Kab mob yog ib lub tswv yim paub rau txhua tus. Tau txais cheese thiab yogurt, tshuaj tua kab mob, kev kho dej phwj tuaj - tag nrho cov no yog ua tau los ntawm ib leeg-celled kab mob. Cia peb paub lawv zoo dua.
Tus kab mob yog leej twg?
Cov neeg sawv cev ntawm lub nceeg vaj ntawm cov tsiaj qus no tsuas yog pab pawg ntawm prokaryotes - cov kab mob uas lawv lub hlwb tsis muaj lub nucleus. Tab sis qhov no tsis txhais hais tias lawv tsis muaj cov ntaub ntawv keeb kwm yav dhau los. DNA molecules yog dawb nyob rau hauv lub cytoplasm ntawm lub cell thiab tsis nyob ib ncig ntawm ib daim nyias nyias.
Vim tias lawv qhov loj me yog qhov microscopic - txog li 20 microns, cov kab mob tau kawm los ntawm kev tshawb fawb ntawm microbiology. Cov kws tshawb fawb tau pom tias prokaryotes tuaj yeem ua ib leeg lossis koom ua ke hauv cov cheeb tsam. Lawv muaj ib tug heev primitive qauv. Ntxiv rau lub nucleus, cov kab mob tsis muaj txhua hom plastids, Golgi complex, EPS, lysosomes, thiab mitochondria. Tab sis txawm li cas los xij, cov kab mob ntawm tes muaj peev xwm ua tiav cov txheej txheem tseem ceeb tshaj plaws hauv lub neej: kev ua pa anaerobic yam tsis siv cov pa oxygen, heterotrophic thiab autotrophic khoom noj khoom haus, asexual reproduction thiab cyst tsim thaum lub sij hawm muaj kev mob tshwm sim.xwm txheej.
Qeb kab mob
Qhov kev faib tawm yog nyob ntawm cov yam ntxwv sib txawv. Ib tug ntawm lawv yog cov duab ntawm lub hlwb. Yog li, vibrios muaj daim ntawv comma, cocci - ib puag ncig. Kauv muaj ib tug kauv puab, thiab bacilli muaj ib tug pas nrig daim ntawv.
Tsis tas li ntawd, cov kab mob sib xyaw ua ke nyob ntawm cov yam ntxwv ntawm lub cell. Cov neeg tiag tiag tuaj yeem tsim cov tshuaj ntsiav slimy nyob ib puag ncig lawv tus kheej ntawm tes thiab tau nruab nrog flagella.
Cyanobacteria, los yog xiav-ntsuab algae, muaj peev xwm ntawm photosynthesis thiab, ua ke nrog fungi, yog ib feem ntawm lichens.
Ntau hom kab mob muaj peev xwm ua kom muaj kev sib haum xeeb - kev sib koom ua ke ntawm cov kab mob. Nitrogen fixers nyob rau hauv cov hauv paus hniav ntawm legumes thiab lwm yam nroj tsuag, tsim nodules. Nws yog ib qho yooj yim los twv seb cov kab mob nodule ua haujlwm li cas. Lawv hloov pauv atmospheric nitrogen, uas yog qhov tsim nyog rau cov nroj tsuag tsim.
Txoj Kev Noj
Prokaryotes yog ib pawg kab mob uas nkag tau rau txhua hom zaub mov. Yog li, cov kab mob ntsuab thiab ntshav liab pub autotrophically, vim lub hnub ci zog. Vim muaj cov plastids, lawv tuaj yeem pleev xim rau hauv cov xim sib txawv, tab sis lawv yuav tsum muaj chlorophyll. Cov kab mob thiab cov nroj tsuag photosynthesis yog qhov sib txawv. Hauv cov kab mob, dej tsis yog ib qho tseem ceeb reagent. Cov khoom siv hluav taws xob tuaj yeem yog hydrogen lossis hydrogen sulfide, yog li cov pa oxygen tsis tso tawm thaum lub sijhawm ua haujlwm no.
Ib pawg loj ntawm cov kab mob pub heterotrophically, uas yog, npaj ua cov organic. Cov kab mob zoo li no siv cov seem ntawm cov kab mob tuag rau zaub mov thiablawv lub neej cov khoom. Cov kab mob ntawm lwj thiab fermentation muaj peev xwm decomposing tag nrho cov paub cov organic tshuaj. Cov kab mob no tseem hu ua saprotrophs.
