Impela ngenkathi useyingane isikole sikufundise nge- ubisi oluhlaza kanye nobisi olucutshungulwayo yemithi. Ubisi oluhlaza luyinhlanganisela yamanzi nosawoti wamaminerali osetshenziselwa isitshalo ukukhiqiza ukudla. Inhloso ukufinyelela emaqabungeni futhi lokhu kuthutha kwenziwa ngeziqu ngamashubhu amahle kakhulu abizwa ngemikhumbi yokhuni. Ngemuva kwenqubo yokukhiqiza, kukhiqizwa insizi echaziwe, okuyiyona esetshenziselwa ukondla isitshalo.
Kulesi sihloko sizokutshela konke odinga ukukwazi mayelana nobisi oluhlaza nolucubunguliwe.
Yini eyakha ubisi oluhlaza nolusetshenzisiwe
I-Sap ibizwa ngokuthi into ewuketshezi edluliswa ngezicubu eziguqukayo zesitshalo, futhi izicubu eziqhubayo zesitshalo zingenye yezicubu zezitshalo eziningi ezikhona. Ngenxa yokukhiqizwa kobisi, izitshalo zingazenzela imithombo yazo yokudla. Kodwa yini eyakha ubisi? Ubisi lwesitshalo luqukethe usawoti omningi wamaminerali, ama-amino acid, namahomoni. Kodwa-ke, lolu ketshezi lwamanzi lwakhiwe ikakhulukazi ngamanzi, ikakhulukazi ama-98%, yize lokhu kungahluka kohlobo olulodwa kuye kolunye.
Kunezinhlobo ezimbili zempuphu ezitholakala ezitshalweni: ubisi oluhlaza kanye nobisi olusetshenzisiwe. Izici zobisi lwangempela ukuthi lwakhiwa ezimpandeni futhi luyiswa nge-xylem luye kuso sonke isitshalo. Ngemuva kwenqubo ye-photosynthesis, iba yincindi ebucayi, ethuthwa isuka emaqabungeni iye ezimpandeni yi-phloem eya kolunye uhlangothi.
Kubalulekile ukwazi ukuthi ukukhuthaza ukukhula kwezitshalo zethu, ukukhiqizwa kobisi kwezinhlobo eziningi kuyaqondana nesikhathi lapho izinga lokushisa likhuphuka. Ngokwalesi sizathu, ukuthena okuningi kwenziwa ebusika ukugwema ukulahleka kwale nto ebalulekile empilweni yezitshalo.
Izinhlobo
Ubisi buhanjiswa yizicubu eziqhubayo zesitshalo: i-xylem ne-phloem. Ngamunye wabo unesibopho sokuhambisa osaps ababili abakhona:
- Ubisi oluhlaza: Kuyinto engamanzi ekhiqizwa izimpande emunca amanzi nosawoti wamaminerali. Lokhu kuthuthwa kusuka ezimpandeni kuya emaqabunga ezitsheni zokhuni.
- I-SAP enwetshiwe: Kungumphumela wokuguqulwa kwesiphu sangempela ngemuva kwenqubo ye-photosynthesis. Ngenxa ye-phloem, ithuthwa iye kolunye uhlangothi, ihambisa ukudla kusuka emaqabungeni naseziqu ngokuhambisa imithambo yegazi ize ifinyelele ezimpandeni ngemithambo yegazi. Ubisi olucutshungulwayo ngukudla kweqiniso kwezitshalo ngoba alinawo usawoti wamanzi namaminerali kuphela, kepha futhi liqukethe noshukela nezilawuli zezitshalo.
Imisebenzi yempuphu eluhlaza kanye nesiphu esetshenzisiwe
Njengoba sishilo ngaphambili, kungukudla kwangempela izitshalo ezinakho. Ngalesi sizathu, sinezinhlobo ezahlukahlukene zemisebenzi efana nale elandelayo:
- Umsebenzi oyinhloko wensisi ukondla isitshalo ukuze sikhule futhi sisebenze ngokujwayelekile.
