Nekuda kwehunhu hwedu, zviri nyore kuti tifungidzire kuti mhuka dzinoberekana sei, sezvo kubereka kwadzo kunowanzofanana neyedu. Nekudaro, zvinotora nguva yakati rebei kuwana kufanana ikoko nenyika yezvirimwa. Vanozviita sei? Chii chinonzi fertilization chezvirimwa?
Chinangwa chechinyorwa chino ndechekutsanangura kuti chii chinonzi fetereza yezvirimwa. Nokuda kweizvi tichataura pamusoro pemapoka maviri makuru aripo: Angiosperms uye gymnosperms. Saka usazeza kuenderera mberi nekuverenga kana uchifarira nyaya uye uchida kuziva zvakawanda nezvekusanganiswa kwezvirimwa.
Kusvirana kwezvirimwa
Tisati tatsanangura mafambisirwo embesa, tinotanga tataura kuti pfungwa yekuberekesa chii. Ndiwo maitiro anoita Magametes maviri, murume nemukadzi, fuse panguva yekubereka. Nenzira iyi, zygote inogadzirwa ine genome, chigadzirwa chevabereki.
Munyika yemiti, Pollination inotanga kuitika. Mashizha echirume ekubereka anoburitsa mbeu dzemukume dzinotakurwa netwupembenene kana nemhepo kuenda kune zvinyadzi. Ndipo padzinomera. Kana tichitaura pamusoro pemiti, hatiwanzoreva gametes, asi kune spores. Tsanga imwe neimwe yemukume inowanzova nemasero maviri echirume ekubereka, kana kuti gametes. Zvisinei, kune nzira dzakasiyana dzinoshandiswa nezvirimwa, sezvo dzisiri marudzi ose akafanana, chaizvoizvo anosiyana zvikuru kana zvasvika pakuberekana.
Sezvaunonyatsoziva, zvirimwa zvinogona kusiyaniswa nenzira dzakawanda. Kune nhamba huru yemapoka, makirasi uye marudzi emiriwo uye imwe neimwe mhando ndeye akati wandei. Zvisinei, kune mapoka makuru maviri anosiyana pakuberekana kwawo. Kuti, Kune miriwo ine maruva uye isina maruva. Iwo ekutanga anozivikanwa seangiosperms uye ndiwo akanyanya kuwanda zvirimwa papasi rino. Mukuwedzera, pamhando mbiri idzi dzemiriwo ndiyo ichangopfuura. Kune rumwe rutivi, zvinomera zvisina maruva chikamu cheboka re gymnosperms. Aya ndiwo aive ekutanga kuoneka paPasi, kunyangwe madhinosaurs asati avapo.
Pakati peangiosperms pane zvirimwa zvakasiyana semakwenzi, miti, azaleas, dimorphothecae, nezvimwe. Nezve magymnosperms, aya anoumbwa kunyanya eiyo conifers. Mimwe mienzaniso yeboka iri ingave misidhari, yews, mipaini. Cycads zvakare ndeye gymnosperm zvidyarwa. Asi musazvinetse, tichataura zvakadzama nezvemhando mbiri dzezvirimwa, maumbirwo adzo uye kuti kuberekesa kunoitwa sei.
Gymnosperms
Ngatitangei nemagymnosperms. Kunyangwe chiri chokwadi kuti zvirimwa izvi zvinozivikanwa nekusave nemaruva, zvinoita, asi kwete iwo chaiwo atinofungidzira. Maruva ayo haana sepals kana petals, asi vakadzi vanoumba rudzi rwehuni uye greenish cone inoguma yava michero yenhema, sepine cones.
Zvirimwa zveboka iri zvine maruva ose echirume neechikadzi. Yekupedzisira ine chikero, mazai maviri uye bract inoumba koni yechikadzi nekuisa zvikwata zvakatenderedza akisi yemaruva. Ovule yega yega ine embryo sac ine maviri archegonia mukati maro. izvo, zvakare, zvine magametes maviri echikadzi kana oospheres imwe neimwe. Ngatijekese pfungwa idzi:
- Archegonia: Inhengo yemukadzi inobereka. mushroom, algae y bryophytes, senge mosses nemimwe miti yevascular yakadai semaferns. Inowedzerwa nenhengo yemurume inonzi antheridium.
- Oospheres: Ndiyo gamete yechikadzi yemiti. Ivo vanobva kune iyo inonzi megaspore kuburikidza nenzira inonzi megagametogenesis. Padanho rekutanga tinogona kutaura kuti izvi zvinosanganisira mitotic divisions. Panguva yekusangana kaviri, ma<em>oospheres anobatana neanoita nuclei kubva pambeu yekukume zvobva zvaita kuti pave neembryo.
Kana ari maruva echirume, aya anoumba makoni echirume akatenderedza akisi yemaruva. Vane chiyero uye zvakare maviri microsporangia kana pollen sacs umo vanoguma voita mai masero ayo anozoita kuti pave nemhodzi dzemukume dzine mukurumbira. Mukati mawo mune magametes maviri echirume, anonziwo antherozoids. Anewo masaga emhepo maviri anobatsira kupararira kusvika asvika paruva remukadzi. Mune ino kesi ndinofunga zvichave zvakare zvakanaka kutsanangura mamwe ma concepts:
- Microsporangia: Iwo maumbirwo anoburitsa uye anewo spores. Aya ndiwo mitumbi ine microscopic ine chinangwa chekupararira uye kurarama kwenguva yakareba.
