Akar

Suatu sistem akar suatu pokok yang tercabut dari tanah

Akar ialah satu organ yang paling penting dalam tumbuhan memaut dan menopangkan tumbuhan dalam sesebuah tempat sambil mendapatkan air atau galian memudahkan tumbesaran tumbuh-tumbuhan ini.[1][2] Jika diperhatikan dengan teliti, akar berbeza daripada satu jenis tumbuhan kepada jenis tumbuhan yang lain sama ada dari fungsi dan sistem akar berkenaan.

Bagi pokok vaskular, akar adalah organ tumbuhan yang pada kebiasaannya terletak di bawah permukaan tanah (berbanding dengan batang pokok). Bagaimanapun, ia bukannya satu kemestian kerana terdapat juga akar udara (aerial) (iaitu, tumbuh di atas permukaan tanah) atau aerating (iaitu, tumbuh atas permukaan tanah atau terutamanya di atas permukaan air). Pada masa yang sama, batang pokok yang biasa terdapat di bawah tanah juga merupakan perkara yang biasa (lihat rizom). Jadi, adalah lebih baik untuk mengistilahkan akar sebagai bahagian pokok yang tiada daun, dengan itu juga ketiadaan node. Dua fungsi utama akar adalah 1) penyerapan air dan galian bukan organik dan 2) mengikat pokok kepada tanah.

Anatomi

Morfologi akar dibahagikan kepada beberapa zon utama:[3]

  • Tudung akar: membantu akar-akar baru menembusi tanah, terkelupas saat akar masuk lebih dalam menciptakan permukaan berlendir yang menyediakan pelumas
  • Meristem apikal: terletak di belakang penutup akar, menghasilkan sel akar baru yang memanjang.
  • rambut akar:menyerap air dan nutrisi mineral dari tanah.[4]

Akar pertama pada tanaman penghasil biji disebut radicle, yang mengembang dari embrio tanaman setelah biji bercambah.

Sebagai respons terhadap konsentrasi nutrisi, akar juga mensintesis sitokinin, yang bertindak sebagai isyarat kimia mempercepatkan pertumbuhan tunas. Akar sering berfungsi sebagai penyimpanan makanan dan nutrisi. Akar dari sebagian besar spesies tumbuhan vaskular bersimbiosis dengan jamur tertentu untuk membentuk mikoriza. Sejumlah besar organisme lain, termasuk bakteria juga seringkali hidup di akar.[5]

Jenis

Rajah menunjukkan akar serabut (A) dengan banyak akar sama besar berbanding akar tunjang (B) yang menumbuhkan suatu akar utama yang besar.

Terdapat beberapa jenis akar yang dibezakan dari bentuk diperhatikan:

  • akar tunjang
  • akar serabut
  • akar sulur: akar yang menghasilkan sulur merayap dalam tanah menghasilkan tunas baru menjadi pucuk suatu anak pokok baharu
  • akar umbi: akar yang membengkak berisi ranum mengandungi kanji tenaga
  • akar udara: mendapatkan bekalan air tumbuhan daripada udara dan kerpasan lembap sekeliling seperti kabus atau embun.[6]
  • akar rendang/akar kanopi: dihasilkan menghubungkan dengan tumbuhan-tumbuhan epifit dan detritus yang menakung air dan galian terkumpul boleh dimanfaatkan pokok perumah.[7]

