Izici zezitshalo ze-Angiosperm
Ama-angiosperm, noma ama-angiosperm, yiqembu lezitshalo elihlukahlukene kakhulu neliningi kakhulu elitholakala ezindaweni ezahlukene zemvelo eMhlabeni. Igama elithi "angiosperm" livela emagameni esiGreki athi angion (isitsha) kanye ne-sperma (imbewu), okubhekisele esimisweni sawo esiyinhloko: imbewu evalelwe ngaphakathi kwesithelo. Impumelelo yama-angiosperm ekubuseni izindawo eziningi zokuhlala ingenxa yezici zawo ezihlukile, okuhlanganisa isakhiwo somzimba wawo, izindlela zokuzala, kanye nokuzivumelanisa nemvelo. Lesi sihloko sixoxa kabanzi ngezici eziyinhloko zama-angiosperm.
1. Yiba nezimbali njengezitho zokuzala
Isici esivelele kakhulu sama-angiosperms ukuba khona kwezimbali. Izimbali ziyizitho zokuzala ezakhiwe izingxenye eziningana, njenge-sepals, amacembe, ama-stamens, nama-pistils. Akuzona zonke izimbali ezinazo zonke lezi zingxenye, kodwa ngokuvamile, izimbali zisebenza njengendawo yokungenisa impova kanye nokufaka umanyolo.
Ukuba khona kwezimbali kunikeza inzuzo yokuziphendukela kwemvelo ngoba zidonsela izinambuzane ezithutha impova ngombala, iphunga, kanye nompe. Le ndlela yokwandisa ithuba lokuthuthwa kwempova, okuholela ekutheni inzalo ibe nokwehluka okukhulu kwezakhi zofuzo kanye nokuzivumelanisa nezimo okukhulu nezinguquko zemvelo.
2. Imbewu imbozwe izithelo
Ngokungafani ne-gymnosperms (izitshalo zembewu ezinqunu), ama-angiosperms anembewu ekhula ngaphakathi kwe-ovary (isithelo). Ngemva kokukhulelwa, i-ovary ikhula ibe yisithelo esivikela imbewu.
Isithelo sinemisebenzi ebalulekile, okuhlanganisa:
– Kuvikela imbewu ekulimaleni ngokomzimba nasekuphazamisekeni okuvela kwezinye izinto eziphilayo.
– Kusiza ekusabalaleni kwembewu ngomoya, emanzini, noma ezilwaneni (isibonelo, izithelo ezinomzimba zidliwa yizilwane, bese imbewu isakazwa ngamaconsi).
– Gcina imbewu isesimweni esimanzi futhi iphephile kuze kube yilapho isilungele ukuhluma.
Izibonelo ezilula zingabonakala kuma-mango, utamatisi, kanye nobhontshisi. Kuzo zonke lezi zibonelo, imbewu itholakala ngaphakathi kwesakhiwo sezithelo.
3. Ukuthola umanyolo ophindwe kabili
Esinye sezici ezivelele kakhulu ze-angiosperms ukukhulelwa kabili. Lokhu kwenzeka lapho ama-nuclei amabili esidoda avela ku-pollen grain evundisa izakhiwo ezimbili ezahlukene:
1. I-nucleus eyodwa yesidoda ivundisa iqanda ukuze yakhe i-zygote (2n) ezokhula ibe umbungu.
2. Enye i-nucleus yesidoda ivundisa i-nucleus yesibili ye-germ sac (ngokuvamile ama-nuclei amabili aphansi) ukuze yakhe i-endosperm (3n), okuyindawo yokugcina ukudla kwe-embryo.
Ukuba khona kwe-endosperm kunikeza imbewu ye-angiosperm ukudla okunempilo, okwenza kube lula ukuthi umbungu usinde futhi ukhule ngempumelelo.
4. Yiba nenethiwekhi yemithambo yegazi ethuthukisiwe kahle
Ama-angiosperm ayizitshalo ezinemithambo yegazi (i-Tracheophyta), okusho ukuthi anezicubu ze-xylem kanye ne-phloem zokuthutha amanzi, amaminerali kanye nemiphumela ye-photosynthesis.
Izici ezibalulekile zama-angiosperms yilezi:
– I-Xylem ngokuvamile inezici zemithambo yegazi ezivumela ukugeleza kwamanzi okuphumelelayo kakhulu kune-tracheids nje njengakuma-gymnosperms amaningi.
– I-Phloem inezakhi zamashubhu esihlungo ezisekelwa amaseli ahambisanayo, ezisekela ukusatshalaliswa okuphumelelayo kwezakhamzimba.
Ukusebenza kahle kwalesi zicubu zemithambo yegazi kusiza ama-angiosperm ukuba akhule ngokushesha, akhe izitho eziyinkimbinkimbi, futhi aphile ezindaweni ezahlukahlukene.
5. Inezinhlobo ezahlukene zezimpande, isiqu kanye nezakhiwo zamaqabunga
Ama-angiosperm abonisa izinhlobo eziningi zomzimba. Asukela kumakhambi (izitshalo ezincane, ezithambile), izihlahla, kuya ezihlahleni ezinkulu. Ngaphezu kwalokho, izakhiwo zawo zezitshalo zikhule kahle.
