaza

Zenza ntoni ii-cytokinins?

Ixesha elide, amafama asebenzisa izityalo ezahlukeneyo ukuphilisa izityalo zawo. Phakathi kwale mibhobho, basebenzisa i-IBA ukulungiselela ukuntywila, i-2,4-D njengeyeza lokutshabalalisa ukhula kunye ne-ANA yokucheba iziqhamo. Ukuba bafuna ukukhuthaza ukukhula kwesityalo kunye neziqhamo zaso, bahlala besebenzisa i-gibberellins efana ne-gibberellic acid, ngelixa i-ethephon iqhele ukusetyenziselwa ukukhula kweziqhamo kunye nokuwa kwamalungu.

Ngokubhekisele kwii-cytokinins, ukusetyenziswa kwazo kwinqanaba lezolimo kuyanda kancinci kancinci. Namhlanje kukho iimveliso zorhwebo ezininzi iifomula zazo zinokuphinda zisebenze kwakhona. Ukusetyenziswa kwayo kunokwenzeka kuzo zonke iintlobo zemifuno, iidiliya zetafile, izityalo zokuhombisa, imithi yeziqhamo kunye nezinye izityalo. Ngokubhekisele kwinqanaba lokuphendula kwesityalo ngasinye, oku kucacile kwaye kuxhomekeke kwizinto ezahlukeneyo, njengexesha lokufaka okanye iminyaka yesityalo. Eyona nto ibalulekileyo kwezi phytohormones yile Umsebenzi wayo uphezulu kakhulu, ke iidosi eziyimfuneko ziphantsi kakhulu.

Inqaku elidibeneyo:

I-Auxin

Eyona njongo iphambili xa usebenzisa ii-cytokinins kwezolimo ukwandisa ubungakanani, ubungakanani kunye nomgangatho weziqhamo. Emva koko siza kuthetha ngezona zicelo ziqhelekileyo.

Ukugcina iziqhamo kunye nokukhula

Kukho iintlobo ngeentlobo zemifuno apho ii-cytokinins zibonakala ngathi zikhuthaza ukubopha iziqhamo okanye ukubamba ngakumbi kwezenyama. Esi siphumo siyaphuculwa ukuba i-gibberellins kunye nee-auxins zisetyenziswa kwiindawo eziphantsi ngaxeshanye.

Njengengxenye ebalulekileyo yokukhula kweziqhamo ezinenyama kunye nezingezizo ezomzimba zenzeka ngokwahlulwa kweseli yezihlunu zazo, ii-cytokinins zikwadlala indima ebalulekileyo kule ndawo. Xa ezi phytohormones zilawulwa ngexesha apho isahlulo seseli sinamandla kakhulu, iziqhamo ziphelela ekubeni zinkulu, egcina inefuthe elihle kwisivuno kunye nomgangatho wesityalo.

Ukukhula kwezityalo

Nangona ukusetyenziswa kwe-asidi ye-gibberellic kunika ukukhula ngokukhawuleza kwezityalo, ii-cytokinins zisetyenziswa kakhulu. Ezi zinempendulo ecothayo kodwa enamandla. Balungiselela isityalo ukuvelisa iziqhamo kunye neentyatyambo. Ukusetyenziswa kwee-cytokinins kusebenza ngakumbi xa izityalo ziphantsi kweemeko zoxinzelelo. Ukongeza, ukusebenzisa ezi phytohormones kwimifuno ebudaleni kunokuphinda kuvuselele isityalo, oko kusolule kwaye kugcine ukukhula kwazo.

Ukuphuhliswa kwamadlelo asecaleni

Phakathi kwezicelo ezininzi ze-cytokinins nayo Ukungeniswa kokuvulwa kwebhlokile ecaleni kweentlobo ezahlukeneyo zezityalo. Kwezinye iimeko apho ukongamela kwe-terminal bud kugqithisile, ukusetyenziswa kwee-cytokinins kunganciphisa ngokuyinxenye oku kulawula kwaye ngenxa yoko kukhuthaze ukuhluma kwamadlelo asecaleni.

Inqaku elidibeneyo:

Microbiology

Ukuyilwa kunye nokuhanjiswa kweefotosyintes

Njengoko ii-cytokinins zidlala indima ebalulekileyo ekwakheni ii-chloroplast, lukhetho olufanelekileyo lokuphucula ifotosinthesisi. Ngabo, umzekelo, ukhuthazo lwe-chlorophyll kunye nokusebenza kwe-enzyme.

Ukulibala kwe-senescence

Unokuthi i-senescence ilingana nokuguga. IiCytokinins zihlala zinxulumene nemveliso yeklorophyll. Ke, Izicubu ezincinci zihlala zinomsebenzi ophezulu kunye nenqanaba lale phytohormone. Zombini ngenxa yoxinzelelo kunye nobudala, amalungu angaphulukana namandla abo okugcina imisebenzi ye-metabolic. Ngenxa yoko, izityalo zidibanisa ii-cytokinins ezincinci.

Ukuhluma kwembewu

Amanqanaba e-cytokinins anyusa umxholo wawo xa inkqubo yokuhluma iphela, ivuselele ngakumbi. Ngokubanzi, ezi phytohormones banefuthe kwinkqubo xa kusetyenziswa ezinye iihomoni njenge-gibberellic acid kunye okanye ngaphambili.

Ngubani ofumene i-cytokinins yesityalo?

Ukufunyanwa kwee-cytokinins kutsha nje kwaye olona phando lwayo lwenziweyo ukusukela ngonyaka we-1950 nguMiller noSkoog. Oososayensi babini bafumanise ukuba ezinye izicatshulwa zezityalo ezithile zazinamandla amakhulu okuvula iiseli.

Ke ngoko, ezi phytohormones zikhuthaza ukwanda kweeseli kunye nokugcina ukukhula kwezicubu zezityalo esele zikhule kwi-vitro. Kungekudala emva kokufunyanwa, uMiller noSkoog bacebisa ithiyori yokuba Ngombulelo kubhalansi phakathi kwee-ains kunye nee-cytokinins ezinokuthi zenziwe ngamalungu ezityalo. Zombini izazinzulu zizamile kwizityalo zecuba kwaye zabonisa ukuba umlinganiso ophezulu wecytokinin wawuthanda ukwakheka kwesiqu, ngelixa umlinganiso ophezulu we-auxin wawuthanda ukwakheka kweengcambu.

IiCytokinins zikwadlala nezinye iindima ngaphandle kokuba ngabalawuli bokubunjwa kwamalungu amatsha. Ukongeza, bayangenelela kuxinzelelo lolawulo lwe-apical, ekuvuleni i-stomata kunye nokuthintela i-senescence yamagqabi.

Njengoko sibona, i-botany lihlabathi liphela ngaphandle kwayo yonke imihla esinokufunda ngakumbi nangakumbi ngezinto. Ukuba unayo nayiphi na imibuzo okanye amava kunye neemveliso eziqukethe ii-cytokinins, ungasishiya nezimvo.