Qhov sib txawv tseem ceeb ntawm cov hlwb sieve thiab cov hlab sieve yog tias cov sieve hlwb tsis tshua muaj tshwj xeeb sieve uas tsis muaj sieve daim hlau thiab tam sim no nyob rau hauv seedless vascular nroj tsuag thiab gymnosperms thaum lub sieve tubes yog heev tshwj xeeb sieve ntsiab uas muaj sieve daim hlau thiab tam sim no nyob rau hauv angiosperms.
Cov nroj tsuag vascular muaj cov kab mob vascular muaj feem ntau ntawm xylem thiab phloem. Xylem yog cov ntaub so ntswg uas thauj dej thiab cov zaub mov nce siab los ntawm cov hauv paus hniav mus rau lwm qhov ntawm cov nroj tsuag. Ntawm qhov tod tes, phloem yog cov ntaub so ntswg uas thauj cov khoom noj lossis cov khoom noj los ntawm photosynthetic qhov chaw ntawm cov nroj tsuag tshwj xeeb tshaj yog los ntawm nplooj mus rau lwm qhov ntawm cov nroj tsuag. Ob qho tib si cov ntaub so ntswg yog cov ntaub so ntswg uas tsim los ntawm ntau hom cell sib txawv. Raws li txoj cai, sieve cell thiab sieve tubes yog ob hom sieve muaj nyob rau hauv cov ntaub so ntswg phloem. Lawv yog cov ntsiab lus tseem ceeb ntawm phloem.
Sieve Cells yog dab tsi?
Sieve cells yog hom sieve muaj nyob hauv cov nroj tsuag tsis muaj vascular thiab gymnosperms. Lawv yog cov qe tshwj xeeb tsawg dua piv rau cov hlab ntsha uas muaj nyob hauv angiosperms. Sieve hlwb yog cov hlwb ntev thiab nqaim nrog tapering xaus.
Tsis tas li ntawd, cov hlwb sieves tsis muaj qhov chaw sieve. Tsis tas li ntawd, lawv muaj cov pores nqaim thoob plaws lub cell phab ntsa. Muab piv rau cov hlab ntsha ntawm angiosperms, cov hlwb no tsis tshua muaj txiaj ntsig hauv kev ua zaub mov. Tsis tas li ntawd, sieve hlwb tsis muaj cov hlwb ua ke. Hloov chaw, lawv muaj cov hlwb tshwj xeeb parenchyma los ua cov haujlwm ntawm cov hlwb sib luag. Tsis tas li ntawd, sieve hlwb tseem nyob ua ib lub hlwb.
Sieve Tubes yog dab tsi?
Sieve tubes yog cov khoom tshwj xeeb tshwj xeeb uas muaj nyob hauv angiosperms los ua zaub mov. Cov hlwb no luv thiab dav dua.
Daim duab 01: Sieve Tube
Tsis tas li ntawd, lawv nrog cov hlwb tshwj xeeb hu ua cov hlwb sib luag. Sieve tubes npaj vertically thiab tsim lub raj ntev kom thauj cov khoom noj kom zoo. Lawv muaj sieve daim hlau, thiab sieve pores tsuas pom nyob rau hauv sieve daim hlau.
Dab tsi zoo sib xws ntawm Sieve Cells thiab Sieve Tubes?
- Sieve cells thiab sieve tubes yog sieve ntawm phloem ntaub so ntswg.
- Ob leeg ua haujlwm ua cov ntaub so ntswg.
- Lawv thauj zaub mov thoob plaws hauv tsob ntoo.
- Ntxiv mus, ob qho tib si yog cov muaj sia nyob, tab sis tsis muaj cov nucleus.
- Tsis tas li, cov hlwb no muaj cov phab ntsa nyias nyias.
- Tsis tas li ntawd, lawv tsis muaj cov thickenings thib ob.
Qhov txawv ntawm Sieve Cells thiab Sieve Tubes yog dab tsi?
Seedless vascular nroj tsuag thiab gymnosperms posses sieve hlwb raws li lawv sieve ntsiab. Tab sis, angiosperms muaj sieve tubes ua lawv cov ntsiab lus sieve. Ntxiv mus, sieve hlwb tsis tshua muaj tshwj xeeb ua cov hlwb thaum sieve hlab yog ntau tshwj xeeb conducting hlwb. Yog li ntawd, qhov no yog qhov sib txawv tseem ceeb ntawm sieve cell thiab sieve tubes. Tsis tas li ntawd, sieve hlwb tsis muaj sieve daim hlau thaum sieve tubes muaj sieve daim hlau. Structurally, sieve hlwb nyob twj ywm raws li ib leeg hlwb thaum sieve hlab nyob twj ywm raws li aggregated hlwb tsim ib lub raj ntev. Yog li, qhov no kuj yog qhov sib txawv tseem ceeb ntawm sieve hlwb thiab cov hlab sieve.
Lwm qhov sib txawv tseem ceeb ntawm sieve hlwb thiab cov hlab sieve yog tias sieve hlwb tsis nrog cov hlwb ua ke thaum sieve hlab ib txwm nrog cov hlwb ua ke. Tsis tas li ntawd, sieve hlwb yog ntev thiab nqaim hlwb nrog tapering xaus thaum sieve hlab yog luv thiab dav hlwb.
Cov hauv qab no nthuav tawm cov ntaub ntawv ntau ntxiv txog qhov sib txawv ntawm cov cell thiab cov kav dej.
Summary – Sieve Cells vs Sieve Tubes
Sieve cells thiab sieve tubes yog sieve hauv cov ntaub so ntswg phloem ntawm cov nroj tsuag. Sieve hlwb yog cov hlwb tsawg dua thaum lub sieve hlab yog cov hlwb tshwj xeeb heev. Tsis tas li ntawd, sieve hlwb yog ntev thiab nqaim hlwb nrog tapering xaus thaum sieve hlab yog luv luv thiab dav hlwb yam tsis tapering kawg. Ntxiv mus, sieve hlwb tsis muaj sieve daim hlau thaum sieve hlab muaj sieve phaj. Nyob rau hauv sieve cell, sieve pores nrhiav nyob rau hauv tag nrho cov thoob lub cell phab ntsa thaum nyob rau hauv sieve tubes, sieve pores nrhiav tsuas yog nyob rau hauv lub sieve daim hlau. Tsis tas li ntawd, sieve hlwb tsis muaj cov hlwb ua ke thaum sieve hlwb nrog cov hlwb ua ke. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm sieve cell thiab sieve tubes.
