Kwezichumiso double

Iinkozo pollen awela phezu ibala ngendlela enye okanye omnye, baqale zintshule. fuku Iinkozo, umungu ityhubhu kwenziwa ukususela iiseli kwezityalo. Ngenxa yoko, iqhuma iqala. Iqokobhe waphula kwindawo thinnest tube umungu. Ukususela incam ityhubhu eyabelwe izinto ezikhethekileyo. Ukuba athambise column amalaphu kunye nokubekwa amabala.

Ngumongo iiseli okuvelisa kunye kwezityalo zidlulela tube umungu. iseli okuzala iyahlula kwaye yenza sperm ezimbini. Esebenzisa micropyle (umngxuma iqokobhe) Ovule umungu ithumbu eyangena Huy mbungu. Ngaphakathi ityhubhu Ingxhowa eyaphukileyo okubhalwe kuyo wathulula.

Emva koko fusion kwenzeka senye iqanda elilodwa. Ngaloo ndlela, a elilodwa, emva koko anike ekuqaleni umbungu imbewu. Kunye nale yesibini idibane ngumongo usembindini ngamadlozi. Oku kukhokelela ekumisweni triploid isiqalo Mhise kamva triploid endosperm, yona ezizisekondari.

Yonke le nkqubo ingentla ibizwa "kwezichumiso kabini izityalo kweentyatyambo."

Antipodes kunye synergids (nuclei ezwi kwi sac bungu) emva kokugqitywa kwenkqubo iqhawulwa, kunye integuments (izigqubuthelo) lwenze idyasi imbewu.

kwezichumiso Double izityalo yafunyanwa ngama Isazinzulu Russian S. Navashin.

Ngethuba lale nkqubo, ngumongo kwi sac osandul jikelele elikhulu kakhulu ngumongo somyeni, nto leyo ibangelwa ekufumaneni interphase lokuqala (kwisigaba esiphakathi). Kule meko kunye nokumila eziba le sac umbungu ungahluka. Ngokomzekelo, amanye kanti elithi ukuze side, maxa wambi jiko, non nucleoli. Ngokubanzi, isidoda zithiwe thaca ngokohlobo eziba ajikelezayo interphase kunye nucleoli, kwezinye iimeko, kuba akukho nshita isakhiwo eziba ababhinqileyo.

kwezichumiso kabini unokuba iintlobo ezimbini, kuxhomekeka kuhlobo yeemanyano eziba inkunzi nemazi.

Ngoko, xa inkqubo lwenzeka eziba ukuntywiliselwa sperm premitotic kwi core nemazi, apho despiralization (imicu) zofuzo. Kule Union iiseti omabini zofuzo nuclei interphase eyenziwa.

kwezichumiso Postmitotic kabini ungeno lwe nuclei inkunzi nemazi, kugcinwe lweShell prophase, esiphela ubudlelwane babo. Imfundo nuclei interphase, eziquka iiseti chromosome, oza emva uya kusingatha division mitotic lokuqala elilodwa.

Xa kwezichumiso kabini kwenzeka kwi iseli yeqanda ngxubevange haploid ezimbini (equlethe kwesiqingatha senani zofuzo) umphakathi, Noko diploid elilodwa nucleus (kunye iseti epheleleyo zofuzo).

Kuxhomekeka inani eziba polar eziqulethwe iseli esembindini ukhandwa chromosome inani nuclei endosperm.

kwezichumiso kabini ikhuthaza iimpawu ukubonisa egqubayo endosperm imbewu (gqith) isityalo endosperm ukusuka uyise. Ngenxa kwii-ndiseyimbumba malu ngemibhobho umungu ezimbalwa, le nkqubo ibandakanya isidoda ityhubhu yokuqala, kwezinye angcakacileyo kwimibhobho isidoda. kwezichumiso Double ngu spermatozoa ezimbini kunqabile kakhulu.

Ngexesha uphando embryological eziliqela esebenzisa abameli angiosperms ezahlukeneyo (Compositae, Ranunculaceae, Liliaceae) sangqineka Navashin endosperm njengomncedisi njengoko umbungu inkqubo Harassment izityalo kweentyatyambo. Esi simo uphawu kuphela nabameli angiosperms izihluma.

Kufuneka kuqatshelwe ukuba umsebenzi Navashin bavunyelwe ukucacisa umbuzo ngemvelaphi endosperm. Okuthethwa iziphumo ze-nzulu ziye luphuhliswa.