Ukuchunyiswa kwezityalo: ukungafani kunye neenkqubo kwi-gymnosperms kunye ne-angiosperms

Inkqubo yokuchumisa kwizityalo Yenye yezona zinto zinomdla kwaye zintsonkothile kwindalo. Sifumana ukuzala kwezilwanyana kulula ukukuqonda kuba sikunxulumanisa neenkqubo ezifana nezethu, kodwa ilizwe lezityalo lineendlela ezikhethekileyo nezahluke kakhulu zokuzala. Ukuqonda indlela izityalo ezivelisa ngayo, yaye ngokukodwa indlela okwenzeka ngayo ukuchumisa kumaqela amabini amakhulu—ii<em>gymnosperms nee<em>angiosperms — kunceda ekuqondeni izitshixo zempumelelo yendaleko yezityalo namandla azo amangalisayo okuziqhelanisa.

Yintoni ukuchumisa kwezityalo?

Ukuchumisa kwezityalo Ibandakanya ukudityaniswa kweegeyithi ezimbini, imazi enye kunye nenkunzi enye, ngexesha lenkqubo yokuzala, okukhokelela kwizygote equlethe ulwazi lwemfuzo oluvela kubazali bobabini. Le zygote, emva koluhlu lwezahlulo zeeseli kunye nokuguqulwa, iya kuvelisa i-embryo kwaye ekugqibeleni ibe yimbewu ekwazi ukugcina uhlobo.

En izityalo eziphezulu okanye i-spermatophytes, njengee-angiosperms (izityalo ezidubulayo) kunye nee<em>gymnosperms (izityalo ezingenazo iintyatyambo zokwenene kodwa ezineendlela ezikhethekileyo zokuzala), ukuchumisa kulandelwa umunguLe nkqubo ibandakanya ukukhutshelwa kwembewu yomungu—ethwala ii<em>gametes eziyindoda—ukusuka kumalungu enzala enkunzi ukuya kumalungu ebhinqa, enoba kungentshukumo yomoya, yezilwanyana, okanye kwanamanzi.

Kulo mongo, ukuthetha nge-gametes kunye ne-spores kubalulekile. pollen iinkozo, umphumo we-microsporogenesis, ngokuqhelekileyo uqulethe iiseli ezimbini zokuzala zamadoda (i-antherozoids). Ukufika kwabo kwi-stigma (kwi-angiosperms) okanye i-micropyle ye-ovule (kwi-gymnosperms) iqalisa inkqubo yokuchumisa.

Inkqubo yokuchumisa iyahluka kakhulu phakathi kwamaqela amabini amakhulu ezityalo zembewu, yiyo loo nto kubalulekile ukuqonda umahluko phakathi kwe-gymnosperms kunye ne-angiosperms.

IiGymnosperms: ukuchumisa kunye nomjikelo wobomi

IiGymnosperms Zibandakanya imithi kunye namatyholo, njengepayina, i-yew, imisedare kunye ne-cycads, ebonakaliswa imbewu yabo ayikhuselwanga nge-ovary, ngokungafaniyo ne-angiosperms. Ngoko ke, azivelisi iintyatyambo okanye iziqhamo zokwenene njengoko sizazi kwizityalo ezidubulayo. Endaweni yoko, amalungu abo okuzala zicwangciswe ngaphakathi iikhoni (strobili), enokuthi ibonise iyantlukwano enkulu ye-morphological ngokuxhomekeke kusapho kunye neentlobo.

Umjikelo wobomi kunye nokutshintshwa kwezizukulwana kwi-gymnosperms

Umjikelo wobomi be-gymnosperms, njengakwi-angiosperms, ubandakanya a ukutshintshwa kwezizukulwana: Inqanaba lediploid elibalaseleyo elibizwa ngokuba yi-sporophyte (umthi opheleleyo okanye isityalo esinesiqu, amagqabi kunye neecones) kunye nesigaba se-haploid esihlala ixesha elifutshane esibizwa ngokuba yi-gametophyte, apho kuveliswa iigeyithi.

