Isigaxa avuke izitshalo stem. indwangu Sikhungo

Izitshalo zikhule konke ukuphila kwabo, futhi lokhu ikhono ngokuphelele ihlukanisa kubo ezilwaneni. Iqhaza main kwetinhlavu amahlumela iphuzu ezikhulayo udlala - isakhiwo ekhethekile lapho amaseli njalo sokuhlukanisa. Le ndawo itholakala ku iziqongo izinso, kanye ngesikhathi sokudlondlobala stem main. Kanjani izitshalo uphathe baqhubeke bekhula?

Isigaxa kuyanda: kuyini futhi iyini indima yalo?

Ngezinye iziqongo stem kanye nezimpande izitshalo kuyinto endaweni division ezikhethekile, kwakhiwa amaseli meristem okuyinto. Isici yalesi izicubu isitshalo yikhono ngokuqhubekayo futhi ngokushesha ukuhlukanisa, okuholela ekwandeni lonke zomzimba ubude kanye ukushuba.

indwangu Sikhungo nayo itholakala phezu kwezihloko izinso oluhlaza. Empeleni, isizathu sokuthi kungani omunye wabo futhi kukhona amahlumela, okuyinto avumele isitshalo ukunweba indawo enkulu bese uthola ngaphezulu amandla elanga ukuze photosynthesis. Kukhona izinhlobo ezintathu izinso: esibulalayo, ezilingene adventitious. Eyokuqala sise sokudlondlobala simila, futhi baqinisile zokukhula evumela umzimba sikhule ubude. Lateral efihlekile atholakala esiqwini futhi banesibopho amagatsha, ie kumiswa ohlangothini amahlumela. Adventitious efihlekile ezibhekwa ithule futhi isebenze lapho wayeka phezulu ukuhlukana meristem.

Uyini Isigaxa ukukhula? Okokuqala, walibumba is by amaseli meristem, okuyinto ukuhlukanisa ngokushesha futhi kamuva ngesikhathi ebizela othile wonke kwezinye izicubu. Okwesibili, indawo ukukhula etholakala eduze Isiqu esingesihle, amacembe kanye esingesihle ihlumela esingesihle, okuzokwenza kwakha isisekelo ukwakheka engumbaleki abasha.

Isigaxa avuke stem kanye nezimpande

izicubu Sikhungo bagxila kakhulu iziqongo izitshalo, okungukuthi ngesikhathi sokudlondlobala stem futhi ichopho impande. Isiqu Ngakho, njengoba impande, okwandisa ubude bayo ngenxa division of mesodermal amaseli. Lesi sakamuva, esikhundleni salokho, kuyinqubo yokuzimisela yakha entsha izinhlobo cell nezicubu. Isiqu kuyinto Indwangu conductive (xylem futhi phloem), lokho okwakha, isembozo, nokunye. D.

ukukhula impande iphuzu has izici zayo siqu. Njengoba kuyintando ekupheleni impande futhi unesibopho ukukhula ubude, inhlabathi okuqinile futhi ababenakho kwakuzophela masinyane ukubhubhisa ezindongeni mncane zemfundo izicubu amaseli, okwakuyoholela ukuyeka umsebenzi ukuqoqwa. Ngakho-ke, phezu indawo sigaba impande cap, okuyinto maseli sloughed off emhlabathini, kanjalo ekuvikeleni amaseli langanakuvikeleka mesoderm nezihlukene izinto lwamafinyila ezisiza ukuthuthukisa isitshalo isitho ithiphu ngomshoshaphansi.

Meristem - isitshalo izicubu zemfundo

Indwangu, bakha ingxenye enkulu yomsebenzi efihlekile ezikhulayo, iziqu kanye nezimpande, ubizwa ngokuthi "meristem" ezaziwayo. Lokhu Indwangu zemfundo yakhiwa amaseli encane mncane-ngabafaka, okuyinto abe ikhenela esikhulu vacuoles eziningi ezincane. Meristem umsebenzi - lokhu okusheshayo cell division nokwanda izitshalo wezinto zokubasa.

Kwasendaweni meristem ihlukaniswe apical, ezilingene ejotshelelwayo.

• meristems apical zitholakala at the amathiphu iziqu kanye nezimpande. Umsebenti wabo oyinhloko ukwandisa ubude simila.
• Side zemfundo Indwangu indandatho emelelwa cambium empandni kanye pericycle impande. Kulesi izitshalo meristem herbaceous iphela ngokushesha, futhi ngo-bok zisetshenziswa kangakanani ukuthi kwenza kube nokwenzeka ekunqandeni nokukhula izimpande ububanzi. Ngenxa yalokho we meristem lateral kwakhiwa okuthiwa izindandatho yonyaka.

• Ejotshelelwayo, noma ejotshelelwayo, meristem kuyinto endaweni izitshalo herbaceous ISIZINDA. Okuhle kunakho konke ukuthi lolu hlobo imfundo kubonakala kudala umndeni okusanhlamvu, njengoba obhekene ukwanda ubude interstices.

Futhi isehlane isilonda meristems, akhiwa esikhundleni umonakalo mechanical kuya umzimba isitshalo by despecialization enyameni ezungezile (ngokuvamile parenchyma).

Ngesikhathi indawo okuvela kuyo meristem zihlukaniswe zamabanga aphansi naphezulu. Ifomu yokuqala somzimba wombungu, kanti isixuku esikhulu sezivele ebonwe izitshalo abasha kwakhiwa.

Ukusebenzisa izici meristem practice

Ngezinye izikhathi nezilwane noma izitshalo engadini eqala ukukhula ngokushesha ubude, hhayi sakhiqiza ezincane side amahlumela. Ukuze ugweme ngokweqile stem ukukhula ukuphakama, aye ayisebenzisa kaningi ukusoka onesiqongo. Ngenxa yalokho, ukukhula Isigaxa esenyamalala, lesi sitshalo iqala ngenkuthalo ekhelini ngenxa ohlangothini gusset kanye nezinso.

Uma, kunalokho, kubalulekile ukuba zidonse inqubo yokukhula ubude, Ukunquma phezulu stem noma kunjalo engenakwenzeka. Lokhu kuzoholela ekulahlekeni nezicubu yemfundo unesibopho ukwanda umzimba isitshalo.

isiphetho

Sibonelo Isigaxa kunendima eyinhloko ekukhuleni flora. Lakhiwa emangqamuzaneni meristem, noma indwangu ezemfundo, okuyinto kwakha amahlumela apical kanye lateral. Isigaxa iyona ukwanda ezinsweni, lapho ukuvikela meristem kusukela imvelo. Empeleni, noma yiluphi ihlumela simenza run entsha emva division by mesoderm amaseli.