Tsarin Haihuwa a Tsire-tsire Masu Fure
Tsire-tsire masu fure, ko angiosperms, su ne rukuni mafi bambancin tsirrai a Duniya. Yaɗuwarsu a wurare daban-daban ya faru ne saboda tsarin haihuwa mai inganci da daidaitawa. A cikin tsire-tsire masu fure, haifuwa tana faruwa ne ta hanyar furanni, gabobin haihuwa waɗanda ke ba da damar yin fure, hadi, samuwar iri, da haɓaka 'ya'yan itace. Wannan labarin ya tattauna tsarin fure, tsarin haifuwar halitta, da bambance-bambance da yawa a cikin dabarun haihuwa a cikin tsire-tsire masu fure.
1. Furanni a matsayin hanyar haifuwa
Furanni an gyara su ne don sake haifuwar tushen da ganye. Gabaɗaya, furanni sun ƙunshi manyan sassa da yawa:
1. Furen furanni (sepals)
Yawanci launinsa kore ne kuma yana taimakawa wajen kare furen yayin da yake ci gaba da zama toho.
2. Kambin fure (fure)
Gabaɗaya suna da launuka masu haske kuma suna aiki don jawo hankalin masu yin fure kamar kwari, tsuntsaye, ko jemagu.
3. Stamen - gabar haihuwa ta maza
Ya ƙunshi:
- Filament
– Anther, inda ake samun pollen.
4. Pistil (carpel) – kwarangwal na haihuwa na mace
Ya ƙunshi:
– Ƙyama: wurin da ƙurar fure ke mannewa.
– Salo: hanyar zuwa kwai.
– Ƙwayoyin halitta (ovaries): inda ƙwayoyin halitta suke.
Ba dukkan furanni ne ke da cikakken tsari ba. Akwai furanni masu kyau (masu stamens da pistils) da furanni marasa kyau (masu furanni maza ko mata kawai). Bugu da ƙari, akwai tsire-tsire masu launuka iri ɗaya (masu furanni maza da mata a kan mutum ɗaya, kamar masara) da tsire-tsire masu launuka iri ɗaya (masu furanni maza da mata a kan mutum ɗaya, kamar 'ya'yan itacen maciji).
2. Samuwar Kwayoyin Halittar Jini a Tsirrai Masu Fure
Haihuwar ƙwayoyin halitta a cikin angiosperms ya ƙunshi samuwar ƙwayoyin halittar maza da mata ta hanyar tsarin raba su na musamman.
a. Samuwar ƙwayoyin halittar maza (pollen/pollen)
Ana samar da ƙwayoyin pollen a cikin anther. A cikin anther, akwai ƙwayoyin microspore waɗanda ke yin meiosis don samar da ƙananan ƙwayoyin haploid. Sannan ƙananan ƙwayoyin za su zama ƙwayoyin pollen waɗanda ke ɗauke da:
– Kwayoyin ganyayyaki (za su samar da bututun pollen)
- Kwayoyin halitta (za su rabu zuwa maniyyi biyu)
Saboda haka, pollen ya zama "mai ɗaukar" ƙwayoyin maniyyi zuwa ga ƙwai.
b. Samuwar ƙwayoyin halittar mata (jakar mahaifa)
Kwayoyin halittar mata suna samuwa a cikin ƙwayoyin halittar da ke cikin ƙwayoyin halittar. Kwayoyin halittar megaspore suna yin meiosis don samar da megaspores guda huɗu, amma yawanci ɗaya ne kawai ke rayuwa kuma yana girma cikin jakar tayin. Jakar tayin tana ɗauke da wasu muhimman ƙwayoyin halitta:
- Ƙwayoyin ƙwai (ovum)
- Ƙungiyoyin polar guda biyu
– Kwayoyin haɗin gwiwa (suna taimakawa tsarin hadi)
- Kwayoyin antipodal (gabaɗaya suna taka rawa a cikin abinci mai gina jiki)
Wannan tsari zai zama wurin da za a yi hadi.
3. Gurɓatar ƙasa
Gurɓatar da ƙura ita ce hanyar canja wurin ƙura daga anther zuwa ga ƙyama. Gurɓatar da ƙura muhimmin mataki ne domin ita ce hanyar shiga taki. Gurɓatar da ƙura tana iya faruwa ta hanyoyi da dama:
1. Rashin Lafiyar Jiki (ta hanyar iska)
Misalai: shinkafa, masara, ciyawa. Furanni yawanci ƙanana ne, ba a iya gani, kuma suna samar da furanni masu yawa, masu sauƙi.
2. Entomogamy (ta hanyar kwari)
Misalai: sunflowers, jasmine. Corollas ɗinsu suna da kyau, galibi suna samar da ruwan 'ya'yan itace da ƙamshi.
3. Ornithogamy (ta tsuntsaye)
Misali: hibiscus a wasu yankuna, ko tsire-tsire waɗanda furanninsu ja ne mai haske kuma suna da wadataccen ruwan 'ya'yan itace.
