Kuyini umbungu sezinhlamvu zezitshalo? Isakhiwo umbungu imbewu

Ngemva kokufunda lesi sihloko, uzofunda ukuthi kukhonani nombungu imbewu. Ngaphezu kwalokho, thina ukuchaza izigaba eziyinhloko sokuthuthuka.

Ukuze ngeso lengqondo ukuthi ngiqonde ukuthini, sibheke isibonelo. Badlule izici jikelele we-embryo nokuthuthukiswa ezigabeni.

Yini kuwukuthi nombungu kakolweni imbewu

Uma thina usike imbewu kakolweni, ungabona ukuthi iningi kangakanani powdery ngendwangu emhlophe. Ibizwa ngokuthi endosperm. amaseli zayo zigcwele ezihlukahlukene izakhi. Akulula ukuthola ukuthi kunani igciwane imbewu kakolweni ngakho. Phela, lincane kakhulu. Kungaba kubhekwe kuphela ngesibona-khulu. Njengoba nombungu ubhontshisi, it has a Isiqu, izimpande kanye gemmule. Nokho cotyledon kwadingeka eyodwa kuphela. Kuyinto ipuleti ezondile, elele eduze endosperm.

Yilokho e nombungu imbewu. Yiqiniso, e izinhlobo ezihlukahlukene zezitshalo, kungcono ezahlukene. Kodwa isibonelo kakolweni Ungahambisa yona isakhiwo bebonke.

Ukwahlukana nele-embryo ne suspensors

Kusaqalwa ukuthuthukiswa umbungu dicots futhi monocots zifana kakhulu. Luqala ngokunikela Ukuhlukaniswa iqanda eselivundisiwe (zygote) ku ovule umbungu esakeni. Ngo kakhulu indiza izimbali ubabonisa transversely besigaba sokuqala (noma kakhulu transversely) ukuze axis awo longitudinal. Lokhu kumisa polarity umbungu: elingenhla (halazalny) esibulalayo - rostovaja zone zako ezisemqoka kanye ephansi (mikropilyarny) yakha uhlobo umlenze - ukumiswa noma suspensors, okubambelela umbungu ngesikhathi micropyle. Ngemva ukwahlukana eziningana kwenzeka ngesikhathi kuphakanyiswa sokugcina umbungu cishe eyindilinga efanele futhi suspensors.

Ukuqala izicubu izinhlelo

Kuyini igciwane imbewu, okuyinto lase lizale nje? Kusukela isihlobo mass kumaseli undifferentiated. Nokho ngokushesha ukushintsha isakhiwo layo langaphakathi kuya phezulu phambili izinhlelo zezitshalo kwezicubu. epidermis Ikusasa (protoderma) kwakheka yangaphandle division periclinal amaseli we-embryo uqobo. division Periclinal ibizwa ngokuthi lapho ipuleti iseli phakathi amaseli ezimbili indodakazi zifana kuya ebusweni izingxenye zalesi sihlahla lapho ukuqoqwa zenzeka.

Ukwahlukana prokabiya futhi meristem eyinhloko

Ngemva kwalokho umehluko kwabantu kanye degree of vacuolization umbungu amaseli kuholele inyumbazana ngenxa procambium futhi meristem eyinhloko. Kugcine, vacuolised namandla futhi kancane obukhulu, kuphakamisa ijwabu ecashile, ezizungezile procambium kancane vacuolated futhi luthe ukuqina, eyandulela kokuqhuba izicubu - xylem futhi phloem.

ukwakheka cotyledons

Protoderma meristem main futhi procambium (okuthiwa meristem eyinhloko) ngaphandle kokuphazamiseka, esisuka cotyledons e-eksisi umbungu. Ukwakhiwa cotyledons ungase uqale noma ngesikhathi noma ngemuva kubekwa meristems oyinhloko (ukuthuthukiswa isinyathelo kuze cotyledons ngokuvamile okuthiwa globular). Ngakho umbungu globular dicotyledonous kancane kancane ithatha bilobed umumo (kulesi sigaba ivame ukubizwa ngokuthi core). Umbungu yenzalo ka amafomu monocotyledonous cotyledon eyodwa kuphela. Ngakho-ke, akudingeki esiteji amise okwenhliziyo.

Jockstrap ukubhujiswa amaseli

Khona-ke, i-cotyledons futhi umbungu-eksisi side (kangaka okuthiwa torpedo esiteji) kanye meristems eyinhloko anikezwa kanye nabo. Welulekela, i-embryo uhlala ngqo noma lwalugobile. Okuwukuphela cotyledon monocots ngokuvamile likhula kangangokuba singesikhulu kunazo zonke kwezingu isakhiwo se-embryonic. Nge okwanda kwamaseli umbungu suspensors kancane kancane ubhujiswe.

cell division

Ngo kusaqalwa embryonic cell division zenzeka kulo kunobukhulu bendawo sporophyte abasha. Nokho, ngesikhathi kumiswa ukuvela nombungu amangqamuzana amasha kancane kancane kuvinjelwe ihlumela meristem apical kanye impande. Ngo dicots wokuqala babo selibekiwe phakathi cotyledons amabili, kuyilapho monocots eyodwa esandleni cotyledons futhi uzungezwe ngokuphelele sangasese - yayifanekisela nomxhantela like isisekelo salo. meristems apical kukhona ezibaluleke kakhulu, ngoba ekugcineni umthombo wonke amaseli amasha, ukuqinisekisa ukuthuthukiswa kwe yisithombo embungwini omdala isitshalo.

Yegatsha ovule

Phakathi naso sonke leso sikhathi kumiswa umbungu izakhi ageleze njalo kulesi simila umzali ezicutshini ovule. Ngenxa yalokho, i-stock abalulekile yabo zanqwabelana endosperm, perisperm noma cotyledons imbewu asathuthuka. Ekugcineni ovule uhlukane Isiqu imbewu exhunywe udonga esibelethweni, bese iba irherho le-closed (ngoba amandla). I uDries imbewu, enika amanzi ukuze imvelo, futhi ijazi imbewu esesindile, sengathi ezungeze "igobolondo zokuzivikela" umbungu, bese nalo supply izakhamzimba.

Ngakho, uyazi ukuthi kuyinto e nombungu imbewu. Njengoba ubona, kuze kufike ukuthuthukiswa yayo Ukuguqulwa yayo. Ngakho-ke, ukwakheka umbungu imbewu ihlukile emazingeni ahlukahlukeneko wendlela ukhona.