Menene hadi na shuke-shuke?

Saboda yanayin mu, yana da sauƙi a gare mu mu yi tunanin yadda dabbobi suke hayayyafa, tun da tsarin hadinsu yawanci kama da namu ne. Koyaya, yana ɗaukar ɗan lokaci kaɗan don nemo waɗannan kamanceceniya da duniyar shuka. Ta yaya suke yin hakan? Menene hadi na shuke-shuke?

Manufar wannan labarin shine don bayyana menene hadi na shuka. Don wannan za mu yi magana game da manyan ƙungiyoyi biyu waɗanda suke: Angiosperms da gymnosperms. Don haka kada ku yi shakka don ci gaba da karantawa idan kuna sha'awar batun kuma kuna son ƙarin sani game da hadi na shuke-shuke.

A hadi na shuke-shuke

Kafin yin bayani game da hadi na tsire-tsire, zamu fara yin tsokaci akan menene manufar hadi. Shi ne tsarin da wanda Gametes guda biyu, namiji da mace, suna fuse yayin haifuwa. Ta wannan hanyar, ana ƙirƙirar zygote wanda ya ƙunshi kwayoyin halitta, samfurin iyaye.

A cikin duniyar shuka, Pollination yana faruwa da farko. Ganyen haifuwa na maza suna haifar da ƙwayar pollen da kwari ke ɗauka ko iska ta kai su ga abin kunya. A nan ne suke tsiro. Lokacin da muke magana game da shuke-shuke, ba yawanci ana nufin gametes ba, amma ga spores. Kowace hatsin pollen yawanci tana ƙunshe da ƙwayoyin haifuwa na maza biyu, ko gametes. Duk da haka, akwai hanyoyi daban-daban da tsire-tsire ke amfani da su, tun da ba kowane nau'in jinsin ba ne, a gaskiya sun bambanta sosai idan ana maganar haifuwa.

Labari mai dangantaka:

Yadda za a gane idan shuka namiji ne ko mace

Kamar yadda ka sani, ana iya bambanta tsire-tsire ta hanyoyi da yawa. Akwai adadi mai yawa na ƙungiyoyi, azuzuwan da nau'ikan kayan lambu kuma kowane nau'in nasa ne da yawa. Duk da haka, akwai manyan ƙungiyoyi biyu waɗanda suka bambanta ta hanyar da suke haifuwa. Don haka, Akwai kayan lambu da furanni da waɗanda ba tare da furanni ba. Na farko an san su da angiosperms kuma sune mafi yawan tsire-tsire a wannan duniyar. Bugu da kari, daga cikin wadannan nau'ikan kayan lambu guda biyu sune na baya-bayan nan. A gefe guda, tsire-tsire ba tare da furanni ba suna cikin rukuni na motsa jiki. Waɗannan su ne farkon da suka bayyana a duniya, tun kafin dinosaur.

Daga cikin angiosperms akwai tsire-tsire iri-iri kamar shrubs, bishiyoyi, azaleas, dimorphothecae, da sauransu. Game da gymnosperms, waɗannan sun ƙunshi galibi daga cikin conifers. Wasu misalan wannan rukunin zasu kasance itacen al'ul, yews, pines. Cycads kuma na cikin tsire-tsire na gymnosperm. Amma kada ku damu, za mu yi magana dalla-dalla game da nau'ikan tsire-tsire guda biyu, tsarinsu da yadda hadi ke faruwa.

Gymnosperms

Bari mu fara da gymnosperms. Ko da yake gaskiya ne cewa waɗannan tsire-tsire an san su da rashin furanni, suna da. amma ba na yau da kullun da muke tunanin ba. Furen sa ba su da sepals ko petals, amma matan suna samar da nau'in mazugi na itace da kore wanda ya ƙare ya zama 'ya'yan itatuwa na ƙarya, kamar pine cones.