I-sporophyte ivelisa i-haploid spores nge meiosis, umahluko phakathi megaspores (ibhinqa) kunye microspores (indoda). Ezi spores zivelisa iigametophyte zabasetyhini kunye namadoda, ngokulandelelanayo.

Izitho zokuzala: iicones zendoda nemazi

IiCones zabasetyhini: La ngamalungu apho imbewu ikhula kwaye yenziwe yi-axis esembindini kunye neeyunithi eziphindaphindiweyo zebract, isikali, kunye ne-macrosporangium (apho i-gametophyte yabasetyhini kunye ne-ovule yenziwa). Kwiintlobo ezininzi, ezi zakhiwo zenza i-pine cones eziqhelekileyo. I-ovule ikhula ze, ingakhuselwanga yi-ovary, kwisikali se-ovuliferous.

Iicones zamadoda: Incinane kunekhowuni yemazi, inkunzi yenkunzi ivelisa ize ikhuphe iinkozo zomungu. Yenziwe yi-axis ephakathi kunye ne-microsporophylls equkethe i-microsporangia, apho i-microspores iveliswa kwaye i-pollen grains ikhula kunye ne-gametes yabo yamadoda. pollen grain Iqukethe umaleko ongaphandle okhuselayo (i-exine) kunye ne-inner layer (i-intine), elungiselelwe ukuxhathisa i-desiccation kwaye iququzelele ukusasazwa emoyeni.

Iintlobo zokuchumisa kwi-gymnosperms

Kwii-gymnosperms kukho iindlela ezimbini zokuchumisa:

• Zooidogamy: Kwenzeka kwi-cycads kunye neginkgo, apho ityhubhu ye-pollen ikhupha iigametes eziziinkunzi ezidadayo ukuya kwigamete yabasetyhini.
• Siphonogamy: Ifumaneka kakhulu kwi-conifers kunye ne-gnetophytes, apho i-gamete yesilisa ihanjiswa nge-tube ye-pollen ukuya kwi-gamete yesifazane ngaphandle kwesidingo se-flagella; indlela efana naleyo yee-angiosperms.

Ukuchumisa kwi-gymnosperms: inkqubo eneenkcukacha

• Uvuvuzelo: Iinkozo ze-pollen, ezidla ngokuthwalwa ngumoya (i-anemophilous pollination), zifikelela kwiicones zemazi. Imiba yokusingqongileyo efana nokunetha kwemvula inokuphembelela ukusebenza kakuhle kokudluliselwa kwepoleni, iququzelele okanye ithintele ukuhamba kwepollen kwi-ovule.
• Ukuphuhliswa kwegametophyte yabasetyhini: Kwi-megasporangium, i-gametophyte ye-multicellular female ikhula (inzima ngakumbi kune-embryo sac ye-angiosperms), ekugqibeleni apho i-archegonia emininzi iyahlula, nganye ineseli enkulu yeqanda (oosphere).
• Ukuchumisa: I-tube ye-pollen ikhula ngokukhawuleza ukusuka kwi-pollen grain ukuya kwi-gametophyte yabasetyhini, idlula kwi-nucellus kwaye ifikelele kwi-archegonium, apho ikhupha iziqulatho zayo. Ngokuqhelekileyo, enye yeegametes zesilisa idibana nomongo weqanda, yenze i-zygote evelisa i-embryo. I-Polyembryony ingenzeka, oko kukuthi, ukuchumisa kwe-archegonia emininzi ngaphakathi kwe-ovule efanayo, nangona inye kuphela idla ngokukhula ibe sisityalo esidala.
• Ukwenziwa kwembewu: Emva kokukhulelwa, i-ovule iyakhanya kwaye ibe yimbewu, ehlala ibonakala kwisikali se-cone de ikhule kwaye isasazwe. Imbewu yokugcina inyama (i-endosperm ngengqiqo engqongqo) ivela kwi-gametophyte yabasetyhini kwaye i-haploid, ngokungafaniyo ne-triploid tissue of angiosperms.