Lihat juga

Rujukan

  1. ^ Harley Macdonald & Donovan Stevens (3 September 2019). Biotechnology and Plant Biology. EDTECH. m/s. 141–. ISBN 978-1-83947-180-3.
  2. ^ "Plant parts - Roots". The Great Plant Escape. University of Illinois Extension.
  3. ^ Yaacov Okon (24 November 1993). Azospirillum/Plant Associations. CRC Press. m/s. 77–. ISBN 978-0-8493-4925-6.
  4. ^ "Backyard Gardener: Understanding Plant Roots". University of Arizona Cooperative Extension.
  5. ^ Sheldrake, Merlin (2020). Entangled Life. Bodley Head. m/s. 148. ISBN 978-1847925206.
  6. ^ Nowak EJ, Martin CE (1997). "Physiological and anatomical responses to water deficits in the CAM epiphyte Tillandsia ionantha (Bromeliaceae)". International Journal of Plant Sciences. 158 (6): 818–826. doi:10.1086/297495. hdl:1808/9858. JSTOR 2475361. S2CID 85888916.
  7. ^ Nadkarni NM (November 1981). "Canopy roots: convergent evolution in rainforest nutrient cycles". Science. 214 (4524): 1023–4. Bibcode:1981Sci...214.1023N. doi:10.1126/science.214.4524.1023. PMID 17808667. S2CID 778003.

Read other articles:

Jalur kereta api Sumari–Gresik–Kandangan

Jalur kereta api Sumari–Gresik–KandanganIkhtisarJenisJalur lintas cabangSistemJalur kereta api rel ringanStatus Beroperasi Kandangan - Indro Tidak Beroperasi Indro - Sumari LokasiJawa TimurTerminusSumariKandanganOperasiDibangun olehNederlandsch-Indische Spoorweg MaatschappijDibuka1 Juni 1902, segmen Sumari–Gresik3 Januari 1924, segmen Kandangan–GresikDitutup1943, segmen Sumari–Gresik1982, segmen Indro–GresikPemilikPT Kereta Api IndonesiaOperator Daerah Operasi VIII Surabaya KAI Co...

 

How I Met Your Mother (season 3)

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: How I Met Your Mother season 3 – news · newspapers · books · scholar · JSTOR (September 2014) (Learn how and when to remove this template message) Season of television series How I Met Your MotherSeason 3The Legendary Season 3 DVD cover artStarring Josh R...

 

Promises (Def Leppard)

Promisessingolo discograficoScreenshot tratto dal video del branoArtistaDef Leppard Pubblicazionemaggio 1999 Durata4:00 Album di provenienzaEuphoria GenereHard rockPop metal EtichettaMercury ProduttorePete Woodroffe e Def Leppard Registrazione1998 FormatiCD Def Leppard - cronologiaSingolo precedenteBreathe a Sigh(1996)Singolo successivoPaper Sun(1999) Promises è un singolo del gruppo musicale britannico Def Leppard, il primo estratto dal loro album Euphoria del 1999. Raggiunse il primo posto...

Assyrians in Iran

Ethnic Group in Iran Iranian Assyriansܐܬܘܪܝܐ ܕܐܝܼܪܵܢ (Syriac) Iranian Assyrians from Sanandaj, IranTotal population20,000 [1]Regions with significant populationsTehran, West Azerbaijan Province (Urmia, Salmas), SanandajLanguagesNeo-Aramaic and PersianReligionSyriac Christianity Assyrians in Iran (Syriac: ܐܬܘܪܝܐ ܕܐܝܼܪܵܢ; Persian: آشوریان ایران), or Iranian Assyrians, are an ethnic and linguistic minority in present-day Iran. The Assyrians of Iran s...

 

Customs House, Sydney

Government administration:, in New South Wales, AustraliaCustoms House, SydneyFront facadeFormer Customs HouseLocation in Sydney central business districtGeneral informationStatusCompletedTypeGovernment administration:Former head office for New South Wales operations of the Australian Customs ServiceTourist and Hospitality VenueCity of Sydney LibraryArchitectural styleVictorian GeorgianAddress45 Alfred Street, Circular Quay, Sydney CBD, New South WalesCountryAustraliaCoordinates33°51′44�...

 

KOAK

For the airport near Oakland, California, assigned ICAO code KOAK, see Oakland International Airport. Radio station in Red Oak, IowaKOAKRed Oak, IowaFrequency1080 (kHz)BrandingCountry Sunshine RadioProgrammingFormatCountryAffiliationsABC Radio/Citadel MediaOwnershipOwnerHawkeye Communications, IncSister stationsKCSIHistoryCall sign meaningRed OakTechnical informationClassDPower250 watts (daytime)Transmitter coordinates41°01′00″N 95°12′46″W / 41.01667°N 95.21278°W&#...