Tsire-tsire na wannan rukunin suna da furanni maza da mata. Na karshen yana da ma'auni, ovules guda biyu da bract wanda ke samar da mazugi na mace ta hanyar taru a kusa da axis na fure. Kowane ovule ya ƙunshi jakar amfrayo mai archegonia biyu a ciki. wanda, bi da bi, yana da mace guda biyu gametes ko ospheres kowace. Bari mu fayyace waɗannan ra'ayoyin:

• Archegonia: Ita ce sashin haihuwa na mace. namomin kaza, algae y bryophytes, irin su mosses da wasu tsire-tsire masu tsire-tsire irin su ferns. Ana cika ta da gabobin namiji da ake kira antheridium.
• Ospheres: Ita ce mace gamete na shuke-shuke. Suna fitowa daga abin da ake kira megaspore ta hanyar tsarin da ake kira megagametogenesis. A matakin asali muna iya cewa wannan ya ƙunshi sassan mitotic. A lokacin hadi ninki biyu, oospheres suna haɗuwa tare da ƙwararrun ƙwayoyin cuta daga ƙwayar pollen kuma don haka haifar da amfrayo.

Amma ga furanni na namiji, waɗannan suna samar da mazugi na maza a kusa da axis na fure. Suna da sikelin da kuma microsporangia biyu ko Jakunkunan pollen wanda a cikinsa sukan samar da sel uwa wanda hakan ya haifar da shahararrun nau'in pollen. A cikin su akwai jimillar gates guda biyu na maza, wanda kuma ake kira antherozoids. Sun kuma ƙunshi buhunan iska guda biyu waɗanda ke taimakawa tarwatsewa har sai sun isa furen mace. A wannan yanayin ina tsammanin zai yi kyau kuma in bayyana wasu ra'ayoyi:

• Microsporangia: Su ne tsarin da ke samar da kuma sun ƙunshi spores. Waɗannan su ne ainihin gawawwakin ƙananan ƙwayoyin cuta waɗanda manufarsu ita ce tarwatsa su tsira na dogon lokaci.
• Antherozoid: Yana da asali na namiji gamete, wanda zai zama daidai da maniyyinmu.

Hadi na gymnosperm shuke-shuke

Sanin kadan game da tsarin namiji da mace furanni na gymnosperms, yanzu za mu yi sharhi game da yadda wannan hadi ke aiki. Ya kamata a lura cewa ƙwayar pollen na iya ɗaukar har zuwa shekara guda don shuka, da zarar furen mace ya kai. Lokacin da wannan ya faru, bututun pollen yana buɗewa a hankali ta hanyar abin da ake kira nucellus na ovule. Lokacin da ya kai gametophyte na mace, aikinsa na gaba shine ya ratsa wuyan archegonium sannan ya shiga cikin oosphere. inda zaku zazzage duk abubuwan ku. A wannan lokacin ne ake yin takin tsire-tsire na gymnosperm.

Labari mai dangantaka:

Angiosperms da motsa jiki

A lokacin wannan tsari, ɗayan gametes yana ƙarewa tare da tsakiya na wannan oosphere wanda yake faruwa. A sakamakon haka, zygote yana samuwa, wanda shine tantanin halitta wanda tayin ke samuwa kuma yana tasowa. Game da tsakiya na vegetative, sauran sel na archegonium da sauran gamete na maza, duk sun lalace. A halin yanzu, endosperm, wanda ya ƙunshi ƙwayoyin ajiya, yana kewaye da amfrayo, wanda ke kare shi ta hanyar integument na ovule, wanda kuma ya zama lignified. Ana ɗaukar tayin ya cika girma lokacin da aka saki tsaba. Wannan tsari na iya ɗaukar shekaru biyu cikin sauƙi daga lokacin da furanni suka bayyana.

Game da tsaba daga pine, gashin iri shine diploid kuma ana samar da shi ta hanyar sporophyte na uwa. Game da endosperm na farko ko ajiyar nama, wannan haploid ne tun da yake wani bangare ne na gametophyte na mace. Bayan hadi, amfrayo diploid yana samuwa, wanda shine sabon sporophyte.

