Wannan shine Welwitschia, tsiron hamada wanda "baya iya mutuwa"

A Afirka mun sami ɗayan wuraren farko da suka fara ɗaukar rayuwar ƙasa: hamada Namib. Ya tsufa saboda an san cewa an riga an ƙirƙira shi a lokacin Babban Zamani, kimanin shekaru miliyan 65 da suka gabata. Tana a kudancin nahiyar, tana da fadin murabba'in kilomita dubu 81. Anan, yana da sauƙi don yanayin zafi ya kai 50ºC a lokacin bazara kuma da wuya ya yi ruwan sama a wurare da yawa, kuma a can ne kawai muke samun ɗayan tsirrai masu tsayayya a duniya: Welwitschia mirabilis, kawai nau'in jinsi Welwitschia.

Wasu na kiranta da tsiron da ba ya mutuwa, ko shukar da ba ta mutuwa. Yana girma a hankali sosai, amma ta dace da muhallin ta har kullum tana son sanin menene sirrin ta. Yanzu, a ƙarshe, binciken kimiyya ya bayyana shi.

Tare da inci biyu kawai na ruwan sama a kowace shekara, da welwitschia Tsirrai ne da ke girma cikin annashuwa, amma hakan ba ya hana ta rayuwa har zuwa shekaru 3000, wanda shine kimanin shekarun wasu samfurori. Wannan yana nufin cewa tsaba sun yi girma a farkon ƙarfe na ƙarfe, lokacin da mu mutane muka koya ba kawai yadda ake aikin ƙarfe ba har ma da yadda ake shuka shuke -shuke. Amma kada mu karkace.

An gano Welwitschia a cikin 1860 ta masanin kimiyyar halittu Friedrich Welwitsch, saboda wannan dalili, ba su yi jinkirin yin amfani da sunan mahaifinsa a matsayin sunan nau'in tsiron ba. Daga baya, Charles Darwin, da sauran masana kimiyya, sun nuna sha’awarsu a kai, kuma musamman musamman, a tsawon rayuwarta. Menene abin da zai ba ku damar rayuwa tsawon shekaru da yawa ba tare da juyawa ba, a ƙarƙashin rana mai tsananin zafi tare da ɗigon ruwan sama a shekara?

Abubuwan ban mamaki na Welwitschia

Yawanci, lokacin da shuka ke fuskantar irin wannan damuwar tana bushewa kawai, amma Welwitschia baya yin hakan. Menene dalili? Kuskure a rabewar sel, wanda ya faru kimanin shekaru miliyan 86 da suka gabata. Wannan "kuskure" ya sa kwayar halittar ta ninka. Amma ba haka ba ne kawai, saboda samun ƙarin kayan halitta yana nufin dole ne a kashe ƙarin kuzari, kuma wannan a cikin hamada kusan manufa ce ta kashe kai, la'akari da yanayin yanayi.

Koyaya, Welwitschia ya san yadda ake daidaitawa ba tare da matsaloli ba. A cewar binciken, kimanin shekaru miliyan biyu da suka gabata aikin retrotransposons (don fahimtar mu: su abubuwa ne da za a iya ƙarawa a cikin kwayar halittar) an ƙarfafa su azaman martani ga damuwar zafi. Wannan ya haifar da canje -canje a cikin kwayoyin halittar amma ba tare da canza tsarin DNA wanda yayi shiru waɗannan abubuwan sake juyawa ba.

Wadannan canje-canje, wanda aka sani da sunan fasaha na epigenetics, suna wucewa daga tsara zuwa tsara, da wanda, zuriyar wancan Welwitschia na farko wanda ya sami nasarar haɓaka don daidaitawa da hamada Namib wanda ya riga ya tsiro da wannan ingancin.

Curiosities da Welwitschia mirabilis

Sakamakon waɗannan muhimman canje -canje an rage girman tsiron, kuma sakamakon haka ma amfani da makamashi. Amma har yanzu akwai sauran: ganye suna tsirowa daga tushe mai tushe, wato, daga tsakiyar shuka, yayin da a cikin yawancin nau'in sabon ganye yana fitowa daga rassan ko tushe.

Wani gaskiyar abin shine yana da ganye biyu kawai. Lokacin da kuka ga hotuna yana ba da jin cewa dole ne ku sami ƙarin, amma da gaske ba haka bane. Sun fara zama cotyledons na kusan milimita 30, kuma kaɗan kaɗan ana canza su zuwa ganyayyun ganye masu laushi da kore waɗanda za su iya auna kusan tsayin mita ɗaya.

Ko da yake fari shine wanda ba a bayyana shi ba na Namib, wannan shuka yana kula da samun ruwa saboda godiya ga raɓa maraice. Muna yawan tunanin tsirrai suna shan ruwa ne kawai daga tushen su, amma babban asalin duk abin da muke gani da sani yana cikin teku. Saboda haka, pores ko stomata suna amsawa ta hanyar buɗewa. Lokacin da ake ruwa sosai, a daya bangaren, ana rufe su saboda yawan ruwa na iya nutsar da su.

Yana da wahala ɗan adam ya ga Welwitschia ya bunƙasa; duk da haka, wasu masu sa'a suna da. Godiya gare su, an san cewa nau'in dioecious ne; wato akwai samfuran maza da sauran mata. Wannan kawai yana rikitar da yuwuwar barin zuriya, wanda shine dalilin da yasa kusan ba zai yuwu a sami tsaba don siyarwa ba, kuma lokacin da aka same su, suna da tsada mai tsada (ta hanyar, idan kun same su, kar ku manta da yi musu magani jan karfe foda saboda suna da rauni sosai ga cututtukan fungal).

An tattara furanni a cikin inflorescences waɗanda ke tsiro daga tsakiyar shuka, kuma suna ja. Ba su da ƙananan furanni, saboda waɗannan su ne sifofi waɗanda a cikin wuri kamar hamada, inda babu ƙwari, kawai za su kashe ruwa mai yawa kuma ba kwata -kwata.

Ta haka ne, Welwitschia mirabilis zai iya taimakawa masu ilimin kimiyyar halittu su haɓaka amfanin gona mafi tsayayya da yanayin bushewa, wani abu da zai zo da amfani idan muka yi la'akari da cewa a sassa da dama na duniya yanayin yana dumama kuma ana ganin gajimare ruwan sama kasa da kasa.

Wannan shine hanyar binciken idan har kuna sha'awar: Nazarin yanayi