Iimpawu zophuhliso lwembewu kunye nokusabalalisa kwi-gymnosperms

Ixesha phakathi kwe ukudluliselwa kwembewu kunye nokuchumisa Inokwahluka kakhulu ngokuxhomekeke kuhlobo, ifikelele kwiinyanga ezilishumi elinesibini kwezinye iipayina. Xa imbewu sele ikhulile, inokuphuhlisa amaphiko ukuququzelela ukusasazwa komoya okanye ikhule ibe yinyama yeziqhamo, njengase Juniperus okanye eTaxus, ekhuthaza ukusasazwa kwezilwanyana.

Kwezinye iimeko, ezifana ne-cone-cone pines, imbewu ihlala ikhuselwe kwi-cone iminyaka ngaphambi kokuba ikhululwe, i-adaptive mechanism ebusweni bomlilo wehlathi okanye imeko engqongileyo. Ukuhluma kunokuxhomekeka kwi-dormancy kwaye kufuna iimeko ezithile zokusingqongileyo ukuba zisebenze.

I-Angiosperms: ukuchumisa kunye nokwahlukana

Ii-Angiosperms Bamele elona qela likhulu kunye nelona lihlukeneyo lezityalo. Babonakala ngokuba namalungu okuzala alungelelanisiweyo iintyatyambo zokwenene, apho iigametes zenkunzi nemazi zikhula. Olona tshintsho luphambili lwe-angiosperms kukuba imbewu ikhula ikhuselwe ngaphakathi kwe-ovary, eya kuthi ivelise isiqhamo emva kokukhulelwa.

I-Anatomy yentyatyambo kunye nezakhiwo zokuzala

• Androecium: Iseti yestamens (imicu ene-anthers), ivelisa iinkozo ze-pollen apho kufumaneka khona iigametes zamadoda.
• Ngumtsalane: Iqela leekhapeli, ezibandakanya i-ovary (apho ii-ovules zifumaneka khona), isitayile, kunye ne-stigma. Ibala lifumana umungu ngexesha lomvumvuzelwano.
• I-Perianth: I-Sepals kunye neepetali ezikhusela amalungu esini kunye nokutsala i-pollinators.

Ingxowa nganye ye-embryo yabasetyhini ineeseli ezikhethekileyo: i-oosphere, i-synergids, i-polar kunye ne-antipodal nuclei, kunye nemisebenzi ethile ngexesha lokuzala.

I-pollination kwii-angiosperms

I-pollination ingaba:

• I-Anemophilic: ngentshukumo yomoya (ihlala kwingca kunye nemithi evuthulukayo).
• Entomophilous: ngezinambuzane (iinyosi, amabhabhathane, amabhungane), iququzelelwa yimibala, iziqhumiso kunye ne-nectar yamagqabi.
• Zoophile: zizilwanyana ezifana neentaka (iingcungcu) kunye namalulwane.
• i-hydrophilicity: ngokukhethekileyo ngamanzi.

Impumelelo yepollination ixhomekeke kubuninzi bemeko yokusingqongileyo kunye nebhayoloji, kwaye inokukhokelela ukuvota ngokwakho (umntu omnye) okanye Ukudluliselwa kwepoleni, enegalelo elikhulu ekuguquguqukeni kofuzo kunye nempumelelo ye-angiosperms.

Ukuchumisa kabini kwe-angiosperms: indlela yeempawu

Emva kokuba i-pollen ifakwe kwi-stigma, ityhubhu ye-pollen ikhula ngesitayela de ifike kwi-ovule ngaphakathi kwe-ovary. Iinuclei ezimbini ezivelisayo (i-antherozoids) zihamba ngale tube:

• Enye ichumisa i-oosphere ukwenza i-diploid zygote, eya kuvelisa i-embryo.
• Enye idibanisa iinuclei ezimbini zepolar ukusuka kwi-embryo sac, yenze i-nucleus ye-triploid apho i-endosperm iphuma khona, izicubu ezinomsoco eziza kugcina oovimba bembewu.

