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Parenchyma
Living cells; variable in morphology and physiology
Parenchyma Thin primary walls; polyhedral
Concerned with vegetative activities of the plant
photosynthesis, assimilation, respiration, storage,secretion,
and excretion
d i
“Para” – beside; “en chein” ---to pour
Ground tissue or fundamental tissue
Developmentally, undifferentiated
Parenchyma
Can resume meristematic activity (dedifferentiate)
--wound healing, regeneration, formation of
adventitious roots and shoots
Totipotent
Parenchyma cells may occur in continuous masses as The Contents of Parenchyma Cells Are a Reflection of
parenchyma tissue or be associated with other cell the Activities of the Cells
types in morphologically heterogeneous tissues Chlorenchyma --- mesophyll of leaves
Pith, cortex of stems and roots - vacuolated; numerous chloroplasts; extensive intercellular
Mesophyll of leaves space system
Flesh of succulent fruits
Endosperm seeds Secretory cells
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Vascular rays, vertical files of living cells in X and P - dense protoplasts,esp. rich in ribosomes,
- and have either numerous Golgi bodies or a massively
developed ER
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Parenchyma cells in storage organs, endosperm, cotyledons
- Starch storing – amyloplasts
Walls of parenchyma
Thin, non lignified primary wall
Parenchyma storing protein/oils ---Proteinoplast/ Plasmodesmata common
Elaioplasts Wood– thick, secondary lignified wall
Parenchyma of flowers and fruits ---Chromoplasts Transfer cells –with cell wall ingrowths
g
-- transfer of solute over short distances
Parenchyma with anthocyanin or tannins or crystals in their -- X and P of small, or minor,veins in cotyledons and foliage leaves
of many herbaceous eudicots
vacuoles
-- leaf traces, placentae, embryo, embryo
-- glandular structures (nectaries, salt glands, glands of
Parenchyma – abundant with water/water storage tissue carnivorous plants)
Shape Arrangement
polyhedral shape--having Usually with intercellular
many sides, or facets spaces– mesophyll; schizogenous
Isodiametric Almost no intercelluar spaces---
endosperm (compact)
Facets tend to approach to 14 Aerenchyma – well developed
(in homogenous parenchyma) air spaces; aquatic and semi
semi-
orthic tetrakaidecahedron a aquatic angiosperms or water-
geometrically perfect 14-sided logged organs
fi gure is a polyhedron with 8 --enhances the diffusion of air
from the leaves to the roots
hexagonal and 6 quadrilateral
--maintain levels of oxygen suffi
facets cient to support respiration.
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