Premier amendement de la Constitution des États-Unis

Cet article traite du Premier amendement de la Constitution américaine. Pour les autres significations, voir Premier amendement (homonymie). Cet article fait partie de la série :Constitution des États-Unis PréambuleArticles de la Constitution I ∙ II ∙ III ∙ IV ∙ V ∙ VI ∙ VII Amendements Déclaration des droits I ∙ II ∙ III ∙ IV ∙ V ∙ VI ∙ VII ∙ VIII ∙ IX ∙ XAmendements additionnels XI ∙ XII ∙ XIII ∙ XIV ∙ XV XVI ∙ XVII ∙ XVIII ∙ XIX ∙ XX...

 

Universitas Nahdlatul Ulama Sulawesi Tenggara

Universitas Nahdlatul Ulama Sulawesi TenggaraDidirikan17 Oktober 2014RektorProf. Dr. H. Nasruddin Suyuthi, M.SiAlamatJln. Mayjend Katamso No 2 Kel. Lepo-Lepo Kec. Baruga , Kendari, Sulawesi Tenggara, IndonesiaSitus webunusra.ac.id Universitas Nahdlatul Ulama Sulawesi Tenggara (UNUSRA) merupakan perguruan tinggi keagamaan islam swasta binaan Nahdlatul Ulama yang bediri pada 17 Oktober 2014 [1], dan mulai beroperasi sejak 2015 [2]. Kampus perguruan tinggi ini berlokasi di kota K...

 

KTCO

Radio station in Duluth, MinnesotaKTCODuluth, MinnesotaBroadcast areaDuluth-SuperiorFrequencyFM 98.9 MHzBrandingKat Country 98.9ProgrammingFormatCommercial; CountryOwnershipOwnerDuey E. Wright(Midwest Communications, Inc.)Sister stationsKDAL, KDAL-FM, KDKE, WDSM, WDULHistoryFirst air dateSeptember 1974Former call signsWAKX (1974–1994)Call sign meaningKaT COuntryTechnical informationFacility ID26591ClassC1ERP100,000 wattsHAAT183 m (600 ft)LinksWebcastListen LiveWebsitekatcountry989...

Keuskupan Nardò-Gallipoli

Keuskupan Nardò-GallipoliDioecesis Neritonensis-GallipolitanaKatolik Katedral NardòLokasiNegaraItaliaProvinsi gerejawiLecceStatistikLuas587 km2 (227 sq mi)Populasi- Total- Katolik(per 2013)211.352210,417 (99.6%)Paroki66Imam124 (diosesan)18 (Ordo Relijius)InformasiDenominasiGereja KatolikRitusRitus RomaPendirian13 Januari 1413 (611 tahun lalu)KatedralBasilica Cattedrale di S. Maria AssuntaKonkatedralBasilica Concattedrale di S. Agata VergineKepemimpinan kin...

 

Bjørn Eidsvåg

This biography of a living person needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately from the article and its talk page, especially if potentially libelous.Find sources: Bjørn Eidsvåg – news · newspapers · books · scholar · JSTOR (April 2010) (Learn how and when to remove this message) You can help expand this a...

 

John F. Lindley

American politician John F. LindleyLieutenant Governor of South DakotaIn office1959–1961GovernorRalph HersethPreceded byL. Roy HouckSucceeded byJoseph H. Bottum Personal detailsBorn(1918-08-29)August 29, 1918Near Reliance, South DakotaDiedApril 23, 1971(1971-04-23) (aged 52)Chamberlain, South DakotaPolitical partyDemocraticAlma materDakota Wesleyan UniversityUniversity of South Dakota School of Law John Frank Lindley (August 29, 1918 – April 23, 1971) was an American attorney and pol...

2017 South Carolina's 5th congressional district special election

2017 South Carolina's 5th congressional district special election ← 2016 June 20, 2017 2018 → South Carolina's 5th congressional districtTurnout18.34%   Nominee Ralph Norman Archie Parnell Party Republican Democratic Popular vote 45,076 42,341 Percentage 51.0% 47.9% County results Precinct resultsNorman:      40–50%      50–60%      60–70%      70–80% &#...

