Download Secondary Wall

First Chapter
Plant Cells
one Form and Structure of Plant Cells
★Definition
The structural and functional unit of a tissue ,
and consequently of the plant body itself , is known
as a cell . Some species or kind of plants consist of
single cell , but large type are make up of
uncountable millions , or even billions , of these
structural units.
Chlamydomonas
Nostoc commune Vauch
1.Shape and Size of Plant Cells
It has various shapes and sizes.

Cell , which distribute in differ part of frond and
perform differ function , has differ form and size .
plant cell , commonly 10～100μm(diameter)

least cell , as if
bacterial diameter only
0.2μm

Big cell , like cell of
storage parenchyma
1mm

Fiber cell of flax(亚麻)
4cm long

Fiber of ramee(苎麻)
55cm long
2.Basic Structure and Function
of Plant cells
Definition
Microscopic structure: there can be seen the cell
structure with microscope, called microscopic
structure.
Submicroscopic structure: there can be seen the cell
structure with electron microscope , termed
submicroscopic structure.
Microscopic structure
1. nuclear
membrane
2. nucleolus
3.chromosome
4. Cell wall
5. plasmalemma
6. vacuole
membrane
7. vacuole
8. Chloroplast
9.Mitochondria
10.microtuble
11. Endoplasmic
reticulum
submicroscopic
1.Cell wall 2.nuclear membrane
structure
3.nucleochylema 4.nucleolus
5.plasmalemma 6.Cytoplasm
7.vacuole membrane 8.chloroplast
9.vacuole
12.Ribosome
13.14.microbody15.
golgi body
一、cell wall
★ constitute
二、protoplast
三、ergastic substance



一、 Cell Wall Layers
intercellular layer
primary wall
secondary wall
Intercellular Layer：
It is thin layers owned in common between cell
wall and cell wall .
Primary Wall:
By cellulose(纤维素) , hemicellulose(半纤维素)
and pectin(果胶) material that protoplasm secrete,
increase in interior side of intercellular layer.
Secondary Wall:
After the cell wall stops growing, are
accumulating some materials coming into being in
the interior of the primary wall on each gradually,
make the cell wall increase and take shape on
concentric storey thick.

Ⅰ. pit

simple pit
bordered pit
half bordered pit
 Ⅱ.plasmodesmata(胞间连丝复数)


Pit

The secondary wall does not increase thick
evenly , leave some and has not increased
the thick part in a lot of places during the
process of thickenning, called the pit.
Ⅰ.Simple pit Ⅱ.bordered pit Ⅲ.half boredered pit
1.tangent plane view 2.exterior view
Bordered pit of pine’s stem and Radix et Rhizoma Rhei

Ⅱ.plasmodesmata

There are a lot of very
thin protoplasm silks that
cross and come into
being the very small hole
on the primary wall and
get in touch each other
among the cells, this kind
of protoplasm silk is
called plasmodesmata.
Plasmodesmata of Persimmon core





Ⅲ. Specification of Cell Walls
lignification
suberization
cutinization
mucilagization
mineralization
1.lignification: The cell wall has increased
more lignin (木质素)while adding and
growing. ①Distinguish: it was stained Red
when adding meta benzene and three
phenol + dense hydrochloric acid is.
 ②Example: vessel(导管) , wood fiber , stone
cell.


2. suberization: Have increased the fat phellem(木
栓质) in the cell wall.

①Distinguish :it was dyed Red when adding
Sudan Ⅲ test solution(TS) is.

②Example: Brown outer bark trunk outside.

3. cutinization：Fat cutin(角质) except not
being pack the cell wall , form a layer of
cuticles outside epidermis of stem often.

①Distinguish :it was dyed when adding
Sudan Ⅲ test solution is orange.

②Example: The seed of the castor-oil(蓖麻
油) plant , stem peel of the sugarcane(甘蔗).

4.mucilagization: Cellulose and such
composition as the pectin ,etc. in the cell
wall change but forms the mucus(黏液).

①Distinguish :it was stained Red when
adding Red reagent of ruthenium(钌红) .

②Example: In the epidermis cells of
plantain(车前) , linseed(亚麻).

5. mineralization: Contain the silicon or the
calcium ,etc. in the cell wall.

①Distinguish :The silicon can be dissolved
in the hydrogen fluoride(HF), but does not
dissolve in the acetic acid (醋酸)or denser
sulphuric acid(浓硫酸).