Qee cov kab mob nroj tsuag tuaj yeem tsim symbiosis nrog lwm yam kab mob: ua ke nrog cov kab mob, lawv yog ib feem ntawm lichens, nitrogen-fixing nodule kab mob coexist kev sib raug zoo nrog cov hauv paus hniav ntawm legumes.
YChemotrophs
Chemotrophs yog lwm pawg zaub mov. Qhov no yog ib hom khoom noj khoom haus autotrophic, thaum lub sij hawm, es tsis txhob siv lub hnub ci zog, lub zog ntawm cov tshuaj sib txuas ntawm ntau yam khoom siv. Nitrogen-fixing kab mob yog ib yam kab mob. Lawv oxidize ib co inorganic tebchaw, thaum muab lawv tus kheej nrog tus nqi tsim nyog ntawm lub zog.
Nitrogen-fixing bacteria: chaw nyob
Cov kab mob uas muaj peev xwm hloov cov nitrogen tebchaw kuj pub zoo ib yam. Lawv hu ua nitrogen-fixing bacteria. Txawm hais tias muaj cov kab mob nyob txhua qhov chaw, qhov chaw nyob ntawm cov tsiaj no yog cov av, los yog cov hauv paus hniav ntawm cov nroj tsuag leguminous.
Kev tsim kho
Dab tsi yog txoj haujlwm ntawm cov kab mob nodule? Nws yog vim lawv cov qauv. Cov kab mob Nitrogen-fixing tau pom meej ntawm qhov muag liab qab. Nyob rau hauv keeb kwm ntawm legumes thiab cereals, lawv nkag mus rau cov nroj tsuag. Nyob rau hauv cov ntaub ntawv no, thickenings yog tsim, nyob rau hauv uas metabolism tshwm sim.
Nws yuav tsum tau hais tias cov kab mob nitrogen-kho cov kab mob yog cov pab pawg ntawm kev sib koom ua ke. Lawv coexistence nrog lwm yam kab mob yog kev sib nrig sib pab. ATThaum lub sij hawm photosynthesis, cov nroj tsuag synthesizes carbohydrate qabzib, uas yog tsim nyog rau lub neej txheej txheem. Cov kab mob tsis muaj peev xwm ntawm cov txheej txheem no, yog li npaj cov suab thaj tau los ntawm legumes.
Nroj tsuag xav tau nitrogen kom nyob. Muaj ntau ntau ntawm cov khoom no hauv qhov xwm txheej. Piv txwv li, cov ntsiab lus nitrogen hauv huab cua yog 78%. Txawm li cas los xij, hauv lub xeev no, cov nroj tsuag tsis muaj peev xwm nqus tau cov tshuaj no. Nitrogen-fixing bacteria absorb atmospheric nitrogen thiab hloov nws mus rau hauv daim ntawv haum rau cov nroj tsuag.
Kev ua haujlwm
Dab tsi yog qhov ua haujlwm ntawm cov kab mob nitrogen-fixing tuaj yeem pom ntawm qhov piv txwv ntawm cov kab mob chemotrophic azospirillum. Cov kab mob no nyob rau hauv cov hauv paus hniav ntawm cereals: barley los yog nplej. Nws raug hu ua tus thawj coj ntawm cov neeg tsim khoom nitrogen. Ntawm thaj av ib hectar, nws muaj peev xwm muab tau txog 60 kg ntawm cov khoom no.
Nitrogen-fixing kab mob ntawm legumes, xws li rhizobitums, sinorhizobiums thiab lwm yam, kuj zoo "cov neeg ua haujlwm". Lawv muaj peev xwm ntxiv ib hectar av nrog nitrogen hnyav txog li 390 kg. Perennial leguminous nroj tsuag yog lub tsev rau nitrogen tsim yeej, uas nws productivity nce mus txog 560 kg ib hectare ntawm arable av.
txheej txheem neej
Txhua cov kab mob nitrogen-kho cov kab mob raws li cov yam ntxwv ntawm cov txheej txheem ntawm lub neej tuaj yeem ua ke ua ob pawg. Thawj pab pawg yog nitrifying. Lub ntsiab ntawm cov metabolism hauv cov ntaub ntawv no yog cov saw hlau hloov pauv tshuaj. Ammonium, los yog ammonia, hloov mus rau nitrites - ntsev ntawm nitric acid. Nitrites, nyob rau hauv lem, hloov mus rau nitrates,kuj yog ntsev ntawm no compound. Nyob rau hauv daim ntawv ntawm nitrates, nitrogen yog zoo absorbed los ntawm lub hauv paus system ntawm cov nroj tsuag.
