Uyini gametophyte (izinhlobo, izici, izici)

Zonke izinto eziphilayo ukuphila uya ngokusebenzisa ezithile umjikelezo wokuphila: kusukela ekuhlaleni kwesisu (amabhukumaka) ekufeni (ukufa), futhi lesi sitshalo akayena okuhlukile. sici yabo esiwuphawu yinqubo ukukhiqizwa kabusha ukuthi kushintshana sporophyte futhi gametophyte.

Futhi yilokho gametophyte - ukuhlaziya kabanzi kulesi sihloko. Kumele ukuthi ngokuvamile yona kanye gametophyte akuyona isehlane, nesikhathi lapho, kanye sporophytes noma kuncike ngqo kuso.

Uyini gametophyte?

Igama elithi "gametophyte" lisuselwa egameni lesiGreki elisho "gamete", ie. E. cell wokuzala kanye phyton (isitshalo) futhi uhumusha njengoba isizukulwane ngokocansi noma omunye izigaba yentuthuko isitshalo. Ngo biology, i-haploid lwegciwane isizukulwane has a ukuqokwa incwadi - «n».

izinhlobo

Ukuze uqonde ukuthi gametophyte kudingeka ukuba uqonde kwakhiwa kanjani it is futhi lokho. Gametophyte isici ehlukile ngazo izitshalo okuqondene ekilasini spore ephakeme. Kuye kwamangqamuzana ku gametophyte angagcina gametangia (izitho okuzala ka ukuzala) ezimbili zama: iduna nensikazi.

zizalela Izici

Yonke inqubo ye ukuzala ezitshalweni kuyinto ngesimo lokuhlanganisa (ezimele protoplast Fusion vegetative amaseli isb. E. amabili). Ngokuvamile eyodwa futhi ngamunye efanayo kungaba kanyekanye ihlakulele gametes noma ezinhlamvu. Kodwa kukhona izimo lapho mpikiswano bayatfutfuka uhlobo olulodwa nje, futhi gametes kuphela ngakolunye. Ngamunye, okuyinto eba ezinhlamvu, ebizwa ngokuthi sporophyte, umuntukazana lapho akhiwa gametes - gametophyte.

Gametophyte ezitshalweni

Gametophyte kuyinto ngithanda abesilisa nabesifazane futhi kobungqingili. Ngo sporophyte nuclei diploid banayo isethi chromosome, kodwa babe benza haploid gametophyte. Abaningi kakhulu kakhulu ulwelwe futhi cishe zonke izitshalo ephakeme abe iphethini ahlukile ukuthuthukiswa cyclical futhi alternation izizukulwane, okuyinto yakhiqizwa asexually futhi ngokocansi.

Schematically, inqubo zizalela kungenziwa elabekwa kanje: gametophyte → → ukukhiqizwa gamete Fusion gametes zygote ukwakheka → → → ukuthuthukiswa a sporophyte diploid nokunye.

Gametophyte isakhiwo wehlukile ngempela, futhi lokhu kuncike hlobo ushintsho imvama labo noma ezinye izinhlobo zezitshalo. Ngokwesibonelo, ulwelwe siyenzeka alternation okuyisidina izizukulwane (isomorphic), ngakho gametophyte besenkolweni kweyunithi ezimele, okuyinto ehlukile futhi akahlukile kusukela sporophyte efanayo.

Futhi lapha ulwelwe laminaria, okuyinto abe ehlukile (heteromorphic) umjikelezo ukuthuthukiswa, le gametophyte kuhluke ngokuphelele, ezahlukene kusukela sporophyte, isakhiwo ngesimo ngaphansi evuthiwe futhi branched thalli filamentous. Cishe bonke abamele sporophytes, kuhlanganise nabangu-Fern, le gametophyte ingabe ampofu futhi kukhona isikhathi esifushane kakhulu.

Ngenxa yokuthi ngokuhamba kwemvelo izitshalo abavelele emphakathini kwakukhona ukunciphisa abushelelezi gametophyte, baye elahlekelwa ukuvelela kwawo ngokocansi. Ngokwesibonelo, izimila eziveza imbewu baphelelwa isizukulwane zabesifazane, zonke izigaba yentuthuko zivele kwi sporophyte.

Female gametophyte gymnosperms emelelwa ezinamangqamuzana amaningi endosperm haploid noma archegonia ngaphezulu njengoba zikaphayini noma ezinye gymnosperms ngokulandelana. Ngo abameleli ravnosporovyh prothallia izitshalo Fern kukhona zabo bobubili ubulili.

Owesilisa izitshalo gametophyte imbewu ine uhlobo impova evela microspores esiyingxenye gametes e germinating impova ishubhu. Kodwa prothallia ravnosporovyh Fern - ngithanda abesilisa nabesifazane.

Ngakho, gametophyte akuxhomekile isikhathi izimila noma isitshalo ukuphila, futhi kuphela nohlobo kanye nezici kwemvelo.

isiphetho

Ngakho, gametophyte, ekubeni isizukulwane ucansi ekuthuthukisweni isitshalo futhi esibonisa alternation oluthile futhi ezilandelanayo zezizukulwane e ngezinhlobo zawo, inezici eziningana. Okokuqala, walibumba is kusuka ingxabano has a isethi haploid wama-chromosomes futhi gametes njalo amafomu kungakhathaliseki kuba ezikhethekile ubulili izitho noma amangqamuzana avamile vegetative.

Manje uyazi ukuthi gametophyte futhi yiziphi izici zayo.