②Example:Gramineous(禾本科) Stem and
leaf


②protoplast
cytoplasm
nuclear membrance
nucleus
nuclear sap
nucleolus
chromatin



plastids




Organelle
chloroplast
leucoplast
chromoplast
vacuoles
There are all life matter in the cell,
called protoplast .
Chloroplast:green little grains(leaf)
 leucoplast:achromatous(无色的) and
global grains (immature organ )
 Chromoplast:anomalous red,yellow,and
orange grains(flower,fruit,seed)
 Three kinds of plastid can convert
mutually.
 Vacuoles:there are many little vacuoles
in the delicate cell , but in mature ones
there is only one big vacuole can be seen
which occupied most part of the cell.

Mutually converting of plastic
 ③Ergastic

Substance
The vegetable cell in the life process, produces
various non- life matter as a result of the
metabolism activity, called Ergastic
Substance.
 Ⅰ.starch grain: hilum , annular striation
lamellae
reserve starch:
①simple starch grain
②compound starch grain
③half compound starch grain
1.2.3.4.simple starch grain
(1.lambdoidal(人字形的) hilum 2.short gap(短缝状) )
5.compound starch grain
 Ⅱ.Inulins

Fan-shaped and yellow


Ⅲ.Proteins(aleurone grain)
Those are composed together by protein crystal ,
spherical albuminous(多胚乳) body and
amorphous(无定型的) stuffed gelatin. Add one
drop iodine-potassium iodide TS , the protein
turns yellow.
Ⅳ.Fats and Fatty Oils
 Add several drops of Sudan Ⅲ TS(试液) oil
droplet contained in the cell stained red.

 Ⅴ.Crystals
①

calcium oxalate crystal
solitary crystal : square-shaped, diamond,
rectangle or double-conical octahedrons(双锥八面
体)

acicular crystal : scattered or needle-like
cluster

cluster crystal: asteroid or clusters

crystal sand: irregular, polyhedrons

columnar crystal : long is cylindrical, the
length approximately is above diameter 4
times

② calcium carbonate crystal

(cysyolith钟乳体): like a string of grape
[locate in Moraceae(桑科) or
Acanthaceae(爵床科)]
Calcium carbonate crystal
Ⅰcysyolith （ tangent plane view ）in fig leaf
Ⅱ exterior view

Besides , physiological active substance
like enzyme , vitamin , auxin , antibiotic ,
tannins，etc.
Two Division of Plant cells

Cell division is necessary and play important
role for embryo to little frond to mature
frond( possessing root , stem and leaf ,
flower , fruit , seed).
 Three
types:(一)mitosis (二)amitosis
(三)meiosis
 ㈠mitosis
 ①interphase
: the cytoplasm is denser ,
the nucleus is big , nuclear menbrane with
the nuclear sap can be seen clearly.
 ②prophase

There inside the nucleus emerge condensed
granulose chromatin and then gradually
become the clubbed chromosome.

③metaphase: the nuclear membrane , the
nuclear sap disappear , the chromosome
and the spindle fibers connect with each
other , and arrange in the surface of the
equator.

④anaphase: the centromere
detaching ,each pair of chromatids set apart
from the equatorial plate to move to the two
poles, thereby to compose the independent
daughter chromosome respectively.

⑤telophase : the two daughter
chromosomes arrive at the two poles ,
chromosome gradually fall into slender ,
emerging of the nuclear membrane with
nuclear sap again . Meanwhile , divide into
two cells in the two poles.
Mitosis
1.Interphase 2-4.prophase 5.metaphase
6-7.anaphase 8.telophase 9.two daughter cells
 ㈡amitosis

Direct nuclear division and it is most simple
and common type of division . (in lower plant)
㈢meiosis
 one especial mitosis , as a result , divide
into four cells in process of sexual
reproductive.
1.第一次分裂前期2.第一次分裂中期3.第一次分裂后期
4.第一次分裂末期5.第二次分裂前期
6.第二次分裂前期7.第一次分裂中期8.第二次分裂后期
9.第二次分裂末期10.胞质分裂

Review Questions
一.Definition
 Pit , plasmodesmata , protoplast , ergastic
substance
 二.simple answer
 1.How about the composing of the cell wall?
 2.what are included in cell wall
characteristics?
 3.which types has crystal?