 

Payradanga railway station

Railway station in West Bengal, India Payradanga Kolkata Suburban Railway stationPayradanga railway stationGeneral informationLocationPayradanga, Nadia, West BengalIndiaCoordinates23°07′42″N 88°32′44″E / 23.128225°N 88.545464°E / 23.128225; 88.545464Elevation15 metres (49 ft)Owned byIndian RailwaysOperated byEastern RailwayLine(s)Sealdah–Ranaghat line of Kolkata Suburban RailwayPlatforms2Tracks2ConstructionStructure typeStandard on ground stationPark...

 

Motore propfan

NASA / GE Unducted Fan Un motore propfan è un turboventola modificato in cui il fan è collocato all'esterno della cappottatura del motore, in asse con le palette del compressore assiale o della turbina. Il concetto che ha portato alla creazione di questa tipologia di motore era quello di unire la velocità e le prestazioni di un turboventola con quelle di economia di combustibile di un motore turboelica. Il motore propfan fa parte dei motori a grande rapporto di diluizione (Ultra High Bypas...

Popular music

Music considered to have widespread appeal Popular song redirects here. For other uses, see Popular Song (disambiguation). For the musical genre, see Pop music. For the 2004 film, see Popular Music (film). Popular music Timeline of musical events 2020s 2010s 2000s 1990s 1980s 1970s 1960s 1950s 1940s 1930s 1920s 1910s 1900s 1890s 1880s 1870s 1860s 1850s 1840s 1830s 1820s 1810s 1800s 1790s 1780s 1770s 1760s 1750s 1740s 1730s 1720s 1710s 1700s 1690s 1680s 1670s 1660s 1650s 1640s 1630s 1620s 1610...

 

Orange County, Florida

County in Florida, United States County in the United StatesOrange CountyCounty Left to right from top down: Downtown Orlando skyline as seen from Lake Eola; Cinderella Castle at the center of the Magic Kingdom in Walt Disney World; Orange County Courthouse in Downtown Orlando; The entrance gate to Universal Studios Florida at Universal Orlando; Boardwalk behind the student union on the campus of the University of Central Florida; Terminal C at Orlando International Airport; Shoppes on Park A...

 

Anguille

Anguille Nom vulgaire ou nom vernaculaire ambigu :l'appellation « Anguille » s'applique en français à plusieurs taxons distincts. Anguille d'Europe Taxons concernés Plusieurs espèces de l'ordre des Anguilliformes dont : Anguilles d'eau douce, les Anguillidae ; Anguilles de vase, Heterenchelyidae ; Anguilles-spaghettis, Moringuidae. L'Electrophorus electricus, des Gymnoptidae Anguilles épineuses, les SynbranchiformesVoir aussi civelle ou pibale, l'alevin d...

Gaćani

Gaćani Гаћани Administration Pays Bosnie-Herzégovine Entité République serbe de Bosnie Ville Prijedor Démographie Population 303 hab. (2013) Densité 48 hab./km2 Géographie Coordonnées 44° 54′ 45″ nord, 16° 42′ 31″ est Altitude 252 m Superficie 635 ha = 6,35 km2 Localisation Géolocalisation sur la carte : Bosnie-Herzégovine Gaćani Géolocalisation sur la carte : Bosnie-Herzégovine Gaćani G�...

 

Battle of Gravelotte

1870 battle of the Franco-Prussian War Battle of GravelottePart of the Franco-Prussian WarThe Cemetery of St. Privat by Alphonse-Marie-Adolphe de Neuville c. 1881Date18 August 1870LocationGravelotte, France49°09′N 6°01′E / 49.150°N 6.017°E / 49.150; 6.017Result Inconclusive, German march advancesBelligerents North German Confederation Prussia Saxony French EmpireCommanders and leaders Wilhelm I Helmuth von Moltke Karl Friedrich von Steinmetz Prince Friedrich Ka...