- Ubisi lunomthwalo wokuhambisa izakhi zokulandela ngomkhondo kanye nama-macroelements emaqabungeni e-photosynthesis, ngaleyo ndlela kuthuthelwe ukudla kuzo zonke izingxenye zesitshalo.
- Lapho nje le nto seyiguqulwe yaba ubisi olucutshungulwayo, ingasetshenziswa hhayi njengokudla kwezitshalo kuphela, kodwa futhi njenge umthombo wokudla kwezilwane ngisho nabantu. Eqinisweni, izinhlobo ezithile zobisi ezikhiqizwa yizinhlobo ezahlukene zezitshalo nazo zisetshenziselwa ukwelapha kwazo. Isibonelo, ubisi lwe-birch luyaziwa kahle.
- Ngosizo lwe-sap, izitshalo zingathuthukisa umthetho wazo wokushisa ngokudlulela kwamaqabunga neziqu zezitshalo.
Vakashela esiqongweni sezihlahla
Ngenxa ye-xylem, ubisi lufinyelela enkomishini futhi lunqobe ukuhanjiswa ngamandla adonsela phansi. Ngaleli phayiphi, usawoti wamanzi namaminerali athathwe yizimpande zezihlahla ezisuka emhlabeni uqobo ziyahanjiswa ukuze ekugcineni zifinyelele kuzo zonke izingxenye zesitshalo, kufaka phakathi umqhele.
I-xylem ne-phloem banesibopho sokuthutha ubisi. Ubisi oluhlaza oludlula kwi-xylem lunohambo olude oluya kuwo wonke amaphuzu we-xylem futhi lunikeza izakhi zomzimba ezidingekayo emaqabungeni. Banesibopho se-photosynthesis eningi, ngaleyo ndlela bayiguqula ibe yisipuni esisetshenzisiwe, okungukuthi, sibe ama-carbohydrate. Lokhu kuthuthwa yi-phloem, enesibopho sokuqinisekisa ukuthuthwa komsoco. Ekugcineni, le nsisi eklanywe ngokucophelela izothutha ukudla iye kuso sonke isitshalo ngendlela ehlukile.
Umehluko phakathi kwempisi eluhlaza kanye nesiphu esetshenzisiwe
Umehluko omkhulu phakathi kwabo ukuthi okuluhlaza kuyinhlanganisela kasawoti wamaminerali nezinye izinto, kanti okucutshungulwayo kwenziwa ngoshukela we-glucose, wamanzi kanye nowe-photosynthetic.
I-crude ithuthwa yi-xylem, eyakhiwe izinto ezincibilikisiwe ezifana namanzi, izakhi zamaminerali kanye nezilawuli zokukhula. Ihamba isuka ezimpandeni iye emaqabungeni ngokusebenzisa ishubhu eliqinile. Le nsipho idluliselwa emaqabungeni, lapho i-photosynthesis iguqulwa ibe usizi olucutshungulwayo. Indlela yokuhamba idale impikiswano enkulu emphakathini wesayensi.
Idluliswa kusuka kwimvelaphi yokwakheka kwayo isuka kufloom iya ezimpandeni ezikumaqabunga aluhlaza neziqu. Iqukethe i- amanzi, ushukela, ama-amino acid, amavithamini, ama-organic organic, amaminerali ancibilikile kanye nabalawuli bezitshalo.
Kulokhu, i-hypothesis yokugeleza kwengcindezi ifinyelelwa njengendlela yezokuthutha yesiphu esiphathwayo. Ithwalwa yi-phloem, okuyi kunguhlobo lwezicubu zezitshalo zemithambo yegazi, ekwazi ukugeleza nhlangothi zombili ukuhambisa izakhi zomzimba kuzo zonke izindawo ezidingwa yisitshalo, kungaba isitho se-photosynthetic.
Kumele sikhumbule ukuthi izihlahla zibalulekile empilweni ngoba ziyizihlahlana ezinkulu zesikhutha, zinikeza umoya-mpilo odingekayo ukuze impilo inikezwe njengoba sazi. Ngalesi sizathu, yonke le ndlela yokudla ibilokhu inendawo enkulu emhlabeni wesayensi. Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngesiphu esingavuthiwe nesicutshunguliwe.