Angiosperms

Mun riga mun san menene gymnosperms da yadda suke aiki, amma menene game da angiosperms? Kafin yin bayani game da hadi na waɗannan tsire-tsire. Da farko dole ne mu fayyace wasu ra'ayoyi Don ƙarin fahimtar tsarin:

• Carpels: Waɗannan ganyen gyaggyarawa ne waɗanda, gaba ɗaya, suna samar da sashin haifuwar mace na furen tsire-tsire na angiosperm. Saitin duk carpels na fure ana kiransa gynoecium.
• Abin kunya: Wannan bangare ne na gynoecium wanda ke karbar pollen lokacin da ake yin pollination.
• Micropyle: Har ila yau, an san shi da micropyle, rami ne ko budewa da aka samo a cikin ɓangaren apical na rudiments na seminal ko ovules.
• Masu haɗin gwiwa: Kwayoyin su ne masu tsakiya da ke samuwa a ƙarshen jakar amfrayo na tsire-tsire na angiosperm. Kowane jakar tayi yana da guda biyu daga cikinsu. Haɗin gwiwar biyu tare suna samar da na'urar filiform ko na'urar filar. Ya kamata a lura cewa suna taimaka wa oosphere yayin aikin hadi.
• Polar nuclei: Wadannan kwayoyin halitta ne da ake samu a cikin jakar amfrayo, gametophyte na mace ko ovary. Suna shiga tsakani a cikin takin kayan lambu.

Ya kamata a ce kowane jakar amfrayo yana da nau'ikan sel daban-daban, wanda masu haifuwa su ne ƙwanƙolin polar da kuma ovule. Duk da haka, wadanda bakararre, waɗanda zasu zama antipodal da synergistic, suma suna yin haɗin gwiwa yayin aikin hadi.

hadi na angiosperm shuke-shuke

Don gamawa da batun hadi a cikin tsire-tsire, za mu yi magana game da aikin angiosperms. Da zarar pollination na carpel ya faru, ruwa mai sukari, wanda ya ƙunshi galibi na sucrose kuma wanda balagagge ya haifar. yana motsa germination na ƙwayar pollen. Daga kowace irin waɗannan hatsi wani bututun pollen ya fito wanda manufarsa ita ce ƙirƙirar hanya ta salon har ya kai ga mace gametophyte ko jakar amfrayo na tsire-tsire na angiosperm. Wannan jakar amfrayo tana cikin kwai.

Labari mai dangantaka:

Menene tsire-tsire na angiosperm?

Namiji gametes ko generative nuclei tafiya ta cikin bututun pollen har sai sun isa micropyle. Bututun pollen ya ratsa ta wannan tsarin kuma yana fitar da duk abinda ke cikin sa cikin jakar tayi. kusa da ɗaya daga cikin synergids guda biyu. Bayan wannan tsari, ƙwararrun ƙwayoyin halitta suna haɗuwa tare da oosphere da polar nuclei, wanda shine dalilin da ya sa ake kiranta "hadi biyu".

Akwai nau'ikan pollen da yawa waɗanda yawanci sukan kai ga abin kunya kuma, saboda haka, suna tsiro. Duk da haka, daya ne kawai daga cikinsu zai samar da hadi. Da zarar ovary ya hadu, sai ya fara girma ya zama 'ya'yan itace. A cikin waɗannan 'ya'yan itatuwa da suke da dama tsaba, akwai kuma hatsi da yawa na pollen wajaba a gare su don haɗawa da kowane ɗayan kwai.

Abin ban dariya ne yadda yanayi ya tsara komai ta yadda nau'ikan kayan lambu za su iya haifuwa, daidai ne? Ba tare da shakka ba, wannan ƙasa tana cike da abubuwan halitta masu ban mamaki da iyawar kiwo.