4. Ciwon Daji (ta hanyar jemagu)
Misali: durian da wasu cacti. Furanninsu suna yin fure da daddare kuma suna da ƙamshi mai ƙarfi.
5. Ruwan sha (ta hanyar ruwa)
Yana faruwa a wasu tsire-tsire na ruwa.
Dangane da asalin pollen, an raba pollination zuwa:
– Cin amana: yin pollination kai (pollination ga pistil a cikin fure ɗaya)
- Geitonogamy: tsakanin furanni akan mutum ɗaya
– Allogamy/Xenogamy: tsakanin mutane daban-daban (yana ƙara bambancin kwayoyin halitta)
4. Hadin Kai Biyu: Halayen da Aka Fi Sani Game da Angiosperm
Bayan ƙwayoyin pollen sun manne da ƙazanta, sai su tsiro su samar da bututun pollen wanda ke girma ta hanyar salon zuwa ga ƙwai. Ƙwayar halittar ta rabu don samar da ƙwayoyin maniyyi guda biyu. Lokacin da bututun ya isa jakar tayi, abin da ake kira angiosperm, hadi biyu, yana faruwa:
1. Manya na farko yana takin ƙwai → yana samar da zygote (2n) wanda zai girma ya zama tayi.
2. Manya na biyu yana takin ƙwayoyin halitta guda biyu na polar → yana samar da endosperm (3n) a matsayin wurin ajiyar abinci ga tayin.
Wannan hadi biyu yana da matuƙar muhimmanci domin endosperm yana samuwa ne kawai lokacin da hadi ya faru, don haka hanyoyin samar da makamashi ga tayin suna samuwa yadda ya kamata.
5. Tsarin Iri da 'Ya'yan Itace
Bayan hadi:
– Ovules suna girma su zama iri
– Kwai (ovary) yana girma ya zama 'ya'yan itace
a. Tsaba
Tsaba gabaɗaya sun ƙunshi:
– Embryo (sabon ɗan takarar shuka)
- Endosperm (ajiyar abinci, a cikin nau'ikan abinci da yawa)
– Rigar iri (testa) a matsayin kariya
Tsarin iri yana bawa shukar damar jure wa yanayi mara kyau (misali bushewa ko sanyi) kuma ya bazu nesa da shukar da ta fi girma.
b. 'Ya'yan itace
'Ya'yan itatuwa suna kare iri kuma suna taimakawa wajen wargaza iri. Wasu 'ya'yan itatuwa suna da nama, suna jan hankalin dabbobin da ke cin 'ya'yan itace (misali, mangwaro), yayin da wasu kuma busassu ne, iska tana yaɗuwa cikin sauƙi (misali, auduga da dandelion). Yaɗuwar iri na iya faruwa ta hanyar iska, ruwa, dabbobi, ko kuma autochory.
6. Tsirrai da Girman Sabbin Mutane
Idan yanayi ya yi kyau (isasshen ruwa, yanayin zafi mai kyau, da kuma wadatar iskar oxygen), iri zai tsiro. Dan tayin zai girma ya zama shuka ta hanyar amfani da ma'adinan abinci na endosperm ko cotyledon. Bayan ya samar da ganyaye da saiwoyi masu amfani, ƙaramin shukar yana iya photosynthesis kuma ya girma ya zama babba, daga ƙarshe ya sake samar da furanni.
7. Bambancin da Sauya Tsarin Haihuwa
Shuke-shuken fure suna da dabaru daban-daban don haɓaka nasarar haihuwa, kamar:
– Bambanci: bambance-bambance a cikin tsawon pistil da stamens don hana gurɓatar da kansu.
– Bambancin ra'ayi: lokacin balaga na stamens da pistils ba iri ɗaya bane.
– Apomixis: samuwar iri ba tare da hadi ba (a wasu tsire-tsire), wanda ke ba da damar hadi cikin sauri tare da halaye iri ɗaya na kwayoyin halitta.
– Juyin halitta tare da masu yin fure: siffar fure, launi, da ƙamshi sun dace da fifikon wasu masu yin fure don ƙara ingancin yin fure.
Penutup
Tsarin haihuwa na tsire-tsire masu fure tsari ne mai kyau na tsari, tun daga samuwar gamete, pollination, hadi biyu, zuwa samuwar iri da 'ya'yan itace. Babban fa'idar angiosperms tana cikin furanninsu a matsayin gabobin haihuwa masu inganci, da kuma hadi biyu, wanda ke tabbatar da cewa tayin yana samun wadataccen abinci. Bambancin hanyoyin pollination da daidaitawar haihuwa yana ba da damar tsire-tsire masu fure su rayu da bunƙasa a kusan kowace yanayin halitta. Fahimtar wannan tsarin ba wai kawai yana da mahimmanci don nazarin ilimin halittu ba har ma yana da amfani a noma, kiwo shuke-shuke, da kiyaye bambancin halittu.