Le nkqubo, ibizwa ukuchumisa kabini, ikhethekileyo kwi-angiosperms kwaye ichaza impumelelo yabo yendaleko, kuba ivumela ukubunjwa kwembewu esebenza kakuhle kwaye ekhuselweyo.

Emva kokukhulelwa, i-ovule iguquka ibe yimbewu kwaye i-ovary ibe sisiqhamo. Uhlobo lweziqhamo kunye ne-dispersal mechanism yahluka kakhulu:

• iziqhamo zenyama (amaqunube, amadrupe): Atsala izilwanyana ukuze zisasaze imbewu.
• Amandongomane kunye neziqhamo ezinamaphiko: Benza lula ukusasazwa ngumoya.
• Iziqhamo ezingaqhelekanga: Zihlala zivaliwe de isilwanyana sizivule.

Ukuhluma kunye nomjikelo wobomi

La ukuntshula Ibandakanya ukuphuhliswa kwe-embryo ibe yimbewu ekwaziyo ukuphila ngokuzimeleyo. Le nkqubo ibalulekile ekusasazekeni nasekuqhubekeni kohlobo kwaye iphenjelelwa zizinto ezifana nobushushu, ukufuma, ukukhanya, kunye nokulala kwembewu.

Kwii-angiosperms, xa imbewu ihluma, umntu unokubona i-radicle (ingcambu yokuqala), i-cotyledons enye okanye ezimbini (kuxhomekeke ekubeni uhlobo luyi-monocotyledonous okanye i-dicotyledonous) kunye nokuphuhliswa kwesiqu kunye namagqabi okwenyaniso.

Umahluko ophambili phakathi kwe-gymnosperms kunye ne-angiosperms ekuchumeni

1. Isisongelo sembewu: I-Angiosperms ivelisa imbewu evalelwe kwaye ikhuselwe kwisiqhamo, ngelixa i-gymnosperms inembewu ehamba ze kwizikali ze-cone.
2. Indlela yokuchumisa: I-Angiosperms idlula kabini (i-zygote kunye ne-endosperm), ivelisa izicubu ze-triploid izondlo; kwii-gymnosperms, ukuchumisa kulula, kwaye izicubu ezigciniweyo zivela kwi-gametophyte yabasetyhini (haploid). Funda ngakumbi ngomahluko ekuveliseni izityalo.
3. Amalungu okuzala: Iintyatyambo ze-angiosperms ziyinkimbinkimbi kwaye zinokuba yi-hermaphroditic okanye i-unisexual; kwii-gymnosperms amalungu okuzala azikhoni ezahlukeneyo.
4. Ukusasazwa kwembewu: I-Angiosperms ineendlela ezininzi ezahlukeneyo (iziqhamo ezidliwayo, amaphiko, ukunamathela), ngelixa i-gymnosperms ithembele kakhulu emoyeni kwaye, ngamanye amaxesha, izilwanyana.
5. Ixesha phakathi komvumvuzelwano kunye nokuchumisa: Kwii-gymnosperms kunokubakho ixesha elide phakathi kwe-pollination kunye nokuchumisa; kwii-angiosperms idla ngokukhawuleza.

