Yintoni intsholongwane yembewu yesityalo? Isakhiwo sembungu yembewu

Emva kokufunda eli nqaku, uya kufumanisa ukuba yintoni intsholongwane yentsholongwane. Ukongeza, sichaza izigaba eziphambili zophuhliso lwazo.

Ukuze sibone oko sikuthethayo, makhe sibone umzekelo. Emva koko siqhubela phambili ukubonakaliswa ngokubanzi kwesibindi kunye nezigaba zokuphuhliswa kwayo.

Iyintoni intsholongwane yembewu yengqolowa

Ukuba uyayinqumla imbewu yengqolowa, uyakubona ukuba ininzi yayo yingubo emhlophe. Kubizwa ngokuba yi-endosperm. Iiseli zayo zizaliswe ngezityalo ezahlukeneyo. Akulula kakhulu ukufumanisa ukuba intsholongwane yenzalo yengqolowa iqulethwe. Emva koko, uncinci kakhulu. Ingabonwa kuphela ngeglasi yokukhulisa. Njengombungu webhontshisi, unesiqu, ingcambu kunye neentso. Nangona kunjalo, une-cotyledon eyodwa kuphela. Le ndawo yincinci encinci, kufuphi ne-endosperm.

Yile nto intsholongwane yembewu iqulethwe. Ewe, iintlobo ezahlukeneyo zezityalo, zihluke. Kodwa ngomzekelo wengqolowa, unokuyicinga ngento yayo ngokubanzi.

Ukuhlukana kwembungu kunye nokumiswa

Amanyathelo okuqala okuveliswa kombungu kwii-dicots kunye ne-monocot zifana kakhulu. Iqala ngoqhekeko lweqanda elichumayo (zygote) kwisikhwama sombungu we-ovule. Kwiintlobo ezininzi zezimbali, iinqwelo zokuqala zendiza zihamba ngaphesheya (okanye phantse ngaphesheya) kwinqanaba layo elide. Ngethuba elifanayo, ubukhulu bombindi lubekwa: umgangatho ophezulu (halazal) uyindawo yayo yokukhula, kunye nesezantsi (micropilar) zenza uhlobo lokumiswa komlenze, okanye ukumiswa, ukumisa umbindi we-micropyle. Emva kwamacandelo amaninzi, ukwahlula kokugqibela kwintsholongwane ejikelezayo kunye nokukhawuleza kwenzeka.

Ukuqala kokuphuhliswa kwezixhobo zeethambo

Iyintoni intsholongwane yembewu eyenziwe nje? Ukususela ubunzima beeseli ezingafaniyo. Nangona kunjalo, kungekudala utshintsho lwalo lwangaphakathi lukhokelela ekuqalekeni kokuphuhliswa kweenkqubo zeetyhulwa zezityalo. I-epidermis yexesha elizayo (i-protoderma) yenziwa ngexesha lokuhlukana kwe-periklinnyh lweseli zangaphandle ze-embryo ezifanelekileyo. I-Periclinal ibizwa ngokuba yi-fission, apho iiflethi zeselluli phakathi kweentombi ezimbini zeentombi zifanelene nomhlaba weso sityalo apho kuhluma khona.

Ukwahlukana kwe-procalibium kunye neentlanganiso zokuqala

Ukwahlukana okuthe xaxa kwinqanaba lokuchithwa kwe-vacuolization kunye nobuxininiso beeseli zamamoriki zikhokelela ekuzimelelweni kwe-procambium kunye ne-basicist. Olu hlobo lokugqibela, lukhuphe kakhulu kwaye lukhulu kakhulu, lunikeza izicubu eziphambili ezijikelezayo nge-procambium encinci kunye ne-denser intambium, i-precursor yokuqhuba izicubu - xylem kunye ne-phloem.

Ukwakhiwa kweCotyledon

IProstermerm, i-meristem kunye ne-procambium (okubizwa ngokuba yi-primary meristems), ngaphandle kokuphazanyiswa, kudlula kwi-cotyledons ukuya kwi-axis ye-embryo. Ukwakhiwa kwamacotyledons kungaqala okanye kwinkqubo okanye emva kokuba i-meristem isisiseko (isigaba sophuhliso ngaphambi kokuba kubonakale i-cotyledon ibizwa ngokuba yi-globular). Kule meko, i-globular embryo yamagqabantshintshi athatha ubunzima obunobumba obubini (eli nqanaba libizwa ngokuba lifana nenhliziyo). Imbewu ye-monocotyledon imbewu yenza i-cotyledon eyodwa kuphela. Ngoko ke, ayinayo isigaba esifane nesimo senhliziyo.

Ukutshatyalaliswa kweeseli zokumiswa

Emva koko ama-cotyledons kunye ne-axis ye-embryo (i-torpedo esecaleni) kwaye i-meristem isiseko isasazwa kunye nabo. Ukubamba, imbungu ihlala iqonde okanye iphihliwe. I-cotyledon enye i-monocotyledon ikhula ngokukhawuleza kangangokuthi iyaba yinto ephezulu kakhulu ye-embryonic structure. Njengoko umbungu uqhubeka ukhula, iiseli zokumiswa zihamba kancane.

Ulwahlulo lweselula

Kwizigaba zokuqala ze-embryogenesis, ukwahlukana kweeseli kwenzeka kwinqanaba le-sporophyte encinane. Nangona kunjalo, ngexesha lokubunjwa kwembungu, ukubonakala kwamaseli amatsha ngokukhawuleza kunqongophele kwiimpawu ze-apical zokudubula kunye neengcambu. Kwiintlobo zeempawu, owokuqala ubeka phakathi kwama-cotyledons amabini, kunye nama-monocotyledon ngecala elinye le-cotyledon kwaye lijikelezwe ngokupheleleyo ngumfazi-inxalenye efana nesiseko sayo. Iimfundiso ze-Apical zixabiseke kakhulu, ekubeni ekugqibeleni zivela kuzo zonke iiseli ezintsha ezinika uphuhliso ukusuka kwintsholongwane yesityalo kunye nomntu omdala.

Isebe le-oviduct

Ngethuba lonke ixesha lokwakheka kwezondlo ze-embryo zihamba rhoqo ukusuka kwisityalo somzali kwizicubu ze-ovule. Ngenxa yoko, isitokisi esikhulu sawo siqokelela kwi-endosperm, kwi-perisperm okanye kwi-cotyledons yembewu ekhulayo. Ekugqibeleni, i-ovules ihlukaniswe kwisigxina, esiyibophelela eludongeni lwe-ovary, kwaye iba yinkqubo evaliweyo (ngokubhekiselele kwisondlo). Imbewu iyomisa, inika amanzi kwimo esingqongileyo, kwaye i-peel imbewu iyanzima, njengokungathi ijikeleza umbungu "ngegobolondo elikhuselekileyo", kunye nayo yonikezelo lwezondlo.

Ngoko, ufunde ukuba intsholongwane yembewu iqulethwe. Njengoko ubona, njengoko ikhula, utshintsho lwayo lwenzeka. Ngako oko, isakhiwo sembungu yembewu sihluke kumanqanaba ahlukeneyo okuba khona.