– Izimpande: zingaba yizimpande eziqinile (ezivame kakhulu kuma-dicot) noma izimpande ezinemicu (ezivame kakhulu kuma-monocot). Izimpande zisebenza ukumunca amanzi namaminerali futhi ziqinise isitshalo endaweni engaphansi komhlaba.
– Iziqu: zingaba yizinkuni noma zingabi yizinkuni. Iziqu zezinkuni (isb., i-teak, i-mango) zine-cambium, evumela ukukhula kwesibili, okubangela ukuthi isiqu sikhule.
– Amaqabunga: eza ngezindlela eziningi ezahlukene, kusukela ebanzi kanye nancane kuya ku-palmate kanye ne-compound. Amaqabunga asebenza njengezikhungo ze-photosynthesis kanye ne-gas exchange.
Lokhu kuhlukahluka kubonisa ukuzivumelanisa nezimo kwama-angiosperms ukuze aphile ezimweni zemvelo ezihluke kakhulu, kusukela ezindaweni ezomile kuya ezindaweni zasemanzini.
6. Ihlukaniswe ngamaMonocot namaDicot
Ngokuvamile, ama-angiosperms ahlukaniswe ngezigaba ezimbili ezinkulu: ama-Monocotyledons (ama-Monocotyledonae) nama-Dicotyledons (ama-Dicotyledonae/ama-Eudicotyledonae). Umehluko omkhulu ungabonakala kulezi zici ezilandelayo:
1. Inani lama-cotyledon (amaqabunga embewu)
– Ama-monocot: i-cotyledon eyodwa (izibonelo: ilayisi, ummbila, ukhukhunathi).
– Ama-Dicot: ama-cotyledon amabili (izibonelo: amakinati, ama-mango, ama-sunflower).
2. Imithambo yamaqabunga
– Ama-monocot: ahambisana noma agobile.
– Ama-Dicotyledon: i-pinnate noma i-palmate.
3. Isistimu yezimpande
– Ama-monocot: izimpande ezine-fibrous.
– Ama-Dicots: impande ethambile.
4. Ukuhleleka kwemikhumbi esiqwini
– Ama-monocot: ahlakazekile.
– Ama-Dicotyledons: ayindilinga.
5. Ukukhula kwesibili
– Ama-Monocot: ngokuvamile awakhuli ngokwesibili (ngaphandle kweminye imikhakha embalwa).
– Ama-Dicots: amaningi akhula ngenxa yokuba khona kwe-cambium.
Lesi sigaba sisiza ukwenza kube lula ukuhlonza nokuqonda izakhiwo ze-angiosperm ezifundweni zezitshalo.
7. Ukuguqulwa kwempova okuhlukahlukene
Ama-Angiosperm anezindlela eziningi ezahlukene zokukhiqiza impova. Ukukhiqiza impova kungenzeka ngokusebenzisa:
– Umoya (anemogamy): isibonelo ilayisi nommbila, ngokuvamile kunezimbali ezincane kanye nempova eningi.
– Izinambuzane (izinambuzane ezincelisayo): isibonelo i-hibiscus nama-orchid, zivame ukuba nemibala ekhangayo futhi zikhiqiza umpe.
– Izinyoni (ornitogamy): isibonelo izimbali ezibomvu noma eziwolintshi ziheha izinyoni ezimunca umpe.
– Amanzi (i-hydrogamy): kwezinye izitshalo zasemanzini.
Lokhu kuhlukahluka kwezindlela zokungenisa impova kwandisa amathuba okuzala ezimweni eziningi zemvelo.
8. Indima enkulu kakhulu kwezemvelo nakwezomnotho
Izici zama-angiosperm zenza abe yiqembu elibalulekile empilweni yabantu kanye nokulinganisela kwemvelo. Ngaphakathi kwendalo, ama-angiosperm asebenza njengabakhiqizi abayinhloko, ahlinzeka nge-oxygen kanye nezakhamzimba kwezinye izinto eziphilayo.
Ngokomnotho, ama-angiosperms ahlinzeka:
– Izithako zokudla: ilayisi, ukolweni, ummbila, umdumbula, amazambane, izithelo.
– Izithako zokwelapha: ijinja, i-turmeric, i-cinchona, i-sambiloto.
– Izinto zokwakha: i-teak, i-mahogany.
– I-fibre nezingubo: ukotini, i-hemp.
– Izitshalo zokuhlobisa: ama-rose, ama-orchid, i-jasmine.
Lezi zinzuzo ezibanzi zenza ama-angiosperm angabalulekile nje kuphela ngokwezinto eziphilayo, kodwa futhi abalulekile empucukweni yabantu.
Isiphetho
Ama-angiosperm abonakala ngezimbali, imbewu evalwe yizithelo, kanye nomanyolo ophindwe kabili okhiqiza i-endosperm njengendawo yokugcina ukudla. Anezicubu zemithambo yegazi ezisebenza kahle, isakhiwo esihlukahlukene sezimpande-isiqu-iqabunga, kanye namasu ahlukahlukene okuthungatha impova. Ngenxa yemvelo yawo eguquguqukayo kakhulu, ama-angiosperm ayiqembu lezitshalo elivelele kakhulu eMhlabeni futhi adlala indima ebalulekile emvelweni yabantu kanye nokuphila komnotho. Ukuqonda izici zama-angiosperm kusisiza siqonde ukuthi lezi zitshalo zikhula kanjani, ziphile kanjani, futhi zisekele impilo ezindaweni ezahlukene.
