Izindlela ze-Phytohormones ekukhuleni kwezitshalo
Izitshalo, ngokungafani nezilwane, azikwazi ukusuka endaweni yazo ngenxa yokushintsha kwezindawo. Esikhundleni salokho, zithuthukise uhlelo oluyinkimbinkimbi kakhulu lokubonisana kwamakhemikhali ukulawula ukukhula, intuthuko, kanye nezimpendulo ezishukumisayo zemvelo. Okubalulekile kulolu hlelo yi-phytohormones, iqembu elihlukahlukene lezinto eziphilayo ezenzeka ngokwemvelo ezithonya izinqubo zomzimba ngamanani aphansi. Lesi sihloko sihlola izindlela zama-phytohormones ahlukahlukene, sikhanyise indlela ahlela ngayo i-choreography eyinkimbinkimbi yokukhula kwezitshalo.
Ayini ama-phytohormone?
Ama-phytohormone, noma ama-hormone ezitshalo, angama-molecule amancane athinta cishe zonke izici zokuphila kwezitshalo, okuhlanganisa ukuhlukaniswa kwamaseli, ukunwebeka, ukuhlukanisa, ukuqhakaza, ukuthela izithelo, kanye nezimpendulo zokucindezeleka. Ngokungafani nama-hormone ezilwane akhiqizwa ezinhlayiyeni ezikhethekile, ama-hormone ezitshalo angakhiqizwa ezicutshini ezahlukene ngisho nasezingxenyeni ezahlukene zeseli elilodwa. Ngokuvamile ahlukaniswa ngamaqembu amakhulu amahlanu: ama-auxin, ama-gibberellins, ama-cytokinins, i-abscisic acid, kanye ne-ethylene. I-phytohormone ngayinye inezindima ezihlukile kodwa ingasebenzisana ngokubambisana noma ngokuphambene ukuze ilawule ukukhula nentuthuko yezitshalo.
Ama-Auxins: Amaphayona Okukhula
Ama-Auxin mhlawumbe angama-phytohormone aziwa kakhulu, ahileleke kakhulu ekunwetshweni kwamaseli. I-auxin eyinhloko ezitshalweni yi-indole-3-acetic acid (IAA). Ama-Auxin akhiqizwa eqoqweni le-apical meristem kanye namaqabunga amancane, lapho athuthwa khona aye kwezinye izingxenye zesitshalo.
Indlela Yokusebenza
Ama-Auxins enza kube lula ukukhula kwezitshalo ngokukhuthaza ukwanda kwamaseli. Lokhu akwenza ngokubopha ku-receptor yenuzi eyaziwa ngokuthi i-TIR1. Le receptor, yona, ivuselela izakhi zofuzo ezihilelekile ekukhululeni udonga lweseli, okuvumela amaseli ukuthi athathe amanzi amaningi futhi ande. Ama-Auxins adlala indima ebalulekile ku-phototropism (ukukhula kuya ekukhanyeni) kanye ne-gravitropism (ukukhula ekuphenduleni amandla adonsela phansi), okwenza kube okubalulekile ekuqondisweni kwezitshalo nasekuzinzeni.
Imisebenzi ebalulekile
1. Ukwandiswa kwamaseli: Ama-Auxin akhulula izindonga zamaseli, okwenza kube lula ukukhula kwamaseli.
2. Ukubusa kwe-apical: Zivimbela ukukhula kwamahlumela aseceleni, ziqinisekisa ukuthi isitshalo sikhula siqonde phezulu.
3. Ukuqaliswa kwezimpande: Ama-Auxin akhuthaza ukwakheka kwezimpande eziseceleni nezingena ngaphakathi.
Ama-Gibberellin: Izinto Ezikhuthaza Ukukhula
Ama-Gibberellin (ama-GA) ayiqembu elibalulekile lama-phytohormone ahilelekile ekukhuthazeni ukunwebeka kwesiqu, ukuhluma, kanye nokuqhakaza. Atholakala okokuqala ku-fungus _Gibberella fujikuroi_, ebangela ukuthi izitshalo zelayisi zikhule zibe zinde ngendlela engavamile futhi zibe zinde.
Indlela Yokusebenza
Ama-Gibberellin asebenza ngokuvula ukuwohloka kwamaprotheni e-DELLA, okuyizinto ezivimbela izakhi zofuzo ezikhuthaza ukukhula. Uma amaprotheni e-DELLA esewohlokile, izakhi zofuzo ezikhuthaza ukuhlukana kwamaseli kanye nokwandiswa kwazo ziyavezwa, okuholela ekukhuleni okukhulu.
Imisebenzi ebalulekile
1. Ukwandiswa kwesiqu: Ama-GA akhuthaza ukwanda kweziqu nama-internode.
2. Ukuhluma kwembewu: Kuphula ukungavuki kwembewu futhi kukhuthaze ukuhluma.
3. Ukuqhakaza: Ama-GA ahilelekile ekushintsheni kusukela ekukhuleni kwezitshalo kuya ekukhuleni kokuzala.
Ama-Cytokinins: Abagqugquzeli Besigaba Samaseli
Ama-Cytokinins aziwa kakhulu ngendima yawo ekukhuthazeni ukuhlukana kwamaseli kanye nokwehluka kwawo. Akhiqizwa ezimpandeni futhi athuthelwe kwezinye izingxenye zesitshalo, ethonya amaphethini okukhula kanye nokwabiwa kwezakhamzimba.