Pab pawg thib ob hu ua denitrifiers. Lawv ua cov txheej txheem rov qab: cov nitrates uas muaj nyob rau hauv cov av tau hloov mus rau hauv gaseous nitrogen. Qhov no yog li cas lub voj voog nitrogen tshwm sim hauv qhov xwm txheej.
Cov txheej txheem ntawm lub neej kuj suav nrog cov txheej txheem ntawm kev yug me nyuam. Nws tshwm sim los ntawm kev faib cell hauv ob. Feem ntau tsawg - los ntawm budding. Cov yam ntxwv rau cov kab mob thiab cov txheej txheem kev sib deev, uas yog hu ua conjugation. Hauv qhov no, kev sib pauv ntawm cov ntaub ntawv keeb kwm tshwm sim.
Vim lub hauv paus system tso tawm ntau yam khoom muaj txiaj ntsig, ntau cov kab mob nyob ntawm nws. Lawv hloov cov nroj tsuag residue rau hauv cov khoom uas cov nroj tsuag tuaj yeem nqus tau. Yog li ntawd, txheej ntawm av nyob ib ncig ntawm acquires tej yam khoom. Nws hu ua rhizosphere.
Txoj kev rau cov kab mob nkag mus rau hauv paus
Muaj ntau txoj hauv kev los qhia cov kab mob hauv cov ntaub so ntswg ntawm cov hauv paus hniav. Qhov no tuaj yeem tshwm sim vim kev puas tsuaj rau cov ntaub so ntswg integumentary los yog nyob rau hauv qhov chaw uas cov hauv paus hniav hluas. Lub hauv paus plaub hau cheeb tsam kuj yog ib txoj hauv kev rau chemotrophs nkag mus rau cov nroj tsuag. Tsis tas li ntawd, cov hauv paus plaub hau tau kis tus kab mob thiab, raws li qhov tshwm sim ntawm kev faib tawm ntawm cov kab mob, cov nodules yog tsim. Cov hlwb invading tsim cov kab mob sib kis uas txuas ntxiv cov txheej txheem nkag mus rau hauv cov ntaub so ntswg. Nrog kev pab los ntawm ib tug conducting system, cov kab mob nodules txuas nrog lub hauv paus. Nyob rau tib lub sijhawm, cov khoom tshwj xeeb tshwm hauv lawv -legoglobin.
Los ntawm lub sijhawm pom kev ua haujlwm zoo, cov nodules tau txais xim liab (vim cov xim legoglobin). Tsuas yog cov kab mob uas muaj legoglobin tuaj yeem kho nitrogen.
Qhov tseem ceeb ntawm chemotrophs
Tib neeg tau pom ntev tias yog tias koj khawb cov nroj tsuag leguminous nrog av, cov qoob loo hauv qhov no yuav zoo dua. Qhov tseeb, lub ntsiab lus tsis yog nyob rau hauv tus txheej txheem ntawm plowing. Cov av zoo li no muaj nitrogen ntau dua, uas tsim nyog rau kev loj hlob thiab kev loj hlob ntawm cov nroj tsuag.
Yog cov nplooj hu ua lub Hoobkas oxygen, ces cov kab mob uas kho nitrogen tuaj yeem raug hu ua nitrate Hoobkas.
Txawm tias nyob rau xyoo pua 19th, cov kws tshawb fawb tau mloog txog lub peev xwm zoo kawg nkaus ntawm cov nroj tsuag leguminous. Vim tsis muaj kev txawj ntse, lawv raug ntaus nqi rau cov nroj tsuag thiab tsis txuam nrog lwm yam kab mob. Nws tau raug pom tias cov nplooj tuaj yeem txhim kho atmospheric nitrogen. Thaum lub sij hawm sim, nws tau pom tias legumes uas loj hlob hauv dej poob qhov peev xwm no. Rau ntau tshaj 15 xyoo, lo lus nug no tseem yog qhov tsis paub. Tsis muaj leej twg xav tias tag nrho cov no tau ua los ntawm cov kab mob nitrogen-kho, qhov chaw nyob uas tsis tau kawm. Nws muab tawm tias qhov teeb meem yog nyob rau hauv symbiosis ntawm cov kab mob. Tsuas yog ua ke legumes thiab kab mob tuaj yeem tsim nitrates rau cov nroj tsuag.
Tam sim no cov kws tshawb fawb tau txheeb xyuas ntau dua 200 cov nroj tsuag uas tsis yog tsev neeg legume, tab sis muaj peev xwm tsim cov kab mob sib xyaw nrog cov kab mob kho nitrogen. Qos yaj ywm, sorghum, nplej kuj muaj txiaj ntsig zoo.
