Le yiWelwitschia, isityalo sentlango "esingenakufa"

EAfrika sifumana enye yeendawo zokuqala ezaqala ukugcina ubomi basemhlabeni: Intlango yaseNamib. Indala kuba iyaziwa ukuba yayisele yenziwe ngexesha le-Era ePhakamileyo, malunga neminyaka engama-65 yezigidi eyadlulayo. Ime emazantsi eli lizwekazi, inommandla we-81 lamawaka eekhilomitha. Apha, kulula ukuba amaqondo obushushu afike kuma-50ºC ehlotyeni kwaye akunzima ukunetha kwiindawo ezininzi, kwaye kulapho kanye apho sifumana esinye sezityalo ezinganyangekiyo emhlabeni: iWelwitschia mirabilis, iindidi kuphela zohlobo lweWelwitschia.

Abanye bayibiza ngokuba sisityalo esingafiyo, okanye isityalo esingafiyo. Ikhula ngesantya esicothayo, kodwa ulungelelene kakuhle nemeko yakhe yokuhlala wayehlala efuna ukwazi ukuba yintoni imfihlo yakhe. Ngoku, okokugqibela, uphando lwenzululwazi luyityhilile.

Ngee-intshi ezimbini kuphela zemvula ngonyaka, i welwitschia Sisityalo esikhula ngesantya sokuphumla, kodwa oko akukuthinteli ekuhlaleni iminyaka engama-3000, oqikelelwa kubudala bemizekelo ethile. Oku kuthetha ukuba imbewu ihlume kwi-Iron Age yokuqala, apho thina bantu sifunde kungekuphela nje indlela yokusebenza kwentsimbi kodwa nendlela yokukhulisa izityalo. Kodwa masingaphambuki.

I-Welwitschia yafunyanwa ngo-1860, ngu Friedrich Welwitsch, ngenxa yesi sizathu, abazange bathandabuze ukusebenzisa ifani yakhe njengegama lohlobo lwesityalo. Emva kwexesha, uCharles Darwin, kunye nezinye izazinzulu, babonisa umdla wabo, ngakumbi ngakumbi kubomi obude. Yintoni le ikwenza ukuba uphile iminyaka engaka ungakhanyisanga, phantsi kwelanga elitshisayo kunye namathontsi emvula ambalwa ngonyaka?

Imfuza engaqhelekanga yeWelwitschia

Ngokwesiqhelo, xa isityalo siphantsi koxinzelelo olunje siyoma nje, kodwa iWelwitschia ayenzi njalo. Siyintoni isizathu? Impazamo kulwahlulo lweeseli, eyenzeka malunga nezigidi ezingama-86 zeminyaka eyadlulayo. Le "mpazamo" yabangela ukuba isityalo semfuza siphindwe kabini. Kodwa ayisiyiyo yonke loo nto, kuba ukuba nezinto ezininzi zemfuza kuthetha ukuchitha amandla amaninzi, kwaye oku entlango kuphantse kube ngumsebenzi wokuzibulala, kuthathelwa ingqalelo iimeko zemozulu.

Nangona kunjalo, i-Welwitschia yayisazi indlela yokuziqhelanisa ngaphandle kweengxaki. Ngokophando, Malunga nezigidi ezibini zeminyaka eyadlulayo umsebenzi weetrotransposons (Ukusiqonda: zizinto ezinokuphakanyiswa kwi-genome) ziqiniswe njengempendulo yoxinzelelo lobushushu. Oku kubangele ukuba utshintsho lwenzeke kwimfuza kodwa ngaphandle kokutshintsha ukulandelelana kwe-DNA okuvale ezi retrotransposons.

Olu tshintsho, Waziwa ngegama lobugcisa le-epigenetics, zidluliselwa kwesinye isizukulwana ziye kwesinye, kunye nayo, inzala yala Welwitschia yokuqala ekwaziyo ukuziguqula ikwazi ukuziqhelanisa nentlango yaseNamib esele ihlumile ngalomgangatho.

Iminqweno iWelwitschia mirabilis

Ngenxa yezi nguqu zibalulekileyo Umthamo wesityalo uncitshisiwe, kwaye ngenxa yoko kwanokusetyenziswa kwamandla. Kodwa kusekho okuninzi: amagqabi ayantshula kwi-basal meristem, oko kukuthi, embindini wesityalo, ngelixa uninzi lweentlobo zamagqabi amatsha avela kumasebe okanye kwizikhondo.

Enye into enomdla kukuba inamagqabi amabini kuphela. Xa ubona imifanekiso inika imvakalelo yokuba kufuneka ube nokuninzi, kodwa ayifani kwaphela. Baqala ukuba iimvumba malunga neemilimitha ezingama-30, kwaye kancinci kancinci ziguqulwa zenziwe amagqabi alula, ateyintiweyo naluhlaza afikelela kumlinganiso omalunga nemitha ubude.

Nangona imbalela ingumlingiswa ophikisayo weNamib, esi sityalo Uyakwazi ukuhlala umbulelwe ngamanzi umbethe ngokuhlwa. Sithanda ukucinga ukuba izityalo zifunxa amanzi ngeengcambu zazo kuphela, kodwa eyona mvelaphi iphambili yayo yonke into esiyibonayo nesiyaziyo iselwandle. Ke ngoko, ii-pores okanye i-stomata zisabela ngokuvula. Xa kunetha kakhulu, kwelinye icala, zigcinwa zivaliwe kuba ukugqitha kwamanzi kunokubarhaxisa.

Kunzima emntwini ukubona iWelwitschia ichuma; Nangona kunjalo, abanye banethamsanqa banalo. Enkosi kubo, kuyaziwa ukuba luhlobo lwe-dioecious; yiyo i kukho iisampulu zamadoda kunye nezinye zabasetyhini. Oku kuphela kwenza ukuba ukushiya inzala kube nzima ngakumbi, yiyo loo nto kunzima ukufumana imbewu ethengiswayo, kwaye xa ifunyenwe, inexabiso eliphezulu (ngasendleleni, ukuba uyayifumana, musa ukulibala ukunyanga kubo ngomgubo wobhedu njengoko besesichengeni sokusuleleka ngundo).

Iintyatyambo ziqokelelwe kwii-inflorescence ezivela embindini wesityalo, kwaye zibomvu. Azinazo iipalali, kuba ezi zizakhiwo kwindawo enjengentlango, apho kungekho zinambuzane, zinokuxabisa kuphela isixa esikhulu samanzi kwaye kungabi njalo.

Ngaloo ndlela, i iWelwitschia mirabilis inokunceda izityalo ukuba zikhulise izityalo ezinganyangekiyo kwindawo ezomileyo, into eza kuza iluncedo ukuba sithathela ingqalelo ukuba kwiindawo ezininzi zehlabathi imozulu iyafudumala kwaye amafu emvula abonwa kancinci kancinci.

Olu khonkco lokufunda ukuba unomdla: Ufundo ngendalo