Indlela Yokusebenza
Ama-Cytokinins avuselela amaprotheni e-receptor kulwelwesi lweseli, aqala uchungechunge lwezigameko ze-phosphorylation. Lokhu kuholela ekusebenzeni kwezinto ezibangela ukubhalwa kwezakhi zofuzo ezikhuthaza izakhi zofuzo ezibangela ukuhlukaniswa nokwehlukaniswa kwamaseli.
Imisebenzi ebalulekile
1. Ukuhlukaniswa kwamaseli: Ama-Cytokinins akhuthaza i-mitosis, ikakhulukazi ezimpandeni nasemahlumeni.
2. Ukubambezeleka kokuguga: Kubambezela ukuguga kwamaqabunga ngokuthuthukisa ukuqongelela izakhamzimba.
3. Ukuqala kokudubula: Ama-Cytokinins akhuthaza ukwakheka kwehlumela kanye nokukhula kwamahlumela.
I-Abscisic Acid: Isiphenduli Sokucindezeleka
I-Abscisic acid (ABA) ivame ukubizwa ngokuthi "i-hormone yokucindezeleka" ngenxa yendima yayo ebalulekile ekwenzeni izitshalo zikwazi ukusinda ezimweni ezimbi njengesomiso, ukucindezeleka kosawoti, kanye nokubanda.
Indlela Yokusebenza
I-ABA ibopha kuma-receptor aziwa ngokuthi yi-PYR/PYL/RCAR, abese evimbela ama-phosphatase e-PP2C. Lokhu kuvinjelwa kusebenzisa ama-kinase e-SnRK2, okuholela ekufakweni kwe-phosphorylation kwama-targets ahlukahlukene angezansi alawula izimpendulo zokucindezeleka.
Imisebenzi ebalulekile
1. Ukuvalwa kwesisu: I-ABA ibangela ukuvalwa kwe-stomata ukuze kuncishiswe ukulahleka kwamanzi.
2. Ukungavuki kwembewu: I-ABA ibangela ukungavuki kwembewu, iqinisekisa ukuthi ukuhluma kwenzeka kuphela ngaphansi kwezimo ezinhle.
3. Ukuvinjelwa kokukhula: Kunciphisa ukukhula ukuze kongiwe amandla ngezikhathi zokucindezeleka.
I-Ethylene: I-hormone Yokuguga
I-ethylene iyi-hormone yegesi ehilelekile ekulawuleni ukuvuthwa kwezithelo, ukuqunjelwa kwamaqabunga, kanye nokuguga. Naphezu kwesakhiwo sayo esilula, i-ethylene inemiphumela emikhulu emzimbeni wezitshalo.
Indlela Yokusebenza
I-Ethylene ibopha kuma-receptors ku-membrane ye-endoplasmic reticulum, okuholela ekusebenzeni kwe-cascade yesignaling ehilela izici zokubhala ze-EIN2 kanye ne-EIN3. Lokhu ku-cascade kuphumela ekuvezweni kwezakhi zofuzo eziphendula i-ethylene ezilawula imiphumela yazo.
Imisebenzi ebalulekile
1. Ukuvuthwa kwezithelo: I-Ethylene ikhuthaza ukuvuthwa kwezithelo eziningi ngokuthuthukisa izinqubo ezifana nokuwohloka kodonga lwamaseli kanye nokwakheka kombala.
2. Ukuqunjelwa kwamaqabunga: Kwenza kube lula ukuqothuka kwamaqabunga, izimbali nezithelo.
3. Ukuguga: I-ethylene isheshisa izinqubo zokuguga kanye nokuguga.
Ukusebenzisana Phakathi Kwama-Phytohormones
Nakuba i-phytohormone ngayinye inemisebenzi ethile, ivame ukusebenza ngokubambisana ukulawula ukukhula nokuthuthukiswa kwezitshalo. Isibonelo, i-auxin ne-cytokinin zinobudlelwano obuphikisanayo ekukhuleni kwezimpande nehlumela. Ama-Gibberellins kanye ne-abscisic acid anemiphumela ephikisanayo ekuhlumeni kwembewu. I-Ethylene ivame ukulinganisa isenzo samanye ama-hormone, njengokuvimbela ukuthuthwa kwe-auxin.
Ukuxhumana okunjalo kwenza izitshalo zikwazi ukulungisa ukukhula kwazo kanye nezimpendulo endaweni eshintsha njalo, okuqinisekisa ukusinda kanye nempumelelo yokuzala. Lokhu kuxhumana okuyinkimbinkimbi kwamahomoni kuwubufakazi bobunzima kanye nokuzivumelanisa nezimo kwempilo yezitshalo.
Isiphetho
Ukuqonda izindlela zama-phytohormones ekukhuleni kwezitshalo kunikeza ukuqonda okubaluleke kakhulu ngebhayoloji yezitshalo kanye ne-ecology. Kuvula iminyango yentuthuko yezolimo, njengokuthuthukisa izitshalo ezingamelana kangcono nokucindezeleka kwemvelo noma ukuthuthukisa izinqubo zokuvuthwa kwezithelo. Njengoba ucwaningo luqhubeka, imininingwane yama-molecule yalaba balawuli bamakhemikhali abathakazelisayo ngokungangabazeki izoletha ukusetshenziswa okusha kakhulu, ngokuyisisekelo kuthuthukise ikhono lethu lokulima nokusebenzisana nombuso wezitshalo.