Impumelelo yendaleko kunye nohlengahlengiso lwee-gymnosperms kunye ne-angiosperms

I-Spermatophytes okanye izityalo zembewu, zombini ii-gymnosperms kunye ne-angiosperms, zizuze impumelelo engaqhelekanga yendaleko ngenxa yohlengahlengiso lweendlela zabo zokuzala:

• Ukumelana nembewu kunye nokulala: Bavumela ukusinda kwiimeko ezimbi kunye nokusabalalisa kwindawo kunye nexesha.
• Ukwahluka kwemfuza: I-cross-pollination kunye nokuchumisa ngokwesondo kwandisa ukuhlukahluka kofuzo, ukuququzelela ukulungelelanisa kunye nekholoni yeendawo zokuhlala ezintsha.
• Ubungcali ekusebenzisaneni ne-pollinators kunye ne-dispersers: Ikakhulu kwii-angiosperms, ukuphuhliswa kweentyatyambo ezibonakalayo kunye neziqhamo ezidliwayo kwandisa amathuba abo okuzala kunye nokufudukela kwiindawo ezintsha.

Izinto ezichaphazela ukuchumisa kunye nokuveliswa kwembewu

La ukuchumisa nokuveliswa kwembewu Banokuchatshazelwa zizinto zangaphakathi nangaphandle:

• Imiba yemozulu: Iqabaka, imbalela, imimoya ebhudla ngamandla okanye imvula inokuchaphazela kakubi ukudubula kweentyatyambo, ukudluliselwa kwembewu kunye nokuvuthwa kweziqhamo, kunciphise impumelelo yokuzala.
• Ukunxibelelana neearhente zebhayoloji: Izinambuzane, iintaka kunye nezilwanyana ezanyisayo zinokusebenza njenge-pollinators kunye ne-seed dispersers, kodwa njengezinambuzane ezinciphisa ukuveliswa kwembewu esebenzayo.
• Ukulala kwembewu kunye nokusebenza: Iimbewu ezininzi ziseka iindlela zokuthi intshule phantsi kweemeko ezifanelekileyo. Ezinye zingahlala zisebenza iminyaka de isiganeko (imvula, umlilo, ukudlula kwindlela yokwetyisa yesilwanyana) siphule i-dormancy yabo.

Kwiindawo zokuhlala zamahlathi nezolimo, ulwazi lwebhayoloji yembewu kunye ne-dormancy lubalulekile ekwandiseni ukuqokelelwa kwembewu, ukugcinwa, nokutyalwa, oko kuqinisekisa uhlaziyo kunye nokuzingisa kweentlobo zomdla wezoqoqosho kunye nendalo.

Ukubaluleka kwendalo kunye noluntu lokuchumisa izityalo

Ukuchumisa nokuveliswa kwezityalo Aziqinisekisi nje kuphela ubukho bezinto eziphilayo, kodwa zikwasisiseko sezinto eziphilayo neendawo eziphilayo. Ukuveliswa kwembewu neziqhamo kondla intaphane yezilwanyana, kulondoloza amatyathanga okutya, yaye kubalulekile kwezolimo, amahlathi nasekuphileni kwabantu.

Uphononongo lweenkqubo zokuzala kwi-angiosperms kunye ne-gymnosperms ivumela izazinzulu kunye nabaphathi bomhlaba ukuba baphuhlise iindlela zokulima ezizinzileyo kunye nokuhlangula iintlobo ezisengozini.

Kuyo yonke indaleko, ukuchumisa kwezityalo kuye kwavelisa iindlela ezahlukeneyo ezimangalisayo, uhlengahlengiso, kunye nezakhiwo, ukusuka kwiintyatyambo ezintsonkothileyo ze-angiosperms ukuya kwiicones ezomeleleyo ze-gymnosperms. Le yantlukwano iye yavumela izityalo ukuba zibe koloni kuzo zonke iindawo ezisingqongileyo zoMhlaba, ukusuka kwiipali ukuya kwiindawo ezishushu, ukusuka entlango ukuya kumahlathi ashinyeneyo, kwaye kubonakaliswa kwiindidi ezininzi zobomi bezityalo ezikhoyo namhlanje.

Inqaku elidibeneyo:

Iimpawu ezineenkcukacha kunye nemizekelo yezityalo ze-vascular: isakhiwo, imisebenzi, kunye nokuhlukahluka