Endodermal cell phab ntsa yog ib feem lignified los tiv thaiv passive txav raws apoplast (lub cell phab ntsa qhov chaw), yog li yuam kom tag nrho cov dej thiab solutes mus dhau lub endodermal cell cytoplasm nyob qhov twg. Kev thauj mus los tuaj yeem tswj tau.
dej tuaj yeem hla lignin?
Lignin tau hais thawj zaug hauv xyoo 1813 los ntawm Swiss botanist A. P. de Candolle, uas tau piav qhia tias nws yog cov khoom siv fiber ntau, tsis qab, insoluble hauv dejthiab cawv tab sis soluble hauv cov tshuaj tsis muaj zog alkaline., thiab uas tuaj yeem ua rau nag los ntawm kev siv cov kua qaub.
YYog lignin impermeable?
Lignin yog ib qho tseem ceeb ntawm cov organic polymer uas muaj ntau nyob hauv cov phab ntsa ntawm tes ntawm qee lub hlwb. Raws li lawv tuag lawm, lawv cement ua ke thiab thauj cov cellulose fibers ntawm phab ntsa cell muab nws cov qauv nruj thiab ntoo. Nws qhia tau hais tias hydrophobic zog, uas txhais tau hais tias lawv tsis sib tov nrog dej thiab yog impermeable.
Puas phloem cells tuag?
Tsis zoo li xylem (uas yog tsim los ntawm cov hlwb uas tuag lawm), lub phloem yog muaj cov hlwb tseem nyob uas thauj cov kua dej. Cov kua txiv hmab txiv ntoo yog cov kua dej, tab sis nplua nuj nyob hauv cov suab thaj ua los ntawm photosynthesis.
Lub hom phiaj ntawm lignin yog dab tsi?
Raws li cov phenolic polymer complex, lignin ua kom cov nroj tsuag cell phab ntsa rigidity, hydrophobic zog thiab txhawb cov zaub mov thauj mus los ntawm vascular bundles hauv cov nroj tsuag [13]. Ntxiv rau,lignin yog ib qho teeb meem tseem ceeb uas tiv thaiv kab tsuag thiab kab mob [14].