- Antherozoids: Iro rinonyanya igete rechirume, rinova rakaenzana nembeu yedu.
Fertilization yemiti yegymnosperm
Kuziva zvishoma nezve maumbirwo emaruva echirume neachikadzi egymnosperms, isu tave kuzotaura pamusoro pekuti fertition iyi inoshanda sei. Zvinofanira kucherechedzwa kuti pollen tsanga inogona kutora kusvika gore kuti imere, kana ruva remukadzi rasvika. Kana izvi zvaitika, pollen chubhu inovhurika zvishoma nezvishoma kuburikidza neinonzi nucellus yeovule. Kana yasvika kumukadzi gametophyte, basa rayo rinotevera nderekuyambuka mutsipa we archegonium uye wozopinda muoosphere. kwaunorodha zvese zvirimo. Iri panguva ino apo kuumbwa kwemiti yegymnosperm kunoitika.
Munguva iyi, imwe yemageteti inoguma yabatana nenyucleus yeiyo oosphere iyo inoitika mairi. Somugumisiro, zygote inoumbwa, inova sero kubva kune iyo embryo inoumbwa uye inokura. Nezvemukati wezvinomera, mamwe masero earchegonium uye mamwe echirume gamete, ese anopera. Zvichakadaro, endosperm, inoumbwa nemasero akachengetwa, inotenderedza embryo, iyo inodzivirirwa nechikamu cheiyo ovule, iyo inozoita lignified. Embryo inoonekwa seyakakura zvakakwana kana mbeu dzaburitswa. Iyi nzira inogona nyore kutora makore maviri kubva panguva iyo maruva anoonekwa.
Muchiitiko chembeu kubva pamapine, jasi rembeu ndiro diploid uye rinobudiswa nesporophyte yaamai. Nezve yekutanga endosperm kana kuchengetedza tishu, iyi haploid sezvo iri chikamu chemukadzi gametophyte. Mushure mekusangana, diploid embryo inoumbwa, inova sporophyte itsva.
Angiosperms
Isu tatoziva kuti magymnosperms chii uye kuti anoshanda sei, asi zvakadini neangiosperms? Ndisati ndatsanangura maberekerwo emiti iyi. Chekutanga tinofanira kujekesa mamwe maconcepts Kuti unzwisise zviri nani maitiro:
- Carpels: Aya ndiwo mashizha akagadziridzwa ayo, mukuzara kwawo, anoumba chikamu chechikadzi chekubereka cheruva remiti yeangiosperm. Iyo seti yeese carpels yeruva inonzi gynoecium.
- Kusekwa Icho chikamu chegynoecium chinogamuchira mukume kana mukume ukaitika.
- Micropyle: Iyo inozivikanwawo se micropyle, igomba kana kuvhura kunowanikwa mune apical chikamu che seminal rudiments kana ovules.
- Synergists: Iwo maseru ane nucleus inowanikwa kumagumo kwe embryo sac ye angiosperm plants. Imwe neimwe embryo sac ine mbiri dzacho. Iwo maviri synergids pamwechete anoumba filiform apparatus kana filar apparatus. Izvo zvinofanirwa kucherechedzwa kuti ivo vanobatsira iyo oosphere panguva yekubereka.
- polar nuclei: Aya nuclei maseru anowanikwa mukati meembryo sac, gametophyte yechikadzi kana ovary. Vanopindira mukusanganiswa kwemuriwo.
Zvinofanira kutaurwa kuti embryo sac imwe neimwe ine marudzi akasiyana emasero, ayo iyo inobereka ndiyo polar nuclei uye ovule. Nekudaro, iyo isina mbereko, ingave iyo antipodal uye iyo synergistic idzo, zvakare dzinobatirana panguva yekuberekesa.
kubereka kweangiosperm zvirimwa
Kupedzisa nenyaya yekuberekesa muzvirimwa, tichataura nezvekushanda kweangiosperms. Kana kamwe kumeseswa kwecarpel kwaitika, mvura ine shuga, inoumbwa zvakanyanya ne sucrose uye inogadzirwa nerusaruro rwakakura, inokurudzira kumera kwembeu yemukume. Kubva pane imwe neimwe yetsanga idzi panobuda pollen chubhu ine chinangwa chekugadzira nzira kuburikidza nesitaera kusvika yasvika pamukadzi gametophyte kana embryo sac yemiti yeangiosperm. Iyi embryo sac inowanikwa mukati mezai.
Mageteti echirume kana kuti nuclei inobereka inofamba nemupollen chubhu kusvika yasvika pamicropyle. Iyo pollen chubhu inopfuura nemuchimiro ichi uye inoburitsa zvese zviri mukati meembryo sac, pedyo nerimwe rema synergids maviri. Mushure mekuita uku, iyo generative nuclei fuse neiyo osphere uye polar nuclei, ndosaka ichinzi "double fertilization".
Kune mbeu zhinji dzemukume dzinowanzosvika pakusemwa uye, nokudaro, dzinomera. Zvakadaro, chimwe chete chazvo chichabereka mbereko. Kana ovary ichinge yasangana, inotanga kukura kuita muchero. Mune michero iyoyo ine akati wandei mhodzi, kunewo tsanga dzakati wandei dzemukume dzinodikanwa kuti dzibatane nechero mazai.
Zvinosekesa kuti zvisikwa zvakaronga sei zvese kuti mhando dzakasiyana dzemiriwo dzibereke, handiti? Pasina kupokana, nyika ino izere nekusika kunoshamisa uye kugona kubereka.