I-Xylem sisihlunu esikhethekileyo esiyimfuneko evumela izityalo ze-vascular ukuthutha amanzi kunye neetyuwa zeminerali ifunxwe ziingcambu namagqabi kunye namanye amalungu. Le nkqubo ibalulekile ekukhuleni kwezityalo, kwiphotosynthesis, nasekulondolozweni kwesakhiwo. Kweli nqaku, uya kufunda ngokweenkcukacha ukuba yintoni i-xylem, isebenza njani, zeziphi iindidi zeeseli eziqukayo, kwaye yahluke njani kwi-phloem, enye izicubu eziqhubayo.
Yintoni ixylem kwaye ibekwe phi?
I-Xylem yi-lignified vascular tissue, okuthetha ukuba ineendonga eziqiniswe yi-lignin, kwaye ikwabizwa ngokuba ngamaplanga, ngakumbi kwiindawo ezivuthiweyo njengesiqu semithi. Iqulunqwe yinethiwekhi eyinkimbinkimbi yeeseli ezilungelelaniswe kwiityhubhu ezisuka kwingcambu ukuya emagqabini, zivumela ukujikeleza kwencindi eluhlaza.
- Kwii-angiosperms, ii-gymnosperms kunye ne-pteridophytes (ezifana neeferns), I-Xylem yinxalenye ye-vascular system kunye ne-phloem.
- Isasazwa kwii-vascular bundles, steles okanye njenge-xylem yesibini kwizityalo ezinemithi.
Umsebenzi wexylem kunye nendlela uthutho lwenzeka ngayo
Umsebenzi oyintloko we-xylem kukuthuthwa kwamanzi kunye neetyuwa zamamineraliOku kuthutha kwenza kube lula ukuba izondlo zifikelele kuzo zonke iindawo zesityalo eziyimfuneko ukuze ziphile.
- Ixylem ithwala umnxeba incindi eluhlaza (amanzi + iityuwa zeminerali) ukusuka kwiingcambu ukuya emagqabini, apho i-photosynthesis iya kwenzeka.
- Kwakhona ibonelela ngenkxaso yoomatshini ngenxa yobunzima kunye nokuqina kweendonga zeeseli zayo, okuvumela ukuba isityalo sihlale sithe tye.
- Kwakhona, iququzelela unxibelelwano lwangaphakathi, kuba yindlela yomqondiso efana nehomoni yezityalo.
Ukuhamba kwamanzi kwenzeka ngeenkqubo ezimbini zomzimba:
- I-Osmosis: Ingcambu ifunxa amanzi ngenxa yeeyantlukwano ezinokwenzeka phakathi komhlaba kunye nezicubu zeengcambu.
- Ukubila kunye nokufunxa: Ukuba ngumphunga wamanzi emagqabini kudala "ukufunxa" okutsalela amanzi phezulu ngemikhumbi yexylem.
Iintlobo ze-xylem kunye nokwahlukana phakathi kweprayimari kunye neyesibini
Kwizityalo zemithambo sahlulahlula iindidi ezimbini eziphambili zexylem:
- I-xylem yokuqala: Ivela kumanqanaba okuqala okukhula kwaye ivela kwiprocambium. Iqulunqwe ngolu hlobo:
- Iprotoxylem: Iphuhliswa kuqala kwaye ilungelelaniswe kwizicubu ezikhulayo, kunye nemikhumbi ejikelezayo okanye ejikelezayo.
- I-Metaxylem: Kubonakala emva kokuba iprotoxylem kunye neeseli zayo zinobubanzi obukhulu, kunye neendonga ezinqamlekileyo kunye nezinamachaphaza, zikhula xa ukunyuswa kwelungu kuphelile.
- I-xylem yesibini: Iveliswa yi-vascular cambium kwizityalo ezinokukhula kwesibini, njengemithi kunye nezihlahla. Yenza ukhuni kwaye inikeze amandla ongezelelweyo.
Zeziphi iiseli ezenza ixylem?
Ixylem yenziwe ziintlobo ezininzi zeeseli, nganye inemisebenzi ethile:
- Uqhoqhoqho: Zinde, iiseli ezimile okwe-spindle ezivumela indlela yamanzi esecaleni kunye nethe nkqo kwimingxuma emincinci kwiindonga zazo. Zizo kuphela uhlobo oluqhubayo kwi-gymnosperms kunye ne-pteridophytes.
- Izinto zeenqanawa (i-tracheas): Zizodwa kwii-angiosperms, zimfutshane, iiseli ezibanzi ezilungelelaniswe enye phezu kwenye ukuze zenze iityhubhu ezinde (iinqanawa) ezikhawulezisa ukuthutha.
- Iiseli ze-Xylem parenchymal: Umsebenzi wayo kukugcina nokugcina amanzi kunye nezondlo.
- Iintsinga zeSclerenchyma: Banikezela ngenkxaso yesakhiwo kunye nokhuseleko.
Umahluko phakathi kwexylem kunye nephloem
Ngoxa i I-xylem ihambisa incindi eluhlaza ukuya phezulu, i-phloem yenza umsebenzi wokusasaza incindi ecutshungulweyo (iswekile kunye nezinye izinto eziveliswa kwiphotosynthesis) kuso sonke isityalo, nakweliphi na icala ngokweemfuno zemetabolism. Ukuze ufumane ukuqonda okunzulu, unokubonisana i-xylem kunye ne-phloem zisebenza njani.
| Isici | Xylem | Phloem |
|---|---|---|
| Izinto ezithuthayo | Amanzi kunye neetyuwa zeminerali (incindi eluhlaza) | Iswekile kunye neekhompawundi eziphilayo (incindi ecoliweyo) |
| Indlela yokuhamba | Ukususela kwiingcambu ukuya emagqabini | I-Bidirectional kwimfuno |
| Iiseli eziphilayo okanye ezifileyo ekuvuthweni | Ufile | Uyaphila |
| Uhlobo oluphambili lweseli yokuqhuba | Iitracheids kunye neenqanawa | Iityhubhu ze-Sieve kunye neeseli zeqabane |
Ukubaluleka kwee-vascular bundles kunye nezifo ezinxulumene nazo
Iinyanda zeVascular ziyimfuneko kuthutho kunye nonxibelelwano kwisityaloUkuba ziyavaleka, umzekelo ziintsholongwane ezibangela izifo ezifana nomngundo okanye ibhaktiriya, ukuhamba kwezondlo namanzi kuyaphazamiseka kwaye isityalo sinokubuna okanye sife. Ukuthintela ezi meko, kunokuba luncedo ukujonga izihloko ezinxulumeneyo. indlela izityalo ezikhupha ngayo amanzi.
- Unyino lwemithambo: Ibangelwa ngumngundo ezifana Ingqameko o I-Fusarium.
- Izifo zebhaktheriya: Xyella fastidiosa Ichaphazela izityalo ezininzi ezahlukeneyo, ibangela isifo sikaPierce esaziwayo, phakathi kwezinye.
- Ukubaluleka kokugcina iiglasi zicocekile: Iququzelela ukufunxwa kwezondlo, ikhusela izifo kwaye iphucula ukusebenza konyango.
