TAIMEFÜSIOLOOGIA KORDUSKÜSIMUSED 2012
inner ring, called bundle sheath cells, contain starch-rich chloroplasts lacking grana, which differ from those in mesophyll
cells present as the outer ring. Hence, the chloroplasts are called dimorphic. This peculiar anatomy is called kranz anatomy,
from the German word for wreath. The primary function of kranz anatomy is to provide a site in which CO2 can be
concentrated around RuBisCO, thereby avoiding photorespiration. In order to maintain a significantly higher CO2
concentration in the bundle sheath compared to the mesophyll, the boundary layer of the kranz has a low conductance to
CO2, a property that may be enhanced by the presence of suberin. Kranz-anatoomia. C4 taimede mesofüllirakkude ja
pärjarakkude vahel on pidev tihe rakukest, millest läbi pääseb vaid plasmodesmide kaudu. Orgaanilise happed siiski
difundeeruvad, sest nende kontsentratsio on 10 -20 mM
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